From majordomo-owner@berlioz.nsc.com Wed Jul 2 13:20:49 1997 Date: Wed, 2 Jul 97 13:20:47 PDT To: jmoss From: majordomo@berlioz.nsc.com Subject: Majordomo file: list 'laser' file 'laser.9706' Reply-To: majordomo@berlioz.nsc.com Content-Length: 334900 -- >From owner-laser Sun Jun 1 15:16:06 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA14731; Sun, 1 Jun 97 15:16:06 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f Date: Sun, 1 Jun 1997 18:11:30 -0400 (EDT) Message-Id: <2.2.16.19970601172131.283fb07a@mail.snet.net> X-Sender: paulc@mail.snet.net X-Mailer: Windows Eudora Pro Version 2.2 (16) Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" To: laser@qsl.net From: "Paul A. Cianciolo" Subject: [LASER] Cloud Bounce.. mission accomplished!! Reply-To: "Paul A. Cianciolo" Sender: owner-laser@berlioz.nsc.com Precedence: bulk Hello All, Well we finally had a cloudy nite and had my first chance to try my 3 mw 670 nm laser and OPT 210. I started at the horizon and got weak but reasonable returns. Gradually I elevated the transmitter and then followed by the RX , a couple of degrees at a time. Signal got stronger as I elevated. I can only elevate to about 20 degrees off of vertical, the camera tripod I am using will not allow me to elevate above this. At 70 degrees above horizon the signal is strong enough to cover 50% of the 5 1/2" RX lens and still have a easy copy. During the experiment the RX and Xmitter were located about 100' apart. Pointing was fairly critical. I was able to see (hear) changes in the signal amplitude and SNR as the clouds moved by. Improvements to be made to the system. 30 mw 830 nm approx 10 db gain in power. 830 nm put the signal near the center of the responsivty curve. I have a 780 nm 3 mw and this works much better than the 670 nm at 3mw The 8 1/2" RX wil be put into service. This has been tried in the terrestrial path with signaficantly stronger signals than the 5 1/2" RX Also I am working on a different RX module from EG&G or Hamamatsu or Centronics. This looks it should provide approx 6 to 10 db Increase in SNR. Filtering is also in the works... I have several to experiment with.. Looking for a bandpass at 830 nm See ya!!! 73's PaulC KB1RP >From owner-laser Mon Jun 2 07:55:55 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA22847; Mon, 2 Jun 97 07:55:55 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f To: laser@qsl.net Date: Mon, 2 Jun 1997 10:59:51 -0400 Subject: [LASER] Laser Skeds via Cloud Bounce ??? Message-Id: <19970602.110032.3534.7.K3PGP@juno.com> X-Mailer: Juno 1.23 X-Juno-Line-Breaks: 0-3,5-8,15-16,19-20,24-26,29-32,40-48 From: k3pgp@juno.com (John K3PGP) Reply-To: k3pgp@juno.com (John K3PGP) Sender: owner-laser@berlioz.nsc.com Precedence: bulk Paul: PS - Re: [LASER] Cloud Bounce.. mission accomplished!! Maybe you consider the mission accomplished but I won't till I work you via laser :-^) ! ----- Anyone out there that thinks they are close enough to me to give this a serious try??? Keep in mind that the really thick overcast skies that seems to be best for this are rather low in altitude. Also, you would have to be close enough so that we have approx. the same weather patterns. Once I know where you are located I'll run some calculations on what we might need as far as cloud layer height and what might be the best elevation angle to use. Please make sure you can hear yourself via cloud bounce first before setting up any two-way skeds. If you can't hear yourself then you have work to do on your system! If you can't hear yourself you can still provide very much needed data by simply providing a signal for me to look for. I'd settle for a one way QSO at the moment just to prove that this can be done! If you want to set up a a beacon let me know so I can look for it. I think we're on the verge of discovering some new propagation modes and possibly setting some new DX records! Based on my experiments, NON line of sight laser communication now seems very likely. Anyone interested??? ----- If you are NOT subscribed to laser@qsl.net, you might want to consider switching over. One of the reasons I pushed for the changeover was because of the speed. laser@qsl.net is fast enough that we can use it to co-ordinate skeds. If you wait for the data to get to you via laser@berlioz you may learn of some exciting experiments after they are over instead of being able to participate. Since cloud bounce communications is weather dependant we must be able to set up and run skeds on relatively short notice. ----- John K3PGP@juno.com www.qsl.net/k3pgp -==- >From owner-laser Mon Jun 2 07:55:57 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA22856; Mon, 2 Jun 97 07:55:57 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f To: laser@qsl.net Date: Mon, 2 Jun 1997 10:55:51 -0400 Subject: Re: [LASER] Cloud Bounce.. mission accomplished!! Message-Id: <19970602.110032.3534.6.K3PGP@juno.com> X-Mailer: Juno 1.23 X-Juno-Line-Breaks: 0-1,4-5,8-9,12-18 From: k3pgp@juno.com (John K3PGP) Reply-To: k3pgp@juno.com (John K3PGP) Sender: owner-laser@berlioz.nsc.com Precedence: bulk Paul: Glad to hear someone else is having success with this. Your findings are exactly the same as mine regarding the signal increase as one scans from the horizon to directly overhead! Where exactly are you located? I don't know how high a cloud layer we would need to be visible to the both of us but it might pay to do some calculations! How's your horizon looking this way? (SW?) I'm thinking seriously about a propagation test signal using an array of diode lasers aimed overhead and just above the horizon that would run 24 hours a day. John K3PGP@juno.com www.qsl.net/k3pgp -==- >From owner-laser Mon Jun 2 07:56:01 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA22868; Mon, 2 Jun 97 07:56:01 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f To: laser@qsl.net Date: Mon, 2 Jun 1997 10:41:43 -0400 Subject: [LASER] Hamfest Message-Id: <19970602.110032.3534.5.K3PGP@juno.com> X-Mailer: Juno 1.23 X-Juno-Line-Breaks: 0-1,4-5,9-10,13-19 From: k3pgp@juno.com (John K3PGP) Reply-To: k3pgp@juno.com (John K3PGP) Sender: owner-laser@berlioz.nsc.com Precedence: bulk I had an experience at a local hamfest this weekend that made me sick. I watched in horror as some guy lit a cigar by sticking it in front of an Nd-Yag laser. They then proceeded to make a deal. He sold the Yag laser for $50 !!! I got there about 10 minutes to late. I saw two other Nd-Yag lasers (the head only - NO power supply) and the guy wanted $300 for one (5.0 x 55 mm) and $400 for the other (6.5 x 75 mm). After seeing the other Yag laser go for $50 (and it was complete and operational) I just passed everything else by. Nd-Yag lasers operate at 1064 nm and seem to be the source of the mystery signal that I observed several months ago. That's what started the cloud bounce experiment! John K3PGP@juno.com www.qsl.net/k3pgp -==- >From owner-laser Mon Jun 2 10:09:47 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA29332; Mon, 2 Jun 97 10:09:47 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f Message-Id: <199706021704.NAA18374@host-04.colby.edu> X-Sender: aballen@colby.edu X-Mailer: Windows Eudora Light Version 1.5.2 Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Date: Mon, 02 Jun 1997 13:04:44 -0500 To: k3pgp@juno.com (John K3PGP) From: "Art Allen, KY1K" Subject: Re: [LASER] Hamfest Cc: laser@qsl.net Reply-To: "Art Allen, KY1K" Sender: owner-laser@berlioz.nsc.com Precedence: bulk At 10:41 AM 06/02/1997 -0400, you wrote: >From owner-laser Mon Jun 2 10:35:43 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA01024; Mon, 2 Jun 97 10:35:43 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f Date: Mon, 2 Jun 97 10:27:10 PDT From: jmoss@berlioz.nsc.com (Jim Moss) Message-Id: <9706021727.AA00430@berlioz.nsc.com> To: laser@qsl.net Subject: [LASER] Fry's laser result Reply-To: jmoss@berlioz.nsc.com (Jim Moss) Sender: owner-laser@berlioz.nsc.com Precedence: bulk Looked at the Fry's laser CL2000 that they were selling last week. Measured 2.8mW and on 661nM (some mode switching results in drift toward longer wavelength with time). These measurements were done on commercial, calibrated equipment. I think the power level has dropped (due to battery voltage) since I originally measured it last week. On my fiber meter, It had read 5.4 dBm, now reads 4.0 dBM after having exercised it during the measuring process. Jim WB9AJZ/6 CM87xi Sunnyvale, CA >From owner-laser Mon Jun 2 11:19:18 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA03751; Mon, 2 Jun 97 11:19:18 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f Date: Mon, 2 Jun 97 11:10:11 PDT From: jmoss@berlioz.nsc.com (Jim Moss) Message-Id: <9706021810.AA03262@berlioz.nsc.com> To: laser@qsl.net Subject: [LASER] VHF Contest LASER Corrdination Frequency? Reply-To: jmoss@berlioz.nsc.com (Jim Moss) Sender: owner-laser@berlioz.nsc.com Precedence: bulk SF Bay Area/N CAL... Looks like there will be half a dozen or more possible LASER operations for the June VHF contest. We started talking about a coordination freq... Let's set it and use it... I'll start the discussion by saying 144.280 SSB (want to say away from the AM stuff on 265, and 250 is a favorite SCAL freq for big stations. I'll be up in CN70, but I may have a view at Diablo or ??? What say? Jim WB9AJZ/6 CM87xi Sunnyvale, CA >From owner-laser Mon Jun 2 11:19:14 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA03744; Mon, 2 Jun 97 11:19:14 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f Date: Mon, 2 Jun 97 11:13:59 PDT From: jmoss@berlioz.nsc.com (Jim Moss) Message-Id: <9706021813.AA03476@berlioz.nsc.com> To: laser@qsl.net Subject: [LASER] HAM LIDAR? Reply-To: jmoss@berlioz.nsc.com (Jim Moss) Sender: owner-laser@berlioz.nsc.com Precedence: bulk Now that a few of us can hear our sigs off clouds... It's been suggested we consider setting up some "beacons" (vertical beam) and do some soundings. If I ever get some more clouds (hi hi) I will try setting up my scope to the TX signal and RX signal and see if I can measure the time delta... May get some interesting stuff showing altitudes and such. Anyone else think this may be a worthwhile experiment? Jim >From owner-laser Mon Jun 2 12:21:53 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA06680; Mon, 2 Jun 97 12:21:53 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f To: laser@qsl.net Date: Mon, 2 Jun 1997 15:24:28 -0400 Subject: Re: [LASER] HAM LIDAR? Message-Id: <19970602.152439.15678.1.K3PGP@juno.com> References: <9706021813.AA03476@berlioz.nsc.com> X-Mailer: Juno 1.23 X-Juno-Line-Breaks: 0-1,3-4,8-9,15-16,18-19,22-23,26-29,32-33,37-38, 40-43,47-48,51-52,56-57,59-60,68-74 From: k3pgp@juno.com (John K3PGP) Reply-To: k3pgp@juno.com (John K3PGP) Sender: owner-laser@berlioz.nsc.com Precedence: bulk Jim: Although measuring the round trip delay to the target (clouds) is a valid way to determine distance, it isn't the only one. You can also use an interferometer technique. I discovered this quite by accident when I mounted my 780 nm laser on the side of my 6 inch reflecting telescope and using the CCD TV camera to take a look at the reflection off the cloud layer. I noticed that as the distance to the target increased the image would shift across the TV screen. At first I was somewhat puzzled by this until I realized that since the laser and the TV camera were pointed at the same place in space but from slightly different angles it started to make sense that the image would tend to shift on the TV screen depending on the distance to the target. I ran this by one of my astronomer friends and he said congratulations. You just discovered how interferometers work! This system seems to have the potential to work with weaker signals than any type of pulse measuring equipment. Also you can improve the accuracy by mounting the receive and transmit optics further apart. By doing this I was able to get just about the same result using an 80 mm telephoto lens on the TV camera. Of course the image wasn't as bright though due to the smaller diameter optics on the receiver. ----- Cloud covers haven't been a problem here lately. The type of cloud covers we've been getting lately completely block out the sun and are solid for hundreds of miles in all directions! It's now been raining for a week! This spring has been terrible. Some trees around here still don't have any leaves. They started three times now and got wiped out by late frosts. The hamfest yesterday turned into a mud bath! You watch though. When it comes time to run skeds with someone, the cloud cover will go away! ----- As far as test signals are concerned, we might need to do some thinking here. I was planning on only turning my on when there was a cloud cover. There's practically ZERO chance of anyone hearing it during clear skies. (On this planet anyway! :-^) My concern is with aircraft. This problem would be even more serious at 630 to 670 nm than it is at my 780 wavelength, but nevertheless it's still a potential problem. I've noticed that when we're really clouded over like we've been for the past week all aircraft traffic is ABOVE the cloud layer, so I feel reasonably safe. But I KNOW it's not a good idea to just aim a laser skyward and leave it run unattended! Although we wouldn't be intentionally aiming it at an aircraft, it's still illegal! What a shame they have to mess up our hobby! I do think that cloud bounce is a viable over the horizon laser propagation mode that needs exploring, especially with the type of cloud covers we get in this area. We just need to use our heads and avoid getting into trouble with aircraft and the FAA! When we're completely clouded over like this spotting an aircraft anywhere is pretty easy so there should be no difficulty in avoiding problems. So far, I've never seen any craft flying below the clouds although I can hear the engines of craft above the clouds. John K3PGP@juno.com www.qsl.net/k3pgp -==- >From owner-laser Mon Jun 2 16:00:32 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA17171; Mon, 2 Jun 97 16:00:32 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f Date: Mon, 2 Jun 97 15:52:49 PDT From: jmoss@berlioz.nsc.com (Jim Moss) Message-Id: <9706022252.AA16731@berlioz.nsc.com> To: laser@qsl.net Subject: [LASER] re: HAM LIDAR Reply-To: jmoss@berlioz.nsc.com (Jim Moss) Sender: owner-laser@berlioz.nsc.com Precedence: bulk John, Shooting straight up gives no aircraft (pilots) a chance to ever see the beam. Unless he is diving into your laser. Beam width at 5000 ft would be 5 ft (for 1mR), 30000ft - 30 ft.... And the angle for visibility is -90 +/- .05 degrees. So I conclude a <5mW beacon at 90 degrees from earth = no issue. Also... The interferometer is fine, but you have to SEE it on the CCD to be able to detect it. Individual pixels won't have the sensitivity of the PMT system. I suggest that only marginal reflection is needed to capture returns on a scope, just enough to get a few visible traces. You can filter where you look for returns to a specific time segment as well. Jim WB9AJZ/6 CM87xi >From owner-laser Mon Jun 2 16:38:05 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA19400; Mon, 2 Jun 97 16:38:05 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f Date: Mon, 2 Jun 1997 19:32:46 -0400 (EDT) From: "C. W. Wright" X-Sender: wwright@wayne.home.net To: "Art Allen, KY1K" Cc: John K3PGP , laser@qsl.net Subject: Re: [LASER] Hamfest In-Reply-To: <199706021704.NAA18374@host-04.colby.edu> Message-Id: Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Reply-To: "C. W. Wright" Sender: owner-laser@berlioz.nsc.com Precedence: bulk > >I saw two other Nd-Yag lasers (the head only - NO power supply) and the > >guy wanted $300 for one (5.0 x 55 mm) and $400 for the other (6.5 x 75 > >mm). After seeing the other Yag laser go for $50 (and it was complete > >and operational) I just passed everything else by. Good move. The power supply and trigger circuits are the more difficult parts. I'm speaking of the pulsed nd-yags I have experience with. > YAG laser ARE NOT of beginners. And, the ABSOLUTLEY CANNOT be aimed skyward. > NEVER NEVER NEVER. Actually they're aimed skyward quite a bit! Visit disneyworld, or many other amusement parks. They operate various high powered lasers and they rapidly move them all over the place. They also file "NOTAMS" (Notice to AIRMEN) to advise pilots of the activity. THe same sort of NOTAMS are filed for search lite activity. If you wanted to operate a yag pointing up, you might double it to 532nm (green) first, and then diverge the beam such that your power density was below the ANSI standards for flash blindness. This would be a wide beam, and would make it quite easy to see and aim remote receiver toward :-) > Comm'l satellite laser ranging stations use this and similar power output > lasers for various research. But, before they go on the air, they specify I just ordered a doubled-yag with only 3mw of 532nm cw output. It was only $600. Not bad! > The YAG laser operates well outside the range of a PMT too, so you need to Not when doubled! PMT's love 532. > use much less sensitive PD receivers. So much of the power gain in the TX is Actually APDs are the best thing for 1064. -Wayne >From owner-laser Mon Jun 2 19:11:45 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA26697; Mon, 2 Jun 97 19:11:45 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f To: laser@qsl.net Date: Mon, 2 Jun 1997 22:13:18 -0400 Subject: [LASER] Beacons & Cloud Bounce Message-Id: <19970602.221321.15446.0.K3PGP@juno.com> References: <9706022252.AA16731@berlioz.nsc.com> X-Mailer: Juno 1.23 X-Juno-Line-Breaks: 0-3,9-10,13-14,18-19,24-27,32-33,40-41,46-47,52-53,56-79 From: k3pgp@juno.com (John K3PGP) Reply-To: k3pgp@juno.com (John K3PGP) Sender: owner-laser@berlioz.nsc.com Precedence: bulk Jim: Thanks for pointing this out !!! Things are happening so fast here that I haven't even had time to sit down and think this out. I had some ideas about a multiple beam test signal with one beam pointing straight up and the others several degrees above the horizon. Based on your observations I think I'll stick with my original idea of one beam pointed straight up and letting it run 24 hours a day! This also gives omni directional coverage. I'm thinking of building up several of these and mounting them at some of my friends locations. That way I can sit at home and see what I can hear. I've been looking at a friends 780 nm beam this evening with the CCD camera. He lives approx. 5 miles from here and is definitely NON line of site because of a big mountain between us. However, he's been S9 + on cloud bounce ever since the sun set! As usual we're completely blanketed with a low altitude cloud cover. I used to hope for clear weather so I could go outside and play around with lasers. Now all I hope for is cloudy weather! I've even starting to have some success with this during the daytime using an IR filter on the detector and camera. ----- I agree with you about the PMT sensitivity. However, with the echoes I'm getting here off the clouds I don't need a PMT! I can even see my 1 mw 670 nm laser pen off the clouds with the CCD camera! The 780 nm signal is extremely strong on the PIN diode detector so for now I'm not using the PMT. Also I've been extremely disappointed with the sensitivity of the PMT's that I have to work with at 780 nm. I've been doing a LOT of work recently with PIN diodes and low noise preamps. I'm now at the point where the PIN diode is almost as good as the PMT at 780 nm. Of course at 632 or 670 nm the PMT is better but my lasers up there don't put out as much power. So for now anyway, I'm getting the best echoes with the 780 nm laser and a PIN diode feeding an experimental low noise preamp. I'm also doing some experimenting with cooling the PIN diode and preamp using a peltier junction. This seems to be worth the extra effort if one needs really weak signal preformance. It's not at all uncommon to see an increase of >10 dB SNR when the detector/preamp is cooled down! My next project is to mount a 780 nm laser diode on another peltier juntion and run some destructive tests to see just how much power I can force out of one before it dies! I have a couple of extras and I feel the sacrifice is worth it to find out once and for all exactly what can be done along these lines. PS - Since you don't seem to get the really solid cloud cover as often as I appear to be getting them, have you given any thought to using that famous California Smog as a reflector? :-^) John K3PGP@juno.com www.qsl.net/k3pgp ----- On Mon, 2 Jun 97 15:52:49 PDT jmoss@berlioz.nsc.com (Jim Moss) writes: >John, >Shooting straight up gives no aircraft (pilots) a chance to ever see >the beam. Unless he is diving into your laser. Beam width at 5000 ft >would be 5 ft (for 1mR), 30000ft - 30 ft.... >And the angle for visibility is -90 +/- .05 degrees. > >So I conclude a <5mW beacon at 90 degrees from earth = no issue. > > > >Jim >WB9AJZ/6 >CM87xi > >From owner-laser Mon Jun 2 19:49:23 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA28459; Mon, 2 Jun 97 19:49:23 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f X-Sender: n6mod@pop.amt.org Message-Id: In-Reply-To: <9706021810.AA03262@berlioz.nsc.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Date: Mon, 2 Jun 1997 19:43:08 -0700 To: jmoss@berlioz.nsc.com (Jim Moss), laser@qsl.net From: Aleksandr Milewski Subject: Re: [LASER] VHF Contest LASER Corrdination Frequency? Reply-To: Aleksandr Milewski Sender: owner-laser@berlioz.nsc.com Precedence: bulk At 11:10 -0700 970602, Jim Moss wrote: >SF Bay Area/N CAL... >Looks like there will be half a dozen or more possible LASER operations >for the June VHF contest. We started talking about a coordination freq... >Let's set it and use it... > >I'll start the discussion by saying 144.280 SSB (want to say away from >the AM stuff on 265, and 250 is a favorite SCAL freq for big stations. >I'll be up in CN70, but I may have a view at Diablo or ??? > >What say? >Jim >WB9AJZ/6 CM87xi Sunnyvale, CA For SSB, .280 is fine, but I'd vote for an FM channel, simply because our Laser guys will be over on the edge of the mountaintop, away from the big SSB stations. I don't know if we have a spare all-mode for Laser liason. (I'll try, though.) In any event, W6AMT will be QRV on Laser from Mt. Diablo, CM97bv. Any and all skeds, no matter how absurd, will be accepted and attempted. 73 de N6MOD -Zandr --------------------------------------------------------------------- Aleksandr Milewski N6MOD CM87um n6mod@amt.org http://w6.amt.org/n6mod/ Member of the W6AMT VHF Contest Team: http://w6.amt.org/June97 >From owner-laser Tue Jun 3 02:18:37 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA18071; Tue, 3 Jun 97 02:18:37 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f To: laser@qsl.net Date: Tue, 3 Jun 1997 04:23:59 -0400 Subject: [LASER] Cloud Bounce Distances Message-Id: <19970603.042412.10934.1.K3PGP@juno.com> X-Mailer: Juno 1.23 X-Juno-Line-Breaks: 3-4,6-19,24-25,31-32,36-37,41-42,45-46,48-54 From: k3pgp@juno.com (John K3PGP) Reply-To: k3pgp@juno.com (John K3PGP) Sender: owner-laser@berlioz.nsc.com Precedence: bulk I ran some numbers this morning to try to determine what kind of range one might expect to get by using cloud bounce and also to get some idea as to where the other station might need to look as far as elevation was concerned assuming one station was aiming straight up. I hope this chart makes it OK. Every time I try to send a chart all the columns get moved around! Cloud Range Range Cover Horizon Shot Straight Up ----------------- ------------------- ---------------- 4000 feet 77 miles 38 miles 5000 86 43 6000 94 47 7500 106 53 10,000 122 61 15,000 149 74 For example: If you point your laser straight up (90 degrees elevation) the most range you will get with a cloud cover at 4000 feet will be 38 miles. If the other station is 38 miles away he will find your signal on the horizon. This may NOT be an ideal situation since he may have to look through other clouds to see your signal. However, if you point at the horizon, using the same cloud cover at 4000 feet, the other station will find you straight overhead! Obviously if you need to work someone 38 to 40 miles away you either need a higher cloud cover or BOTH of you need to point at angles other than 0 or 90 degrees elevation. A good starting point might be 45 degrees for both of you, but I haven't done any calculations for 45 degrees at this distance. If anyone feels like playing around with these numbers go right ahead. I'm not the best with math. I ended up using a formula normally used for calculating the range of satellites at altitudes of 500 to 600 miles and it may not translate well down to heights of 4000 to 15,000 feet! I KNOW this system works at distances out to five miles or so and I have been able to work stations that I normally can't work via laser any other way. However, so far I don't have anyone else set up that's farther away. Keep in mind that pointing your laser straight up is probably fairly safe as pointed out by Jim. However, be extremely careful to avoid aircraft if using angles other than 90 degrees. The lower cloud covers seem to be more dense and produce the best signals especially when looking straight up. All my tests have been at 780 nm. John K3PGP@juno.com www.qsl.net/k3pgp -==- >From owner-laser Tue Jun 3 05:40:19 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA26698; Tue, 3 Jun 97 05:40:19 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f Message-Id: <199706031235.IAA24532@host-04.colby.edu> X-Sender: aballen@colby.edu X-Mailer: Windows Eudora Light Version 1.5.2 Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Date: Tue, 03 Jun 1997 08:35:44 -0500 To: laser@qsl.net From: "Art Allen, KY1K" Subject: Re: [LASER] Cloud Bounce Distances Reply-To: "Art Allen, KY1K" Sender: owner-laser@berlioz.nsc.com Precedence: bulk These figures look good John. Few of us have a zero degree horizon tho. But even at 3 degrees, or 5 degrees, the ultimate ranges aren't affected much. This is good news and sheds a new light (sorry) on the need for PMT's and DSP enhanced reception! If we don't have to leave home to go to a hilltop, then that certainly makes our task easier. If both ends of the qso operate from home, who cares if the QSO takes 2 days to complete hi hi-use modified meteor scatter protocol maybe? I'm looking forward to running over the water non-los tests with aa1a later this year (central maine coast to cape cod), but at this point I hadn't thought too much about the practicality/possibility of an actual 2 way qso. I had been planning on pointing the laser at zero degrees elevation and sweeping the horizon. Perhaps I should be looking at 15 degree elevations and the possibility of cloud scatter too. Incidently, I heard some guys were going to San Clemente Island for the June contest. How far is that Island from the mainland, and would this be a good oppourtunity to test non-los optical ducting of lightwave sigs? My atlas doesn't show Islands (unfortunately). What say? GL, Art... At 04:23 AM 06/03/1997 -0400, you wrote: >I ran some numbers this morning to try to determine what kind of range >one might expect to get by using cloud bounce and also to get some idea >as to where the other station might need to look as far as elevation was > >>>>>>>>>>>good stuff snipped>>>>>>>>>>>>> >John >K3PGP@juno.com >www.qsl.net/k3pgp >-==- > > >From owner-laser Tue Jun 3 12:09:03 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA16980; Tue, 3 Jun 97 12:09:03 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f From: daveaa1a@ssih.com Date: Tue, 3 Jun 1997 15:05:18 -0400 Message-Id: <199706031905.PAA09481@ssih.com> Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Subject: [LASER] OPT211 To: laser@qsl.net X-Mailer: SPRY Mail Version: 04.00.06.17 Reply-To: daveaa1a@ssih.com Sender: owner-laser@berlioz.nsc.com Precedence: bulk Gudday Light Bugs, Just fired up opt211 for first time.. Geez, what a lot of gain.. With 10meg rf i get saturation at ambient room light.. Only works in near dark without saturating.. Guess will have to put that opt177 feedback chip in and try.. How do you fellas use yours as far as bias/light goes?? Ordered the Supercircuits CCD camera (try ww.supercircuits.com) will report.. 73 all de daveaa1a >From owner-laser Tue Jun 3 14:43:17 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA25154; Tue, 3 Jun 97 14:43:17 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f To: laser@qsl.net Date: Tue, 3 Jun 1997 17:46:25 -0400 Subject: Re: [LASER] OPT211 Message-Id: <19970603.174712.4990.3.K3PGP@juno.com> References: <199706031905.PAA09481@ssih.com> X-Mailer: Juno 1.23 X-Juno-Line-Breaks: 0-3,5-6,10-13,16-17,21-22,24-39 From: k3pgp@juno.com (John K3PGP) Reply-To: k3pgp@juno.com (John K3PGP) Sender: owner-laser@berlioz.nsc.com Precedence: bulk Dave: How does the OPT-xxx devices compare to your PIN diode detector? I'm making relative comparisons between many different detectors in preparation for some data on my web page. I wasn't particularly impressed with any of the OPT devices. A well designed high impedance low noise preamp following a PIN diode seems to run the pants off any of the OPT devices. However, you can't beat the OPT design for simplicity! I was just wondering if your findings are similar. I must add that I've been spending a LOT of time on optimizing the input circuit of my preamp and it's really paying off. Before I did this the OPT devices looked pretty good! The input impedance is now >100 megs! Running at room temp it just about equals my PMT (which suffers from severe red droop, like most!), but when I cool the PIN diode and preamp with a peltier junction the noise floor really drops and it's then the most sensitive detector I own for use at 780 nm! Of course at shorter wavelengths (like green!) the PMT blows everything else away. John K3PGP@juno.com www.qsl.net/k3pgp ----- On Tue, 3 Jun 1997 15:05:18 -0400 daveaa1a@ssih.com writes: > >Gudday Light Bugs, > >Just fired up opt211 for first time.. Geez, what a lot of gain.. -==- >From owner-laser Tue Jun 3 16:37:47 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA01358; Tue, 3 Jun 97 16:37:47 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f Message-Id: <339480F7.6A00@lan.nsc.com> Date: Tue, 03 Jun 1997 13:39:19 -0700 From: Dave Fifield Organization: National Semiconductor Corp. X-Mailer: Mozilla 3.01 (Win95; I) Mime-Version: 1.0 To: Aleksandr Milewski Cc: Jim Moss , laser@qsl.net Subject: [LASER] VHF Contest - Laser Rover References: Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Reply-To: Dave Fifield Sender: owner-laser@berlioz.nsc.com Precedence: bulk I will have my equipment finished by the end of this weekend. I have 4mW 670nm CW laser TX, OPT210 with 8.5x11 fresnel lens on RX. I will be roving in the S.F. bay area during the contest, trying to get as many laser qso's as possible, and giving away points of course! If you need the points and want me to go to a specific place to try a qso with you let me know. Send me email or listen for me on the Laser coodination frequency (144.280 ssb) over the contest weekend. 73, Dave AD6AY >From owner-laser Tue Jun 3 16:33:18 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA01119; Tue, 3 Jun 97 16:33:18 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f Message-Id: <3394C44A.76A9@midstate.tds.net> Date: Tue, 03 Jun 1997 18:26:34 -0700 From: Michael Berg Organization: none X-Mailer: Mozilla 2.01 (Win16; U) Mime-Version: 1.0 To: laser reflector Subject: [LASER] MWLaser module Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Reply-To: Michael Berg Sender: owner-laser@berlioz.nsc.com Precedence: bulk Received the $47 laser module from Midwest Laser Products yesterday and it powered up on 12 volts just as advertized. As I'm only used to my 670 nm laser pointer, the 632.8 HeNe beam is noticably brighter. Also purchased the modulation kit which is a bit over priced as it only contains a 8 to 1000 ohm audio transformer (2 bucks at Radio Shack). In their defense, the transformer installed neatly into the cavity at the back of the unit where it's out of harm's way. In a brief test the unit modulated my universal light receiver (ala McComb) with audio from my scanner perfectly. Now to learn how to do all those other neat things I read about here... 73 Mike N0QBH -- >~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~< >From owner-laser Tue Jun 3 17:18:30 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA03354; Tue, 3 Jun 97 17:18:30 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f Date: Tue, 3 Jun 97 15:40:29 PDT From: jmoss@berlioz.nsc.com (Jim Moss) Message-Id: <9706032240.AA28030@berlioz.nsc.com> To: laser@qsl.net Subject: [LASER] LIDAR stuff Reply-To: jmoss@berlioz.nsc.com (Jim Moss) Sender: owner-laser@berlioz.nsc.com Precedence: bulk check out: http://www.speedtrap.com/speedtrap/faqonlid.html No I'm not kidding... 25W on 900nM! 5nS 1KHz, 4mR .... >From owner-laser Tue Jun 3 17:18:19 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA03341; Tue, 3 Jun 97 17:18:19 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f Date: Tue, 3 Jun 97 15:32:40 PDT From: jmoss@berlioz.nsc.com (Jim Moss) Message-Id: <9706032232.AA27603@berlioz.nsc.com> To: laser@qsl.net Subject: Re: [LASER] OPT211 Reply-To: jmoss@berlioz.nsc.com (Jim Moss) Sender: owner-laser@berlioz.nsc.com Precedence: bulk Dave, Try just having a 100k resistor that you can short across the 10M. That will bring it down into usable for daylight. (DC adjustment) Simple... Jim WB9AJZ/6 CM87xi >From owner-laser Tue Jun 3 23:24:02 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA20198; Tue, 3 Jun 97 23:24:02 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f Message-Id: <33956B4D.1EB1@slip.net> Date: Wed, 04 Jun 1997 06:19:09 -0700 From: "Walter E. Miller" Organization: AJ6T X-Mailer: Mozilla 3.0 (Win95; U) Mime-Version: 1.0 To: Jim Moss Cc: laser@qsl.net Subject: [LASER] Rejecting ambient light References: <9706032232.AA27603@berlioz.nsc.com> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Reply-To: "Walter E. Miller" Sender: owner-laser@berlioz.nsc.com Precedence: bulk Jim Moss wrote: > > Dave, > Try just having a 100k resistor that you can short across the 10M. That will > bring it down into usable for daylight. (DC adjustment) Simple... > > Jim WB9AJZ/6 CM87xi The "Rejecting Ambient Light" feedback circuit in the Burr Brown application note for the OPT211 looks like a very neat way to avoid op amp saturation. According to Burr Brown, this should work OK for the OPT210 as well. The feeback bucks out the DC component of the photocurrent, allowing operation with an ambient light background. See Figure 4 in the OPT211 data sheet and application bulletin AB-061, both of which are available on the web in Adobe Acrobat format. I have not tried this circuit yet, but I hope to experiment with it soon. It looks very promising. 73, Walt AJ6T CM87 Laser and 1296 from Loma Prieta, CM97, in June contest >From owner-laser Tue Jun 3 23:52:42 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA21469; Tue, 3 Jun 97 23:52:42 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f Message-Id: <3395720E.53A4@slip.net> Date: Wed, 04 Jun 1997 06:47:58 -0700 From: "Walter E. Miller" Organization: AJ6T X-Mailer: Mozilla 3.0 (Win95; U) Mime-Version: 1.0 To: Jim Moss Cc: laser@qsl.net Subject: Re: [LASER] VHF Contest LASER Corrdination Frequency? References: <9706021810.AA03262@berlioz.nsc.com> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Reply-To: "Walter E. Miller" Sender: owner-laser@berlioz.nsc.com Precedence: bulk Jim Moss wrote: > > SF Bay Area/N CAL... > Looks like there will be half a dozen or more possible LASER operations > for the June VHF contest. We started talking about a coordination freq... > Let's set it and use it... > > I'll start the discussion by saying 144.280 SSB (want to say away from > the AM stuff on 265, and 250 is a favorite SCAL freq for big stations. > I'll be up in CN70, but I may have a view at Diablo or ??? > > What say? > Jim > WB9AJZ/6 CM87xi Sunnyvale, CA Jim (et al): I will be up on Loma Prieta in CM97 with my 5 mW 670 nm MCW laser setup for the June contest. I'm working on a new receiver with the PMT I got from you, and expect to have it ready in time (if not, I will use last years OPT210 receiver). Receive optics probably will be the same Celestron C90 telescope. I prefer to use 2m SSB for liason work, and 144.280 sounds fine to me. The W6AMT boys on Diablo at over 50 miles should be easy to work, and I hope that Dave, AD6AY, will rove around and activate some other grids. I would be glad to spend some time running a sked with you up in CN70 on a non-LOS path, hoping for cloud bounce or some other scatter path. That makes four of us in northern California on laser....anybody else? I will also try and bring my 1296 SSB setup with me so I can have something to do while waiting for the lasers to get aimed properly. 73, Walt AJ6T CM87 >From owner-laser Wed Jun 4 10:33:06 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA18971; Wed, 4 Jun 97 10:33:06 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f From: daveaa1a@ssih.com Date: Wed, 4 Jun 1997 13:30:09 -0400 Message-Id: <199706041730.NAA12245@ssih.com> Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Subject: [LASER] re-print LASER TRANSVERTER To: laser@qsl.net X-Mailer: SPRY Mail Version: 04.00.06.17 Reply-To: daveaa1a@ssih.com Sender: owner-laser@berlioz.nsc.com Precedence: bulk <---- Begin Forwarded Message ----> From: daveaa1a@ssih.com Subject: re-print LASER TRANSVERTER To: laser@qsl.com 4 June 1997 Gudday Light Bugs.. here is reprint and update as to Laser Transverter.. Seems to be a flurry of new interest here.. (Hamming ain't dead yet) <---- Begin Forwarded Message ----> Return-Path: microwaveeast@wa1mba.org Date: Sat, 29 Mar 1997 13:44:39 -0500 From: Dave Riley To: laser@berlioz.nsc.com CC: bill@ietc.ca, microwave@wa1mba.org Subject: Laser Transverter Reply-To: microwaveeast@wa1mba.org Gudday Light Bugs.. Well after the flurry of activity caused by K3PGP et al, I finally finished up a long thought out project.. A Laser Transverter that handles Wideband, SSB, CW, Data, ???.. After taking a clue from my hb 10ghz transverter, I decided what with limited parts on hand and a love for the least common denominator approach, I would try the following.. It came out as follows... 10 Ghz. transverter = Laser Transverter =================== ================== Antenna 1' dish = 4" lense receive Colimated 5mw diode transmit Receiver/ Ku Band LNA (reworked) = Pin Photo Diode Mixer sma 10ghz mixer j-fet preamp,Vlf converter I.F. Gasfet preamp into IC-706 into IC-706 receiver any mode.. Transmitter/ IC-706 @ 146 mhz = IC-706 @ 4.040mhz Mixer same sma and gasfet preamp Attenuator, sampler, DBMixer L.O. is same brick L.O. is same as one above.. Output 1/4 watt amp., 1' dish = NPN series modulator into 5mw 650nm laser diode.. The thing that makes this fly easier is a RF sensed remote mast mounted type preamplifier.. I send +12 volts up the rg-58 in each case to power the RF switch, Rx/Tx.. It makes a remote setup easier and it's nice to be in the car having a qso just like it was 75 meter AM.. Have also used a set-up like this on the LOWFER band 160-190 khz.. Guess you could say the IC-706 is good for D.C. through light.. This was fun and now am ready for some springtime hilltop qso's.. FN42/41/51 anyone?? Am off to another project but will be listening.. This mode is a GREAT no-code license free ham band eh?? I see many members on this list never make any comments..??.. We could use some discussion in this fertile area.. No question is stupid and answers are always welcome.. Keep the Light on..73..de Dave Riley - AA1A - Marshfield, Mass...... sk Gudday Light Bugs.. Thought I would re-post this from a few months ago.. Along with update.. Here goes: Am currently building a basic universal RF switched transverter for the IC-706 with dual Balanced Modulators that will supply 0-500khz at 1mw. in any mode for transmit and likewise receive down into the noise... This is all similar to the last set-up explained in previous messages to the list only full duplex... If the LOWFER head is plugged into the switcher than I can receive and transmit 160-190khz any mode with 1 watt output.. An E-Probe on the receive channel and a loaded wire or flat-top for transmit antenna makes portable work easier.. If the LASER head is plugged in then I receive light from baseband up to 500 khz++ and transmit with 3mw coherent diode with any mode from the Icom.. With Coherent/BPSK in mind for adding to the above, one can truly say that the Icom-706 covers DC to light with a few SMALL transverters.. I am planning to use the L.O. out of the Icom so that 'netting on Coherent' will be a reality.. With the optional Txo, things stay nice and stable for Coherent.. Even the stock unit is good once the offset is known.. Thanks to VE2IQ for the neat software and ideas.. You can get his version 6.0 Coherent BPSK software and other neat helper programs from his site: www.ietc.ca/home/bill/bbs.htm He also has some pre-made S-D boards to make life real easy as far as interfacing your radio to PC.. Anybody else doing a rig like this?? QRU-QRV from FN51/41/42 Lowfer through Light.. 73 de Dave Riley AA1A.. June 97 UpDate: Well things are always changing and it's hard to keep up with you guys.. SEE what WE can do via this mode with give/take, win/win..!! Don't be SHY, Share some IDEAS.. The Burr-Brown chips with their trick circuits are doing better than I figured..The first attempt was with 10meg rf and it was real hot. The daylight saturated the amp.. Al's idea of lower resistance worked well and the feedback op177 sure did make a nice AGC.. The dark test will see the s/n differences though. It seems we have the transmit power, receive gain and large enough 'antennas' to do some serious work.. The thing I still find worth some thought is the AIMING.. With the help of some micrometer X/Y tables from a flea market and some surplus 4X rifle scopes, it seems fairly easy once you find a stable platform (stone wall, rail, etc).. I'm looking for some old camera pan/tilt heads to put the laser stuff into... Will try drive belts on the micrometers from some small dc motors or servos.. Can hardly wait to try the ccd camera attached to the rifle scope to remote aim/view.. As for the transverter, here is a talk through of what I did here.. Take any ham rig hf through uhf, build a RF power sampler/detector, two way double balanced mixers, a diode modulator, Photo diode and associated op-amps, and a local oscillator.. Now there are as many ways to do this as there are readers.. Here is how I do it at this end for narrow band subcarrier qso's/data.. An Icom 706 presently is running as a 4mhz I.F. which equals 0 hz.. 4020khz = 20 khz, 4067 khz = 67 khz etc.. I can get sigs up past 500 khz (4500khz) but they get dim because of the PD bandwidth... The 20, 40, 67 khz etc. frequencies are fine and you avoide a lot of ambient light and 60/120hz noise.... Here is a signal flow from the IC706 in transmit mode then in receive.. The transceiver is keyed up in any mode at 4 mhz.. It delivers 10 watts to a converted mast head vhf pre-amplifier which upon detection puts the relays in the transmit mode, provides a dummy load for the 706 and uses cap. coupling to deliver 10mw (+10dbm) to a double balanced mixer that has a 4 mhz xtal osc. looking into the L.O. port.. On the output of this mixer is your original 4mhz signal plus modulation.. So I pick 4.020 mhz transmit frequency which will send a milliwatt or so of 20 khz signal out of the mixer with the same modulation impressed upon it as the original 4020 khz sig. had.. This new 20 khz (say ssb) signal is now 1 milliwatt and feeds a simple NPN transistor amplifier set to directly modulate the laser diode.. I pick an idle current of 50ma on these diodes of the 3-5 mw variety.. Modulate them at the most linear setting since the diode output is not very linear or pure by itself.. Now you have transmitted your HF or VHF rig out onto a light beam that is Coherent.. (Pick your own I.F. and L.O.) OK, someone picks you up with the same set-up and here is how the signal looks coming back.. A beam of light is shining onto the Photo Diode, amp, and output is a 20 khz signal with upper sideband attached.. So the original vhf amp is replaced by a DB mixer and it's L.O. is the same 4mhz as in the receiver.. Now there is no RF to key my former mast head pre-amp so the 20 khz sig goes through the receive side of the mast/amp and the mixer spits out 4020 khz. with sideband just like what came out of the transmitter originally.. The next generation BASEBAND TRANSVERTER will be 10 mhz. by taking the 30mhz. VERY ACCURATE Oscillator in the IC706 via a source follower delivering 30 mhz to a /3 and deriving 10 mhz. for L.O. for BASEBAND The reason for this is the Integrity of the L.O. in the 706 is plenty good enough to 2x BPSK work on HF with VE2IQ, K7RR, K0LR etc.. Believe me, watching a screen print good data while hearing only white noise in the speaker is spooky.. So you want wideband for TV or Data?? use a GunnPlexer (non-radiating) and watch the bandwidth grow, but we are into DX here with the least effort approach for mileage.. (Or kilometers in new world order).. An E-Probe Antenna (10khz - 500 khz) applied to the modulator sends that band across your light beam and comes out at the I.F. frequency thus giving you a free LOWFER CONVERTER.. (Go ahead and transmit on 160-190 khz while your at it..) Also using Coherent (BPSK or CW) sigs for another several DB's in case you really like WEAK SIGNAL DXing.. I'm off from labor to refreshment.. 73's Wellness to everyone, keep America Humming.. 73 de daveaa1a <---- End Forwarded Message ----> >From owner-laser Wed Jun 4 16:19:05 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA06644; Wed, 4 Jun 97 16:19:05 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f To: laser@qsl.net Date: Wed, 4 Jun 1997 19:13:51 -0400 Subject: [LASER] Web Updates ! Message-Id: <19970604.191353.8958.1.K3PGP@juno.com> X-Mailer: Juno 1.23 X-Juno-Line-Breaks: 0-10 From: k3pgp@juno.com (John K3PGP) Reply-To: k3pgp@juno.com (John K3PGP) Sender: owner-laser@berlioz.nsc.com Precedence: bulk More neat LASER stuff on the web page at: www.qsl.net/k3pgp/index.html More coming, time permitting :-^) ! John K3PGP@juno.com www.qsl.net/k3pgp -==- >From owner-laser Thu Jun 5 09:39:50 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA21774; Thu, 5 Jun 97 09:39:50 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f From: daveaa1a@ssih.com Date: Thu, 5 Jun 1997 12:25:12 -0400 Message-Id: <199706051625.MAA02505@ssih.com> Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Subject: [LASER] Re: CCD Camera To: k3pgp@juno.com (John K3PGP), laser@qsl.net In-Reply-To: <19970603.220058.4278.0.K3PGP@juno.com> X-Mailer: SPRY Mail Version: 04.00.06.17 Reply-To: daveaa1a@ssih.com Sender: owner-laser@berlioz.nsc.com Precedence: bulk On Tue, 3 Jun 1997, k3pgp@juno.com (John K3PGP) wrote: >Dave: > >Let me know how this camera plays for you! > Howdy John, The cameras are on back order for 1 week.. I ordered the 'C' mount one with the .05lux and 410 line resolution and the basic one at 380 lines .2lux.. You can see them at www.supercircuits.com 73 de daveaa1a >From owner-laser Thu Jun 5 09:51:55 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA22390; Thu, 5 Jun 97 09:51:55 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f From: daveaa1a@ssih.com Date: Thu, 5 Jun 1997 12:22:22 -0400 Message-Id: <199706051622.MAA02486@ssih.com> Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Subject: Re: [LASER] OPT211 To: k3pgp@juno.com (John K3PGP), laser@qsl.net In-Reply-To: <19970603.174712.4990.3.K3PGP@juno.com> X-Mailer: SPRY Mail Version: 04.00.06.17 Reply-To: daveaa1a@ssih.com Sender: owner-laser@berlioz.nsc.com Precedence: bulk Hi John, >you wrote >How does the OPT-xxx devices compare to your PIN diode detector? Well the seperate PD and op amp seem a few db's better off than the opt211.. I have no other references yet.. Just installed a red LED out on the old Moon-Bounce Tower and feeding with variable TTL from .1hz to 10 khz. and 0-full brilliance.. Can detect to below where I can see it with the eye.. What was the approx. distance on that .avi file.. It looked like maybe you were first aiming straight up then tilting down to the horizon..?? Was that near I/R into the CCD camera?? Keep the LIGHT ON.. 73 de daveaa1a >From owner-laser Thu Jun 5 18:10:55 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA17048; Thu, 5 Jun 97 18:10:55 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f Message-Id: <33975E13.2326@prodigy.net> Date: Thu, 05 Jun 1997 19:47:16 -0500 From: KC5AN Organization: Prodigy Internet X-Mailer: Mozilla 3.0 (Win95; I) Mime-Version: 1.0 To: Laser Reflector Subject: [LASER] Laser Cloud Measurements Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Reply-To: KC5AN Sender: owner-laser@berlioz.nsc.com Precedence: bulk Those of you who are engaged in cloudbounce experiments might be interested in a laser "ceilometer" described in www.on.doe.ca/readac/cloudsen.htm. It uses laser pulses to measure the altitudes of cloud layers. I wish I could join in the experiments, but at this time I am only on the assembly of my "2nd generation" setup, based on the Lyte Optronics pointer described by K3PGP et al, and the OPT 210 discussed here. In case there is a typo in the web address (and somehow I always do get one wrong) a search of "laser&cloud" on YAHOO will probably do it. 73 kc5an John North Texas >From owner-laser Fri Jun 6 00:10:54 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA02522; Fri, 6 Jun 97 00:10:54 PDT From: Lbo@kktv.com Message-Id: <199706060706.AAA29206@natsemi-bh.nsc.com> To: laser@berlioz.nsc.com Date: 5 Jun 1997 18:38:30 -0700 Subject: Photoamps Sender: owner-laser@berlioz.nsc.com Precedence: bulk There is a good article in "Sensors" magazine June 97, entitled "Keeping the Signal Clean in Photosensing Instrumentation" Check it out... Paul Signorelli, Las Brisas Observatory, (View LBO's Web Page at http://shell.rmi.net/~mugele/lbo) LBO@KKTV.COM, P.O. BOX 6069, Colorado Springs, CO 80934 <>< Wise Men Still Seek HIM <>< >From owner-laser Fri Jun 6 19:23:27 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA22636; Fri, 6 Jun 97 19:23:27 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f To: laser@qsl.net Date: Fri, 6 Jun 1997 22:17:09 -0400 Subject: [LASER] Web Site Message-Id: <19970606.221712.14382.1.K3PGP@juno.com> X-Mailer: Juno 1.38 X-Juno-Line-Breaks: 1-6,8-14,16-23 From: k3pgp@juno.com (John K3PGP) Reply-To: k3pgp@juno.com (John K3PGP) Sender: owner-laser@berlioz.nsc.com Precedence: bulk Today I added some new things, updated files, fixed some bugs, added new links plus posted some pix of my laser radar setup. It's all at: http://www.qsl.net/k3pgp/index.html PS - New stuff being added daily. Now all I have to do is sit down and take the time to organize all of it so it makes more sense! More sound, video & pix are in the works... ----- To all that sent me Email: I'm presently swamped with Email. All will be answered in the order I received it. Just be patient! (And keep it coming, as I enjoy it :-^) ! ----- John K3PGP@juno.com http://www.qsl.net/k3pgp/index.html -==- >From owner-laser Sun Jun 8 07:26:52 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA06440; Sun, 8 Jun 97 07:26:52 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f Message-Id: <339ADB97.17C3@midstate.tds.net> Date: Sun, 08 Jun 1997 09:19:35 -0700 From: Michael Berg Organization: none X-Mailer: Mozilla 2.01 (Win16; U) Mime-Version: 1.0 To: laser reflector Subject: [LASER] Burr-Brown sensors Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Reply-To: Michael Berg Sender: owner-laser@berlioz.nsc.com Precedence: bulk I've been reading a lot about the Burr-Brown OPT210 IC here on the reflector and was wondering about using some of the other optical sensors in their line up. One in particular is the OPT101 chip. Looking at the product data sheets I noticed many of the specs are the same with the exception of bandwidth. (14 kHz) I was thinking that for baseband modulation applications, this shouldn't be a problem. I also like the single power supply aspect and that DigiKey carries it in their catalog. Also, I'm wondering what circuitry you folks are using to bring the OPT210 output up to audio levels? Thanks and 73 -- >~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~< >From owner-laser Mon Jun 9 09:38:28 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA05783; Mon, 9 Jun 97 09:38:28 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f Date: Mon, 9 Jun 97 09:29:06 PDT From: jmoss@berlioz.nsc.com (Jim Moss) Message-Id: <9706091629.AA05269@berlioz.nsc.com> To: laser@qsl.net Subject: [LASER] Photoamps Reply-To: jmoss@berlioz.nsc.com (Jim Moss) Sender: owner-laser@berlioz.nsc.com Precedence: bulk sent to laser@berlioz.nsc.com resending to laser@qsl.net ... Jim ----- Begin Included Message ----- >From owner-laser Fri Jun 6 03:12:33 1997 From: Lbo@kktv.com To: laser@berlioz.nsc.com Date: 5 Jun 1997 18:38:30 -0700 Subject: Photoamps Sender: owner-laser@berlioz.nsc.com Content-Length: 348 There is a good article in "Sensors" magazine June 97, entitled "Keeping the Signal Clean in Photosensing Instrumentation" Check it out... Paul Signorelli, Las Brisas Observatory, (View LBO's Web Page at http://shell.rmi.net/~mugele/lbo) LBO@KKTV.COM, P.O. BOX 6069, Colorado Springs, CO 80934 <>< Wise Men Still Seek HIM <>< ----- End Included Message ----- >From owner-laser Mon Jun 9 14:18:22 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA20208; Mon, 9 Jun 97 14:18:22 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f Message-Id: <339C643F.218C@lan.nsc.com> Date: Mon, 09 Jun 1997 13:14:55 -0700 From: Dave Fifield Organization: National Semiconductor Corp. X-Mailer: Mozilla 3.01 (Win95; I) Mime-Version: 1.0 To: Laser Email List Subject: [LASER] Fresnel Lenses - Focus/Attenuation Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Reply-To: Dave Fifield Sender: owner-laser@berlioz.nsc.com Precedence: bulk I was boxing up my laser receiver over the weekend. I have made a nice ply box with slots cut to slide the lens and rear panel in/out. It's going to be a nice platform to experiment on. Anyway, whilst I was messing about with the page magnifier fresnel lens and the focus point. I noticed something interesting. With the smooth side of the lens facing the sky, the lens focuses the object very cleanly (a point light source remains a point when focused). When I reverse the lens, so the "ribs" are facing the sky, the lens does not seem to focus the point source so well BUT, it is a LOT brighter at the focal point. I haven't measured the difference yet, but I will. If you take one of these lenses and just hold it up and move it to about 13 inches from your face, you can SEE the difference between having the smooth/ribbed side facing out. With the ribs facing out, the lens has much more gain. I'm sure the physics of this is easy to understand - maybe someone else would like to explain why this is... I will be using my fresnel lens with the ribs facing outwards to the sky on my receiver - suggest y'all do the same. 73, Dave AD6AY >From owner-laser Mon Jun 9 19:45:06 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA07005; Mon, 9 Jun 97 19:45:06 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f To: laser@qsl.net Date: Mon, 9 Jun 1997 18:50:21 -0400 Subject: Re: [LASER] Fresnel Lenses - Focus/Attenuation Message-Id: <19970609.223853.14726.4.K3PGP@juno.com> References: <339C643F.218C@lan.nsc.com> X-Mailer: Juno 1.38 X-Juno-Line-Breaks: 0-1,8-9,12-20,22-30 From: k3pgp@juno.com (John K3PGP) Reply-To: k3pgp@juno.com (John K3PGP) Sender: owner-laser@berlioz.nsc.com Precedence: bulk Dave: As far as I know this is the correct way to mount a fresnel lens (ribs facing outwards) and the way I have always used mine. Mine also produces a clearer and brighter image this way. The fresnels with better optical properties seem to have more lines per inch but there are other factors that enter into this as well. Keep in mind that not all fresnels are created equal so the results may vary from lens to lens when turned around backwards. The theory behind fresnel lens was in an old Edmund Sci. catalog, but it doesn't seem to be in my current catalog. I'll see if I can find the old one! John K3PGP@juno.com http://www.qsl.net/k3pgp/index.html ----- On Mon, 09 Jun 1997 13:14:55 -0700 Dave Fifield writes: > >I will be using my fresnel lens with the ribs facing outwards to the >sky on my receiver - suggest y'all do the same. > >73, Dave AD6AY > -==- >From owner-laser Wed Jun 11 10:07:47 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA18614; Wed, 11 Jun 97 10:07:47 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f From: daveaa1a@ssih.com Date: Wed, 11 Jun 1997 13:06:14 -0400 Message-Id: <199706111706.NAA16063@ssih.com> Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Subject: [LASER] Re: QTH ??? / misc... To: laser@qsl.net X-Mailer: SPRY Mail Version: 04.00.06.17 Reply-To: daveaa1a@ssih.com Sender: owner-laser@berlioz.nsc.com Precedence: bulk <---- Begin Forwarded Message ----> From: daveaa1a@ssih.com Subject: Re: QTH ??? / misc... To: k3pgp@juno.com (John K3PGP) Hi John, >Where exactly are you located? Do you have latitude and longitude? 42-05-45n 70-42-25w >Are you game for any over the horizon laser tests? Oh sure but am gonna try locally to see how far to put the bar down next try. >The reason I ask is that I am now able to detect 780 nm laser signals >scattered back from clear sky! NO CLOUDS! Beware of local coupling, When I have a leaky source, it gets right into the receiver and I have to check it by covering the lense to make sure.. Sorta like the old EME days when I thought I heard something then, BAMM an S1 signal seemed to crush the receiver.. >You might consider bypassing your HF rig entirely for BPSK laser work. Ya know, it ain't no big deal with all the PD/mixer/HF receiver, audio filter.. The original Steve Knoll receiver seems as good as anything and like you say forget the accurate RF freq.. The thing I'm not sure of now is am I receiving as good as I can?? Well this is what I get out of all 3 receivers weather base band or I.F. type. A radio shack jumbo led out on the tower in daylight with about 1.5volt sq wave at 1000hz and 2 ma. is detectable on all 3 receivers within a few db's.. If bugs fly even close they modulate very nicely with audio tones.. Other things happening round the yard also reflect into the scope and cause detection.. My cameras have not yet arrived, will be nice to have that for locating.. Do you think the ccd element is a good as our PD's ?? I will send you another 650nm diode then I'm afraid it's down to the botom of the barrel.. I want to qsy to IR also cuz the propagation looks to be way better.. Trouble with the IR diodes and colimator is how do you adjust em for a tight spot when you can't see it..?? A fixed IR diode in fixed colimator is the answer but have you tried reverse telescope?? Whats your best solid state receiver front end..?? I think I'm at the noise floor or close to it here.. How do you radar?? I take and look at tx on scope 'A' (Sync) channel and look at receive output on 'B' channel measure 6.18 us. for range mile.. Havn't tried pulse yet.. but why not.. Thinking of nice application using IR diode and low level altimeter for aircraft.. When I was in the business they had something at 1500 mhz. that wasn't usable below 100 feet or so.. As for the best front end here, I gotta say the EG&G PD and the Burr-Brown op-amp is the best.. the 211 is a litle beneath it and the PD into a FET into the VLF converter into the HF receiver is nice but at baseband not quite as good as PD/op-amp but then again the subcarrier of it all make for more versatile.. My friend in Plymouth is getting on LIGHT and has a clear horizon to you.. I bet he will want to try a BEACON.. The diode is in the mail..TRUST ME..hi.. Keep the light on.. 73s de dave ps.. in search of best front end.. Think the diode 3mw and 4" lenses adaquate enough.. A fiber optic detector may be fine for bandwidth but it may also need a lot of light.. A CCD element without horizontal/vertical or sync. seems like a good candidate with some up front color filtering.. How about VIDEO out of the camera with NO SCAN just a few center pixels turned ON.. ?? <---- End Forwarded Message ----> >From owner-laser Wed Jun 11 17:31:27 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA11096; Wed, 11 Jun 97 17:31:27 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f To: laser@qsl.net Date: Wed, 11 Jun 1997 20:27:26 -0400 Subject: [LASER] Laser Backscatter Signals Detected! Message-Id: <19970611.202730.6414.1.K3PGP@juno.com> X-Mailer: Juno 1.38 X-Juno-Line-Breaks: 0-11,17-18,24-25,28-29,37-38,40-41,44-50 From: k3pgp@juno.com (John K3PGP) Reply-To: k3pgp@juno.com (John K3PGP) Sender: owner-laser@berlioz.nsc.com Precedence: bulk Dave: On Mon, 9 Jun 1997 22:38:18 -0400 K3PGP writes: >>The reason I ask is that I am now able to detect 780 nm laser signals >>scattered back from clear sky! NO CLOUDS! >~~~~~ On Wed, 11 Jun 1997 13:06:14 -0400 daveaa1a@ssih.com writes: >Beware of local coupling, When I have a leaky source, it gets right into >the receiver and I have to check it by covering the lense to make sure.. >Sorta like the old EME days when I thought I heard something then, BAMM >an S1 signal seemed to crush the receiver.. This is NOT a leaky source nor coupling. Covering the lens produces NO signal. Same with blocking the laser path. It has been confirmed with another station approx. 5 miles away. We are now able to detect 780 nm laser signals bouncing back from dust particles and pollution in the atmosphere! Exactly what the over the horizon range of this mode is unknown at this time. Signals vary from -25 dB below the noise floor aiming straight up into clear sky (BPSK is solid copy at this level using the VE2IQ program Coherent) to +4 dB when pointing just above the horizon. If I accidently hit the horizon the S-meter hits the pin! The atmosphere is thinner looking straight up. Less atmosphere = less scattering medium = less signal. Distance from the scattering medium is being measured with an interferometer setup as signals are too weak to use a wideband pulse setup. The fact that I can detect 780 nm signals scattered back from clear sky was only discovered a couple of days ago right after installing a new receive front end. (All the work I've been doing on the receiver is starting to pay off! :-^) I knew these signals had to be there as they are being measured with commercial setups that use these backscattered signals to measure air pollution. They also run a LOT more power!!! However, up till now I never had enough receive sensitivity to find them with my low power laser. More when I get a chance to make more measurements! (Or work someone farther away over the horizon via backscatter!) PS - The VE2IQ BPSK program COHERENT is now available via a link from my web site! You will need to contact Bill (VE2IQ) directly to order the interface. John K3PGP@juno.com http://www.qsl.net/k3pgp/index.html -==- >From owner-laser Thu Jun 12 09:38:26 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA19744; Thu, 12 Jun 97 09:38:26 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f To: laser@qsl.net Date: Thu, 12 Jun 1997 12:33:58 -0400 Subject: [LASER] Laser Troposcatter & Cloud Bounce Experiments! Message-Id: <19970612.123400.16838.2.K3PGP@juno.com> X-Mailer: Juno 1.38 X-Juno-Line-Breaks: 0-2,6-7,11-12,14-17,21-22,30-33,36-37,41-42,50-51, 56-59,66-70,75,80-83,88-89,99-102,105-106,117-118,120-121, 126-129,134-135,143-150,154-155,158-167,171-172,177-184 From: k3pgp@juno.com (John K3PGP) Reply-To: k3pgp@juno.com (John K3PGP) Sender: owner-laser@berlioz.nsc.com Precedence: bulk Laser Troposcatter & Cloud Bounce Experiments ----------------------------------------------------------------------- As many of you are aware I have been experimenting with bouncing laser signals off of the low cloud layers that we have been experiencing over the past few weeks. Using these signals I was able to optimize my system. This past week I installed a new receive front end that I've been working on for the past couple of months. Using this new front end and the optimized system above I am now able to detect weak signals being scattered back from CLEAR SKY! That's right, NO CLOUDS! The characteristics of these scattered signals are completely different from those obtained using clouds as the reflecting medium. Cloud Bounce -------------------- Using the cloud layer signals ALWAYS were the strongest when the system was pointed straight up. Signal levels would vary from +4 dB when aimed just above the horizon to >27 dB above the noise floor when pointed directly overhead. I'm sure a lot of the difference in signal level is due to the fact that the clouds that are directly overhead are quite a bit closer. However, the angle at which the laser beam hits the cloud layer may also enter into this. Although I can't prove it at this point, it's my feeling that when aiming at clouds near the horizon most of the energy is being reflected in the FORWARD direction and very little is being reflected or scattered back to the transmitting station. I won't be able to determine this until I get another station or beacon on that is over the horizon. Troposcatter ------------------ The second mode of propagation was discovered over the weekend and has been observed every night so far. This mode involves crystal clear skies, something that we haven't seen in this area for months! Unlike the cloud bounce experiments these signals are weakest when pointing straight overhead and peak just above the horizon. Signal levels are also much weaker (but a LOT more stable) than anything observed during the cloud bounce tests. Typical signal levels run approx. -25 dB below the noise floor when pointed straight up. (DSP, FFT, and long term integration techniques are necessary to even detect these signals!) However, as I drop the elevation angle the signals gradually build in signal level peaking approx. +4 dB out of the noise when aimed just above the horizon. This is completely opposite of the cloud bounce tests! When one considers the fact that the atmosphere is thinnest looking straight up this makes sense. Less atmosphere = less scattering volume = less signal! Exactly what is causing the backscatter during clear skies is not known at this time but I'm sure it's very similar to microwave troposcatter propagation with the added benefit that the much shorter wavelength (780 nm) can also be reflected and scattered by dust particles, water vapor, and pollutants in the atmosphere. Observation ----------------- I find it interesting that the signal levels detected just above the horizon were about the same (+4 dB) during both the cloud bounce and clear sky troposcatter tests. Perhaps what I detected on the horizon that cloudy night wasn't due to clouds! It's pretty difficult to determine what's on the horizon in the dark during cloudy weather! It's very possible that the skies were clear on the horizon in that direction.) Early Experimenters ------------------------------ It is my feeling that over the horizon troposcatter QSOs are indeed possible. After discovering the fact that I can detect these signals I made several trips to the library and discovered that test like these were conducted back in the late 60's by the Federal Telephone Company. They were using ruby rod transmitters and were able to communicate with other stations 150 miles away! I was amazed to learn that their original goal was to try to bounce laser signals (used for communications) off of clouds. However, they also discovered that there was a residual signal present all the time. Exactly the same results that I am getting! Proof? -------- With the lens covered on my receiver or the laser beam blocked there is NO residual signal. Also the fact that the signal levels vary from -25 dB to +27 dB depending on the propagation mode and pointing angle seems to indicate that the signals are indeed coming from what is out in front of the optics and not something generated in the equipment. The only station I have been able to use for verification of these results is approx. 5 miles from here and he is definitely NON line of sight as we are blocked with several very high hills between us. (I live on the west side of and in the foothills of the Allegheny mountains with the result that our elevation is all over the place from lows of 500 to 600 feet up to 2700 feet!) The fact that I can hear him by each of us pointing up in the sky seems to indicate that the signals being detected are indeed the real thing. However, until I get someone on the air further away there's not a whole lot more I can do to determine what can be done using cloud bounce or troposcatter. How to Participate --------------------------- I must add that in order to make use of troposcatter signals with the typical laser powers that most stations are running (<5 mw) it will be necessary to use computer processing to dig the signals out of the noise. I do NOT suggest that all of us increase power levels because of the safety hazards that this would create plus the fact that we are pointed up in the sky creating an air traffic hazard! Although the air traffic hazard is minimal when aimed straight up and using cloud bounce, it appears that troposcatter is most easily worked when pointing near the horizon. If you try any of these experiments use your head and don't endanger yourself or anyone flying in the skies above! Be especially careful of horizon shots where an oncoming aircraft could be in your beam for many miles! Aim something (binoculars, telescope, or CCD camera with a telephoto lens) in the direction your firing and watch for strobe lights! If you want to jump on the computer processing bandwagon I have a couple of suggestions. First off make sure your using the most sensitive receive setup that you can build. There is no substitute for a good front end! All the computer processing you can afford will never bring back a signal that isn't there in the first place and if you can't hear them you certainly aren't going to work them! Weak Signal Software -------------------------------- I have discovered two weak signal computer programs that seem to work extremely well with weak laser signals. Keep in mind that these are intended for serious weak signal work only. If you primarily use your laser for line of sight communications you do NOT need either of these programs! The first program is from VE2IQ. Actually there are two of them, FFT and COHERENT. FFT is useful for finding signals buried in the noise by using the integrate mode. COHERENT is a full blown communications program that will allow you not only to detect signals below the noise floor but be able to communicate with them! Signal levels of -25 to -30 dB are solid copy using this program! It's really weird to watch text coming across the computer screen when nothing can be heard coming from the speaker other than white noise! Both of these programs are available for free! Log onto my web site at: http://www.qsl.net/k3pgp/index.html Follow the link: Weak Signal Software * VE2IQ BPSK & FFT Software Keep in mind that BOTH programs require a special interface that plugs into the serial port of any IBM style PC and run from DOS. You can see details of the interface and FFT program in the January 1992 issue of QST. The interface is available from VE2IQ and is in my mind a real bargain! Contact Bill, VE2IQ and tell him I sent you. Definitely check this one out !!! The second program is available from AF9Y. It is also available via a link at my web site: http://www.qsl.net/k3pgp/index.html Follow the link: Weak Signal Software * AF9Y FFTDSP Program This program is available in a demo form only. It will run for something like 60 seconds or so then it will quit. It can be run as many times as you want but it will time out again. If you try this program and decide you like it, you must contact AF9Y for a key to unlock the program. If your goal is unattended monitoring of a beacon then the AF9Y program is probably a good choice. You can let it run all night and check the results in the morning! However, it offers NO communication capability like the VE2IQ programs do. This program runs with any Sound Blaster compatible card but must be run from DOS. ----- John K3PGP@juno.com http://www.qsl.net/k3pgp/index.html -==- >From owner-laser Thu Jun 12 17:29:58 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA14185; Thu, 12 Jun 97 17:29:58 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f Date: Thu, 12 Jun 97 17:21:32 PDT From: jmoss@berlioz.nsc.com (Jim Moss) Message-Id: <9706130021.AA13785@berlioz.nsc.com> To: laser@qsl.net Subject: [LASER] more Laser Troposcatter Reply-To: jmoss@berlioz.nsc.com (Jim Moss) Sender: owner-laser@berlioz.nsc.com Precedence: bulk Like John, I also have played with sending sigs up into the empty sky. We don't get as many clouds out here, but we do sometimes get scattered ones! I can hear returns from straight up with NO clouds... Like John, I used the cover with hand trick on both the laser and the lens. The signal is surely coming in from above the optics. However... It may be from close proximity scattering, not necessarily far away. I don't have enough info from my own experiments to determine this yet. I plan to seperate the TX and RX sites and that should do it. Tonight hope to work a station up on Mt Diablo.. about 50 miles... He will be on thru the weekend for the contest. I am taking my 4mW and PMT+8x10 lens along with my bino setup to CN70 for the contest. Jim WB9AJZ/CN70xa >From owner-laser Thu Jun 12 18:04:30 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA15606; Thu, 12 Jun 97 18:04:30 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f Date: Thu, 12 Jun 1997 20:59:14 -0400 (EDT) From: "C. W. Wright" X-Sender: wwright@wayne.home.net To: Jim Moss Cc: laser@qsl.net Subject: Re: [LASER] more Laser Troposcatter In-Reply-To: <9706130021.AA13785@berlioz.nsc.com> Message-Id: Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Reply-To: "C. W. Wright" Sender: owner-laser@berlioz.nsc.com Precedence: bulk > the lens. The signal is surely coming in from above the > optics. However... It may be from close proximity > scattering, not necessarily far away. I don't have > enough info from my own experiments to determine this > yet. I plan to seperate the TX and RX sites and > that should do it. I havn't looked up, but look down from aircraft with high power pulsed lasers all the time. We have to set our range gate to acquire the signal from the desired range, and if we don't the system will trigger on the atmospheric scatter. The scatter is much stronger on hazy days, and is very strong near the aircraft. We can tell from where its coming from because it's pulsed and we see the returns in the time domain on a wideband digital scope. -Wayne wright@lidar.net >From owner-laser Thu Jun 12 19:56:15 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA20462; Thu, 12 Jun 97 19:56:15 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f To: laser@qsl.net Date: Thu, 12 Jun 1997 22:50:55 -0400 Subject: Re: [LASER] more Laser Troposcatter Message-Id: <19970612.225058.10678.0.K3PGP@juno.com> References: <9706130021.AA13785@berlioz.nsc.com> X-Mailer: Juno 1.38 X-Juno-Line-Breaks: 0-1,6-7,17-18,25-26,31-32,38-39,41-68 From: k3pgp@juno.com (John K3PGP) Reply-To: k3pgp@juno.com (John K3PGP) Sender: owner-laser@berlioz.nsc.com Precedence: bulk Jim: The distance to the scattering medium can be measured by using the laser setup as an interferometer. (More details on this as I refine the technique!) Using this technique I can tell approx. what distance the signal is coming from and can seperate the scatter occuring right in front of the optics from those signals coming from further out. And you are correct. Unless you take great care to determine exactly where the signal is coming from you can be fooled by signals scattered back from right in front of the lens! Also another tip off is these signals usually do NOT vary in signal strength with elevation. The signals I'm detecting vary from approx. +4 dB just above the horizon to -25 below the noise floor when looking straight up. This seems to agree with the characteristics of scatter signals and the amount of atmosphere one is looking through. (One also has to be careful of extraneous light getting into the system and changing the gain characteristics of the system!) If you are able to HEAR signals when pointed straight up then I would have to say that you are NOT hearing troposcatter signals as they usually aren't strong enough to hear. You definitely need some type of DSP to work troposcatter (at least with the laser power I have!) as the signals very seldom get strong enough to detect by ear. Most likely you are hearing something right in front of the lens or a short distance in front of it. The signals I am seeing appear to be coming from several miles up. I'm still collecting data to try to refine the distance. The fact that I can hear another station that is NON line of sight by both of us pointing to the same general area of the sky seems to indicate that I am indeed detecting backscatter signals. By the way he can NOT hear me! His receiving capabilities are no where near what mine are nor does he have any type of computer DSP receive equipment to find the signal buried in the noise. All he hears is noise yet he's solid copy on this end with the signal running approx. -25 dB below the noise floor! All I hear coming out of my speaker is noise as well! I'm hoping to get someone on a little further out, perhaps 30 miles or so to see if I can hear them as well. John K3PGP@juno.com http://www.qsl.net/k3pgp/index.html ----- On Thu, 12 Jun 97 17:21:32 PDT jmoss@berlioz.nsc.com (Jim Moss) writes: >Like John, >I also have played with sending sigs up into the empty >sky. We don't get as many clouds out here, but we do >sometimes get scattered ones! I can hear returns >from straight up with NO clouds... Like John, I >used the cover with hand trick on both the laser and >the lens. The signal is surely coming in from above the >optics. However... It may be from close proximity >scattering, not necessarily far away. I don't have >enough info from my own experiments to determine this >yet. I plan to seperate the TX and RX sites and >that should do it. > >Jim >WB9AJZ/CN70xa > -==- >From owner-laser Fri Jun 13 09:12:31 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA16685; Fri, 13 Jun 97 09:12:31 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f From: daveaa1a@ssih.com Date: Fri, 13 Jun 1997 12:12:03 -0400 Message-Id: <199706131612.MAA21719@ssih.com> Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Subject: [LASER] better front end To: k3pgp@juno.com (John K3PGP) Cc: laser@qsl.net In-Reply-To: <19970612.123400.16838.2.K3PGP@juno.com> X-Mailer: SPRY Mail Version: 04.00.06.17 Reply-To: daveaa1a@ssih.com Sender: owner-laser@berlioz.nsc.com Precedence: bulk Hi John, Well Friday 13th good news here.. All receivers with about the same sense were using the EG&G PD's and I figured they were pretty good.. Well what a surprize when I tried a Radio Shack Infrared Phototransistor p/n 276-145a It is an order of magnitude better signal recovery.. bias is reverse 82k to 9vdc. Thats even better cuz I am qsy'ing to IR on the transmit and think there are more DX sigs there.. Diode left today.. 73s de daveaa1a >From owner-laser Fri Jun 13 10:11:04 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA19098; Fri, 13 Jun 97 10:11:04 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f Message-Id: <199706131602.MAA18387@outpost.ietc.ca> X-Sender: bill@ietc.ca X-Mailer: Windows Eudora Light Version 1.5.2 Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Date: Fri, 13 Jun 1997 13:02:35 -0400 To: laser@qsl.net From: Bill de Carle Subject: [LASER] Version 6.1 of COHERENT available Reply-To: Bill de Carle Sender: owner-laser@berlioz.nsc.com Precedence: bulk Hi Laser Folks: At the suggestion of Dave Riley, I have added a command to COHERENT which allows the program to send a small message over and over. This can be used as a "Beacon" mode if you like. The latest version of the program (V6.1) is available for downloading from my web page: http://www.ietc.ca/home/bill/bbs.htm Also, if you would like to set up a stand-alone beacon (without dedicating a computer) - there are some suggestions for simple BPSK keyers - check out the Longwave Club of America's Digital references page at: http://users.aol.com/part15/digitlib.htm Bill de Carle VE2IQ >From owner-laser Fri Jun 13 15:05:36 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA29196; Fri, 13 Jun 97 15:05:36 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f Message-Id: <33A1B4B0.5EDF@lan.nsc.com> Date: Fri, 13 Jun 1997 13:59:28 -0700 From: Dave Fifield Organization: National Semiconductor Corp. X-Mailer: Mozilla 3.01 (Win95; I) Mime-Version: 1.0 To: Laser Email List Subject: [LASER] Contest this weekend Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Reply-To: Dave Fifield Sender: owner-laser@berlioz.nsc.com Precedence: bulk Guys, I am now 100% QRV on 670nm MCW. I will be "roving" around the S.F. Bay Area looking for laser contacts Saturday nightime. I have heard through the grapevine that there are likely to be up to 6 stations (!!!?) doing the same, although I don't have any details of where/when any of you will be. If someone would be kind enough to fill me in as to the grand plan, I'd be most grateful. Please email me at fifield@pacbell.net I'll be monitoring 144.280 ssb (the de facto laser coord. freq.) most of the time, so get on and announce that you're looking for contacts. I will go wherever needed to complete as many contacts as possible and give away grids. 73, Dave AD6AY >From owner-laser Sat Jun 14 04:52:11 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA20145; Sat, 14 Jun 97 04:52:11 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f Date: Sat, 14 Jun 1997 07:47:47 -0400 (EDT) Message-Id: <2.2.16.19970614065536.26c7482e@mail.snet.net> X-Sender: paulc@mail.snet.net X-Mailer: Windows Eudora Pro Version 2.2 (16) Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" To: laser@qsl.net From: "Paul A. Cianciolo" Subject: [LASER] RX improvement Cc: k3pgp@juno.com Reply-To: "Paul A. Cianciolo" Sender: owner-laser@berlioz.nsc.com Precedence: bulk Hello John and the group Got a chance to try cloud bounce again last night. But before I did I decided to do some tests on the RX since I was not all that happy with it's sensitivity. The RX again is a OPT 210 and a 5 1/2" lens. Powered by a DC to DC converter to get +/- 12vdc for the OPT 210. The last time I had looked at the RX output signal on the scope I was using 2) 9 volt batteries to power the RX. While looking at the output of the OPT 210 with an oscilloscope I discovered there was a ton of noise riding on the 800 hz signal!! I had done some filtering of the DC to DC converter but evidently it was not enough. So I put 2200 mfd across each side of the +/- power supply and the noise got slightly better. Then I lifted the input to the DC to DC converter and the OPT 210 would run off the caps for about 20 secs. The noise level dropped tremendously during the time the RX was being powered off just the caps. So I made a little RC network to feed the OPT 210 instead of just the caps. This cleaned up the output of the to the same level as when running off the caps. BTW I have a .1 mfd bypass cap across ea. supply at the socket inside the RX. Testing: I set up the gear outside and waited for darkness Conditions small wispy clouds in patches and other areas of dark thick clouds. Tests were started at about 30 degs above the horizon. Signals weak, very readable and consistent. As I moved up from the horizon the sigs again, as in my last tests got progressively stronger. I made changes to the tripod so I can now elevate the RX to about 80 degs above the horizon. At 80 degs elevation I left the setup running for about 1 hour. During that time a number of cloud formations moved in and out of range. I noticed that when the wispy clouds were about the signal was very weak but readable and also fairly consistent in level. Also it was very well defined as to the pointing of the RX . As thicker clouds rolled in the signal would vary as the edge approached and the get very strong as the thick clouds were in the path. Strong enough to cover 75% of the lens and still copy CW easily. The exact pointing of the RX ( best signal ) would change. I could always hear the 800 hz strong.. but the peak was moving around. I did these tests at about 10 feet apart... I repeated at about 150 feet apart during the last half of the nights work. Same results Tonight will be cloudless and I will be trying the setup again. BTW watch out for "heat lightning " when you have a high gain RX pointed up to the sky listening for weak signals. Even a distant flash produces an ear shattering pulse in the headphones!! John , I ordered the Sigma Delta board yesterday and will begin experimenting with BPSK. I am looking for some SNR enhancements there. All the tests are being done with a old LC type audio filter about 500 hz(guess) I don't know if it is centered in the at 800 hz or not. Time to break out the DSP filter. I would like to know what filters if any others are using Wrap up: 1) SNR is much better in practice now as the scope results have indicated 2) Some weak sigs seem to be readable with out much cloud cover. More on this tonight. 3) Still waiting for 30 mw IR laser... will be in late next week!!!!! Looking for comments!! 73's PaulC KB1RP >From owner-laser Sat Jun 14 08:24:36 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA24834; Sat, 14 Jun 97 08:24:36 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f To: laser@qsl.net Date: Sat, 14 Jun 1997 11:20:48 -0400 Subject: [LASER] Cloud Noise ! Message-Id: <19970614.112050.-27810.4.K3PGP@juno.com> X-Mailer: Juno 1.38 X-Juno-Line-Breaks: 1-15,18-21,26-27,33-38,40-41,45-46,49-55 From: k3pgp@juno.com (John K3PGP) Reply-To: k3pgp@juno.com (John K3PGP) Sender: owner-laser@berlioz.nsc.com Precedence: bulk On Sat, 14 Jun 1997 07:47:47 -0400 (EDT) "Paul A. Cianciolo" writes: >Hello John and the group > ~~~~~~ > >BTW watch out for "heat lightning " when you have a high gain RX >pointed up to the sky listening for weak signals. Even a distant >flash produces an ear shattering pulse in the headphones!! > >73's >PaulC KB1RP > Paul: I am observing something down here when there is NO evidence of lightning or other types of electrical activity. It is usually observed when skies are crystal clear with a few thin clouds around. Two signals are associated with these clouds. #1 - Man made light can be heard bouncing off the bottom of these clouds. If I run the signal into a spectrum analyzer and look at the harmonics of the signal the spectrum changes as the cloud passes over various ground lighting sources! When the could moves away from the city lights the hum goes away! #2 - A rhythmic clicking sound is also heard. It sounds mechanical like it's man made but it's probably due to some type of electrical activity in the cloud causing small flashes of light in the IR and/or UV range. No corresponding flashes could be seen with the CCD camera. However, this may be due to the fact that they are too brief or of too low an amplitude for the CCD camera to pick up. A sample of this signal is at: http://www.qsl.net/k3pgp/index.html Under LASER near the bottom of the page you will find Mystery signal Number 2! Remember to click on reload or view then refresh to update your browser if it cashes to disk as this web site is update frequently and if you don't do this you may be looking at an old page on your hard drive instead of what is currently on the web site! And while your at it, remember you will get faster response time from the laser reflector if you subscribe to laser@qsl.net. Instructions on how to do this is at the bottom of the first page at the same web site. John K3PGP@juno.com http://www.qsl.net/k3pgp/index.html -==- >From owner-laser Sat Jun 14 11:42:10 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA29196; Sat, 14 Jun 97 11:42:10 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f Date: Sat, 14 Jun 1997 14:39:53 -0400 (EDT) From: "C. W. Wright" X-Sender: wwright@wayne.home.net To: John K3PGP Cc: laser@qsl.net Subject: Re: [LASER] Cloud Noise ! In-Reply-To: <19970614.112050.-27810.4.K3PGP@juno.com> Message-Id: Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Reply-To: "C. W. Wright" Sender: owner-laser@berlioz.nsc.com Precedence: bulk My last post should have started with: From anywhere in the US, Call: 1-800-wx-brief ( 800-992-7433 ) and get the current cloud types, altitudes, surface visibility, haze, smoke,fog, or other viz. restrictions. :-) Wayne >From owner-laser Sat Jun 14 11:41:50 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA29179; Sat, 14 Jun 97 11:41:50 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f Date: Sat, 14 Jun 1997 14:36:46 -0400 (EDT) From: "C. W. Wright" X-Sender: wwright@wayne.home.net To: "Paul A. Cianciolo" Cc: laser@qsl.net, k3pgp@juno.com Subject: Re: [LASER] RX improvement In-Reply-To: <2.2.16.19970614065536.26c7482e@mail.snet.net> Message-Id: Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Reply-To: "C. W. Wright" Sender: owner-laser@berlioz.nsc.com Precedence: bulk > Conditions small wispy clouds in patches and other areas of dark thick clouds. From anywhere in the US, Call: 1-800-wx-brief ( 800-992-7433 ) and get the current could types, altitudes, surface visibility, haze, smoke, fog, or other viz. restrictions. The service is for pilots, but anyone can call. Usually there's a tape recorded message of options. You'll need to find the "3 letter ident" of an airport near you. They will give the conditions for that airport if it reports weather. You can hit " # * " and actually talk to a weather briefer. Tell hime your a radio amateur, and you'd like the "current surface conditions" at XYZ (where XYZ is the 3 letter id for your nearby airport ). The inforamtion is updated at least every hour, and if things change sooner, special observations are taken and put out right away. If you have a pilot certificate, you can get the stuff on-line too. Just telnet to duat.gtefsd.com. Having the actual weather conditions will help you make comparisions from day to day, and also let the rest of us know what the atmosphnere looked like when you did your exp. Below is a sample of what the information looks like from the duats system. When you see "3 miles" that's the viz. the words "scattered" "broken" "overcast" describe the type of cloud cover. The "altimeter" is actually the sea-lavel barometer. The following has several special observations due to low clouds,, low viz, and rain here today. Here's the data: ******** Surface Observations ******** current hourly report not available for SBY Salisbury MD (Salisbury-Ocean City Wicomico Regional) [SBY] hourly observation on the 14th at 11:50am EDT (1550Z), wind 300 degrees at 8 knots, visibility 3 miles, light rain, haze, 1,000 feet few, 4,000 feet scattered, 15,000 feet broken, 25,000 feet overcast, temperature 26C (79F), dewpoint 20C (68F), altimeter 29.76, rain began at 35 minutes past the hour, sea level pressure 29.76" Hg (1007.8 hPa). Salisbury MD (Salisbury-Ocean City Wicomico Regional) [SBY] special observation on the 14th at 12:14pm EDT (1614Z), wind 320 degrees at 5 knots, visibility 2 1/4 miles, light rain, haze, 1,000 feet few, 3,000 feet broken, 9,000 feet overcast, temperature 26C (79F), dewpoint 20C (68F), altimeter 29.76. Salisbury MD (Salisbury-Ocean City Wicomico Regional) [SBY] special observation on the 14th at 12:30pm EDT (1630Z), wind 360 degrees at 7 knots, visibility 1 3/4 miles, light rain, haze, 1,000 feet few, 3,000 feet broken, 9,000 feet overcast, temperature 25C (77F), dewpoint 20C (68F), altimeter 29.76. Salisbury MD (Salisbury-Ocean City Wicomico Regional) [SBY] special observation on the 14th at 12:45pm EDT (1645Z), wind 320 degrees at 4 knots, visibility 1 1/4 miles, light rain, haze, 1,000 feet few, 3,000 feet broken, 9,000 feet overcast, temperature 24C (75F), dewpoint 20C (68F), altimeter 29.77. Salisbury MD (Salisbury-Ocean City Wicomico Regional) [SBY] special observation on the 14th at 12:50pm EDT (1650Z), wind 340 degrees at 3 knots, visibility 1 1/4 miles, light rain, mist, 1,000 feet few, 2,800 feet broken, 9,000 feet overcast, temperature 24C (75F), dewpoint 21C (70F), altimeter 29.77, sea level pressure 29.77" Hg (1008.2 hPa). Salisbury MD (Salisbury-Ocean City Wicomico Regional) [SBY] special observation on the 14th at 1:32pm EDT (1732Z), wind 060 degrees at 3 knots, visibility 1 3/4 miles, light rain, mist, 2,000 feet few, 2,800 feet scattered, 9,000 feet overcast, temperature 24C (75F), dewpoint 21C (70F), altimeter 29.76. -Wayne >From owner-laser Sat Jun 14 20:56:12 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA11767; Sat, 14 Jun 97 20:56:12 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f To: laser@qsl.net, daveaa1a@ssih.com, PaulC@snet.net, cbuttsch@slonet.org, bill@ietc.ca Date: Sat, 14 Jun 1997 23:52:32 -0400 Subject: [LASER] New Stuff on Web Site! Message-Id: <19970614.235235.13646.0.K3PGP@juno.com> X-Mailer: Juno 1.38 X-Juno-Line-Breaks: 1-2,7-8,10-11,15-16,20-21,25-26,33-39 From: k3pgp@juno.com (John K3PGP) Reply-To: k3pgp@juno.com (John K3PGP) Sender: owner-laser@berlioz.nsc.com Precedence: bulk Dave, Paul, Cliff, Bill, anyone with the VE2IQ BPSK hardware, and anyone else that's curious about all this laser backscatter stuff: I left my 780 nm laser beacon running tonight and took a drive approx. 26 miles away and set up the laser receiver and laptop computer and was able to find my beacon on backscatter! I was able to get solid copy at 20 ms / bit. The signal was routed to the AFM audio input of an 8 mm camcorder for recording. The skies were crystal clear and relatively cool for this time of year. Not a cloud in sight! I have placed a digital recording of the signals on my web site under LASERS near the bottom of the page. Let me know if any of you are able to copy the signal. There are instructions on how to set up the COHERENT program to acquire the signal. Remember to click on reload or view then refresh to update your browser if it cashes to disk as the web site is updated frequently and if you don't do this you may be looking at an old page on your hard drive instead of what is currently on the web site! Believe it guys. Laser backscatter IS possible and we're about to change the way people think about optical communications. All I need is another station over the horizon with BPSK capability and a good receiver and the rest will be history! Let's get with it!!! PS - Bill (VE2IQ) - Thanks for the REP command. I was going to suggest that one myself but have been so busy I just never got around to it. It sure came in handy tonight!!! Now how about some way to measure delays of less than 1.25 ms. I'd like a way to tell how far away something is by copying my own signals in full duplex and most targes are too close to provide 1.25 ms of delay! That is until we start using the moon as a reflector! John K3PGP@juno.com http://www.qsl.net/k3pgp/index.html -==- >From owner-laser Sun Jun 15 07:40:13 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA26140; Sun, 15 Jun 97 07:40:13 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f Message-Id: <199706151335.JAA08374@outpost.ietc.ca> X-Sender: bill@ietc.ca X-Mailer: Windows Eudora Light Version 1.5.2 Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Date: Sun, 15 Jun 1997 10:35:33 -0400 To: k3pgp@juno.com (John K3PGP), laser@qsl.net, daveaa1a@ssih.com, PaulC@snet.net, cbuttsch@slonet.org From: Bill de Carle Subject: Re: [LASER] New Stuff on Web Site! Reply-To: Bill de Carle Sender: owner-laser@berlioz.nsc.com Precedence: bulk At 11:52 PM 6/14/97 -0400, John K3PGP wrote: >I left my 780 nm laser beacon running tonight and took a drive approx. 26 >miles away and set up the laser receiver and laptop computer and was able >to find my beacon on backscatter! I was able to get solid copy at 20 ms >/ bit. The signal was routed to the AFM audio input of an 8 mm camcorder >for recording. > >The skies were crystal clear and relatively cool for this time of year. >Not a cloud in sight! > >I have placed a digital recording of the signals on my web site under >LASERS near the bottom of the page. Let me know if any of you are able >to copy the signal. There are instructions on how to set up the COHERENT >program to acquire the signal. Sounds great, John. I listened to the recording and heard only noise. Then I decided to have a go at analyzing the signal. Didn't try to play the .wav file back through a sound card, I just worked with the digital data, and was able to recover your message all except for a couple of garbled characters near the end. [begin recovered message] }}}}}}}}}}}}}}}}}}} VVV de K3PGP 780 nm Laser Scatter Test! The quick brown fox jumped over the lazy dog's back. Tehtfng 1234567890. [end recovered message] >PS - Bill (VE2IQ) - Thanks for the REP command. I was going to suggest >that one myself but have been so busy I just never got around to it. It >sure came in handy tonight!!! Now how about some way to measure delays >of less than 1.25 ms. I'd like a way to tell how far away something is >by copying my own signals in full duplex and most targes are too close to >provide 1.25 ms of delay! That is until we start using the moon as a >reflector! The front-end assembly language code of COHERENT calculates the phase of the 800-Hz tone every bit time to a precision of 0.1 degrees. Of course if the signal is noisy there will be some error in this measure- ment, but by averaging over a large number of bits and removing the 180-degree ambiguity introduced by modulation, we should be able to get the ultimate phase approaching within 0.1 degree or so. At 800 Hz this would be about 347 nanoseconds. Assuming round trip, the distance to target would be resolvable to within about 175 feet. If necessary we could calculate the phase to a hundredth of a degree, but I'd have to change the ML code to do it. The big problem would be getting a reference phase - we'd have to find a way for the program to measure the phase of the transmit signal as soon as the light leaves the laser, then switch over quickly to measure the phase of the signal being received due to reflection from the target. I suppose it could be done. But it sounds like extra work for me, hi! Congrats on your great results, John. This inspires me to get cracking on a laser set-up here. I got a 670 nm 5-mw Tx working last night, but so far I have no idea what to use for a receiver. 73 de Bill VE2IQ >From owner-laser Sun Jun 15 07:53:29 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA26404; Sun, 15 Jun 97 07:53:29 PDT From: Lbo@kktv.com Message-Id: <199706151447.HAA03308@natsemi-bh.nsc.com> To: laser@berlioz.nsc.com Date: 15 Jun 1997 08:55:38 -0700 Subject: QRPp on 670nm! Sender: owner-laser@berlioz.nsc.com Precedence: bulk Well folks, I thought you may be interested to hear about my latest foray into the fringes of QRP operation -- this is definately NOT your normal H.F. QRP CW stuff -- read on.... I just got back from making my first and second contacts on the 670nm band with Walt, AJ6T - I rovered from CM97 and CM87 to give him 2 grids for the VHF/UHF contest. First contact was about 11 miles and the second was about 20.5 miles. My TX - about 2mW MCW at approx 450 THz, no antenna (coherent light doesn't need one!) My RX - 8.5 x 11 inch fresnel lens feeding an OPT210 photodiode/amp into an LM380N audio amp. We used 1 million candle power handheld halogen spotlamps to find each other initially (definately not QRP, but they save a whole ton of time wondering which direction to look in) then used the az/el adjusters (VERY fine) built into our laser rig set-ups to align the TX and RX pairs. Signals, when you are pointed just right, are 599 normally. We had a bit of trouble with gusty wind blowing our cheapo tripods about, so made do with 449/559 reports. We used 144MHz SSB (QRP I hasten to add!) as a coordination channel. The two contacts took about an hour each to complete - most of the time is spent aligning the lasers, once this is done, the CW QSO is over in a minute! Boy this stuff is FUN! I'll bring the rig along to the next Norcal meeting and try to persuade Jerry Parker to put a piccy of it up on the Norcal www page for your ammusement. Just think how far I could go with a whole 5 Watts of laser power.... :-) 72, Dave AD6AY >From owner-laser Sun Jun 15 09:14:58 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA28246; Sun, 15 Jun 97 09:14:58 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f To: bill@ietc.ca, laser@qsl.net Date: Sun, 15 Jun 1997 12:12:43 -0400 Subject: [LASER] Distance Measurements Message-Id: <19970615.121245.13166.1.K3PGP@juno.com> References: <199706151335.JAA08374@outpost.ietc.ca> X-Mailer: Juno 1.38 X-Juno-Line-Breaks: 0-19,21-32,34-35,41-42,49-50,55-56,63-64,70-71, 76-77,79-85 From: k3pgp@juno.com (John K3PGP) Reply-To: k3pgp@juno.com (John K3PGP) Sender: owner-laser@berlioz.nsc.com Precedence: bulk Bill: On Sun, 15 Jun 1997 10:35:33 -0400 Bill de Carle writes: >At 11:52 PM 6/14/97 -0400, John K3PGP wrote: > >The front-end assembly language code of COHERENT calculates the phase >of the 800-Hz tone every bit time to a precision of 0.1 degrees. Of >course if the signal is noisy there will be some error in this >measurement, but by averaging over a large number of bits and >removing the 180-degree ambiguity introduced by modulation, >we should be able to get the ultimate phase approaching within >0.1 degree or so. At 800 Hz this would be about 347 nanoseconds. >Assuming round trip, the distance to target would be resolvable to >within about 175 feet. > >If necessary we could calculate the phase to a hundredth of a degree, >but I'd have to change the ML code to do it. > >The big problem would be getting a reference phase - we'd have to find >a way for the program to measure the phase of the transmit signal as >soon as the light leaves the laser, then switch over quickly to measure the >phase of the signal being received due to reflection from the target. > >I suppose it could be done. But it sounds like extra work for me, hi! > > >73 de Bill VE2IQ > > ----- I certainly don't want to create extra work for you! However, if it's easy to display the phase to within 0.1 degree then why not put this in the program and see what I can do with it. I could aim the system at a close target, take a reading which would include any delays in the system itself, then aim it at a cloud layer or troposcatter reflection and subtract off the previous reading to get the actual delay. From this I could get an approx. distance. Since every system would have different built in delays this seems like the best way to handle it for now. This doesn't have to be a high accuracy thing. Even if it was accurate to within a mile it would be a BIG help! This would certainly be a LOT easier than what I have to go through now with my interferometer setup! None of these close in targets are far enough away to produce 1.25 ms delay. About the highest layer that I can detect any appreciable backscatter from is approx. 30 miles up. Beyond that the only useable target would have to be either a satellite or the moon! By the way, the EME experiment will have to use another system for long term integration since I am now able to detect backscatter of the laser signal from clear skies. This signal is strong enough that it will wipe out any chance of hearing a lunar reflection and is one of the reasons why I've been studying it's characteristics. I am in the process of writing some software that will use your interface but with a Tx / Rx sequencing system similar to what I used to do at radio frequencies. Something like Tx for approx. 2.5 seconds, 100 ms dead time, listen for approx. 2.5 seconds and integrate on signal, then integrate on noise only for 2.5 seconds for reference, then repeat the sequence. Progressive sequences would be stacked to allow the signal to build up while the noise is averaged. This is very similar to the technique used to get the first radar echoes from the sun back in the '60s. The problem was the massive amount of background noise present in the receiver when pointed at the sun! This system however, will be used only to confirm the presence of a lunar echo and how far below the noise floor it is. For communications I would then switch over to COHERENT! Again thanks for a great program and interface. Without it I would never have been able to confirm the presence of the backscatter signals that I am detecting. They are extremely stable but as you heard they're below the noise floor! Knowing they exist though is of great importance for my upcoming EME experiments! PS - For those of you interested in Bill's program and hardware follow the VE2IQ link from my web site! John K3PGP@juno.com http://www.qsl.net/k3pgp/index.html -==- >From owner-laser Sun Jun 15 11:49:53 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA01827; Sun, 15 Jun 97 11:49:53 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f Message-Id: <199706151743.NAA10630@outpost.ietc.ca> X-Sender: bill@ietc.ca X-Mailer: Windows Eudora Light Version 1.5.2 Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Date: Sun, 15 Jun 1997 14:44:23 -0400 To: k3pgp@juno.com (John K3PGP), laser@qsl.net, daveaa1a@ssih.com, PaulC@snet.net, cbuttsch@slonet.org From: Bill de Carle Subject: [LASER] Version 6.2 of COHERENT available Reply-To: Bill de Carle Sender: owner-laser@berlioz.nsc.com Precedence: bulk Hi folks: At the suggestion of John, K3PGP, I have added a feature to COHERENT. If you invoke the program with the SHOWPHASE parameter, it will display the measured phase angle up on the STAT screen near right side. This may be useful in computing distance to target while using lasers. Note that this is *not* an averaged value, and the angle is always shown modulo 180 degrees. For most consistent results you will want to generate your 800 Hz tone from the same reference the SD board uses to make its sampling clocks. In other words, divide the 14,400 Hz squarewave (pin 6 of the HC4060 chip) by 9 to get 1600 Hz, then divide that by 2 to get a squarewave at 800.0 Hz. Use this squarewave as your reference tone to modulate the laser. The phase displayed in the STAT window updates every second or so, and you may be able to use it to calculate the distance to a reflecting surface. One tenth of a degree of phase lag is equal to about 347 nanoseconds of propagation time. If your source of 800.0 Hz is *not* locked to the 1.8432 Mhz XTAL on the SD board, then you will see a continual drift in the phase angle at a rate proportional to the difference between the two frequencies. Unless the two crystals are absolutely on the same frequency, this will no doubt get annoying to the max, so if you haven't already done so, now would be a good time to get your 800 Hz from the SD board. Good luck. Version 6.2 is available for downloading from my web page: http://www.ietc.ca/home/bill/bbs.htm Have fun, 73 de Bill VE2IQ >From owner-laser Sun Jun 15 12:44:52 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA03163; Sun, 15 Jun 97 12:44:52 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f To: laser@qsl.net Date: Sun, 15 Jun 1997 15:41:31 -0400 Subject: [LASER] FFT Program Message-Id: <19970615.154220.6382.0.K3PGP@juno.com> X-Mailer: Juno 1.38 X-Juno-Line-Breaks: 0-1,7-8,14-15,17-20,22-24,28-29,31-34,36-43,45-46, 48-49,51-57 From: k3pgp@juno.com (John K3PGP) Reply-To: k3pgp@juno.com (John K3PGP) Sender: owner-laser@berlioz.nsc.com Precedence: bulk To anyone that's curious about laser BPSK signals: Although I was told by Bill (VE2IQ) that his program is NOT designed to work with Windows .WAV files, I have found the following to work and I thought those of you that are curious about what can be done with FFT programs might enjoy playing around with this since you don't have to buy anything! After you see it work though, I'm sure you'll want to contact Bill about getting the hardware! Follow the link on my web site to VE2IQ. Download the FFT.ZIP program. Within this archive you will find a program called FFTZZ.COM. You will also need to get the BPSK file SCATTER1.ZIP from my web site. Both are near the bottom of the LASER page. Put BOTH programs in the same directory. Although this is a DOS program it seems to work fine in a DOS window under Windows 95. Give a listen to SCATTER1.WAV first to get an appreciation for just how weak a signal you are about to process! Bring up FFTZZ.COM. #1 - It will ask for Samples per second [7200]: Type in 8000 and push ENTER. #2 - FFTlength (max=8192) 512: Type in 8192 and push ENTER. NOTE: Although the program will run faster with lower numbers, you will miss some detail by using anything lower than 8192. For instance the 120 hz signal will disappear when using 4096! The FFT length is in powers of two (8192, 4096, 2048, 1024, 512). #3 - Name of .AUD file - [use "SERIAL" for COM1]: Type in SCATTER1.WAV and push ENTER. #4 - Load: Single or Double precision ? [S]: Push ENTER #5 - Enter lowest, highest freqs of interest (max = 4000 hz): Type 0 1200 push ENTER. #6 - SPOT, INTEGRATE, CONTINUOUS? [C]: Type I then push ENTER #7 - Software AGC? (Y,N) [Y]: Push ENTER. Watch the signals come up out of the noise! Feel free to experiment with different numbers but the above will get you started. If you're interested in pursuing this matter further contact Bill (VE2IQ) for information on the hardware and software. If you need help with interfacing it to your laser system, drop me a note. John K3PGP@juno.com http://www.qsl.net/k3pgp/index.html -==- >From owner-laser Sun Jun 15 14:36:43 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA05649; Sun, 15 Jun 97 14:36:43 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f From: daveaa1a@ssih.com Date: Sun, 15 Jun 1997 17:37:02 -0400 Message-Id: <199706152137.RAA27189@ssih.com> Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Subject: [LASER] bpsk Sunday To: Bill de Carle Cc: laser@qsl.net In-Reply-To: <199706151743.NAA10630@outpost.ietc.ca> X-Mailer: SPRY Mail Version: 04.00.06.17 Reply-To: daveaa1a@ssih.com Sender: owner-laser@berlioz.nsc.com Precedence: bulk Howdy Bill, You were the only taker both days and today I used the 160m Inverted 'L' cause it always hears better on CB and 10 than my low small beam.. Let me know if you or anyone is interested in some more bpsk beacon.. Re: Laser stuff.. It's getting hot, I just changed to a Radio Shack IR LED as the receiver test gen.. It is on the old EME tower fed by 1000hz square wave with variable input.. At 50' it breaks threshold with just under 100 microamps and scope measures .9v peak leaving here.. I was using a Jumbo Red LED and it took about .8 ma to get threshold.. John is doing better and I have not tried his solution of direct PD to fet-gate input yet.. Bugs flying through the field of view sound loud though.. Maybe we can use an adopted standard, John has an IR LED 500' away with a few microamps giving him signals.. Thats the target for this week for me.. Maybe we can adopt the same measuring stick and see..eh?? 73s for now de dave >From owner-laser Sun Jun 15 18:55:37 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA11605; Sun, 15 Jun 97 18:55:37 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f Message-Id: <199706160047.UAA15623@outpost.ietc.ca> X-Sender: bill@ietc.ca X-Mailer: Windows Eudora Light Version 1.5.2 Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Date: Sun, 15 Jun 1997 21:47:56 -0400 To: laser@qsl.net From: Bill de Carle Subject: Re: [LASER] FFT Program Reply-To: Bill de Carle Sender: owner-laser@berlioz.nsc.com Precedence: bulk At 03:41 PM 6/15/97 -0400, John K3PGP wrote: >To anyone that's curious about laser BPSK signals: > >Although I was told by Bill (VE2IQ) that his program is NOT designed to >work with Windows .WAV files, I have found the following to work and I >thought those of you that are curious about what can be done with FFT >programs might enjoy playing around with this since you don't have to buy >anything! Bill (VE2IQ) stands by his cautions about this. If you want it to give the right answers you should first convert the (unsigned) 8-bit samples in the SCATTER1.WAV file to signed values. Failing to do this, you still get the spectral lines at all the right frequencies but extra noise is generated and spreads all over the place. Then you should remove the .WAV header (first 48 bytes of the file if I recall correctly) - otherwise the header info gets treated like all the other data samples and crunched into the solution. If you are integrating and the number of data samples is very large compared to the 48-byte header, the header is like a drop in the ocean; you probably wouldn't even notice anything wrong. Still makes me feel better to remove it so it won't contaminate the spectral plot. 73 de Bill VE2IQ >From owner-laser Sun Jun 15 22:29:59 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA16387; Sun, 15 Jun 97 22:29:59 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f Date: Mon, 16 Jun 1997 00:24:31 edt Message-Id: <40040@port.ve3mch.ampr.org> From: "Bob (Boudewijn) M. G. Tenty" To: laser@qsl.net Subject: [LASER]  Reply-To: "Bob (Boudewijn) M. G. Tenty" Sender: owner-laser@berlioz.nsc.com Precedence: bulk   >From owner-laser Sun Jun 15 22:55:54 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA16984; Sun, 15 Jun 97 22:55:54 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f To: bill@ietc.ca, laser@qsl.net Date: Mon, 16 Jun 1997 01:50:49 -0400 Subject: Re: [LASER] FFT Program Message-Id: <19970616.015055.10350.2.K3PGP@juno.com> References: <199706160047.UAA15623@outpost.ietc.ca> X-Mailer: Juno 1.38 X-Juno-Line-Breaks: 0-3,5-6,8-9,12-13,21-64 From: k3pgp@juno.com (John K3PGP) Reply-To: k3pgp@juno.com (John K3PGP) Sender: owner-laser@berlioz.nsc.com Precedence: bulk Bill: Agreed! That's why the disclaimer at the top of the message. :-^) Just trying to wet the appetite and get some more people interested in weak signal work. (I need a laser scatter QSO!) It doesn't cost anything to try this and it's still pretty impressive errors included! To be honest with you though, I don't see a whole lot of difference on weak signals even with the errors. On stronger signals though it's obvious things aren't exactly right! PS - The phase indicator seems to be working fine and I want to thank you for doing this patch as quickly as you did! My original calculation placed the main scatter reflection at approx. 30 miles above the earth during clear sky conditions using an interferometer technique. Using the phase indicator I come up with approx. 32 miles. As you said, it does bounce around a bit and you kind of have to average it but it's pretty handy as it is! I'll refine the accuracy after I check the phase response of my amplifier chain vs signal level tomorrow. John K3PGP@juno.com http://www.qsl.net/k3pgp/index.html ----- On Sun, 15 Jun 1997 21:47:56 -0400 Bill de Carle writes: >At 03:41 PM 6/15/97 -0400, John K3PGP wrote: >>To anyone that's curious about laser BPSK signals: >> >>Although I was told by Bill (VE2IQ) that his program is NOT designed >to >>work with Windows .WAV files, I have found the following to work and >I >>thought those of you that are curious about what can be done with FFT >>programs might enjoy playing around with this since you don't have to >buy >>anything! > >Bill (VE2IQ) stands by his cautions about this. > >If you want it to give the right answers you should first convert the >(unsigned) 8-bit samples in the SCATTER1.WAV file to signed values. >Failing to do this, you still get the spectral lines at all the right >frequencies but extra noise is generated and spreads all over the >place. > >Then you should remove the .WAV header (first 48 bytes of the file if >I recall correctly) - otherwise the header info gets treated like all >the other data samples and crunched into the solution. If you are >integrating and the number of data samples is very large compared to >the >48-byte header, the header is like a drop in the ocean; you probably >wouldn't even notice anything wrong. Still makes me feel better to >remove it so it won't contaminate the spectral plot. > >73 de Bill VE2IQ > > -==- >From owner-laser Sun Jun 15 23:41:12 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA18018; Sun, 15 Jun 97 23:41:12 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f Date: Mon, 16 Jun 1997 01:30:54 EDT Message-Id: <5072@ve3tok.ampr.org> From: "Bob (Boudewijn) M. G. Tenty" To: laser@qsl.net Subject: [LASER] Re:BPSK Reply-To: "Bob (Boudewijn) M. G. Tenty" Sender: owner-laser@berlioz.nsc.com Precedence: bulk Re: k3pgp could receive his laser beacon at 26 miles. Hi John and everybody at this list, Congratulations with your distance record. How was your laser beacon pointing? (angle) 73 - Bob HAMILTON, ON. CANADA Sysop Internet/Amprnet Gateway ve3mch +-----------------------------------------------------------------------+ | Bob(Boudewijn) M.G.Tenty - VE3TOK / PA0TOK///// //// //// / //// | | AMPRnet : ve3tok@ve3tok.ampr.org / / //// / //// | | PBBS : VE3TOK@VE3TOK.#SCON.ON.CAN.NA//// / / / | | Internet/UUCP : ve3tok@port.ve3mch.ampr.org | +-----------------------------------------------------------------------+ | Recyclable bits and bytes have been used for the message above. | +-----------------------------------------------------------------------+ World Wide Web http://www.ve3mch.ampr.org 60+ Reflectors/lists for the experimenter >From owner-laser Mon Jun 16 03:48:16 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA26005; Mon, 16 Jun 97 03:48:16 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f Date: Mon, 16 Jun 1997 06:43:58 -0400 (EDT) Message-Id: <2.2.16.19970616055125.281fa20a@mail.snet.net> X-Sender: paulc@mail.snet.net X-Mailer: Windows Eudora Pro Version 2.2 (16) Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" To: laser@qsl.net From: "Paul A. Cianciolo" Subject: Re: [LASER] FFT Program Reply-To: "Paul A. Cianciolo" Sender: owner-laser@berlioz.nsc.com Precedence: bulk >Return-Path: >X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f >To: bill@ietc.ca, laser@qsl.net >Date: Mon, 16 Jun 1997 01:50:49 -0400 >Subject: Re: [LASER] FFT Program >References: <199706160047.UAA15623@outpost.ietc.ca> >X-Juno-Line-Breaks: 0-3,5-6,8-9,12-13,21-64 >From: k3pgp@juno.com (John K3PGP) >Reply-To: k3pgp@juno.com (John K3PGP) >Sender: owner-laser@berlioz.nsc.com > Hello John, A few things are puzzling me If the scattering is the greatest lower in the atmosphere as you state in a previous post, why would returns on your laser setup come from an area precisely 32 miles up (or out). I have spoken to laser range finder manufacturers and they say that they need a range gate to keep the detector off for a specified period of time, after the pulse leaves the Xmitter or the detector will saturate from aerosol scattering that happens at close range (first few thousand feet) Another indicator of this is the visual scattering that occurs in a carbon arc spot light one sees so often in the skies these days.(nights). There is no finite cut off of the light. It either hits a cloud or slowly attenuates as it goes upward, with most of that being closest to the earth. Also As I indicated I have ordered the Coherent SD board from Bill DeCarle. When you were out at the 26 mile point how did you acquire the signal? What was your pointing strategy? What angle above the horizon were you pointing at ? \What azimuth relative to the Xmitter. What did you use for a beacon source? I will be trying to build the beacon keyer that bill suggest to use here on this end. Also the past couple of nights my RX has been quite noisy due the ambient noise from the bright moon and clear skies. Do you use a front end filter to eliminate this? Sorry for all the questions in in shot like this but I and puzzled, and I am sure some of the other guys would be intersted in this info as I am in the pursuit of NON-LOS QSO's Thanks John >PS - The phase indicator seems to be working fine and I want to thank you >for doing this patch as quickly as you did! My original calculation >placed the main scatter reflection at approx. 30 miles above the earth >during clear sky conditions using an interferometer technique. Using the >phase indicator I come up with approx. 32 miles. As you said, it does >bounce around a bit and you kind of have to average it but it's pretty >handy as it is! I'll refine the accuracy after I check the phase >response of my amplifier chain vs signal level tomorrow. > > >John >K3PGP@juno.com >http://www.qsl.net/k3pgp/index.html > >----- > >On Sun, 15 Jun 1997 21:47:56 -0400 Bill de Carle writes: >>At 03:41 PM 6/15/97 -0400, John K3PGP wrote: >>>To anyone that's curious about laser BPSK signals: >>> >>>Although I was told by Bill (VE2IQ) that his program is NOT designed >>to >>>work with Windows .WAV files, I have found the following to work and >>I >>>thought those of you that are curious about what can be done with FFT >>>programs might enjoy playing around with this since you don't have to >>buy >>>anything! >> >>Bill (VE2IQ) stands by his cautions about this. >> >>If you want it to give the right answers you should first convert the >>(unsigned) 8-bit samples in the SCATTER1.WAV file to signed values. >>Failing to do this, you still get the spectral lines at all the right >>frequencies but extra noise is generated and spreads all over the >>place. >> >>Then you should remove the .WAV header (first 48 bytes of the file if >>I recall correctly) - otherwise the header info gets treated like all >>the other data samples and crunched into the solution. If you are >>integrating and the number of data samples is very large compared to >>the >>48-byte header, the header is like a drop in the ocean; you probably >>wouldn't even notice anything wrong. Still makes me feel better to >>remove it so it won't contaminate the spectral plot. >> >>73 de Bill VE2IQ >> >> > >-==- > > 73's PaulC KB1RP >From owner-laser Mon Jun 16 06:49:14 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA00438; Mon, 16 Jun 97 06:49:14 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f Message-Id: <3.0.1.32.19970616084224.0085c300@colby.edu> X-Sender: aballen@colby.edu X-Mailer: Windows Eudora Light Version 3.0.1 (32) Date: Mon, 16 Jun 1997 08:42:24 -0500 To: laser@qsl.net From: "Art Allen, KY1K" Subject: [LASER] 30 mile high optical reflector? Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Reply-To: "Art Allen, KY1K" Sender: owner-laser@berlioz.nsc.com Precedence: bulk Hi Everyone, I have to admit, that I was reluctant to believe that a 30 or 32 mile high reflecting layer could exist! There ain't much air up there and I'm not sure how particles or ice crystals could remain suspended there for very long (without wind currents). But, we now have 2 forms of verification (bills software and john interferometry calculations). Either one of these, by itself, we might be able to question, but not BOTH... This brings up some world shaking revelations.... If we are willing to slow down the data rate, can we really do a 300 mile laser Q using the 30 mile high reflecting layer? With a reflecting layer this high, QSO's in the multiple 100's of miles should be possible, in theory, atleast. What's the ultimate capability of Bills software to dig out weak signals-can we recover a 100 db down signal if we are willing to settle for one byte per second (or one byte per minute) intergration? Maybe John should point his laser towards Maine and see if we can work (kidding of course, kinda, but....). The thing I'm really curious about is the 32 mile high reflecting layer, and WHAT IS IT? What makes laser light bounce at that altitude? Any ideas? I'm wondering if any of the big astronomy types might be able to shed light on this topic? I can probably make some phone calls to the College regarding this, although I don't think Colby has an Astronomy Professor at the moment. I can see good times on the horizon for laser experimenters and no doubt, we owe John a BIG thanks for his efforts and for posting the info. Keep dem lasers lit...Art... >From owner-laser Mon Jun 16 08:30:46 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA03446; Mon, 16 Jun 97 08:30:46 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f From: daveaa1a@ssih.com Date: Mon, 16 Jun 1997 11:30:39 -0400 Message-Id: <199706161530.LAA29002@ssih.com> Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Subject: [LASER] Receiver SNR quest To: laser@qsl.net X-Mailer: SPRY Mail Version: 04.00.06.17 Reply-To: daveaa1a@ssih.com Sender: owner-laser@berlioz.nsc.com Precedence: bulk <---- Begin Forwarded Message ----> From: daveaa1a@ssih.com Subject: Receiver SNR quest To: k3pgp@juno.com (John K3PGP) Hi John and group, The receiver quest is ON... Hi Hi, Roger on the low sense receiver John, well I was planning for daylight ops. between buildings with data etc.. Sorta like poor mans LAN.. Now you got me on this Moon Bounce Caper.. Here is new record SNR (for me anyway!!!).. The signal generator is a Radio Shack 276-143c type led IR diode and is 50' away and I get threshold (TO THE EAR) (equal sigs) at 40 microamps.. indicated at .9 vpp leaving shack via rg8x.. Let's see: 1. 50' is the adjacent leg.. 2. 4" is the opposite leg.. 3. Figuring 50% efficiency loss in diode = 20 microamps.. averaging on a .9 vpp square wave leaving the shack.. 18 microwatts to diode... 4. 45 degrees is the half power point looking away from the diode..so loose another 50 pct diode power.. 9 microwatts... 5. Looks like 9 microwatts coming to me spread out over a 1900 sq. ft. circle by the time it gets here 50' away... I see a 4" dia. worth of this circle which is .342 sq. ft. or .00018 * the 9 microwatts is .00162 microwatts.. 6. Now subtract one window pane and 50' propagation loss.. (not much) 7. This looks the equivalent of about -60dbm if it were RF.. 8. Gain another 20 db for Coherent BPSK (ala VE2IQ) and now it's starting to be a receiver.. -80dbm down.. 30 uv. sensitivity...hummm.. should probably be improved.. 9. The detector is a R/S 276-145 infrared photo transistor.. Bets are on for big improvement with PD in place of phototransistor biased correctly for NIGHT TIME USE.. K3PGP has already done this.. A couple of orders of magnitude better and we're ready for tropo OK... Now for a comparison, I hear stations 300 miles away on 2m running from 100-1000 watts in a beam say what? 30 degrees wide. What is the power density hitting my 13 element yagi?? If the two correspond within 10-20 db's then maybe I'll start agreeing with Stephen Hawking.. (if I could understand his book that is) Is my (quick) math in the ball park?? I'll settle for +/- 10 db for now.. What say out there?? 73 de daveaa1a <---- End Forwarded Message ----> >From owner-laser Mon Jun 16 08:52:18 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA04373; Mon, 16 Jun 97 08:52:18 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f To: laser@qsl.net Date: Mon, 16 Jun 1997 11:43:34 -0400 Subject: Re: [LASER] 30 mile high optical reflector? Message-Id: <19970616.114336.11334.6.K3PGP@juno.com> References: <3.0.1.32.19970616084224.0085c300@colby.edu> X-Mailer: Juno 1.38 X-Juno-Line-Breaks: 1-4,6-14,18-19,23-30 From: k3pgp@juno.com (John K3PGP) Reply-To: k3pgp@juno.com (John K3PGP) Sender: owner-laser@berlioz.nsc.com Precedence: bulk On Mon, 16 Jun 1997 08:42:24 -0500 "Art Allen, KY1K" writes: >Hi Everyone, > >I have to admit, that I was reluctant to believe that a 30 or 32 mile >high reflecting layer could exist! There ain't much air up there and I'm >not sure how particles or ice crystals could remain suspended there for >very long (without wind currents). > >But, we now have 2 forms of verification (bills software and john >interferometry calculations). Either one of these, by itself, we might >be able to question, but not BOTH... > Actually two different types of measurements by the same person is in my mind still questionable! I won't consider this proven until either someone else is able to observe it or better yet I work someone that's 200 to 300 miles away via laser scatter. As indicated in a previous (library research) post however, the fact that light can be scattered by some unknown mechanism that seems to exist in the very high regions of our atmosphere has been documented over thirty years ago. It's about time we put it to good use! John K3PGP@juno.com http://www.qsl.net/k3pgp/index.html -==- >From owner-laser Mon Jun 16 09:31:37 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA06007; Mon, 16 Jun 97 09:31:37 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f To: laser@qsl.net Date: Mon, 16 Jun 1997 12:22:47 -0400 Subject: [LASER] Test - Ignore! Message-Id: <19970616.122251.15886.1.K3PGP@juno.com> X-Mailer: Juno 1.38 X-Juno-Line-Breaks: 1-2,4-9 From: k3pgp@juno.com (John K3PGP) Reply-To: k3pgp@juno.com (John K3PGP) Sender: owner-laser@berlioz.nsc.com Precedence: bulk I seem to be having trouble getting stuff through laser@qsl.net this morning. This is a test to see if this makes it through. If it does I'll resend everything that seems to be missing! John K3PGP@juno.com http://www.qsl.net/k3pgp/index.html -==- >From owner-laser Mon Jun 16 11:08:50 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA10981; Mon, 16 Jun 97 11:08:50 PDT Date: Mon, 16 Jun 1997 12:56:04 -0500 (CDT) Message-Id: <199706161756.MAA05271@firefly.prairienet.org> From: w9sz@prairienet.org (Zack Widup) To: aballen@colby.edu Subject: Re: [LASER] 30 mile high optical reflector? Cc: laser@berlioz.nsc.com Reply-To: w9sz@prairienet.org Sender: owner-laser@berlioz.nsc.com Precedence: bulk > >Hi Everyone, > >I have to admit, that I was reluctant to believe that a 30 or 32 mile high >reflecting layer could exist! There ain't much air up there and I'm not >sure how particles or ice crystals could remain suspended there for very >long (without wind currents). > >But, we now have 2 forms of verification (bills software and john >interferometry calculations). Either one of these, by itself, we might be >able to question, but not BOTH... > >This brings up some world shaking revelations.... > >If we are willing to slow down the data rate, can we really do a 300 mile >laser Q using the 30 mile high reflecting layer? With a reflecting layer >this high, QSO's in the multiple 100's of miles should be possible, in >theory, atleast. > >What's the ultimate capability of Bills software to dig out weak >signals-can we recover a 100 db down signal if we are willing to settle for >one byte per second (or one byte per minute) intergration? > >Maybe John should point his laser towards Maine and see if we can work >(kidding of course, kinda, but....). > > >The thing I'm really curious about is the 32 mile high reflecting layer, >and WHAT IS IT? What makes laser light bounce at that altitude? Any ideas? > >I'm wondering if any of the big astronomy types might be able to shed light >on this topic? I can probably make some phone calls to the College >regarding this, although I don't think Colby has an Astronomy Professor at >the moment. > >I can see good times on the horizon for laser experimenters and no doubt, >we owe John a BIG thanks for his efforts and for posting the info. > >Keep dem lasers lit...Art... Hi Art, It may not just be "reflecting". Back in the mid-70's I participated a bit in a project at the University of Illinois which the lab I was working in as a grad student (Radio Research) did jointly with the Aeronomy lab. We built a rhodamine-6G dye laser (megawatts pulsed!) and a special Fresnel lens - PMT LIDAR telescope. The dye laser fired pulses into the upper reaches of the atmosphere and excited the D-line doublets of sodium which then returned to be picked up by the telescope. The purpose was to examine upper-atmosphere air currents and directions of flow. I haven't researched what elements up there may be excited by the wavelengths in question here, but it is possible that the same phenomenon is occurring. This may actually return a greater percentage of the laser's energy than an ordinary reflection, depending on what is up there to be excited. Just a thought! Zack W9SZ -- >From owner-laser Mon Jun 16 11:44:47 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA12955; Mon, 16 Jun 97 11:44:47 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f To: laser@qsl.net Date: Mon, 16 Jun 1997 14:20:33 -0400 Subject: [LASER] Ignore - Test Message ! Message-Id: <19970616.142035.9350.7.K3PGP@juno.com> X-Mailer: Juno 1.38 X-Juno-Line-Breaks: 0-5 From: k3pgp@juno.com (John K3PGP) Reply-To: k3pgp@juno.com (John K3PGP) Sender: owner-laser@berlioz.nsc.com Precedence: bulk Test message - Email problems - Ignore! John K3PGP@juno.com http://www.qsl.net/k3pgp/index.html -==- >From owner-laser Mon Jun 16 11:44:49 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA12957; Mon, 16 Jun 97 11:44:49 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f Date: Mon, 16 Jun 97 17:54:51 UT From: "John Yurek" Message-Id: To: laser@qsl.net Subject: [LASER] Library Research - Laser Scatter & Cloud Bounce Reply-To: "John Yurek" Sender: owner-laser@berlioz.nsc.com Precedence: bulk From: K3PGP To: laser@qsl.net Date: Mon, 16 Jun 1997 11:57:17 -0400 Subject: Library Research - Laser Scatter & Cloud Bounce Message-ID: <19970616.115840.11334.8.K3PGP@juno.com> PS - I posted this several times this morning, but it never came back from the reflector, so I'm sending it again! This is the FOURTH post! If it eventually shows up four times, my apologies! ----- To all: Before I get into more details about my laser scatter research project, I must report the following! I couldn't wait for the library to open this morning. I thought I remembered reading something pertaining to my research and it was a mad dash through many books at the library to find it, but I found it! At the time I didn't realize the significance of what I read nor the fact that it could be done with amateur type equipment and at low power levels. These signals are so weak that without computer processing I might have totally missed them! Thanks again to VE2IQ for his FFT program which was how I originally discovered these signals. ----- The first is from, "Revolution in Light" by Irwin Stamber, 1972 Page 96: "On the very first night the lidar was operated, experimenters gained new and sometimes unexpected information about the atmosphere. Myron Ligda, the hear of the Stanford Research Institute Aerophysics Laboratory, found he could detect things in the atmosphere previously observable with difficulty or not at all. Among the new data were reflections from the upper atmosphere THIRTY MILES above the earth's surface. These indicated the presence of some light reflecting layers that meteorologists had not been aware of before." ----- The second is from "LASERS, Tools of Modern Technology, 1968 Page 82: Scientists at the International Telephone and Telegraph Federation laboratories in New Jersey have tried using clouds as the reflecting medium. They found that the typical cumulus clouds can scatter the beam to a receiver more than 150 km. from the transmitter. ----- It took over thirty years but the above work has now been verified, by amateurs! All we need now is some two way activity which will be the final proof! John K3PGP@juno.com http://www.qsl.net/k3pgp/index.html -==- >From owner-laser Mon Jun 16 11:44:59 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA12975; Mon, 16 Jun 97 11:44:59 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f To: laser@qsl.net Date: Mon, 16 Jun 1997 14:15:39 -0400 Subject: [LASER] Library Research - Laser Scatter & Cloud Bounce Message-Id: <19970616.142035.9350.5.K3PGP@juno.com> X-Mailer: Juno 1.38 X-Juno-Line-Breaks: 0-5,8-13,15-16,19-20,25-29,37-41,45-47,50-56 From: k3pgp@juno.com (John K3PGP) Reply-To: k3pgp@juno.com (John K3PGP) Sender: owner-laser@berlioz.nsc.com Precedence: bulk From: K3PGP To: laser@qsl.net Date: Mon, 16 Jun 1997 11:57:17 -0400 Subject: Library Research - Laser Scatter & Cloud Bounce Message-ID: <19970616.115840.11334.8.K3PGP@juno.com> PS - I posted this SEVERAL times earlier this morning, but it never came back from the reflector, so I'm sending it again! .... and again.... and again.... till something happens! This is the fifth post. If it eventually shows up 5 times, my apologies! ----- Before I get into more details about my laser scatter research project, I must report the following! I couldn't wait for the library to open this morning. I thought I remembered reading something pertaining to my research and it was a mad dash through many books at the library to find it, but I found it! At the time I didn't realize the significance of what I read nor the fact that it could be done with amateur type equipment and at low power levels. These signals are so weak that without computer processing I might have totally missed them! Thanks again to VE2IQ for his FFT program which was how I originally discovered these signals. ----- The first is from, "Revolution in Light" by Irwin Stamber, 1972 Page 96: "On the very first night the lidar was operated, experimenters gained new and sometimes unexpected information about the atmosphere. Myron Ligda, the hear of the Stanford Research Institute Aerophysics Laboratory, found he could detect things in the atmosphere previously observable with difficulty or not at all. Among the new data were reflections from the upper atmosphere THIRTY MILES above the earth's surface. These indicated the presence of some light reflecting layers that meteorologists had not been aware of before." ----- The second is from "LASERS, Tools of Modern Technology, 1968 Page 82: Scientists at the International Telephone and Telegraph Federation laboratories in New Jersey have tried using clouds as the reflecting medium. They found that the typical cumulus clouds can scatter the beam to a receiver more than 150 km. from the transmitter. ----- It took over thirty years but the above work has now been verified, by amateurs! All we need now is some two way activity which will be the final proof! John K3PGP@juno.com http://www.qsl.net/k3pgp/index.html -==- >From owner-laser Mon Jun 16 11:44:58 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA12973; Mon, 16 Jun 97 11:44:58 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f To: laser@qsl.net Date: Mon, 16 Jun 1997 14:17:17 -0400 Subject: [LASER] Resend - Laser Scatter # 2 ! Message-Id: <19970616.142035.9350.6.K3PGP@juno.com> X-Mailer: Juno 1.38 X-Juno-Line-Breaks: 0-5,7-13,15-18,20,22-26,28,30,32-36,39-40,44-45, 50-51,59-62,64-71,76-77,83-84,93-94,98-99,105-107,109-114, 116-117,120-122,127-128,132-133,139-141,143-156 From: k3pgp@juno.com (John K3PGP) Reply-To: k3pgp@juno.com (John K3PGP) Sender: owner-laser@berlioz.nsc.com Precedence: bulk From: K3PGP To: PaulC@snet.net, laser@qsl.net Date: Mon, 16 Jun 1997 11:18:20 -0400 Subject: Re: [LASER] FFT Program Message-ID: <19970616.111822.11334.4.K3PGP@juno.com> On Mon, 16 Jun 1997 06:43:58 -0400 (EDT) "Paul A. Cianciolo" writes: >Hello John, > >A few things are puzzling me > > >If the scattering is the greatest lower in the atmosphere as you >state in a previous post, why would returns on your laser setup come from an >area precisely 32 miles up (or out). > >I have spoken to laser range finder manufacturers and they say that >they need a range gate to keep the detector off for a specified period of >time, after the pulse leaves the Xmitter or the detector will saturate from >aerosol scattering that happens at close range (first few thousand >feet) > >Another indicator of this is the visual scattering that occurs in a >carbon arc spot light one sees so often in the skies these days.(nights). >There is no finite cut off of the light. It either hits a cloud or slowly >attenuates as it goes upward, with most of that being closest to the earth. ----- Well first off either I mis-typed something or you mis-read what I typed! It's NOT precisely 32 miles, it's APPROX. 30 to 32 miles and this is the MAXIMUM distance to any observable reflection. Like all good lasers DXers I'm looking for maximum DX! The problem with these observations, as you and others have pointed out, is all the clutter from reflections closer in. Unless you provide some means to discriminate against this you will be inundated with reflections coming from everywhere including right in front of the system! The reflection from the layer that's approx. 30 miles up is only observable under extremely clear sky conditions, which we had again last night. However, even during this run I was also seeing some reflections from approx 19 miles up plus an occasional echo from 3 to 4 miles up, most likely due to some extremely fine clouds drifting by. What I find so interesting about this is the reflection that's occurring approx. 30 miles out is extremely stable and seems to be there all the time. I can't prove that it's there all the time though because of all the other reflections from stuff closer in that usually masks this much weaker signal. You can imagine the signal level change when a cloud drifts by and the path suddenly changes from a 60 mile round trip via backscatter to something more solid like a cloud that's only thousands of feet away! ----- >Also As I indicated I have ordered the Coherent SD board from Bill >DeCarle. When you were out at the 26 mile point how did you acquire the signal? What was your pointing strategy? >What angle above the horizon were you pointing at ? \What azimuth >relative to the Xmitter. > >What did you use for a beacon source? I will be trying to build the >beacon keyer that bill suggest to use here on this end. > The beacon is a 780 nm laser running into a small telescope. It is a FOCUSED laser and NOT a collimated laser. The focused laser seems to produce more backscatter signal probably because the power density is higher in the focused beam 30 miles out. It's normally focused on infinity. Actually the signal was observed from several locations. The max ground distance was approx. 26 miles. I wasn't keeping very good track of what I was doing as I only wanted to prove one thing. Either the signal is detectable or it isn't. Whether I'm 2 miles away or 30 miles away from the source doesn't seem to make any difference in signal levels which is as it should be if this is indeed backscatter! I pointed the test signal approx. 20 degrees above the NE horizon since I can hit this easily from my front porch where the laser can sit beneath an overhand on the house where it is protected from the weather. Most storms come from the West. I tried to keep the elevation angle as low as possible without hitting any obstructions as backscatter signals seem to be strongest near the horizon. I also didn't want to have to limit my observation to only locations with a good shot at the NE horizon. You can usually hit 20 degrees up from just about anyplace other than right alongside a hill! As far as acquiring the signal, it ALWAYS seemed to come from the same direction no matter where I checked it. I didn't have any readouts on the cheap TV tripod I was using but if I'd aim it NE and approx. 20 degrees up I could always find the signal in a couple of minutes. A few times I could actually hear the signal buried in the noise! Since I spent many hours copying CW signals via EME I have developed the ability to hear CW signals that are -15 to -17 dB below the noise floor. Everything has to be right for me to do this though! The only problem I have with this laser stuff is my natural in head CW filter seems to peak around 575 Hz. 800 Hz is kind of out of my range! >Also the past couple of nights my RX has been quite noisy due the >ambient noise from the bright moon and clear skies. Do you use a front end >filter to eliminate this? > This is another reason I pointed NE! The moon was to my back. I haven't had much trouble with this unless of course I point at the moon! I do have an IR filter but very seldom use it. Make sure you are controlling light scattering around inside the focusing tube. Paint it flat black, (which really isn't all that good at absorbing light!) or get some flocking paper from Edmund Sci. as suggested by Paul, KY1K. The problem is the moon, or any undesired source of light, will go through the lens even if it's way off angle and cause an image to occur on the inside wall of the focusing tube. If the wall is at all reflective it will bounce around and eventually some of it will hit your detector. Result? The noise floor comes up! If your system is properly designed you should be able to point within a couple degrees of the moon and not have this problem. Of course how close you can get depends on the active area of your detector and the focal length and diameter of your lens. In my case I am able to focus on the UNLIT part of the moon during the first and last quarter while discriminating against the brightly lit region. This kind of performance will be REQUIRED to work laser EME as there's no way I can compete with the sun! You need to build your detector setup with same care one would use to build a telescope! That is if you want max. nightime performance. >Sorry for all the questions in in shot like this but I and puzzled, >and I am sure some of the other guys would be intersted in this info as I am in >the pursuit of NON-LOS QSO's >Thanks John > >73's >PaulC KB1RP > ----- John K3PGP@juno.com http://www.qsl.net/k3pgp/index.html -==- >From owner-laser Mon Jun 16 12:07:33 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA14284; Mon, 16 Jun 97 12:07:33 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f From: daveaa1a@ssih.com Date: Mon, 16 Jun 1997 14:58:50 -0400 Message-Id: <199706161858.OAA29463@ssih.com> Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Subject: [LASER] Receiver front ends.. To: laser@qsl.net X-Mailer: SPRY Mail Version: 04.00.06.17 Reply-To: daveaa1a@ssih.com Sender: owner-laser@berlioz.nsc.com Precedence: bulk Holy Sheep Dip Brothers.. John is right.. In my haste to optimize the daylight data pipe, I took it for granted that in the dark the sensitivity would be OK.. Well it's OK for 20 mile local stuff but NOW.. OUI.. I dunno.. ReCap: PD directly into gate of mpf102 fet.. Gonna try mgf1302 too.. Use lotsa decoupling, THEN feed to input to Op-Amp.. Treat the circuit like it's UHF or higher.. Avoid oscillations, but I would like to see a controlled super-regen. detector here.. When the diode gets real dark locally, this thing gets hot.. Next step is to try a potentiometer bias/bypass combo to the cold side of the PD for several conditions: 1. Daylight, (crummy) local data only..In the dark or at Noonday.. 2. Overdrive, (sensitive) good for some DX.. 3. Dark, (noise dive) EME, troposcatter ??? Stealthy, quiet workhorse.. Anybody got a lead on some APD's ?? 73s de daveaa1a KEEP THE LIGHTs ON.. <---- End Forwarded Message ----> >From owner-laser Mon Jun 16 13:43:18 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA19259; Mon, 16 Jun 97 13:43:18 PDT To: laser@berlioz.nsc.com Date: Mon, 16 Jun 1997 16:06:36 -0400 Subject: who laser Message-Id: <19970616.160638.14678.1.K3PGP@juno.com> X-Mailer: Juno 1.38 X-Juno-Line-Breaks: 0 From: k3pgp@juno.com (John K3PGP) Sender: owner-laser@berlioz.nsc.com Precedence: bulk who laser >From owner-laser Mon Jun 16 13:52:43 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA19765; Mon, 16 Jun 97 13:52:43 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f To: laser@qsl.net Date: Mon, 16 Jun 1997 16:09:37 -0400 Subject: [LASER] Ignore - Test Message ? Message-Id: <19970616.160938.14678.2.K3PGP@juno.com> X-Mailer: Juno 1.38 X-Juno-Line-Breaks: 0-5 From: k3pgp@juno.com (John K3PGP) Reply-To: k3pgp@juno.com (John K3PGP) Sender: owner-laser@berlioz.nsc.com Precedence: bulk No response from the reflector? What's up? John K3PGP@juno.com http://www.qsl.net/k3pgp/index.html -==- >From owner-laser Mon Jun 16 14:14:32 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA21058; Mon, 16 Jun 97 14:14:32 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f To: laser@qsl.net, aballen@colby.edu Date: Mon, 16 Jun 1997 10:36:39 -0400 Subject: [LASER] Library Research - Laser Scatter & Cloud Bounce Message-Id: <19970616.103641.11334.2.K3PGP@juno.com> X-Mailer: Juno 1.38 X-Juno-Line-Breaks: 0-1,3-4,7-8,13-18,26-30,34-36,39-45 From: k3pgp@juno.com (John K3PGP) Reply-To: k3pgp@juno.com (John K3PGP) Sender: owner-laser@berlioz.nsc.com Precedence: bulk To all: Before I get into more details about my laser scatter research project, I must report the following! I couldn't wait for the library to open this morning. I thought I remembered reading something pertaining to my research and it was a mad dash through many books at the library to find it, but I found it! At the time I didn't realize the significance of what I read nor the fact that it could be done with amateur type equipment and at low power levels. These signals are so weak that without computer processing I might have totally missed them! Thanks again to VE2IQ for his FFT program which was how I originally discovered these signals. ----- The first is from, "Revolution in Light" by Irwin Stamber, 1972 Page 96: "On the very first night the lidar was operated, experimenters gained new and sometimes unexpected information about the atmosphere. Myron Ligda, the hear of the Stanford Research Institute Aerophysics Laboratory, found he could detect things in the atmosphere previously observable with difficulty or not at all. Among the new data were reflections from the upper atmosphere THIRTY MILES above the earth's surface. These indicated the presence of some light reflecting layers that meteorologists had not been aware of before." ----- The second is from "LASERS, Tools of Modern Technology, 1968 Page 82: Scientists at the International Telephone and Telegraph Federation laboratories in New Jersey have tried using clouds as the reflecting medium. They found that the typical cumulus clouds can scatter the beam to a receiver more than 150 km. from the transmitter. ----- It took over thirty years but the above work has now been verified, by amateurs! All we need now is some two way activity which will be the final proof! John K3PGP@juno.com http://www.qsl.net/k3pgp/index.html -==- >From owner-laser Mon Jun 16 15:25:48 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA24598; Mon, 16 Jun 97 15:25:48 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f To: PaulC@snet.net, laser@qsl.net Date: Mon, 16 Jun 1997 11:18:20 -0400 Subject: Re: [LASER] FFT Program Message-Id: <19970616.111822.11334.4.K3PGP@juno.com> References: <2.2.16.19970616055125.281fa20a@mail.snet.net> X-Mailer: Juno 1.38 X-Juno-Line-Breaks: 1-7,9-12,14,16-20,22,24,26-30,33-34,38-39,44-45, 53-56,58-65,70-71,77-78,87-88,92-93,99-101,103-108,110-111, 114-116,121-122,126-127,133-135,137-150 From: k3pgp@juno.com (John K3PGP) Reply-To: k3pgp@juno.com (John K3PGP) Sender: owner-laser@berlioz.nsc.com Precedence: bulk On Mon, 16 Jun 1997 06:43:58 -0400 (EDT) "Paul A. Cianciolo" writes: >Hello John, > >A few things are puzzling me > > >If the scattering is the greatest lower in the atmosphere as you >state in a previous post, why would returns on your laser setup come from an >area precisely 32 miles up (or out). > >I have spoken to laser range finder manufacturers and they say that >they need a range gate to keep the detector off for a specified period of >time, after the pulse leaves the Xmitter or the detector will saturate from >aerosol scattering that happens at close range (first few thousand >feet) > >Another indicator of this is the visual scattering that occurs in a >carbon arc spot light one sees so often in the skies these days.(nights). >There is no finite cut off of the light. It either hits a cloud or slowly >attenuates as it goes upward, with most of that being closest to the earth. ----- Well first off either I mis-typed something or you mis-read what I typed! It's NOT precisely 32 miles, it's APPROX. 30 to 32 miles and this is the MAXIMUM distance to any observable reflection. Like all good lasers DXers I'm looking for maximum DX! The problem with these observations, as you and others have pointed out, is all the clutter from reflections closer in. Unless you provide some means to discriminate against this you will be inundated with reflections coming from everywhere including right in front of the system! The reflection from the layer that's approx. 30 miles up is only observable under extremely clear sky conditions, which we had again last night. However, even during this run I was also seeing some reflections from approx 19 miles up plus an occasional echo from 3 to 4 miles up, most likely due to some extremely fine clouds drifting by. What I find so interesting about this is the reflection that's occurring approx. 30 miles out is extremely stable and seems to be there all the time. I can't prove that it's there all the time though because of all the other reflections from stuff closer in that usually masks this much weaker signal. You can imagine the signal level change when a cloud drifts by and the path suddenly changes from a 60 mile round trip via backscatter to something more solid like a cloud that's only thousands of feet away! ----- >Also As I indicated I have ordered the Coherent SD board from Bill >DeCarle. When you were out at the 26 mile point how did you acquire the signal? What was your pointing strategy? >What angle above the horizon were you pointing at ? \What azimuth >relative to the Xmitter. > >What did you use for a beacon source? I will be trying to build the >beacon keyer that bill suggest to use here on this end. > The beacon is a 780 nm laser running into a small telescope. It is a FOCUSED laser and NOT a collimated laser. The focused laser seems to produce more backscatter signal probably because the power density is higher in the focused beam 30 miles out. It's normally focused on infinity. Actually the signal was observed from several locations. The max ground distance was approx. 26 miles. I wasn't keeping very good track of what I was doing as I only wanted to prove one thing. Either the signal is detectable or it isn't. Whether I'm 2 miles away or 30 miles away from the source doesn't seem to make any difference in signal levels which is as it should be if this is indeed backscatter! I pointed the test signal approx. 20 degrees above the NE horizon since I can hit this easily from my front porch where the laser can sit beneath an overhand on the house where it is protected from the weather. Most storms come from the West. I tried to keep the elevation angle as low as possible without hitting any obstructions as backscatter signals seem to be strongest near the horizon. I also didn't want to have to limit my observation to only locations with a good shot at the NE horizon. You can usually hit 20 degrees up from just about anyplace other than right alongside a hill! As far as acquiring the signal, it ALWAYS seemed to come from the same direction no matter where I checked it. I didn't have any readouts on the cheap TV tripod I was using but if I'd aim it NE and approx. 20 degrees up I could always find the signal in a couple of minutes. A few times I could actually hear the signal buried in the noise! Since I spent many hours copying CW signals via EME I have developed the ability to hear CW signals that are -15 to -17 dB below the noise floor. Everything has to be right for me to do this though! The only problem I have with this laser stuff is my natural in head CW filter seems to peak around 575 Hz. 800 Hz is kind of out of my range! >Also the past couple of nights my RX has been quite noisy due the >ambient noise from the bright moon and clear skies. Do you use a front end >filter to eliminate this? > This is another reason I pointed NE! The moon was to my back. I haven't had much trouble with this unless of course I point at the moon! I do have an IR filter but very seldom use it. Make sure you are controlling light scattering around inside the focusing tube. Paint it flat black, (which really isn't all that good at absorbing light!) or get some flocking paper from Edmund Sci. as suggested by Paul, KY1K. The problem is the moon, or any undesired source of light, will go through the lens even if it's way off angle and cause an image to occur on the inside wall of the focusing tube. If the wall is at all reflective it will bounce around and eventually some of it will hit your detector. Result? The noise floor comes up! If your system is properly designed you should be able to point within a couple degrees of the moon and not have this problem. Of course how close you can get depends on the active area of your detector and the focal length and diameter of your lens. In my case I am able to focus on the UNLIT part of the moon during the first and last quarter while discriminating against the brightly lit region. This kind of performance will be REQUIRED to work laser EME as there's no way I can compete with the sun! You need to build your detector setup with same care one would use to build a telescope! That is if you want max. nightime performance. >Sorry for all the questions in in shot like this but I and puzzled, >and I am sure some of the other guys would be intersted in this info as I am in >the pursuit of NON-LOS QSO's >Thanks John > >73's >PaulC KB1RP > ----- John K3PGP@juno.com http://www.qsl.net/k3pgp/index.html -==- >From owner-laser Mon Jun 16 15:22:40 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA24474; Mon, 16 Jun 97 15:22:40 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f To: laser@qsl.net Date: Mon, 16 Jun 1997 11:57:17 -0400 Subject: [LASER] Library Research - Laser Scatter & Cloud Bounce Message-Id: <19970616.115840.11334.8.K3PGP@juno.com> X-Mailer: Juno 1.38 X-Juno-Line-Breaks: 1-6,8-9,12-13,18-23,31-35,39-41,44-50 From: k3pgp@juno.com (John K3PGP) Reply-To: k3pgp@juno.com (John K3PGP) Sender: owner-laser@berlioz.nsc.com Precedence: bulk PS - I posted this earlier this morning, but it never came back from the reflector, so I'm sending it again! ----- To all: Before I get into more details about my laser scatter research project, I must report the following! I couldn't wait for the library to open this morning. I thought I remembered reading something pertaining to my research and it was a mad dash through many books at the library to find it, but I found it! At the time I didn't realize the significance of what I read nor the fact that it could be done with amateur type equipment and at low power levels. These signals are so weak that without computer processing I might have totally missed them! Thanks again to VE2IQ for his FFT program which was how I originally discovered these signals. ----- The first is from, "Revolution in Light" by Irwin Stamber, 1972 Page 96: "On the very first night the lidar was operated, experimenters gained new and sometimes unexpected information about the atmosphere. Myron Ligda, the hear of the Stanford Research Institute Aerophysics Laboratory, found he could detect things in the atmosphere previously observable with difficulty or not at all. Among the new data were reflections from the upper atmosphere THIRTY MILES above the earth's surface. These indicated the presence of some light reflecting layers that meteorologists had not been aware of before." ----- The second is from "LASERS, Tools of Modern Technology, 1968 Page 82: Scientists at the International Telephone and Telegraph Federation laboratories in New Jersey have tried using clouds as the reflecting medium. They found that the typical cumulus clouds can scatter the beam to a receiver more than 150 km. from the transmitter. ----- It took over thirty years but the above work has now been verified, by amateurs! All we need now is some two way activity which will be the final proof! John K3PGP@juno.com http://www.qsl.net/k3pgp/index.html -==- >From owner-laser Mon Jun 16 16:25:16 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA27944; Mon, 16 Jun 97 16:25:16 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f Date: Mon, 16 Jun 1997 19:24:50 -0400 (EDT) From: "C. W. Wright" X-Sender: wright@twc2.betaweb.com To: daveaa1a@ssih.com Cc: laser@qsl.net Subject: [LASER] APD detectors... In-Reply-To: <199706161858.OAA29463@ssih.com> Message-Id: Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Reply-To: "C. W. Wright" Sender: owner-laser@berlioz.nsc.com Precedence: bulk I just ordered some APDs. Heres' the details on a couple of them: S2381 APD 1000 mhz cut-off $67.51 each S2383 APD 600Mhz cut-off $132.39 S5343 APD Blue Enhanced 250 mhz cut-off $132.39 Here's one of their US Sales offices: Hamamatsu Photonics 360 Foothill Road P.O. Box 6910 Bridgewater Nj. 08807-0910 http://www.hamamatsu.com Phone: 908-231-0960 Fax: 908-231-0405 -Wayne >From owner-laser Mon Jun 16 16:24:02 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA27883; Mon, 16 Jun 97 16:24:02 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f Date: Mon, 16 Jun 1997 16:18:12 -0700 (PDT) From: Walter Miller X-Sender: aj6t@slip-3 To: "Paul A. Cianciolo" Cc: laser@qsl.net, k3pgp@juno.com Subject: Re: [LASER] RX improvement In-Reply-To: <2.2.16.19970614065536.26c7482e@mail.snet.net> Message-Id: Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Reply-To: Walter Miller Sender: owner-laser@berlioz.nsc.com Precedence: bulk Hello Paul and the laser group, Very interesting to read about your laser scatter success. I have a couple of questions for you (perhaps I missed some of your equipment details in earlier posts): 1. What feedback resistor are you using on the OPT210? I currently have mine up to 88 megohms, and I dont think that my setup is anywhere close to sensitive enough to see lidar returns off the clouds (using a Celestron C90 telescope as my receive optics). 2. What kind of post-OPT210 amp are you using? 3. How far out of the noise are your returned signals? 73, Walt ------------------------------------------------------------------------ Walter Miller, AJ6T Saratoga, CA USA CM87 Reply to aj6t@slip.net >From owner-laser Mon Jun 16 17:00:04 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA00383; Mon, 16 Jun 97 17:00:04 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f To: laser@qsl.net Date: Mon, 16 Jun 1997 19:01:04 -0400 Subject: Re: [LASER] Receiver front ends.. Message-Id: <19970616.190106.23126.1.K3PGP@juno.com> References: <199706161858.OAA29463@ssih.com> X-Mailer: Juno 1.38 X-Juno-Line-Breaks: 0-1,3-4,7-10,12-13,15-39 From: k3pgp@juno.com (John K3PGP) Reply-To: k3pgp@juno.com (John K3PGP) Sender: owner-laser@berlioz.nsc.com Precedence: bulk Dave: Uh-huh, and you thought your receiver was hot before! I wonder how many other "HOT" front ends out there are actually dead! When you're done with it let me know how many dB SNR you picked up on night time mode. Remember to optimize everything under dark conditions with a weak signal and for max SNR and NOT gain! Let me know when you're ready to work PA on tropo-scatter! PS - There was a problem at qsl.net with the Email reflectors just before noon today. Problem seems to be fixed now! And watch that Sheep Dip. It's no good on chips! (Unless you're talking buffalo chips! :-^) John K3PGP@juno.com http://www.qsl.net/k3pgp/index.html ----- On Mon, 16 Jun 1997 14:58:50 -0400 daveaa1a@ssih.com writes: > > >Holy Sheep Dip Brothers.. > >John is right.. In my haste to optimize the daylight data pipe, >I took it for granted that in the dark the sensitivity would be OK.. >Well it's OK for 20 mile local stuff but NOW.. OUI.. I dunno.. >~~~~~ >73s de daveaa1a > >KEEP THE LIGHTs ON.. ><---- End Forwarded Message ----> > -==- >From owner-laser Mon Jun 16 17:34:06 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA02436; Mon, 16 Jun 97 17:34:06 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f To: laser@qsl.net Date: Mon, 16 Jun 1997 13:07:45 -0400 Subject: [LASER] Library Research - Laser Scatter & Cloud Bounce Message-Id: <19970616.130747.15886.2.K3PGP@juno.com> X-Mailer: Juno 1.38 X-Juno-Line-Breaks: 0-5,7-8,10-15,17-18,21-22,27-32,40-44,48-50,53-59 From: k3pgp@juno.com (John K3PGP) Reply-To: k3pgp@juno.com (John K3PGP) Sender: owner-laser@berlioz.nsc.com Precedence: bulk From: K3PGP To: laser@qsl.net Date: Mon, 16 Jun 1997 11:57:17 -0400 Subject: Library Research - Laser Scatter & Cloud Bounce Message-ID: <19970616.115840.11334.8.K3PGP@juno.com> PS - I posted this earlier this morning, but it never came back from the reflector, so I'm sending it again! This is the third post. If it eventually shows up three times, my apologies! ----- To all: Before I get into more details about my laser scatter research project, I must report the following! I couldn't wait for the library to open this morning. I thought I remembered reading something pertaining to my research and it was a mad dash through many books at the library to find it, but I found it! At the time I didn't realize the significance of what I read nor the fact that it could be done with amateur type equipment and at low power levels. These signals are so weak that without computer processing I might have totally missed them! Thanks again to VE2IQ for his FFT program which was how I originally discovered these signals. ----- The first is from, "Revolution in Light" by Irwin Stamber, 1972 Page 96: "On the very first night the lidar was operated, experimenters gained new and sometimes unexpected information about the atmosphere. Myron Ligda, the hear of the Stanford Research Institute Aerophysics Laboratory, found he could detect things in the atmosphere previously observable with difficulty or not at all. Among the new data were reflections from the upper atmosphere THIRTY MILES above the earth's surface. These indicated the presence of some light reflecting layers that meteorologists had not been aware of before." ----- The second is from "LASERS, Tools of Modern Technology, 1968 Page 82: Scientists at the International Telephone and Telegraph Federation laboratories in New Jersey have tried using clouds as the reflecting medium. They found that the typical cumulus clouds can scatter the beam to a receiver more than 150 km. from the transmitter. ----- It took over thirty years but the above work has now been verified, by amateurs! All we need now is some two way activity which will be the final proof! John K3PGP@juno.com http://www.qsl.net/k3pgp/index.html -==- >From owner-laser Mon Jun 16 18:10:05 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA04267; Mon, 16 Jun 97 18:10:05 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f Date: Mon, 16 Jun 1997 21:04:46 -0400 (EDT) From: "C. W. Wright" X-Sender: wright@twc2.betaweb.com To: "Art Allen, KY1K" Cc: laser@qsl.net Subject: Re: [LASER] 30 mile high optical reflector? In-Reply-To: <3.0.1.32.19970616084224.0085c300@colby.edu> Message-Id: Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Reply-To: "C. W. Wright" Sender: owner-laser@berlioz.nsc.com Precedence: bulk Hi Guys, I may be calculating this wrong.. But given the geometry John described where his transmitter was at ~20 degrees above the horz, and the receiver also at 20 degrees and I "ASSUMED" they were directed toward each other with approx. 26 statue miles betwee them. Give that, I calculated that the tx beam would intersect the rx F.O.V at roughly 24,500 feet altitude. TO calculate it, I used the formula y = r*sin(angle) or with the actual values altitude = 13 * sin(20) which gives 4.45 miles of altitude * 5280ft/mile or 23,476 feet altitude. The 13 is half the 26 mile separation. It's also in the ballpark of the "top of the haze" which is quite pronounced when observed from flight. For the altitude to be 30 miles given a 26 mile separation, I calculate the angle above the horz should be 66.5 degrees above the horz. That calculated by: angle = atan ( 30/13) where the 30 is the height and the 13 is half the separation again. the formula is just what I barely remember from trig with oscar, apples and things. I used the Tan-of-angle is equal to opposite / adj. sides of a triangle. All this assumes a flat earth, near perfect measurement of the inclination angle of the actual beam and receiver optics. I also assume he directed the tx and rx toward each other so they would see forward scatter. I'm not into math and I could easily be calculating it wrong. No matter what though, 26 nm tx to rx with only atmospheric scatter, diode detectors, is very very good work indeed. There's an airborne experiment called "Dial Lidar" which uses two very high powered ( several joules ) at multiple wavelengths to probe upward from an airborne platform. The project scientist is "Ed Browell" from Langley Research center. If you search altavista, I'm sure you can find reference to his work and most probably some actual backscatter graphs as a function of altitude. You might even start at www.nasa.gov then go to langley form there. He's also published tons of papers on atmospheric back scatter. :-) Wayne >From owner-laser Mon Jun 16 19:04:52 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA06997; Mon, 16 Jun 97 19:04:52 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f To: laser@qsl.net Date: Mon, 16 Jun 1997 13:07:45 -0400 Subject: [LASER] Library Research - Laser Scatter & Cloud Bounce Message-Id: <19970616.130747.15886.2.K3PGP@juno.com> X-Mailer: Juno 1.38 X-Juno-Line-Breaks: 0-5,7-8,10-15,17-18,21-22,27-32,40-44,48-50,53-59 From: k3pgp@juno.com (John K3PGP) Reply-To: k3pgp@juno.com (John K3PGP) Sender: owner-laser@berlioz.nsc.com Precedence: bulk From: K3PGP To: laser@qsl.net Date: Mon, 16 Jun 1997 11:57:17 -0400 Subject: Library Research - Laser Scatter & Cloud Bounce Message-ID: <19970616.115840.11334.8.K3PGP@juno.com> PS - I posted this earlier this morning, but it never came back from the reflector, so I'm sending it again! This is the third post. If it eventually shows up three times, my apologies! ----- To all: Before I get into more details about my laser scatter research project, I must report the following! I couldn't wait for the library to open this morning. I thought I remembered reading something pertaining to my research and it was a mad dash through many books at the library to find it, but I found it! At the time I didn't realize the significance of what I read nor the fact that it could be done with amateur type equipment and at low power levels. These signals are so weak that without computer processing I might have totally missed them! Thanks again to VE2IQ for his FFT program which was how I originally discovered these signals. ----- The first is from, "Revolution in Light" by Irwin Stamber, 1972 Page 96: "On the very first night the lidar was operated, experimenters gained new and sometimes unexpected information about the atmosphere. Myron Ligda, the hear of the Stanford Research Institute Aerophysics Laboratory, found he could detect things in the atmosphere previously observable with difficulty or not at all. Among the new data were reflections from the upper atmosphere THIRTY MILES above the earth's surface. These indicated the presence of some light reflecting layers that meteorologists had not been aware of before." ----- The second is from "LASERS, Tools of Modern Technology, 1968 Page 82: Scientists at the International Telephone and Telegraph Federation laboratories in New Jersey have tried using clouds as the reflecting medium. They found that the typical cumulus clouds can scatter the beam to a receiver more than 150 km. from the transmitter. ----- It took over thirty years but the above work has now been verified, by amateurs! All we need now is some two way activity which will be the final proof! John K3PGP@juno.com http://www.qsl.net/k3pgp/index.html -==- >From owner-laser Mon Jun 16 18:56:47 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA06625; Mon, 16 Jun 97 18:56:47 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f To: laser@qsl.net Date: Mon, 16 Jun 1997 19:01:04 -0400 Subject: Re: [LASER] Receiver front ends.. Message-Id: <19970616.190106.23126.1.K3PGP@juno.com> References: <199706161858.OAA29463@ssih.com> X-Mailer: Juno 1.38 X-Juno-Line-Breaks: 0-1,3-4,7-10,12-13,15-39 From: k3pgp@juno.com (John K3PGP) Reply-To: k3pgp@juno.com (John K3PGP) Sender: owner-laser@berlioz.nsc.com Precedence: bulk Dave: Uh-huh, and you thought your receiver was hot before! I wonder how many other "HOT" front ends out there are actually dead! When you're done with it let me know how many dB SNR you picked up on night time mode. Remember to optimize everything under dark conditions with a weak signal and for max SNR and NOT gain! Let me know when you're ready to work PA on tropo-scatter! PS - There was a problem at qsl.net with the Email reflectors just before noon today. Problem seems to be fixed now! And watch that Sheep Dip. It's no good on chips! (Unless you're talking buffalo chips! :-^) John K3PGP@juno.com http://www.qsl.net/k3pgp/index.html ----- On Mon, 16 Jun 1997 14:58:50 -0400 daveaa1a@ssih.com writes: > > >Holy Sheep Dip Brothers.. > >John is right.. In my haste to optimize the daylight data pipe, >I took it for granted that in the dark the sensitivity would be OK.. >Well it's OK for 20 mile local stuff but NOW.. OUI.. I dunno.. >~~~~~ >73s de daveaa1a > >KEEP THE LIGHTs ON.. ><---- End Forwarded Message ----> > -==- >From owner-laser Mon Jun 16 20:41:52 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA11612; Mon, 16 Jun 97 20:41:52 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f To: laser@qsl.net Date: Mon, 16 Jun 1997 22:40:09 -0400 Subject: [LASER] Weather Pictures Message-Id: <19970616.224011.3910.4.K3PGP@juno.com> X-Mailer: Juno 1.38 X-Juno-Line-Breaks: 1-2,4-5,7-8,10-16 From: k3pgp@juno.com (John K3PGP) Reply-To: k3pgp@juno.com (John K3PGP) Sender: owner-laser@berlioz.nsc.com Precedence: bulk Those of you that are into watching weather patterns and cloud clover might be interested in playing around with Earth View Expert. It's accessible from the link page of my web site near the bottom under Weather. I didn't play around with it very much but it seems to allow one to get pictures of weather patterns from Geosync Wx satellites! Remember to refresh your browser otherwise you might be looking at an old page cached on your hard drive! John K3PGP@juno.com http://www.qsl.net/k3pgp/index.html -==- >From owner-laser Mon Jun 16 20:55:17 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA12221; Mon, 16 Jun 97 20:55:17 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f To: laser@qsl.net Date: Mon, 16 Jun 1997 22:16:13 -0400 Subject: [LASER] Email Problems Message-Id: <19970616.221616.3910.1.K3PGP@juno.com> X-Mailer: Juno 1.38 X-Juno-Line-Breaks: 1-2,4-5,8-9,13-14,16-26 From: k3pgp@juno.com (John K3PGP) Reply-To: k3pgp@juno.com (John K3PGP) Sender: owner-laser@berlioz.nsc.com Precedence: bulk I apologize for all the multiple posts that laser@qsl.net is now spitting out. Something happened this morning and it appears ALL of the Email reflectors went down sometime around noon today. Late this afternoon I got a bunch of error messages, some kind of a message about the system being reset, then a whole bunch of error messages about outgoing Email not being able to be delivered. Now I'm getting multiple copies of Email messages that should have cleared the system hours ago. I think I now have something like 16 or more copies of one piece of Email that I sent once! You don't even want to know about the ones I sent multiple times! Hopefully all of this will clear out this evening and we can get back to 'normal' operation. Again I'm sorry for all the clutter! Just dump everything you have multiple copies of... John K3PGP@juno.com http://www.qsl.net/k3pgp/index.html -==- >From owner-laser Mon Jun 16 21:55:06 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA14855; Mon, 16 Jun 97 21:55:06 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f To: wright@web-span.com, laser@qsl.net, aballen@colby.edu Date: Mon, 16 Jun 1997 22:08:09 -0400 Subject: Re: [LASER] 30 mile high optical reflector? Message-Id: <19970616.220811.3910.0.K3PGP@juno.com> References: X-Mailer: Juno 1.38 X-Juno-Line-Breaks: 0-1,3-8,10,12,14-15,19-20,24-25,27-90 From: k3pgp@juno.com (John K3PGP) Reply-To: k3pgp@juno.com (John K3PGP) Sender: owner-laser@berlioz.nsc.com Precedence: bulk Wayne: On Mon, 16 Jun 1997 21:04:46 -0400 (EDT) "C. W. Wright" writes: > > >Hi Guys, > >I may be calculating this wrong.. But given the geometry John >described where his transmitter was at ~20 degrees above the horz, and the >receiver also at 20 degrees and I "ASSUMED" they were directed toward each >other with approx. 26 statue miles betwee them. Give that, I calculated BOTH the transmitter and receiver were pointed North East and approx. 20 degrees above the horizon. NOT at each other! I have never been able to hear anything by pointing back toward the transmitter when using this low an elevation! My portable receiver has NO calibrations on either Elevation or Azimuth so these are only approx. numbers. Probably +- 10 degrees Az and +- a couple of degrees in Elevation. I didn't keep real good track of this since I don't have any calibrations on the cheap TV tripod I was using. You might want to re-read the previous post. Sorry if it I didn't word things more clearly. John K3PGP@juno.com http://www.qsl.net/k3pgp/index.html ----- On Mon, 16 Jun 1997 06:43:58 -0400 (EDT) "Paul A. Cianciolo" > writes: >>Also As I indicated I have ordered the Coherent SD board from Bill >>DeCarle. When you were out at the 26 mile point how did you acquire >the signal? What was your pointing strategy? >>What angle above the horizon were you pointing at ? \What azimuth >>relative to the Xmitter. >> >>What did you use for a beacon source? I will be trying to build the > >>beacon keyer that bill suggest to use here on this end. >> On Mon, 16 Jun 1997 11:18:20 -0400 K3PGP writes: > >The beacon is a 780 nm laser running into a small telescope. It is a >FOCUSED laser and NOT a collimated laser. The focused laser seems to >produce more backscatter signal probably because the power density is >higher in the focused beam 30 miles out. It's normally focused on >infinity. > >Actually the signal was observed from several locations. The max >ground distance was approx. 26 miles. I wasn't keeping very good >track of what I was doing as I only wanted to prove one thing. Either >the signal is detectable or it isn't. Whether I'm 2 miles away or 30 >miles away from the source doesn't seem to make any difference in >signal levels which is as it should be if this is indeed backscatter! > >I pointed the test signal approx. 20 degrees above the NE horizon >since I can hit this easily from my front porch where the laser can >sit beneath an overhand on the house where it is protected from the >weather. Most storms come from the West. I tried to keep the >elevation angle as low as possible without hitting any obstructions as >backscatter signals seem to be strongest near the horizon. I also >didn't want to have to limit my observation to only locations with a >good shot at the NE horizon. You can usually hit 20 degrees up from >just about anyplace other than right alongside a hill! > >As far as acquiring the signal, it ALWAYS seemed to come from the same >direction no matter where I checked it. I didn't have any readouts on >the cheap TV tripod I was using but if I'd aim it NE and approx. 20 >degrees up I could always find the signal in a couple of minutes. > >A few times I could actually hear the signal buried in the noise! >Since I spent many hours copying CW signals via EME I have developed >the ability to hear CW signals that are -15 to -17 dB below the noise >floor. Everything has to be right for me to do this though! The only >problem I have with this laser stuff is my natural in head CW filter >seems to peak around 575 Hz. 800 Hz is kind of out of my range! > > >John >K3PGP@juno.com >http://www.qsl.net/k3pgp/index.html -==- >From owner-laser Mon Jun 16 22:10:00 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA15539; Mon, 16 Jun 97 22:10:00 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f To: laser@qsl.net Date: Tue, 17 Jun 1997 00:32:26 -0400 Subject: Re: [LASER] 30 mile high optical reflector? Message-Id: <19970617.003228.16726.4.K3PGP@juno.com> References: X-Mailer: Juno 1.38 X-Juno-Line-Breaks: 1-6,8,10-16,18-24 From: k3pgp@juno.com (John K3PGP) Reply-To: k3pgp@juno.com (John K3PGP) Sender: owner-laser@berlioz.nsc.com Precedence: bulk On Mon, 16 Jun 1997 21:04:46 -0400 (EDT) "C. W. Wright" writes: > > >Hi Guys, > >I may be calculating this wrong.. But given the geometry John >described where his transmitter was at ~20 degrees above the horz, and the >receiver also at 20 degrees and I "ASSUMED" they were directed toward each >other with approx. 26 statue miles betwee them. >:-) Wayne > Wayne: Both Tx and Rx aimed North East and NOT at each other. See previous post! John K3PGP@juno.com http://www.qsl.net/k3pgp/index.html -==- >From owner-laser Tue Jun 17 01:20:28 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA24997; Tue, 17 Jun 97 01:20:28 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f To: laser@qsl.net Date: Mon, 16 Jun 1997 17:18:47 -0400 Subject: [LASER] Library Research - Laser Scatter & Cloud Bounce Message-Id: <19970616.171849.14678.8.K3PGP@juno.com> X-Mailer: Juno 1.38 X-Juno-Line-Breaks: 0-5,8-13,15-16,19-20,25-29,37-41,45-47,50-56 From: k3pgp@juno.com (John K3PGP) Reply-To: k3pgp@juno.com (John K3PGP) Sender: owner-laser@berlioz.nsc.com Precedence: bulk From: K3PGP To: laser@qsl.net Date: Mon, 16 Jun 1997 11:57:17 -0400 Subject: Library Research - Laser Scatter & Cloud Bounce Message-ID: <19970616.115840.11334.8.K3PGP@juno.com> PS - I posted this SEVERAL times earlier this morning, but it never came back from the reflector, so I'm sending it again! .... and again.... and again.... till something happens! This is the SIXTH post. If it eventually shows up 6 times, my apologies! ----- Before I get into more details about my laser scatter research project, I must report the following! I couldn't wait for the library to open this morning. I thought I remembered reading something pertaining to my research and it was a mad dash through many books at the library to find it, but I found it! At the time I didn't realize the significance of what I read nor the fact that it could be done with amateur type equipment and at low power levels. These signals are so weak that without computer processing I might have totally missed them! Thanks again to VE2IQ for his FFT program which was how I originally discovered these signals. ----- The first is from, "Revolution in Light" by Irwin Stamber, 1972 Page 96: "On the very first night the lidar was operated, experimenters gained new and sometimes unexpected information about the atmosphere. Myron Ligda, the hear of the Stanford Research Institute Aerophysics Laboratory, found he could detect things in the atmosphere previously observable with difficulty or not at all. Among the new data were reflections from the upper atmosphere THIRTY MILES above the earth's surface. These indicated the presence of some light reflecting layers that meteorologists had not been aware of before." ----- The second is from "LASERS, Tools of Modern Technology, 1968 Page 82: Scientists at the International Telephone and Telegraph Federation laboratories in New Jersey have tried using clouds as the reflecting medium. They found that the typical cumulus clouds can scatter the beam to a receiver more than 150 km. from the transmitter. ----- It took over thirty years but the above work has now been verified, by amateurs! All we need now is some two way activity which will be the final proof! John K3PGP@juno.com http://www.qsl.net/k3pgp/index.html -==- >From owner-laser Tue Jun 17 05:02:09 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AB04031; Tue, 17 Jun 97 05:02:09 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f Date: Tue, 17 Jun 1997 07:57:50 -0400 (EDT) Message-Id: <2.2.16.19970617070507.26b78d00@mail.snet.net> X-Sender: paulc@mail.snet.net X-Mailer: Windows Eudora Pro Version 2.2 (16) Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" To: laser@qsl.net From: "Paul A. Cianciolo" Subject: Re: [LASER] Resend - Laser Scatter # 2 ! Reply-To: "Paul A. Cianciolo" Sender: owner-laser@berlioz.nsc.com Precedence: bulk Hello John and the group, Looks like there were some problems with the reflector yesterday. Thanks for all the info in the reply to my questions. Precisely was not the correct word to use here, my interest was in the fact that a signal could pass through the relatively reflective layers close in and not influence the return from approx 30 miles up.. You did not mis-type anything With your laser pointing at 20 degs.. a(approx) above the horizon and returns being calculated at 60 miles round trip would not the reflecting layer be at les than 30 miles? It seem like a right triangle problem. I would think that the return would be on a 60 mile round trip would be 30 miles up only if its angle was 90 degs between .. straight up? I was never any good at math anyways!! ---- >Well first off either I mis-typed something or you mis-read what I typed! > >It's NOT precisely 32 miles, it's APPROX. 30 to 32 miles and this is the >MAXIMUM distance to any observable reflection. Like all good lasers >DXers I'm looking for maximum DX! > >The reflection from the layer that's approx. 30 miles up is only >observable under extremely clear sky conditions, which we had again last >night. However, even during this run I was also seeing some reflections >from approx 19 miles up plus an occasional echo from 3 to 4 miles up, >most likely due to some extremely fine clouds drifting by. > What did you use for a keyer to send the beacon signal? How did you send the signal do you have 2 computer setups and 2 Sigma Delta boards? >>What did you use for a beacon source? I will be trying to build the >>beacon keyer that bill suggest to use here on this end. >> > >The beacon is a 780 nm laser running into a small telescope. It is a >FOCUSED laser and NOT a collimated laser. The focused laser seems to >produce more backscatter signal probably because the power density is >higher in the focused beam 30 miles out. It's normally focused on >infinity. > >> >I pointed the test signal approx. 20 degrees above the NE horizon since I >can hit this easily from my front porch where the laser can sit beneath >an overhand on the house where it is protected from the weather. Most >storms come from the West. I tried to keep the elevation angle as low as >possible without hitting any obstructions as backscatter signals seem to >be strongest near the horizon. I also didn't want to have to limit my >observation to only locations with a good shot at the NE horizon. You >can usually hit 20 degrees up from just about anyplace other than right >alongside a hill! > >As far as acquiring the signal, it ALWAYS seemed to come from the same >direction no matter where I checked it. I didn't have any readouts on >the cheap TV tripod I was using but if I'd aim it NE and approx. 20 >degrees up I could always find the signal in a couple of minutes. I am wondering what bandwidth was being used in the RX when you could hear this. If it was narrow seems like Coherent would be a waste of time for you. I have talked a few guys using coherent and they said that they feel coherent will rcopy signals to about 6-8 db below what they can perceive, using a 15 hz filter. AT 12 wpm. I have talked K1FO about this topic and he has a similar ability. I think Irecall him stating that his peak was also lower than the 800 hz we use. Actually I believe there are graphs that the show the freq versus bandwith ratios of the organic filter. >A few times I could actually hear the signal buried in the noise! Since >I spent many hours copying CW signals via EME I have developed the >ability to hear CW signals that are -15 to -17 dB below the noise floor. >Everything has to be right for me to do this though! The only problem I >have with this laser stuff is my natural in head CW filter seems to peak >around 575 Hz. 800 Hz is kind of out of my range! > I am well aware of the possibility of light bouncing around in the RX. I have the inside covered with very black felt. I also have a light stop which is a circle cut out a disk that fits in the light path. This is also covered with the felt. I looked a velvet and this felt and the felt a\was actually blacker and a lot cheaper >>Also the past couple of nights my RX has been quite noisy due the >>ambient noise from the bright moon and clear skies. Do you use a front >end >>filter to eliminate this? >> > >This is another reason I pointed NE! The moon was to my back. > >I haven't had much trouble with this unless of course I point at the >moon! I do have an IR filter but very seldom use it. > >Make sure you are controlling light scattering around inside the focusing >tube. Paint it flat black, (which really isn't all that good at >absorbing light!) or get some >flocking paper from Edmund Sci. as suggested by Paul, KY1K. > >The problem is the moon, or any undesired source of light, will go >through the lens even if it's way off angle and cause an image to occur >on the inside wall of the focusing tube. If the wall is at all >reflective it will bounce around and eventually some of it will hit your >detector. Result? The noise floor comes up! > >If your system is properly designed you should be able to point within a >couple degrees of the moon and not have this problem. Of course how >close you can get depends on the active area of your detector and the >focal length and diameter of your lens. > >In my case I am able to focus on the UNLIT part of the moon during the >first and last quarter while discriminating against the brightly lit >region. This kind of performance will be REQUIRED to work laser EME as >there's no way I can compete with the sun! You need to build your >detector setup with same care one would use to build a telescope! That >is if you want max. nightime performance. > >>Sorry for all the questions in in shot like this but I and puzzled, >>and I am sure some of the other guys would be intersted in this info as >I am in >>the pursuit of NON-LOS QSO's >>Thanks John >> >>73's >>PaulC KB1RP >> > >----- > >John >K3PGP@juno.com >http://www.qsl.net/k3pgp/index.html >-==- > > 73's PaulC KB1RP >From owner-laser Tue Jun 17 05:02:20 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA04039; Tue, 17 Jun 97 05:02:20 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f Date: Tue, 17 Jun 1997 07:59:10 -0400 (EDT) Message-Id: <2.2.16.19970617070626.18e7dbee@mail.snet.net> X-Sender: paulc@mail.snet.net X-Mailer: Windows Eudora Pro Version 2.2 (16) Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" To: laser@qsl.net From: "Paul A. Cianciolo" Subject: [LASER] follow up questions about the layer Reply-To: "Paul A. Cianciolo" Sender: owner-laser@berlioz.nsc.com Precedence: bulk Hello John and the group, Looks like there were some problems with the reflector yesterday. Thanks for all the info in the reply to my questions. Precisely was not the correct word to use here, my interest was in the fact that a signal could pass through the relatively reflective layers close in and not influence the return from approx 30 miles up.. You did not mis-type anything With your laser pointing at 20 degs.. a(approx) above the horizon and returns being calculated at 60 miles round trip would not the reflecting layer be at les than 30 miles? It seem like a right triangle problem. I would think that the return would be on a 60 mile round trip would be 30 miles up only if its angle was 90 degs between .. straight up? I was never any good at math anyways!! ---- >Well first off either I mis-typed something or you mis-read what I typed! > >It's NOT precisely 32 miles, it's APPROX. 30 to 32 miles and this is the >MAXIMUM distance to any observable reflection. Like all good lasers >DXers I'm looking for maximum DX! > >The reflection from the layer that's approx. 30 miles up is only >observable under extremely clear sky conditions, which we had again last >night. However, even during this run I was also seeing some reflections >from approx 19 miles up plus an occasional echo from 3 to 4 miles up, >most likely due to some extremely fine clouds drifting by. > What did you use for a keyer to send the beacon signal? How did you send the signal do you have 2 computer setups and 2 Sigma Delta boards? >>What did you use for a beacon source? I will be trying to build the >>beacon keyer that bill suggest to use here on this end. >> > >The beacon is a 780 nm laser running into a small telescope. It is a >FOCUSED laser and NOT a collimated laser. The focused laser seems to >produce more backscatter signal probably because the power density is >higher in the focused beam 30 miles out. It's normally focused on >infinity. > >> >I pointed the test signal approx. 20 degrees above the NE horizon since I >can hit this easily from my front porch where the laser can sit beneath >an overhand on the house where it is protected from the weather. Most >storms come from the West. I tried to keep the elevation angle as low as >possible without hitting any obstructions as backscatter signals seem to >be strongest near the horizon. I also didn't want to have to limit my >observation to only locations with a good shot at the NE horizon. You >can usually hit 20 degrees up from just about anyplace other than right >alongside a hill! > >As far as acquiring the signal, it ALWAYS seemed to come from the same >direction no matter where I checked it. I didn't have any readouts on >the cheap TV tripod I was using but if I'd aim it NE and approx. 20 >degrees up I could always find the signal in a couple of minutes. I am wondering what bandwidth was being used in the RX when you could hear this. If it was narrow seems like Coherent would be a waste of time for you. I have talked a few guys using coherent and they said that they feel coherent will rcopy signals to about 6-8 db below what they can perceive, using a 15 hz filter. AT 12 wpm. I have talked K1FO about this topic and he has a similar ability. I think Irecall him stating that his peak was also lower than the 800 hz we use. Actually I believe there are graphs that the show the freq versus bandwith ratios of the organic filter. >A few times I could actually hear the signal buried in the noise! Since >I spent many hours copying CW signals via EME I have developed the >ability to hear CW signals that are -15 to -17 dB below the noise floor. >Everything has to be right for me to do this though! The only problem I >have with this laser stuff is my natural in head CW filter seems to peak >around 575 Hz. 800 Hz is kind of out of my range! > I am well aware of the possibility of light bouncing around in the RX. I have the inside covered with very black felt. I also have a light stop which is a circle cut out a disk that fits in the light path. This is also covered with the felt. I looked a velvet and this felt and the felt a\was actually blacker and a lot cheaper >>Also the past couple of nights my RX has been quite noisy due the >>ambient noise from the bright moon and clear skies. Do you use a front >end >>filter to eliminate this? >> > >This is another reason I pointed NE! The moon was to my back. > >I haven't had much trouble with this unless of course I point at the >moon! I do have an IR filter but very seldom use it. > >Make sure you are controlling light scattering around inside the focusing >tube. Paint it flat black, (which really isn't all that good at >absorbing light!) or get some >flocking paper from Edmund Sci. as suggested by Paul, KY1K. > >The problem is the moon, or any undesired source of light, will go >through the lens even if it's way off angle and cause an image to occur >on the inside wall of the focusing tube. If the wall is at all >reflective it will bounce around and eventually some of it will hit your >detector. Result? The noise floor comes up! > >If your system is properly designed you should be able to point within a >couple degrees of the moon and not have this problem. Of course how >close you can get depends on the active area of your detector and the >focal length and diameter of your lens. > >In my case I am able to focus on the UNLIT part of the moon during the >first and last quarter while discriminating against the brightly lit >region. This kind of performance will be REQUIRED to work laser EME as >there's no way I can compete with the sun! You need to build your >detector setup with same care one would use to build a telescope! That >is if you want max. nightime performance. > >>Sorry for all the questions in in shot like this but I and puzzled, >>and I am sure some of the other guys would be intersted in this info as >I am in >>the pursuit of NON-LOS QSO's >>Thanks John >> >>73's >>PaulC KB1RP >> > >----- > >John >K3PGP@juno.com >http://www.qsl.net/k3pgp/index.html >-==- > > 73's PaulC KB1RP >From owner-laser Tue Jun 17 08:17:00 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA10638; Tue, 17 Jun 97 08:17:00 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f To: laser@qsl.net Date: Tue, 17 Jun 1997 11:08:00 -0400 Subject: Re: [LASER] follow up questions about the layer Message-Id: <19970617.111054.6758.0.K3PGP@juno.com> X-Mailer: Juno 1.38 X-Juno-Line-Breaks: 1-5,7-11,13-17,19-24,29-30,34-35,39-43,51-52,61-62, 68-69,75-80,82-84,86-93,106-114,124-125,135-136,142-147,149-164,172-181 From: k3pgp@juno.com (John K3PGP) Reply-To: k3pgp@juno.com (John K3PGP) Sender: owner-laser@berlioz.nsc.com Precedence: bulk On Tue, 17 Jun 1997 07:59:10 -0400 (EDT) "Paul A. Cianciolo" writes: >Hello John and the group, > > >Precisely was not the correct word to use here, my interest was in >the fact that a signal could pass through the relatively reflective layers >close in and not influence the return from approx 30 miles up.. > ----- There were NO lower reflective layers to amount to anything that particular night. It was EXTREMELY clear, that's why I ran the tests. ----- >With your laser pointing at 20 degs.. a(approx) above the horizon and >returns being calculated at 60 miles round trip would not the >reflecting layer be at les than 30 miles? It seem like a right triangle problem. >I would think that the return would be on a 60 mile round trip would be >30 miles up only if its angle was 90 degs between .. straight up? >I was never any good at math anyways!! ----- The returns were NOT calculated at the 20 degree elevation. I have NO idea what the distance was! As one lowers the elevation you start looking through more and more atmosphere with returns from multiple distances and it gets extremely hard to determine exactly what your looking at! I did the ranging that night pointed straight up as I usually do. The only thing I saw was a weak signal being returned from approx. 30 miles up. Since this appeared to be the only return detected I thought it was a very rare opportunity to run this experiment! The 20 degree angle was chosen because signal levels always seem stronger closer to the horizon when skies are clear. I didn't want to aim any lower because it might be difficult to get a low angle shot from other locations. *** NOTE *** I think many of you are trying to read too much into this experiment. The only thing I was trying to prove by this experiment is that either a signal could be detected on a NON line of sight path by pointing up at the sky or it couldn't. I had no intention of trying to determine how the signal was being propagated or how far away the signal was being scattered from. I didn't see any reason to drag any more equipment around on this first attempt as there might not have been anything to measure! You have to find the signal before you can measure it! The fact that both the Tx and Rx had to be pointed in approx. the same direction tells me that the reflection was coming from pretty far out. However, how well can one estimate where a 10 inch lens is pointed when mounted on a cheap TV tripod with no calibrations? About all I can say is it was pointed NE and relatively low to the horizon, approx. 20 degrees and it never seemed to change much from several different locations where I checked. If I went south it did seem to be slightly lower in elevation. When I went north it seemed like it was slightly higher. If you guys want more accurate data either you are going to have to get out there and do it yourself, or wait till I get another clear day when I have the time to do this. Unfortunately we don't get many days around here when the atmosphere is this transparent! Normally there are multiple reflections from many different distances and it's just about impossible sometimes to figure out what's going on! At this point I learned all that I want to know. I now know that 780 nm signals can be propagated over the horizon by some means in the upper atmosphere. I'll let someone else figure out what the propagation mode is as I'm not that interested in exactly how it's done, just the fact that it's possible! The next thing I want to hear is someone over the horizon that wants to run skeds! ***** ----- >What did you use for a keyer to send the beacon signal? How did you >send the signal do you have 2 computer setups and 2 Sigma Delta boards? ----- I have several setups. One is another computer and the other is an EPROM keyer. ----- >I am wondering what bandwidth was being used in the RX when you could >hear this. If it was narrow seems like Coherent would be a waste of time >for you. ----- Not when the signal is less than -25 or more below the noise floor! Detecting a signal that's -15 to -17 dB below the noise floor and copying it are two entirely different things and remember this was the PEAK level and is only an estimate since I didn't drag along my HP audio test set. 99% of the time I couldn't hear anything other than noise coming from the speaker! Also COHERENT works ALL THE TIME at these signal levels and produces nearly 100% copy. I can't say the same for my organic filter, especially with external distractions and lack of sleep! If you or anyone else feels you can do better with your ears then use MCW and forget BPSK. However, I'm convinced BPSK is the best way to do laser scatter with the present systems we have to use. I've evaluated many weak signal systems over the years and this is the first one that seems to work as well as claimed! ----- >I have talked a few guys using coherent and they said that they feel >coherent will rcopy signals to about 6-8 db below what they can >perceive, using a 15 hz filter. AT 12 wpm. ----- The key word here is perceive NOT copy! I find COHERENT a LOT better than 6 to 8 dB. Either my CW copying ability is worse than these guys or perhaps it's the fact that laser signals are a LOT more phase stable than the typical HF radio communications circuit. Remember we don't have any RF oscillator drift to put up with when using lasers nor the peculiarities of the ionosphere! Laser scatter signals fortunately seem to be quite stable in both phase and amplitude. However, you can get some pretty gross distortion when dealing with multiple layers and the resulting multiple reflections! COHERENT seems to deal with this distortion very well. As far as weak signal CW work is concerned, I prefer NO filter other than the normal 2 to 3 Khz SSB filter and it has to be flat as I find little peaks extremely annoying with white noise going through the system. I've played around with narrow filters (<50 Hz) and find them extremely hard on the nerves. Plus I find my weak signal copying ability rapidly deteriorates after using one of these for even a few minutes. It seems my ears/brain use the background noise to establish some kind of phase relationship to the signal. When I listen through a narrowband filter I seem to loose this reference and can't copy anything! This is probably a personal thing. I think everyone is different in this respect. The laser setup actually uses TWO filters. One a highpass to get rid of most of the harmonics caused by man made light followed by a low pass to eliminate noise above approx. 3.5 Khz to keep it out of the A/D converter. These are very gentle filters, mostly RC type. I don't like the effects of most op-amp filters and especially HI-Q peaked ones! Again this is a personal preference! The VLF converter feed is taken before the filters. ----- >I have talked K1FO about this topic and he has a similar ability. I >think Irecall him stating that his peak was also lower than the 800 hz we >use. > >Actually I believe there are graphs that the show the freq versus >bandwith ratios of the organic filter. > >>>73's >>>PaulC KB1RP >>> >> >>----- >> ----- To anyone: How about we get with the program and make a laser scatter QSO instead of spending all this time talking about it! My only purpose in running these tests is to prove (to myself anyway!) that laser scatter signals do exist. I really don't care if the signal is scattered by something that's 3 miles away or a hundred just so I can hear you! After we work each other we can let someone else figure out how the signal is propagated! I never had much interest in studying signal propagation on the lower bands and I don't have much more interest at 780 nm! I'm open for skeds! ----- John K3PGP@juno.com http://www.qsl.net/k3pgp/index.html -==- >From owner-laser Tue Jun 17 10:06:02 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA14603; Tue, 17 Jun 97 10:06:02 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f From: daveaa1a@ssih.com Date: Tue, 17 Jun 1997 12:59:25 -0400 Message-Id: <199706171659.MAA32689@ssih.com> Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Subject: [LASER] QSO's To: k3pgp@juno.com (John K3PGP), laser@qsl.net In-Reply-To: <19970617.111054.6758.0.K3PGP@juno.com> X-Mailer: SPRY Mail Version: 04.00.06.17 Reply-To: daveaa1a@ssih.com Sender: owner-laser@berlioz.nsc.com Precedence: bulk John, (the old noise diver) I think many are about to break out and go on the roamer circuit.. This Rx seems like I need to go hear the horizon and tell how much better off the RX is now.. If I had a low look to the southwest, I would point a beam out the window at you and leave it there but maybe Merv down in Plymouth (NC1K) will want to do this.. He is just about on the air..I will go hilltopping and send to you on schedule as soon as I pick up another laptop for the portable BPSK stuff.. This new front end is deaf in the daytime but still plenty good for short hops with wide bandpass.. This morning I tried a variable DC bias arrangement through 40megs to the diode and ran into and interesting effect.. While going positive with the bias I ran into and area that sounded like it was gonna break out in the regen mode, then a quiet area that behaved much better with more light.. The Test Bench: For my latest tests of the 'front end', I sealed a R/S IR diode in one end of a 6" piece of heavy duty shrink tube.. The other end plugs onto the PD.. The unit is covered with a black/opaque cloth to emulate night condx. I get threshold (to the ear) at .5 ua. ( half a microamp @ .7volts pp ) from a variable square wave 1 khz. ttl gen.. 3 or 4 microamps is quite loud and way over the noise 20-30 db's... Is this easy enough to use as a 'standard' ?? What say for a consensus... To the folks at 'televar' out by Whidby Island: Maybe this is being done out that way in the sound?? What are you using for tx/rx?? Do either of you have a shot to Cherry Point or Bellingham?? C.W. Wright, Tks for the APD info.. Sounds like the prices have come down quite a bit.. What kind of difference do you see on the SNR.. Geez, 1000mhz cut-off.. Now thats SOME data pipe.. KY1K please QSO Jon, WS1K who is also on here.. He has a direct shot your way with about a 100 ft handicap.. to dave@riley.net.. Have you tried any short Video Hops or multiplex wireless around the station??.. Well it's always good to hear from y'all.. Keep the Light ON.. 73s de daveaa1a >From owner-laser Tue Jun 17 11:29:57 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA18059; Tue, 17 Jun 97 11:29:57 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f To: laser@qsl.net Date: Tue, 17 Jun 1997 14:20:28 -0400 Subject: [LASER] Weak Signal Source Message-Id: <19970617.142031.14278.3.K3PGP@juno.com> References: <199706171659.MAA32689@ssih.com> X-Mailer: Juno 1.38 X-Juno-Line-Breaks: 0-21,23-24,31-32,37-38,43-44,49-50,55-56,61-62, 64-65,67-68,71-77 From: k3pgp@juno.com (John K3PGP) Reply-To: k3pgp@juno.com (John K3PGP) Sender: owner-laser@berlioz.nsc.com Precedence: bulk On Tue, 17 Jun 1997 12:59:25 -0400 daveaa1a@ssih.com writes: > > >John, (the old noise diver) > HEY !!! What with this OLD stuff ??? >For my latest tests of the 'front end', I sealed a R/S IR diode >in one end of a 6" piece of heavy duty shrink tube.. >The other end plugs onto the PD.. The unit is covered with a >black/opaque cloth to emulate night condx. >I get threshold (to the ear) at .5 ua. ( half a microamp @ .7volts pp ) >from a variable square wave 1 khz. ttl gen.. >3 or 4 microamps is quite loud and way over the noise 20-30 db's... >Is this easy enough to use as a 'standard' ?? >What say for a consensus... At least two problems, maybe more! This is fine for optimizing a PARTICULAR detector but isn't very good for comparing two different detectors with different active areas! The detector with the largest active area will intercept more light and will appear more sensitive than a detector with a smaller active area even though the smaller detector may in fact be the better detector! You could end up convincing yourself that the detector with the larger active area is the best to use when in reality the performance could be quite different when the signal is focused down to a small sized dot with a lens. I fell into this trap also when I first did this! You have to be extremely careful about this especially when trying to compare something like a PMT with a 2 inch active area vs a PIN diode with maybe 0.5 mm active area but it also applies to different PIN diodes or any detector for that matter with different sized active areas! You might want to try a pinhole aperture right in front of the detectors to be compared. The diameter of the pinhole would have to be smaller than the active area of the smallest detector to be measured and you'd have to be careful about alignment since the pinhole would have to be right in front of the detector to be effective. If you do this, make sure the IR LED can't shine directly through the pinhole! The IR LED should either shine through a diffuser of some type (near the LED before the pinhole) or use an indirect projection setup with the IR LED shining on a white piece of paper (or white cotton!) inside the tube with the output pinhole at some angle or behind the LED. Don't overlook the possibility of using a piece of fiber optic material or even a thin piece of plastic tubing or thin lucite rod as a light pipe. This would produce an extremely small dot of light that you could place directly in front of the detector and would also provide electrical isolation between the signal source and the detector. For this to be meaningful as a standard we'd all have to use the same identical LED that you are using and maybe even from the same batch! There is a tremendous variation among IR LEDs from different manufactures as well among the same manufacturer and to a lesser degree among IR LEDs of the same type number! Also many people are using detectors with different spectral response curves. Your particular LED may not match their response curve. Like I said it's an excellent way to optimize a particular detector. As far as a standard goes, forget it other than for your own use! Now if you want to take on the project of building calibrated signal sources and send them around that's another story! I've kicked that one around myself. John K3PGP@juno.com http://www.qsl.net/k3pgp/index.html -==- >From owner-laser Tue Jun 17 12:03:51 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA19624; Tue, 17 Jun 97 12:03:51 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f To: laser@qsl.net Date: Tue, 17 Jun 1997 13:51:45 -0400 Subject: [LASER] FFT Program Mods Message-Id: <19970617.135152.14278.1.K3PGP@juno.com> X-Mailer: Juno 1.38 X-Juno-Line-Breaks: 0-1,3-6,14-15,20-21,24-25,29-30,32-40 From: k3pgp@juno.com (John K3PGP) Reply-To: k3pgp@juno.com (John K3PGP) Sender: owner-laser@berlioz.nsc.com Precedence: bulk Bill (VE2IQ): I am posting this to laser@qsl.net as well as it may be of some use to other laser users! What's the possibility of adding a reset function to the FFT program? I have found FFT invaluable in the initial acquisition of laser signals that I can't hear! I point the receiver in approx. the correct position then fire up FFT in the integrate mode and see what's floating around below the noise floor. I can see a laser signals that I can't even begin to hear! By judging how long it takes to build up out of the noise I can get a rough estimate of how strong the signal is. I can also 'wiggle' the receiver around and try to get an approx. peak or find the signal if it's not there. The only problem with this is after the FFT program runs for awhile it becomes harder to determine changes in signal level or to acquire the signal in the first place. I then have to break out of the program and restart it. The most annoying thing about doing this is all the numbers I need to type back in to get it in the proper mode. What I would like to see is a key that could be pushed that would reset everything back to start conditions with NO change in the startup parameters! If you do this PLEASE make sure it's NOT a key than can accidently be bumped while fumbling around in the dark! Some two key combination that can be hit with one hand might be nice like ALT something or CTL something or other.... Maybe ALT R or CRL R for reset! If this function is already in the program I've overlooked it and need help in locating the correct key! Thanks and keep up the good work! John K3PGP@juno.com http://www.qsl.net/k3pgp/index.html -==- >From owner-laser Tue Jun 17 12:21:42 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA20518; Tue, 17 Jun 97 12:21:42 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f Date: Tue, 17 Jun 97 12:13:47 PDT From: jmoss@berlioz.nsc.com (Jim Moss) Message-Id: <9706171913.AA20123@berlioz.nsc.com> To: laser@qsl.net Subject: [LASER] QRPp on 670nm! Reply-To: jmoss@berlioz.nsc.com (Jim Moss) Sender: owner-laser@berlioz.nsc.com Precedence: bulk forward from laser@berlioz.nsc.com ----- Begin Included Message ----- >From owner-laser Sun Jun 15 10:58:08 1997 From: Lbo@kktv.com To: laser@berlioz.nsc.com Date: 15 Jun 1997 08:55:38 -0700 Subject: QRPp on 670nm! Sender: owner-laser@berlioz.nsc.com Content-Length: 1562 Well folks, I thought you may be interested to hear about my latest foray into the fringes of QRP operation -- this is definately NOT your normal H.F. QRP CW stuff -- read on.... I just got back from making my first and second contacts on the 670nm band with Walt, AJ6T - I rovered from CM97 and CM87 to give him 2 grids for the VHF/UHF contest. First contact was about 11 miles and the second was about 20.5 miles. My TX - about 2mW MCW at approx 450 THz, no antenna (coherent light doesn't need one!) My RX - 8.5 x 11 inch fresnel lens feeding an OPT210 photodiode/amp into an LM380N audio amp. We used 1 million candle power handheld halogen spotlamps to find each other initially (definately not QRP, but they save a whole ton of time wondering which direction to look in) then used the az/el adjusters (VERY fine) built into our laser rig set-ups to align the TX and RX pairs. Signals, when you are pointed just right, are 599 normally. We had a bit of trouble with gusty wind blowing our cheapo tripods about, so made do with 449/559 reports. We used 144MHz SSB (QRP I hasten to add!) as a coordination channel. The two contacts took about an hour each to complete - most of the time is spent aligning the lasers, once this is done, the CW QSO is over in a minute! Boy this stuff is FUN! I'll bring the rig along to the next Norcal meeting and try to persuade Jerry Parker to put a piccy of it up on the Norcal www page for your ammusement. Just think how far I could go with a whole 5 Watts of laser power.... :-) 72, Dave AD6AY ----- End Included Message ----- >From owner-laser Tue Jun 17 17:36:33 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA06773; Tue, 17 Jun 97 17:36:33 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f Date: Tue, 17 Jun 1997 20:31:55 -0400 (EDT) Message-Id: <2.2.16.19970617193907.265f44f4@mail.snet.net> X-Sender: paulc@mail.snet.net X-Mailer: Windows Eudora Pro Version 2.2 (16) Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" To: laser@qsl.net From: "Paul A. Cianciolo" Subject: [LASER] follow up and future BPSK skeds Reply-To: "Paul A. Cianciolo" Sender: owner-laser@berlioz.nsc.com Precedence: bulk Hello John, It certainly looks like you have proved that the NON-LOS QSO is possible. I am looking forward to the day that I can QSO with you 780 or in my case 830 nm via this NON-LOS path. MY intention here is to learn as much as possible about the transmission mode so as to better utilize it, as well as be able to predict what natural occurrences might enhance or detract from its natural value. This is the reason that I am so interested in all the details. BTW I went to the library and picked up "The Revolution in Light as well as other laser books to see if more info can be found about this mode. I am also investigating "local talent" at the universities to se if I dig up anything in that direction. >>I think many of you are trying to read too much into this experiment. >The only thing I was trying to prove by this experiment is that either a >signal could be detected on a NON line of sight path by pointing up at >the sky or it couldn't. I had no intention of trying to determine how >the signal was being propagated or how far away the signal was being >scattered from. I didn't see any reason to drag any more equipment >around on this first attempt as there might not have been anything to >measure! You have to find the signal before you can measure it! >> >At this point I learned all that I want to know. I now know that 780 nm >signals can be propagated over the horizon by some means in the upper >atmosphere. I'll let someone else figure out what the propagation mode >is as I'm not that interested in exactly how it's done, just the fact >that it's possible! The next thing I want to hear is someone over the >horizon that wants to run skeds! Soon I will have a beacon keyer running here using BPSK. At that point I can leave my 512 IR diodes array on pointing towards you and run it all night. I realize that the relative power density might be low but I would be glad to leave it on for any testing you might have in mind. It is located at 60' level of the 130' tower here with an unlimited view at 0 degs in the SW direction. Did you give me your Coords once? I will look to see your exact azimuth. Your thoughts on the above? >----- >I have several setups. One is another computer and the other is an EPROM >keyer. >----- > >>I am wondering what bandwidth was being used in the RX when you could >>hear this. If it was narrow seems like Coherent would be a waste of time >>for you. > >- This is all good news.. I had already ordered the SD board >99% of the time I couldn't hear anything other than noise coming from the >speaker! Also COHERENT works ALL THE TIME at these signal levels and >produces nearly 100% copy. I can't say the same for my organic filter, >especially with external distractions and lack of sleep! If you or >anyone else feels you can do better with your ears then use MCW and >forget BPSK. However, I'm convinced BPSK is the best way to do laser >scatter with the present systems we have to use. I've evaluated many >weak signal systems over the years and this is the first one that seems >to work as well as claimed! >----- > > >As far as weak signal CW work is concerned, I prefer NO filter other than >the normal 2 to 3 Khz SSB filter and it has to be flat as I find little >peaks extremely annoying with white noise going through the system. I've >played around with narrow filters (<50 Hz) and find them extremely hard >on the nerves. Plus I find my weak signal copying ability rapidly >deteriorates after using one of these for even a few minutes. It seems >my ears/brain use the background noise to establish some kind of phase >relationship to the signal. When I listen through a narrowband filter I >seem to loose this reference and can't copy anything! This is probably >a personal thing. I think everyone is different in this respect. I agree > >The laser setup actually uses TWO filters. One a highpass to get rid of >most of the harmonics caused by man made light followed by a low pass to >eliminate noise above approx. 3.5 Khz to keep it out of the A/D >converter. Anti-aliasing I presume? on the lowpass? >To anyone: > >How about we get with the program and make a laser scatter QSO instead of >spending all this time talking about it! My only purpose in running >these tests is to prove (to myself anyway!) that laser scatter signals do >exist. I really don't care if the signal is scattered by something >that's 3 miles away or a hundred just so I can hear you! After we work >each other we can let someone else figure out how the signal is >propagated! I never had much interest in studying signal propagation on >the lower bands and I don't have much more interest at 780 nm! > >I'm open for skeds! I should be ready for business in about 2 weeks. At that time I wll also have the 30mw 830 available for use... Hopefully I am off for some testing myself 73's PaulC KB1RP >From owner-laser Tue Jun 17 18:28:32 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA09563; Tue, 17 Jun 97 18:28:32 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f Date: Tue, 17 Jun 1997 21:23:51 -0400 (EDT) From: "C. W. Wright" X-Sender: wwright@wayne.home.net To: laser@qsl.net Subject: [LASER] Internet Atmospheric scatttering data gif images In-Reply-To: <9706171913.AA20123@berlioz.nsc.com> Message-Id: Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Reply-To: "C. W. Wright" Sender: owner-laser@berlioz.nsc.com Precedence: bulk Hello all, Take a look at: http://asd-www.larc.nasa.gov/lidar/pwa/pemwesta.html for lots of actual atmospheric scattering data including locations, and digital waveform data in gif image form. It was taken from onboard a DC-8 flying at 10km altitude with lasers looking up and down at the same time. I think they're on 800nm. This site: http://asd-www.larc.nasa.gov/lidar/datasets.html contains an index to all their data sets. The main page seems to be: http://asd-www.larc.nasa.gov/lidar/lidar.html Their list of publications is at: http://asd-www.larc.nasa.gov/lidar/pub.html :-) Wayne >From owner-laser Tue Jun 17 20:21:23 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA14888; Tue, 17 Jun 97 20:21:23 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f Date: Tue, 17 Jun 1997 23:19:48 -0400 (EDT) From: "C. W. Wright" X-Sender: wwright@wayne.home.net To: daveaa1a@ssih.com Cc: John K3PGP , laser@qsl.net Subject: Re: [LASER] QSO's In-Reply-To: <199706171659.MAA32689@ssih.com> Message-Id: Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Reply-To: "C. W. Wright" Sender: owner-laser@berlioz.nsc.com Precedence: bulk > C.W. Wright, Tks for the APD info.. Sounds like the prices have > come down quite a bit.. What kind of difference do you see on the > SNR.. Geez, 1000mhz cut-off.. Now thats SOME data pipe.. I don't know yet. I just ordered them today. I'm going to be evaluating several pmt's some apds and pins; some for pulsed lidar applications, but others for mod. cw experiments with a 532nm diode pumped doubled yag ( 20mw cw at 532 ). We'll probably be building a small calibration source/box to test things in. It will cover the range from 0dbm to -200dbm with a second channel to introduce calibrated amounts of ambient light since we operate during the daytime. Some of the pmts may be interesting, as they are in a To-5 transistor can. They are also by hamamatsu and span from abt 400 to 800nm. Cost abt $650 each. They have a rise time of 650ps. THe gain is only on the order of 10 to the 5th power or abt 10,000 though. -Wayne >From owner-laser Tue Jun 17 21:28:31 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA17923; Tue, 17 Jun 97 21:28:31 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f To: laser@qsl.net Date: Wed, 18 Jun 1997 00:25:34 -0400 Subject: Re: [LASER] 30 mile high optical reflector? Message-Id: <19970618.002536.11142.9.K3PGP@juno.com> References: <199706161756.MAA05271@firefly.prairienet.org> X-Mailer: Juno 1.38 X-Juno-Line-Breaks: 1-4,6-32,36-49 From: k3pgp@juno.com (John K3PGP) Reply-To: k3pgp@juno.com (John K3PGP) Sender: owner-laser@berlioz.nsc.com Precedence: bulk This was posted to the wrong reflector and never made it to laser@qsl.net. ----- On Mon, 16 Jun 1997 12:56:04 -0500 (CDT) w9sz@prairienet.org (Zack Widup) > > >It may not just be "reflecting". > >Back in the mid-70's I participated a bit in a project at the >University of Illinois which the lab I was working in as a grad >student (Radio Research) did jointly with the Aeronomy lab. >We built a rhodamine-6G dye laser (megawatts pulsed!) and >a special Fresnel lens - PMT LIDAR telescope. The dye laser >fired pulses into the upper reaches of the atmosphere and excited >the D-line doublets of sodium which then returned to be picked >up by the telescope. The purpose was to examine >upper-atmosphere air currents and directions of flow. > >I haven't researched what elements up there may be excited by the >wavelengths in question here, but it is possible that the same >phenomenon is occurring. This may actually return a greater >percentage of the laser's energy than an ordinary reflection, >depending on what is up there to be excited. > >Just a thought! > >Zack W9SZ > ----- You can make everyone's life a LOT easier if you would PLEASE post all laser messages to laser@qsl.net! If you have NOT switched your service over to qsl.net please do so! All posts to qsl.net are echoed on BOTH reflectors. If you post to Berlioz not everyone may get you message! To subscribe, send an email to majordomo@qsl.net Inside the body type: subscribe laser. Then post messages to laser@qsl.net ! If you need further help let me know! John K3PGP@juno.com http://www.qsl.net/k3pgp/index.html -==- >From owner-laser Wed Jun 18 07:02:35 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA13941; Wed, 18 Jun 97 07:02:35 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f To: laser@qsl.net Date: Wed, 18 Jun 1997 10:00:32 -0400 Subject: [LASER] Scatter Test: Follow Up Thoughts Message-Id: <19970618.100034.15126.4.K3PGP@juno.com> X-Mailer: Juno 1.38 X-Juno-Line-Breaks: 0-1,3-8,10-14,16-21,26-27,32-33,41-45,51-53,58, 61-62,69-70,76-77,82-85,89-90,95-105 From: k3pgp@juno.com (John K3PGP) Reply-To: k3pgp@juno.com (John K3PGP) Sender: owner-laser@berlioz.nsc.com Precedence: bulk Wayne: On Mon, 16 Jun 1997 21:04:46 -0400 (EDT) "C. W. Wright" writes: > >Hi Guys, > >For the altitude to be 30 miles given a 26 mile separation, I calculate >the angle above the horz should be 66.5 degrees above the horz. That >calculated by: angle = atan ( 30/13) where the 30 is the height and the >13 is half the separation again. the formula is just what I barely >remember from trig with oscar, apples and things. I used the >Tan-of-angle is equal to opposite / adj. sides of a triangle. > >All this assumes a flat earth, near perfect measurement of the inclination >angle of the actual beam and receiver optics. I also assume he directed >the tx and rx toward each other so they would see forward scatter. > >:-) Wayne I'm sorry I can't supply more accurate data but as I mentioned before the portable mount I have has no calibrations on it. Azimuth was guessed by looking at the stars which unfortunately were constantly moving! Elevation was again guessed by looking at the mount. And the Tx and Rx were aimed in the SAME general direction! However, after thinking about it, your calculations now have me wondering! I think the one rather large error that may be throwing things off in the above calculation is that it does NOT take into consideration the position of the Tx and Rx stations vs the position of the reflecting or scattering layer. Like I said I'm really not into studying the propagation of laser signals. Right now I'm just fascinated by the fact that anything can be detected! However, without running any numbers, it appears to me that the elevation would only be 66.5 degrees above the horizon in one special case and that being if the Rx was NE of the Tx, that is in the line of fire. And of course there remains the unknown of exactly what was the scattering mechanism and far out was it. The only data I have is a couple of soundings taken with the system at home pointed straight up. ----- NOTE: (For those that may not have the previous post: I got primarily one return that night from something approx. 30 to 32 miles out, straight up. This indicated unusually clear skies, something we don't see around here very often and is precisely why I did the tests that night. What the atmosphere looked like when pointed 20 degrees above the horizon is unknown. I am assuming it was approx. the same.) ----- As the Rx is moved in the opposite direction (SW) it would seem to me that the apparent elevation should drop. If it were moved at a right angle to the line of fire, (NW or SE) the elevation should remain somewhat constant (until the curvature of the earth entered into the calculations) while the azimuth changed. Only if were moved in the line of fire (NE) would the elevation increase! Unfortunately there aren't any good roads running NE of me. Most go east and west but are actually closer to NW and SE. Although the change was small, I thought it looked to me like the elevation was slightly higher when I was north of the Tx and slightly lower when I was south of the Tx. However, these measurements were taken relatively close in because of the bad roads I had to drive on to go these directions. I was more amazed by the fact that I could find the signal and really didn't pay a whole lot of attention to where I had to point to find it other than in relative terms. It's been raining here the past couple of days so I haven't been able to do much other than measure the distance to the bottom of clouds! I'm really not set up to do any precision measuring from other locations with the portable mount that I have but I can see that some work along those lines might be beneficial. However, it would probably change from night to night. What I eventually would like to see are some beacons placed on the air around me in various directions so measurements could be taken on a nightly basis under various types of weather conditions. That makes a LOT more sense to me than driving around on these back country roads at night! PS - Anyone want to make the first laser scatter contact? I'm only going to do this with another station rather than counting any tests by myself. It has become quite apparent to me that most doubt the existence of any type of useable scattering mechanism in the upper atmosphere. My advice is once we make this thing work we better invite as many of our ham friends over as possible to witness the contact because most simply are NOT going to believe that anything like this is possible! And have those tape machines rolling, preferably a camcorder with a Hi-Fi or AFM sound track to preserve the BPSK signal as well as possible! Just an observation from several people that I talked to so far! This is starting to remind me of the cold fusion experiments! :-^) John K3PGP@juno.com http://www.qsl.net/k3pgp/index.html -==- >From owner-laser Wed Jun 18 14:12:06 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA05077; Wed, 18 Jun 97 14:12:06 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f From: daveaa1a@ssih.com Date: Wed, 18 Jun 1997 17:12:45 -0400 Message-Id: <199706182112.RAA04227@ssih.com> Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Subject: [LASER] Quiet Receiver To: laser@qsl.net X-Mailer: SPRY Mail Version: 04.00.06.17 Reply-To: daveaa1a@ssih.com Sender: owner-laser@berlioz.nsc.com Precedence: bulk Re: Quiet Front End... Well I ran out of test equipment today.. After chasing noises, oscillations and outside sigs (voice of america, pulses, etc.) out of the J-Fet front end and forming a soft copper 'E' shield, here is what I get.. With the IR led 6" away in a tube and at normal room light, (no local lamps): Signal threshold is at .5 microamps into the IR LED type diode.. After darkening the amp. with black cloth, I can hear the 1khz square wave without ANY perceivable current on a large 0-5 microamp meter.. I get the tone just before I can see ANY movement up from zero... The scope measures .15 vpp to the diode.. Anybody have a meter that measures below 0 microamps?? The PD and j-fet are one unit and with a ferrite bead between.. C.W.,' Wayne's' light meter sounds like a real neat package.. Does anyone read these ramblings?? Y'all sure are bashful.. 73 de daveaa1a >From owner-laser Wed Jun 18 22:34:39 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA27223; Wed, 18 Jun 97 22:34:39 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f Date: Thu, 19 Jun 1997 01:28:54 EDT Message-Id: <5155@ve3tok.ampr.org> From: "Bob (Boudewijn) M. G. Tenty" To: laser@qsl.net Subject: [LASER] schematics Reply-To: "Bob (Boudewijn) M. G. Tenty" Sender: owner-laser@berlioz.nsc.com Precedence: bulk Hi Guys, Need some schematics here for light/laser receiver to build. As I understand John's setup he only uses a telescope for the laser tx itself only but not for the rx Are you just using one lens to focus the light on the photo detector transistor John? Are you using the basic setup as in those IR remote's ? PD - Amp - Limiter - B.P.F - demodulator - integrator >> Sigma Delta interface You did mention previously also a VLF convertor hooked-up before the B.P.F , are you also monitoring the output of the limiter for signals (instead of the demodulator output)? But I'm really interested in the complete schematics (parts) to start as you already optimized it for min. noise. Maybe I missed it at your Web page. Thanks to all! 73 - Bob HAMILTON, ON. CANADA Sysop Internet/Amprnet Gateway ve3mch +-----------------------------------------------------------------------+ | Bob(Boudewijn) M.G.Tenty - VE3TOK / PA0TOK///// //// //// / //// | | AMPRnet : ve3tok@ve3tok.ampr.org / / //// / //// | | PBBS : VE3TOK@VE3TOK.#SCON.ON.CAN.NA//// / / / | | Internet/UUCP : ve3tok@port.ve3mch.ampr.org | +-----------------------------------------------------------------------+ | Recyclable bits and bytes have been used for the message above. | +-----------------------------------------------------------------------+ World Wide Web http://www.ve3mch.ampr.org 60+ Reflectors/lists for the experimenter >From owner-laser Thu Jun 19 08:03:19 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA18900; Thu, 19 Jun 97 08:03:19 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f To: laser@qsl.net Date: Thu, 19 Jun 1997 10:58:16 -0400 Subject: Re: [LASER] Schematics and other Comments! Message-Id: <19970619.105818.3574.0.K3PGP@juno.com> References: <5155@ve3tok.ampr.org> X-Mailer: Juno 1.38 X-Juno-Line-Breaks: 1-8,11-12,16-17,20-32,34-35,37-38,45-46,50-51,53, 58-63,69-74,79-80,87-88,94-95,97-98,105-106,109-110,112-113, 119-120,125-126,131-132,135-136,141-152 From: k3pgp@juno.com (John K3PGP) Reply-To: k3pgp@juno.com (John K3PGP) Sender: owner-laser@berlioz.nsc.com Precedence: bulk On Thu, 19 Jun 1997 01:28:54 EDT "Bob (Boudewijn) M. G. Tenty" writes: > >Hi Guys, > >Need some schematics here for light/laser receiver to build. >As I understand John's setup he only uses a telescope for the >laser tx itself only but not for the rx The six inch reflecting telescope is used for tracking purposes only and is NOT used for laser transmission or reception. My goal is laser EME and I have to know precisely where the laser is pointing! There is a much smaller telescope on the laser itself. It's only about 3 or 4 inches long and maybe 1 1/2 inches in diameter. I've found the returns from clouds and troposcatter to be much higher using a focused laser as opposed to a collimated laser. Keep in mind that this makes the laser a LOT harder to aim since the beamwidth is a LOT smaller! It may NOT be the best setup for short range work. >Are you just using one lens to focus the light on the photo detector >transistor John? >Are you using the basic setup as in those IR remote's ? > >PD - Amp - Limiter - B.P.F - demodulator - integrator >> Sigma >Delta interface Nothing that complicated! I actually have two basic setups. One is a PMT (Photomultiplier Tube) into a preamp, amplifier then the S-D board (the interface to the VE2IQ software). The second setup, and the one I use most of the time now, is a PIN diode into a preamp, amplifier then the S-D board. There are NO limiters, integrators or bandpass filters in the conventional sense. I do use distributed RC type high pass filters to reduce the signal strength of man made light harmonics. This is used in conjunction with distributed RC low pass filters to reduce signals above approx. 3.5 Khz and prevent aliasing problems in the S-D board since it samples at 7.2 Khz / second. All the narrow band filtering is done by software running on the computer. I find narrow band HI-Q filters very hard on the nerves and difficult to listen to. This is a personal preference. If you like them, use them! However, be advised that some also cause a phase shift vs signal level making distance measurements based on phase rather difficult! In both cases the optics are simply a large lens mounted in front of the detector. There are provisions for fine tuning the focal point. If you are using a detector with a small active area you would do best to stick with high quality glass lens. However, if you have a detector with a rather large active area (maybe 1/4 inch or larger) you can also do very well with a fresnel lens. >You did mention previously also a VLF convertor hooked-up >before the B.P.F , are you also monitoring the output of the limiter >for signals (instead of the demodulator output)? As explained above, there is NO limiter or demodulator. The output of the receiver is converted to binary data by the S-D board (basically an A/D converter) and all further processing is done on a digital level by the VE2IQ software that comes with the S-D board. The VLF convertor is used for modes other than MCW, such as SSB, nbfm, etc. It also allows one to use subcarriers in the 10 to 100 Khz (or higher) region. >But I'm really interested in the complete schematics (parts) to start >as you already optimized it for min. noise. >Maybe I missed it at your Web page. There are none available at the moment. The laser front end has been evolving and changing on an almost daily basis now for the past year or so. Now that I'm starting to have some success things are now starting to stabilize a bit but just last night I was in there with the soldering iron making even more changes! Since I intend to eventually publish this work I'm not sure of the legal implications after something is published on a web site! Also I would like to have at least one laser scatter QSO completed before publishing anything. It doesn't have to be a DX attempt. All I'm out to do right now is prove the existence of a scattering mechanism in the atmosphere that can be used (with suitable equipment) for over the horizon laser work. >From my research so far it looks like there are at least two different propagation modes suitable for over the horizon laser work. Reflection from clouds and pollutants in the atmosphere, and some form of scattering that occurs in some unknown (to me) layer much higher up. I have found vague references to this in past publications but to my knowledge no one has tried to use it for communications. My final goal is laser EME work. The reason I stopped at this point is two+ fold. Number one is the backscatter signals are essentially bad news to my laser EME experiments as I originally envisioned them as they will produce QRM! Originally I wanted to be able to let the Tx run continuously and use long term integration to dig any possible echoes out of the noise. That's not possible since there appears to be a weak backscatter signal coming from the upper atmosphere present all the time. This means conventional Tx / Rx sequencing will have to be used. The second reason: I've found that these backscattered signals are an excellent source of weak signals that can be used to test out new ideas and optimize equipment. A possible third reason is the potential of using this mode of propagation for over the horizon laser scatter contacts! One has to appreciate just how weak laser scatter signals are before completely understanding why I am going to these lengths to process the received signal. Laser EME will be an even greater challenge with the amount of laser power that I presently have. The only way I can ever hope to detect anything at all will be by using as much computer processing power as possible to dig the signal out of the noise. Please keep in mind that I am working in an area where few others are experimenting. You don't need anything this complex to make laser QSOs over conventional line of sight paths. Even the present laser DX record of 150+ miles was made using much simpler equipment than this. My present setup would be a very poor choice for line of sight work! A good starting point would be a laser pen and one of the OPT-xx devices described on the wb9ajz Amateur Radio Laser Communications Web Page. There is a link on my web page to this site. A setup like this will work any line of sight terrestrial path that you are likely to encounter, unless of course you goal is to set a new world's record! A more sensitive receive setup can be built using a PIN diode into a discrete component preamp. This will produce a lower noise floor than most op-amps are capable of. Beyond that you're looking at APD (Avalanche Photodiodes) or PMTs (Photomultiplier tubes). If you run across any PMTs be advised that they are easily damaged by exposure to light (even when NOT powered up) and most suffer from severe red droop making the reponse extremely poor in the 630 to 830 nm range where most common lasers operate. > >Thanks to all! > 73 - Bob HAMILTON, ON. CANADA > > Sysop Internet/Amprnet Gateway ve3mch John K3PGP@juno.com http://www.qsl.net/k3pgp/index.html -==- >From owner-laser Thu Jun 19 13:53:26 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA06566; Thu, 19 Jun 97 13:53:26 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f To: laser@qsl.net Date: Thu, 19 Jun 1997 16:53:18 -0400 Subject: Re: [LASER] Test - Please Ignore/Delete - No really, it doesn't say anything.... Message-Id: <19970619.165320.3726.3.K3PGP@juno.com> References: <33A98CBD.2CC1@lan.nsc.com> X-Mailer: Juno 1.38 X-Juno-Line-Breaks: 1-5 From: k3pgp@juno.com (John K3PGP) Reply-To: k3pgp@juno.com (John K3PGP) Sender: owner-laser@berlioz.nsc.com Precedence: bulk On Thu, 19 Jun 1997 12:47:09 -0700 Dave Fifield writes: >Told you..... > Just checking to make sure! >From owner-laser Thu Jun 19 13:50:33 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA06418; Thu, 19 Jun 97 13:50:33 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f Message-Id: <33A98CBD.2CC1@lan.nsc.com> Date: Thu, 19 Jun 1997 12:47:09 -0700 From: Dave Fifield Organization: National Semiconductor Corp. X-Mailer: Mozilla 3.01 (Win95; I) Mime-Version: 1.0 To: Laser Email List Subject: [LASER] Test - Please Ignore/Delete - No really, it doesn't say anything.... Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Reply-To: Dave Fifield Sender: owner-laser@berlioz.nsc.com Precedence: bulk Told you..... >From owner-laser Thu Jun 19 15:46:11 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA12617; Thu, 19 Jun 97 15:46:11 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f Message-Id: From: chrise@n0jcf.com (Chris Elmquist) Subject: [LASER] light damage to unpowered PMTs ? To: k3pgp@juno.com Date: Thu, 19 Jun 1997 17:42:32 -0500 (CDT) Cc: laser@qsl.net In-Reply-To: <19970619.105818.3574.0.K3PGP@juno.com> from "John K3PGP" at Jun 19, 97 10:58:16 am X-Mailer: ELM [version 2.4 PL23] Content-Type: text Reply-To: chrise@n0jcf.com (Chris Elmquist) Sender: owner-laser@berlioz.nsc.com Precedence: bulk John K3PGP wrote: > (Photomultiplier tubes). If you run across any PMTs be advised that they > are easily damaged by exposure to light (even when NOT powered up) and ^^^^^^^^^^^^^^^^^^^^^^^^ I keep hearing this... and was banned from the "geek table" at lunch... when I mentioned it in front of a bunch of PhD physists and EEs. They all insist that if the PMT is not under bias, then it can not be damaged by exposure to light. I was convinced by these guys that this is an urban myth. Can someone explain the mechanism for damage when the PMT is not powered up ? I'd appreciate it... I'd like to get back to the geek table. Chris -- Chris Elmquist, N0JCF chrise@n0jcf.com n0jcf@amsat.org >From owner-laser Thu Jun 19 17:24:56 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA18125; Thu, 19 Jun 97 17:24:56 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f From: daveaa1a@ssih.com Date: Thu, 19 Jun 1997 20:27:17 -0400 Message-Id: <199706200027.UAA08223@ssih.com> Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Subject: [LASER] Quieter Receiver To: laser@qsl.net X-Mailer: SPRY Mail Version: 04.00.06.17 Reply-To: daveaa1a@ssih.com Sender: owner-laser@berlioz.nsc.com Precedence: bulk Hello Lights, Well it's getting down to the fuzzy sound of nature.. Todays effort was a new PD into a jfet into a opa 177, all optimized for NO oscillations and minimal 'E' field pickup/noise.. The local bench receiver test gen. is a 1 khz square wave TTL into a variable pot. into a IR LED stuffed into the end of a 6" piece of shrink tube all placed on a black cloth matt, covered with very opaque black cloth till the sounds of the universe start up.. This is where it gets sensitive.. Since I get a sig. through the front end BELOW where the series current 0-5 microamp meter indicates anything but ZERO ua., I refer now to the peak/peak voltage waveform across the IR diode sig. gen. for relative threshold... Yesterday the sig. threshold (to the ear) was .15 volt pp.. (150mv) This was just before the 0-5 microammeter started to move up from zero.. Today with the new amp. it is 40 millivolts pp.. Now it's WAY before the 0-5 micrometer starts to move.. Maybe I'm near the end of practicality for now. Tomorrow will try some SELECTED jfets, gassfets, even a ku band fet.. Sure it's only audio but the highest gate 'Z' will probably win the test.. Oh, try variable D.C. (vcc) and find where the best SNR is also.. 9v is best here.. Here are some numbers as requested by some of the folks.. Digi-Key has the opt211p-nd IC photocell but this is a local/tropo medium DX receiver only, but is real slick and requires minimum external parts.. A opt177 can be used for good AGC from day/night changes.. The opa-177gp-nd is a nice QUIET op-amp with 130db gain and easy to stabilize and make quiet.. EG&G Vactec VTP1188s PD's from Newark are what I'm still using for a PD.. Anyone know of better PD?? 3's and Light from daveaa1a >From owner-laser Fri Jun 20 10:26:02 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA23325; Fri, 20 Jun 97 10:26:02 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f Date: Fri, 20 Jun 97 10:09:34 PDT From: jmoss@berlioz.nsc.com (Jim Moss) Message-Id: <9706201709.AA22319@berlioz.nsc.com> To: laser@qsl.net Subject: [LASER] Laser Q in June VHF + other stuff Reply-To: jmoss@berlioz.nsc.com (Jim Moss) Sender: owner-laser@berlioz.nsc.com Precedence: bulk I successfully QSO'd with KD6OSV during the contest from CN70xb to CN70xa. (not too far). But it was the first Q using my PMT and 8x10 fresnel RX. Signals of course were 599! The other side of the Q was 59mm binos with a RadioShack photo transistor. Also did some scatter testing with the setup. With the moon up, we could hear very good returns off of trees > 1 mile away. Also were able to hear a return from clear sky at a low angle. Jim WB9AJZ/6 CM87xi (Sunnyvale, CA) >From owner-laser Fri Jun 20 11:05:24 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA25468; Fri, 20 Jun 97 11:05:24 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f From: daveaa1a@ssih.com Date: Fri, 20 Jun 1997 14:07:17 -0400 Message-Id: <199706201807.OAA11210@ssih.com> Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Subject: Re: [LASER] Quieter Receiver To: Walter Miller Cc: laser@qsl.net In-Reply-To: X-Mailer: SPRY Mail Version: 04.00.06.17 Reply-To: daveaa1a@ssih.com Sender: owner-laser@berlioz.nsc.com Precedence: bulk Howdy Walt, >I am trying to sort out the various ideas and claims made here on the >reflector. Would you please describe your PD JFET circuit to me. A PD from the ground plane directly into the jfet gate, NO RESISTOR.. Drain is 10k fil resistor and .01 into op-amp... Much decoupling between stages.. Source r/c is enough to cause about 400 ua. a film resistor.. Tried mgf1302 with no improvement.. Using mpf102.. Burr Brown op177 follows.. In dark, this amp. gets very sensitive.. It is somewhat deaf in the day but then a reverse bias in series with a 82k to 9vdc resistor fixes that.. >So far all I have used for my handful of 10-20 mile laser QSOs is an >OPT210 on the back of a Celestron C90 spotting telescope. >with a large enough feedback resistor it should be more sensitive >than that. Yes, it's a beaut. front end and plenty good.. Now the PD into jfet is a order of magnitude or two improvement in SNR.. then its fed to the op-amp.. Luckily the pins on the 211 are available so that the front end can be patched to take the output from the jfet.. bypassing the built in PD.. >What size receiver optic are you using? 4" normal, 10" fresnel dx.. On the bench it is PD directly into IR diode 6" to 2' away inside a tube and the front end is covered up with opaque cloth.. Best senstivity so far is with 20mv pp into the diode at 1khz.. >external noise, or by dark current noise in your PD, or by noise from the >post amp? Not sure what you mean here but when the diode is dark, it sure hears a lot lower signal level.. Outside noises are loud and clear even if I don't know what some of em are.. I can tell leaves, strobes, bugs etc.. > >Would appreciate you comments. Yours too Walt, Always wanting to learn more.. Am building better mouse trap.. I liked your idea on the diode into mirrored dish for wide beam for local LAN work and not having to worry about the snow/rain/birds cutting link.. Any pointers appreciated, 73 de daveaa1a >From owner-laser Fri Jun 20 14:03:54 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA03495; Fri, 20 Jun 97 14:03:54 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f To: laser@qsl.net Date: Fri, 20 Jun 1997 17:04:57 -0400 Subject: [LASER] Summer Humidity ! Message-Id: <19970620.170459.4390.8.K3PGP@juno.com> X-Mailer: Juno 1.38 X-Juno-Line-Breaks: 0-1,7-8,14-15,22-28 From: k3pgp@juno.com (John K3PGP) Reply-To: k3pgp@juno.com (John K3PGP) Sender: owner-laser@berlioz.nsc.com Precedence: bulk I tried to run some tests last night but was extremely disappointed. The sky looked quite clear, for around here anyway, so I dragged everything out on the front porch and began setting up. I did notice that it felt rather sticky, sort of like a jungle but I did notice that I could see the stars quite clearly. It has been raining here the past couple of days and this was the first day the sun come out with the result that the temp was up in the 80's and lots of humidity. Well to make a long story short, I couldn't detect any signals other than those right in front of the lens! It didn't make any difference if I was pointed straight up or just above the horizon the signal level was the same. This was surprising to me because to the eye the atmosphere looked quite clear. The only obvious problem was the high humidity which I guess isn't compatible with 780 nm laser work! Unlike the laser scatter signals that I reported on earlier these signals were extremely strong. Those of you contemplating experimenting with laser scatter or cloud bounce might want to keep this in mind. Since this is my first summer trying to observe weak back scattered laser signals I don't know if this is going to hinder research or not. My guess is that I will have progressively fewer and fewer suitable days to run experiments until the weather cools off and the humidity goes down. John K3PGP@juno.com http://www.qsl.net/k3pgp/index.html -==- >From owner-laser Fri Jun 20 13:53:22 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA03061; Fri, 20 Jun 97 13:53:22 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f To: laser@qsl.net Date: Fri, 20 Jun 1997 16:50:39 -0400 Subject: Re: [LASER] Quieter Receiver Message-Id: <19970620.165411.4390.6.K3PGP@juno.com> References: <199706201807.OAA11210@ssih.com> X-Mailer: Juno 1.38 X-Juno-Line-Breaks: 0-6,9-10,14-15,21-22,27-28,34-35,40-41,44-45,47-55 From: k3pgp@juno.com (John K3PGP) Reply-To: k3pgp@juno.com (John K3PGP) Sender: owner-laser@berlioz.nsc.com Precedence: bulk On Fri, 20 Jun 1997 14:07:17 -0400 daveaa1a@ssih.com writes: >A PD from the ground plane directly into the jfet gate, NO RESISTOR.. >Drain is 10k fil resistor and .01 into op-amp... >Much decoupling between stages.. >Source r/c is enough to cause about 400 ua. a film resistor.. >Tried mgf1302 with no improvement.. Using mpf102.. Most people seem to be under the impression that a good RF device has to be a good quiet audio device. After all it does make sense, the lower frequency should allow a lower noise figure! Unfortunately this isn't always true and in fact is quite rare. Although all GasFets display higher noise figure with increasing frequency is it not widely known that many also display higher noise figure as the RF frequency is dropped below the design frequency. This became very apparent when many tried to use 12 Ghz GasFets for EME work on 432, 220 and 144 Mhz. Although they worked, cheaper lower frequency devices usually outperformed the more exotic and expensive devices. As one heads toward DC this problem gets progressively worse with some very good RF devices becoming real noise generators. This unfortunately is also true of many bipolar RF transistors. It's hard to beat the MPF-102 for an input device if you need the extremely high input impedance that a PIN photodiode requires to achieve optimum SNR. (>100 megohm input impedance!) I've also had good success with the 2N3819. However, some devices are quieter than others so sometimes by proper selection you can pick up a few dB SNR. To a lesser degree the second stage is also important. It's been my findings that a good low noise AUDIO NPN transistor plays better here than most op-amps. Either a 2N5088 or a 2N4124 are both suitable devices. You will most likely need something larger than an .01 for coupling though when using a bipolar second stage to achieve optimum coupling. I wouldn't consider dumping the MPF-102 directly into an op-amp. Although sometimes you can get away with it, the noise figure may be degraded somewhat and the MPF-102 can become unstable as Dave found out! A properly designed MPF-102 / 2N5088 preamp will be unconditionally stable without any special attention to filtering. And above all, the entire unit must be completely shielded. It doesn't take much coupling with a 100 meg input impedance to induce all sorts of unwanted noise! My favorite container is a tin can! Also, be especially careful when comparing detectors with different size active areas! I hope this is of some help to those seeking better sensitivity. John K3PGP@juno.com http://www.qsl.net/k3pgp/index.html -==- >From owner-laser Fri Jun 20 14:42:10 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA05428; Fri, 20 Jun 97 14:42:10 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f To: laser@qsl.net Date: Fri, 20 Jun 1997 17:38:57 -0400 Subject: [LASER] Answers! Or is is it more Questions ??? Message-Id: <19970620.173900.4390.9.K3PGP@juno.com> X-Mailer: Juno 1.38 X-Juno-Line-Breaks: 0-1,3-4,6-8,10-11,13,15,17,19,21-23,25-26,34-35, 45-46,51-55,57-58,60-63,65-68,70-74,76-77,79,81-82,84-87,94-95, 100-101,103-104,106-112 From: k3pgp@juno.com (John K3PGP) Reply-To: k3pgp@juno.com (John K3PGP) Sender: owner-laser@berlioz.nsc.com Precedence: bulk Bill: Sorry to overload your Email box today, but I'm working on a computer project so I'm right by the machine today! >When I analyzed that scatter1.wav file you presented I noticed it decoded >perfectly except for a couple of characters relatively close to the end >of the message. I wondered if perhaps the sampling clock wasn't at >*exactly* 8000 samples per second. When I decoded the data I assumed the >sampling rate was exactly 8000 s/s i.e. 160 samples per bit, and I also >assumed your 800 Hz tone was exactly on freq (i.e. that the 1.8432 Mhz xtal >on your SD board had been trimmed to freq). If the crystal in the SB was >off a bit it would explain why the errors did crop up near the end of the >record - my phasing would be starting to go off. I didn't make any attempt >to track the bit phase transitions - just found the best solution over the >whole file and imposed it everywhere. Now you know another reason why I dislike sound blaster cards or comestibles! My S-D board is on. However, the Pro-Audio sound card isn't and it can't be trimmed as it's one of those sealed in a can oscillators and I know for a fact that NONE of sample rates are on, something which always crops up when I'm doing precision audio work. (I own a 16 track digital audio recording studio based on the Alesis ADAT digital audio tape machines.) This gets to be a real pain when doing video editing on the computer. The lip sync always drifts off because of sample rate errors associated with the sound card! Keep in mind that particular audio track came off the logger machine which is a VHS Hi-Fi video tape recorder. The phase response and timing accuracy of this particular machine are better than my sound card as it's locked to a quartz crystal. It plays back pretty much what goes into it as long as you play the tape back on the same machine that recorded it! Otherwise the difference in the cheap crystal oscillator they use becomes obvious! No two machines run at exactly the same speed! Temperature stability is probably not the greastest either if you really push the issue, unless of course you are locked to an external standard which I can do with this machine. If I play the SCATTER1.WAV back into the S-D board I get 100% copy. However, is sounds like your direct method may be pushing the accuracy of my Pro-Audio card a bit. It's the weak link NOT the tape machine! I'll keep this in mind next time I record something. By the way did I mention the fact that I HATE SOUND CARDS???? ----- >>The only problem with above is that the MINIMUM time I can program the >>hard drive shutdown for is something like 7 minutes! I think the options >>are disable (runs all the time), 7, 15, and 30 minutes! Apparently it >>takes more energy to bring the drive up to speed than what would be saved >>by cutting it off immediately. Of course it also makes access time >>unbearable. > >There is another solution - define a small RAMDISK area and run the program >from that. If you use the TRACE mode, make sure the RAMDISK has enough >space allocated to handle the expected output. This fixes access time but the hard drive still keeps running! I'm already using a 2 Mb ram disk. Thanks for the suggestion though. ----- >Them's nice words, John. >But the SD board isn't all that great - the dual op-amp in the integrator >comparator section is way too slow for the job. It was used as a >compromise - cheap solution with good enough performance for most people. >If you replace it with a faster part the ability to follow a fast-changing >signal with a lot of bits of digitization will improve. Use one with >the fastest slew rate even though it will eat up your battery. I never do >this with my SD boards, but I have received reports from people who have >made the change and they say they noticed an improvement in performance. I know the S-D board can be improved. I have a couple of Sigma-Delta type boards in my studio that run at the CD audio sampling rate of 44.1 Khz so I know what they are capable of. However, I thought the present board was plenty fast enough to digitize an 800 Hz signal at 7.2 Khz / second. I can understand the improvement when following a fast changing signal but I find it hard to believe that much improvement can be done at 800 Hz. If you feel I can pick up some performance by some modifications I'd like to know more about it and any suggested parts. Believe me the EME experiment is going to be going to be tough going with the amount of laser power that I have! Even a couple of dB could make the difference between success and failure. Since I have a rather elaborate array of audio test equipment I can easily document the change (if any) in performance at 800 H. My S-D board is powered from the same AC power that powers the laser so batter power isn't a factor. John K3PGP@juno.com http://www.qsl.net/k3pgp/index.html -==- >From owner-laser Fri Jun 20 15:32:56 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA07721; Fri, 20 Jun 97 15:32:56 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f Date: Fri, 20 Jun 1997 15:28:09 -0700 (PDT) From: Walter Miller X-Sender: aj6t@slip-3 To: laser@qsl.net Subject: [LASER] Using cheap pan/tilt heads Message-Id: Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Reply-To: Walter Miller Sender: owner-laser@berlioz.nsc.com Precedence: bulk Here is a simple (and obvious) tip for those of us using inexpensive tripods with conventional pan/tilt heads. In previous work with my laser transceiver (OPT210 behind a Celestron C90 telescope, and 670 nm laser pointer boresighted to each other), I had a lot of trouble pointing the assembly on target and holding it there. The target was the bright laser beam from WB9AJZ/R 20 miles away visible in the C90 finder scope. It recently became obvious to me that a big part of the pointing difficulty was due to sag in the tilt (elevation) direction as I attempted to lock the mechanism in place. Simply scabbing on a homebrew counterweight which balanced the telescope/laser assembly made it MUCH easier to point and lock the pan/tilt head. My last-minute counterweight mechanism came from the hardware store the morning of the VHF contest. It consisted of a metal "mending plate" with a very heavy steel washer held onto it by a screw and wing nut. The mending plate was attached to the pan/tilt head with a C-clamp, and the heavy washer was positioned on the right hole in the plate to achieve a balance. With this arrangement (and after the laser and telescope were boresighted to each other), I was able to move the entire assembly right onto alignment with AD6AY's million candlepower lamp and complete a QSO without any more fuss with alignment on my end. By the way, the only reports of laser QSOs that I have seen from the recent VHF contest were from one east coast multi-multi (N2YB?) reported on the VHF reflector, WB9AJZ and captive rover KD6OSV (short distance in the wilds of CN70), and AD6AY/AJ6T (two QSO/grids, 20 miles over Silicon Valley). Anybody else have any laser QSOs to report? 73, Walt ------------------------------------------------------------------------ Walter Miller, AJ6T Saratoga, CA USA CM87 Reply to aj6t@slip.net >From owner-laser Sat Jun 21 08:53:52 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA16505; Sat, 21 Jun 97 08:53:52 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f To: chrise@n0jcf.com, laser@qsl.net, aballen@colby.edu, k3tkj@qsl.net Date: Sat, 21 Jun 1997 11:50:34 -0400 Subject: Re: [LASER] light damage to unpowered PMTs ? Message-Id: <19970621.115037.19326.0.K3PGP@juno.com> References: X-Mailer: Juno 1.38 X-Juno-Line-Breaks: 1-3,5-27,32-35,37,40-41,45-46,49-50,54-58,60-61, 66-67,69-71,73-74,79-80,86-89,94-111,113-115,117-122,124-133, 135,137-142,144-148,150,152,154-174,177-180,182-191,194-198,200,202-218 From: k3pgp@juno.com (John K3PGP) Reply-To: k3pgp@juno.com (John K3PGP) Sender: owner-laser@berlioz.nsc.com Precedence: bulk On Thu, 19 Jun 1997 17:42:32 -0500 (CDT) chrise@n0jcf.com (Chris Elmquist) writes: >>John K3PGP wrote: >>(Photomultiplier tubes). If you run across any PMTs be advised that >>they are easily damaged by exposure to light (even when NOT powered up) >>and ^^^^^^^^^^^^^^^^^^^^^^^^ ----- >I keep hearing this... and was banned from the "geek table" >at lunch... when I mentioned it in front of a bunch of PhD physists >and EEs. They all insist that if the PMT is not under bias, then it >can not be damaged by exposure to light. > >I was convinced by these guys that this is an urban myth. > >Can someone explain the mechanism for damage when the PMT is not >powered up ? > >I'd appreciate it... I'd like to get back to the geek table. > >Chris > >-- >Chris Elmquist, N0JCF >chrise@n0jcf.com >n0jcf@amsat.org > Sorry this took so long Chris, but since you asked for an "explanation of the mechanism involved" I wasn't sure how to respond. I have seen a detailed article on exactly what happens that was published many years ago but unfortunately I don't remember where the article was published. I think it was some type of journal related to astronomy. About all I can offer is personal experience and the comments of others. I recently tested 193 PMTs that were not in boxes and were sitting in a warehouse under fluorescent lights. Result: Only 10 tubes were useable and even those had high dark current. So you say this doesn't prove anything as the tubes were probably bad before they were stored. Possibly! However, they were removed from WORKING equipment! The tubes that were marginally good were always located near the bottom of the box away from the light! None of the ones on top were any good. They worked electrically but the dark current was so high any hope of recovering a useable signal was hopeless. After storing for three months under dark conditions (and checked once a month) the dark current steadily dropped and is now about back to normal... On SOME of the tubes !!! Since these tubes were taken from working equipment and are showing signs of recovery after being stored under dark conditions I have to assume that the high dark current was caused by exposure to normal room lighting conditions. The only reference I could come up with at the moment is the following: ----- >From QST September, 1990; "A Laser Communications Primer", Bryan Bergeron, N1UN: "PMTs should never be exposed to ordinary light levels, because after even a short exposure to normal daylight, the PMT may require a day or more to return to normal dark-current levels. For example, the flash I used in taking the photo of Fig 6, resulted in an abnormally high dark current in that PMT for almost 2 days. (20) P. Horowitzh and W.Hill, "Measurement and Signal Processing," The Art of Electronics (Cambridge, Ma; Cambridge University Press 1980) ----- The photograph in Fig 6, shows the PMT laying on a table, not hooked to anything and obviously NOT under any bias! A couple of years ago before I knew better, I was playing around with a Dumont 6292 PMT which was working just fine. I opened the housing to do some mechanical work on the mounting system and never bothered to cover the PMT. Like your friends, I assumed that if the HV was turned off no damaged could be done. WRONG! When I powered the thing back up I was shocked at the noise floor! I didn't change anything electrical. After checking and rechecking I couldn't find anything wrong. Only after several days did the noise floor (dark current) start to fall but it took several weeks for it to get back to where it was before I exposed the PMT to normal room lighting! I'm told I was extremely lucky as some PMTs NEVER recover! >From my own experience I can state that the sensitivity doesn't seem to change much after a brief exposure to normal room lighting. HOWEVER, the BIG problem is the noise floor comes up (dark current) with a result that the SNR (signal to noise ratio) is degraded. This was from an exposure of less than five minutes to normal room lighting. ----- >From PREVIOUS posts to this laser reflector: ----- Begin Included Messages ----- >From music@Tempe.ate.slb.com Wed Apr 23 10:00 MST 1997 From: music@Tempe.ate.slb.com (Doug Music) Date: Wed, 23 Apr 1997 10:06:25 -0700 (MST) Subject: PMT repairs and HV adjustments To: c1040@azfms.com Mime-Version: 1.0 The surface of the photocathode is EXTREMELY sensitive to having a layer of unwanted atoms on it. The silver on the inside of the glass is often a RESULT of the "getter" firing. The internal thermal mass of the tube is damned tiny. Ok, here goes the story. Normally, as has been reported, the tube is stinkin hot when sealed. This degasses the surfaces. You'd think that just firing the getter again would do, but the problem isn't free atoms in the vacuum, it's more likely atoms stuck on the photocathode and dynodes. So... We heat up the tube to a few hundred degrees and the atoms are teased off the surface and the still active chemistry in the getter and on the silver surface deposit grab hold of these atoms when they happen by. The reason we heat for so long is that we want to use the minimum heat and chemistry runs forward based on heat, concentration, time, etc. The reaction to the getter material is two way but the low heat radically prefers the silver over the photocathode and/or dynodes. Also, temp is an average of the molecular energy and we are playing on the 2 and 3 sigma part that imparts thousand degree+ temps on single molecules from time to time. You exponentially drive this forward as you increase the temp. The trick is knowing when your beginning to drive atoms back off the silver and other good stuff from the getter. That's why 450 degrees over time is better than 600 over a short time. HV adjustments: Yes, PMT's do behave with certain "personalities" in regard to the voltage and SNR. They also do this for voltage vs sensitivity. The bummer is that the highly sensitive domain is also noisy as all get out. Use of a ferrous metal container is important because these PMT's make great receivers. You need to block all sources of light, heat, magnetics and RF. Your food can idea is right on target. Cool... Oh yeah, if you want to see noise go down, use a TE cooler on the tube and chill it down. As you push toward max sensitivity, thermal noise gets real bad. -Doug ----- John, DON'T THROW AWAY THAT PMT!!! [unless you want to throw it to me ;-) - rusty] If your interested, try this trick. Put the light zapped PMT in your oven and bring it to 250 F. Wait 10 minutes and bring it to 350 F. Wait 10 minutes and bring it to 425 F. Wait 4-8 hours and turn it off. LEAVE THE TUBE IN THERE TILL BELOW 150 F. Give the tube a try again. This ONLY works for bakeproofed tubes (thermoset as opposed to thermo plastic bases). If your tube has thermo plastic it will melt. If it has thermoset plastic, it will not. Your call. This trick works on a lot of imaging tubes and can be used to drive the sensitivity way up. This also CREAMS A LOT OF TUBES so don't do this to a known good tube. Oh... do this in dark conditions...NO light AT ALL while hot. -Doug Some PMT's have a glass base so nooo problem. The way tubes get creamed (and why you should NOT try this on a good tube you can't afford to cream) is when the internal "getter" boils off and deposits crud on things it shouldn't. You want to SLOWLY activate the getter just a little. That scrubs the vacuum. But it can also do the big nasty to the photocathode surface and dynodes. This is why baking IR tubes is soooo tricky. I've been able to take totally dead IR tubes and PMTs and get them to outperform spec. This is where the PMT's that Rusty and I have goofed with came from. But I must admit to having learned the tricks the expensive way. I totally creamed a fair number of marginal devices. (blush) Oh well... -Doug ----- I hope this helps. Perhaps some others can offer their input on this.... John K3PGP@juno.com http://www.qsl.net/k3pgp/index.html -==- >From owner-laser Sat Jun 21 17:33:27 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA04352; Sat, 21 Jun 97 17:33:27 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f Message-Id: <33AC646A.11ACD32C@qsl.net> Date: Sat, 21 Jun 1997 19:31:54 -0400 From: K3TKJ Organization: http://www.qsl.net X-Mailer: Mozilla 3.01Gold (X11; I; Linux 2.0.28 i486) Mime-Version: 1.0 To: alllists@qsl.net Cc: qsl-net@qsl.net Subject: [LASER] Invitation to join QSL.NET Content-Type: text/plain; charset=us-ascii; name="radio1" Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="radio1" Reply-To: K3TKJ Sender: owner-laser@berlioz.nsc.com Precedence: bulk Dear Fellow Radio Amateur, As a user of a mail reflector from QSL.NET, I would like to personally invite you to use the other *FREE* services available here. If you haven't already..... check out http://www.qsl.net This is what you'll get: E-mail account that you can use locally or have forwarded to your regular account (Example: K3TKJ@qsl.net , NE3Y@qsl.net , YOURCALL@qsl.net) 35 Ham Radio List Servers (reflectors) (mail majordomo@qsl.net with the message "lists" for the latest list) Coming soon Ham Radio IRC Channel Coming soon News Server FTP privleges....anonymous as well as a private area Your own personal Web site....Try these pages now at: http://www.qsl.net/k3ap/useridx.html ( No size quotas.... I just ask you to be reasonable) Here are the rules: 1) NO COMMERCIAL USE! 2) I'm not going to write the page for you. Isn't it time you learned something new? ( but we do have volunteers who will help you through the rough spots....we won't let you fail) 3) You have an Amateur License. (You mean you don't have it yet?? Then e-mail me for info on SWL.NET all the same services!!) That's it.... If you want to try it signup at http://www.qsl.net/signup.html Need more info? E-mail: k3tkj@qsl.net 73, Al Waller K3TKJ Laurel, Delaware QSL.NET, QTH.NET and SWL.NET are owned, operated and funded by K3TKJ.....don't ask me why I don't have a clue. >From owner-laser Mon Jun 23 08:12:32 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA22946; Mon, 23 Jun 97 08:12:32 PDT Date: Mon, 23 Jun 1997 10:09:04 -0400 Message-Id: <199706231409.KAA06167@ns1.qsl.net> X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f From: Frank Alwine X-Mailer: Mozilla 2.02E-KIT (Win16; U) Mime-Version: 1.0 To: laser@qsl.net Subject: [LASER] *Help with laser Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Reply-To: Frank Alwine Sender: owner-laser@berlioz.nsc.com Precedence: bulk A friend just gave me a 2mW Helium Neon laser he got at a swap meet... the previous owner claimed the laser is OK but the power supply that was attached was shot. I'm not sure what this laser was pulled from but all the case markings are in German. There's a diagram at the end where the cable from the power supply enters the case that shows a 1/4"-type phone plug with tip positive and ring ground and "12V 1A". So far, so good! However, I'm not sure if this is 12V DC, AC, or ? Last clue, and this is where I hope someone out there can help, is a European electrical marking that looks something like this: ----- - - - next to the 12V 1A marking. OK, so does this mean DC, rectified AC, AC, or ??? Thanks, Frank N1GPY >From owner-laser Mon Jun 23 10:25:48 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA28956; Mon, 23 Jun 97 10:25:48 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f Date: Mon, 23 Jun 1997 13:16:49 EDT Message-Id: <5251@ve3tok.ampr.org> From: "Bob (Boudewijn) M. G. Tenty" To: laser@qsl.net Subject: [LASER] Re: *Help with Laser Reply-To: "Bob (Boudewijn) M. G. Tenty" Sender: owner-laser@berlioz.nsc.com Precedence: bulk ___________ - - - - - - sign means DC direct current 73 - Bob HAMILTON, ON. CANADA Sysop Internet/Amprnet Gateway ve3mch +-----------------------------------------------------------------------+ | Bob(Boudewijn) M.G.Tenty - VE3TOK / PA0TOK///// //// //// / //// | | AMPRnet : ve3tok@ve3tok.ampr.org / / //// / //// | | PBBS : VE3TOK@VE3TOK.#SCON.ON.CAN.NA//// / / / | | Internet/UUCP : ve3tok@port.ve3mch.ampr.org | +-----------------------------------------------------------------------+ | Recyclable bits and bytes have been used for the message above. | +-----------------------------------------------------------------------+ World Wide Web http://www.ve3mch.ampr.org 60+ Reflectors/lists for the experimenter >From owner-laser Mon Jun 23 13:00:05 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA06345; Mon, 23 Jun 97 13:00:05 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f Date: Mon, 23 Jun 1997 12:54:46 -0700 From: c1040@azfms.com (Rusty Carruth) Message-Id: <9706231954.AA23644@fmsserv99.azfms.com> To: laser@qsl.net Subject: Re: [LASER] light damage to unpowered PMTs ? X-Sun-Charset: US-ASCII Reply-To: c1040@azfms.com (Rusty Carruth) Sender: owner-laser@berlioz.nsc.com Precedence: bulk from my remotely-connected (to the list) friend: ----- Begin Included Message ----- > Can someone explain the mechanism for damage when the PMT is not > powered up ? Simple. Any PMT can be creamed by light when not powered up. All you do is increase the light until the dynodes begin to melt. ;-) ;-) Naw, I know they can be harmed when powered up by several mechanisms, but powered down?? I don't see a mechanism for this unless it is by photo-induced hydrogen bonding to the photo cathode or dynodes. When this happens, the "getter" can be used to recover. Simply heat the PMT on a dark oven for a few hours. I have recovered "bad" PMT's at as low as 450 to 550 degrees. -Doug Douglas E. Music Voice: (602) 345-3625 FAX: (602) 345-8793 Pager: (888) 710-1508 Pager email: 905071@pagenet.net (200 chars) Email: music@san-jose.ate.slb.com Email: music@goodnet.com __o _`\<,_ _______(*)/_(*)__________ ----- End Included Message ----- >From owner-laser Mon Jun 23 13:59:26 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA09272; Mon, 23 Jun 97 13:59:26 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f To: laser@qsl.net Date: Mon, 23 Jun 1997 16:52:26 -0400 Subject: [LASER] Re: PMT Damage Message-Id: <19970623.165228.4822.0.K3PGP@juno.com> References: <3.0.1.32.19970621061327.008799a0@colby.edu> X-Mailer: Juno 1.38 X-Juno-Line-Breaks: 0-4,6-17,23-28,33-34,39-40,44-45,47-50,52-53,60-66 From: k3pgp@juno.com (John K3PGP) Reply-To: k3pgp@juno.com (John K3PGP) Sender: owner-laser@berlioz.nsc.com Precedence: bulk OK, Here's another one from another 'remotely connected friend !!! >I asked the Hamamatsu Sales Rep about this once, several years >ago. He explained to me that the photocoating had to be rugged >(mechanically), electrically conductive and yet the STILL needed >to respond when a single photon of light hit it! This is a TALL order >as most of us could imagine (after thinking about it a little). >Of course, in this entire process, it has to sit there and NEVER >generate any secondary or extraneous emissions! > >When pressed further, the guy finally stated that the coating was >VERY VERY thin and that light has mass and therefore can do >damage on a molecular level. His next sentence was something >about not being able to give further details, due to the proprietary >nature of the Hamamatsu coatings. Could this refer to the photo-induced hydrogen bonding to the photo cathode or dynodes? It would seem to me that something like this would take a LOT of light over a period of time! Either that or there was a lot of hydrogen floating around in the tube before the light hit it meaning it was already bad! But I never understood things like this anyway that's why I'm searching for answers! ----- Tell you what guys... I'm presently sitting on a number of marginal PMTs. When I get some free time I'm going to take some measurements on a PMT, remove it from the test gig and purposely expose it to various types of light (while powered down) then power it back up and measure the dark current again to see if it changed. I don't know if this will prove anything or not as I will NOT be doing it with one of my most sensitive tubes. Unfortunately it would probably be the most sensitive tube to this type of abuse. But it seems to me if this is a real problem (which I am told it is) than ANY tube should show some degradation. All I can tell you right now is I've accidently and very briefly exposed PMTs to normal room light while powered down and the dark current was noticeably higher for a couple days after doing so. However, this time I'm going to document it one way or another!!! If I succeed in degrading the tube I'll try baking it and either finish it off or recover it! How's that for an experiment??? Maybe we can even auction the tube off to the LOWEST bidder after I'm done with it! PS - I've noticed that 'SOME' new PMTs that I've seen come with a light tight cap over the front end. Why would they take this precaution if extraneous light weren't a problem??? (Most if not all are shipped in a powered down condition :-^) !!! Maybe this isn't true of all manufactures though since I've only ever seen a couple of brand new ones and only some of them had the cover in place. Other's came wrapped in aluminum foil. John K3PGP@juno.com http://www.qsl.net/k3pgp/index.html -==- >From owner-laser Mon Jun 23 20:23:12 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA28680; Mon, 23 Jun 97 20:23:12 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f Date: Mon, 23 Jun 1997 23:18:11 -0400 (EDT) From: "C. W. Wright" X-Sender: wwright@wayne.home.net To: John K3PGP Cc: laser@qsl.net Subject: Re: [LASER] Re: PMT Damage In-Reply-To: <19970623.165228.4822.0.K3PGP@juno.com> Message-Id: Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Reply-To: "C. W. Wright" Sender: owner-laser@berlioz.nsc.com Precedence: bulk > extraneous light weren't a problem??? (Most if not all are shipped in a > powered down condition :-^) !!! Most? I've yet to see a single one shipped with power on !! :-) I want to see the poor guy who gets to remove the powered-up PMT from the box with 1500 to 2000 volts already applied. I've operated various pmts at the back end of a 12" telescope which is always used to look at targets during the day, we've changed them out with the lights on ( power off) many times before. In almost twenty years, I've only seen two tubes fail for no apparent reason, and they probably had dynode resistor problems. We have noticed the gain increase with application of abmient light just before saturation. That is, the pulsed signal will increase as the ambient light level is somewhat below the saturation point, then the pulse disappears after ambient saturation is reached. Remove the ambient light, and the pulse returns. No noticable increase in noise. Just got one of the Hammamatsu TO-8 can pmts today and it looks *very* good. Risetime 0.65ns, gain 5x10+5, small, even a builtin hv power supply so the thing runs from 12vdc with only 12ma of current. It operates from 300-800nm and we looked at a doubled yag with a pulse width of 1.27ns and got 3.1ns pulse from the pmt. The whole little package is $650. We were getting 2.5 volts of output into 50 ohms even while looking throuh a paper cover on the tube, toward the laser. It was seeing the exiting pulse as well as reflections from both ends of the room easily. I think the To-8 tube alone is $450. -Wayne >From owner-laser Mon Jun 23 20:38:53 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA29348; Mon, 23 Jun 97 20:38:53 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f To: laser@qsl.net Date: Mon, 23 Jun 1997 23:35:38 -0400 Subject: [LASER] Re: PMT Damage Message-Id: <19970623.233539.8830.0.K3PGP@juno.com> References: X-Mailer: Juno 1.38 X-Juno-Line-Breaks: 1-7,9-20 From: k3pgp@juno.com (John K3PGP) Reply-To: k3pgp@juno.com (John K3PGP) Sender: owner-laser@berlioz.nsc.com Precedence: bulk On Mon, 23 Jun 1997 23:18:11 -0400 (EDT) "C. W. Wright" writes: > >> extraneous light weren't a problem??? (Most if not all are shipped >in a powered down condition :-^) !!! > > >Most? I've yet to see a single one shipped with power on !! :-) I >want to see the poor guy who gets to remove the powered-up PMT from the box >with 1500 to 2000 volts already applied. > Hey, Cliff this was meant to be a JOKE !!! :-^) Thanks for the input. Your type of experience is what I'm looking for! John K3PGP@juno.com http://www.qsl.net/k3pgp/index.html -==- >From owner-laser Mon Jun 23 22:38:45 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA05191; Mon, 23 Jun 97 22:38:45 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f To: laser@qsl.net Date: Tue, 24 Jun 1997 01:33:43 -0400 Subject: [LASER] Re: PMT Damage Message-Id: <19970624.013344.13670.2.K3PGP@juno.com> X-Mailer: Juno 1.38 X-Juno-Line-Breaks: 1-7,10-11,14-15,21-22,29-30,33-34,39-40,44-45,47-50, 56-57,62-63,65-66,71-72,76-84 From: k3pgp@juno.com (John K3PGP) Reply-To: k3pgp@juno.com (John K3PGP) Sender: owner-laser@berlioz.nsc.com Precedence: bulk On Mon, 23 Jun 1997 23:18:11 -0400 (EDT) "C. W. Wright" writes: > >I've operated various pmts at the back end of a 12" telescope which is >always used to look at targets during the day, we've changed them out Wayne: After thinking about this I'm not sure you would be able to observe the shift in parameters that we're talking about. I don't think you would notice it under daylight conditions! As I said before I recently tested approx. 200 PMTs. These were tested for dark current (absolute darkness no signal) then with a weak signal and a strong signal. ALL tubes but one passed the strong signal test. Any of these tubes would work find under daylight conditions or under high ambient light conditions such as moonlight or man-made light bouncing off of clouds where the external light levels would mask the internal noise of the tube. Most of these tubes however, would be unsuitable for my work as I am working with signals that are much weaker than this. Out of the whole batch only 10 tubes passed the weak signal test because of elevated dark current. After storing for approx. 3 months under dark conditions many of the other tubes that I had previously marked bad due to high dark current now appeared to be in pretty good condition. Although the weak signal test was dramatically improved there was NO change in strong signal performance. The only difference I could detect was a drop in dark current. I think there is a difference in how the tube is being used as to whether this is a problem or not and may explain why there is a difference of opinion. >From what I remember the first time I heard of this was either back in the late 60's or early 70's when pulsars were first discovered. There was an article in one of the astronomy journals that described how one of the observatories was trying to detect optical pulsars and match them to radio emissions. I don't remember the reason why but the dome was open when they decided to add some modifications to the PMT setup and the tubes were exposed to daylight for a couple of minutes. Of course the power was off so no one got knocked on their can. The article went on to say that the performance of the instrument was seriously degraded for several weeks after this. I'll see if I can locate the article next time I'm at the library. The shift in dark current that I have seen is such that it does NOT affect strong signal performance. Although I usually don't run any of my PMT setups in daylight, I have tried using one with a small pin hole in front of it and I can tell you that even with the pin hole the noise floor was so high that it would mask any degradation effect from elevated dark current. I am typically running with signals that are right at the noise floor or as much as -43 dB below it under dark conditions. The signals require computer DSP to even be detectable! Any increase in dark current would immediately be noticeable and would mask what little signal I have to work with. I value your observation very much. I think your application though is different enough that you may not be troubled by this problem. What I am going to do is take a known PMT and gradually expose it to various light levels (with NO power applied) then re-check the dark current. This unfortunately will have to be done with a tube that is in pretty good condition, that is one that has been stored under dark conditions. What I think will be observed is an increase in dark current which would affect extremely weak signals under dark conditions but would have absolutely NO effect on strong signals or when the tube is run under high ambient light conditions which would mask the internal noise of the tube. I'll let you know my findings... John K3PGP@juno.com http://www.qsl.net/k3pgp/index.html -==- >From owner-laser Tue Jun 24 05:26:25 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA22117; Tue, 24 Jun 97 05:26:25 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f Date: Tue, 24 Jun 1997 08:22:11 -0400 (EDT) From: "C. W. Wright" X-Sender: wwright@wayne.home.net To: John K3PGP Cc: laser@qsl.net Subject: Re: [LASER] Re: PMT Damage In-Reply-To: <19970624.013344.13670.2.K3PGP@juno.com> Message-Id: Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Reply-To: "C. W. Wright" Sender: owner-laser@berlioz.nsc.com Precedence: bulk > After thinking about this I'm not sure you would be able to observe the > shift in parameters that we're talking about. I don't think you would > notice it under daylight conditions! This may very well be true, although we slice the entire visible spectrum into 10nm slices, and feed each slice to a different tube. Also, we have to operate the tubes near their maximum voltage to achive the desired signal levels. We extract two different signals from the tube. The first being the laser return pulse, and the second the ambient light level. The load resistor for the ambient light signal is 100,000 ohms and a full scale signal would be 10 volts which indicates a current flow of 70ua from the pmt. We digitize to the 12 bits which give us 4096 counts, so one count is equal to 17.1 pico amps of current and 1.71 milivolts. The bandwidth of the ambient channel is a few kilohertz. > tube. Most of these tubes however, would be unsuitable for my work as I > am working with signals that are much weaker than this. Below the "single photon level" ??? > Out of the whole batch only 10 tubes passed the weak signal test because > of elevated dark current. After storing for approx. 3 months under dark > conditions many of the other tubes that I had previously marked bad due > to high dark current now appeared to be in pretty good condition. How about powering them up under complete darkness for a time? Maybe the spare trons in there could be removed quicker that way. This effect must be related to trons being kicked off the cathode and having no motivation ( voltage) to head toward the anode, then when the voltage is applied they start migrating that way. Just a thought. > I think there is a difference in how the tube is being used as to whether > this is a problem or not and may explain why there is a difference of > opinion. Very possible. When you connect a receiver capable of seeing fractions of a microvolt, in a narrow passband, I'm not sure how to relate that to our generally wideband pulse work in terms of noise. > The article went on to say that the performance of the instrument was > seriously degraded for several weeks after this. If they wrote a refed. journal article on the topic, it would be interesting and informative to read. > I am typically running with signals that are right at the noise floor or > as much as -43 dB below it under dark conditions. The signals require Just exactly where the actual noise floor is in terms of absolute -dbm radio terms may be the question. I think what's needed is a dependable weak signal source of known and reliable signal strength. Wayne K3ap >From owner-laser Tue Jun 24 18:34:46 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA29944; Tue, 24 Jun 97 18:34:46 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f Date: Tue, 24 Jun 1997 21:29:47 -0400 (EDT) From: "C. W. Wright" X-Sender: wwright@wayne.home.net To: John K3PGP Cc: laser@qsl.net Subject: Re: [LASER] Re: PMT Damage In-Reply-To: <19970624.013344.13670.2.K3PGP@juno.com> Message-Id: Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Reply-To: "C. W. Wright" Sender: owner-laser@berlioz.nsc.com Precedence: bulk > The article went on to say that the performance of the instrument was > seriously degraded for several weeks after this. Al ( K3tkj ) and I ran a quick and dirty test looking for the "after exposure" noise. Here's what we did. 1) connected the subject tube to a 1ghz digital scope, 50 ohm terminated, pmt cathode covered, voltage set to 1900 volts. We also fed a frequency counter with the pmt output so we could measure the noise events crossing a given milivolt threshold. Before we exposed the tube to the overhead fluro. lights, we observed noise pulse events at approx .5 hz. After exposing for two minutes with the voltge off and cathode exposed, we then recover the cathodes, and re-applied the voltage. We then observed a noise pulse rate increase to approx 70 hz, with an exponential decay down to the 4 to seven per second rate after abount 12 minutes. After that, the guy who owns the counter came and took it back so we don't know if it decayed all the way back down to the ..5 hz level of not. The area between these noise pulses is dead quiet, nothing there at all for very long periods of time, then another noise pulse. The tube we tested is a new tube ( rca 8644 ) 1/2" dia tube with a gain of approx. 50,000. For whatever it's worth... :-) Wayne >From owner-laser Tue Jun 24 19:03:48 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA01295; Tue, 24 Jun 97 19:03:48 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f To: laser@qsl.net Date: Tue, 24 Jun 1997 22:01:32 -0400 Subject: [LASER] PMT Experiments Message-Id: <19970624.220141.11902.1.K3PGP@juno.com> X-Mailer: Juno 1.38 X-Juno-Line-Breaks: 0-1,4-5,9-10,18-19,22-23,25-31 From: k3pgp@juno.com (John K3PGP) Reply-To: k3pgp@juno.com (John K3PGP) Sender: owner-laser@berlioz.nsc.com Precedence: bulk Wayne: VERY INTERESTING experiment! I really appreciate you running this test. I plan on doing something similar up here. It sounds like you're seeing something similar to what I'm seeing. When my PMT is running it sounds more like the white noise hiss that comes out of a VHF receiver with no signal applied. The noise is coming from the PMT and NOT the preamp. If I kill the HV it gets extremely quiet. Do you have anything between the PMT and the output such as a noise gate or some type of threshold device that may be holding back the noise floor? Some of my PMTs do have a noise gate electrode but it's biased so that it's on all the time. I know your setup is more oriented toward detecting pulses where mine is more like a conventional analog receiver. I don't do any type of processing (other than some gain stages) between the PMT and the A/D converter which feeds the computer. The VLF convertor takeoff is just before the A/D converter. PS - Where are you located? Any thoughts about some over the horizon laser scatter tests? If so you might want to check out VE2IQ's software for weak signal work... PS #2 - Didn't know you worked with Al. It's a very small world and shrinking isn't it! John K3PGP@juno.com http://www.qsl.net/k3pgp/index.html -==- >From owner-laser Tue Jun 24 19:56:52 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA03438; Tue, 24 Jun 97 19:56:52 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f Date: Tue, 24 Jun 1997 22:51:39 -0400 (EDT) From: "C. W. Wright" X-Sender: wwright@wayne.home.net To: John K3PGP Cc: laser@qsl.net Subject: Re: [LASER] PMT Experiments In-Reply-To: <19970624.220141.11902.1.K3PGP@juno.com> Message-Id: Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Reply-To: "C. W. Wright" Sender: owner-laser@berlioz.nsc.com Precedence: bulk > When my PMT is running it sounds more like the white noise hiss that > comes out of a VHF receiver with no signal applied. The noise is coming > from the PMT and NOT the preamp. If I kill the HV it gets extremely > quiet. For sure. With the gain of most any pmt being in the tens of thousands, no preamp is necessary. If you work backwards, you should find that even a single photo ( yes I mean one! ) can cause a fairly large "bunch" of electrons to flow. Your preamp is between the photo-cathode and the anode! We find pmts very nice to work with when compared to most solid state sensors and amplifier combinations. > Do you have anything between the PMT and the output such as a noise gate > or some type of threshold device that may be holding back the noise > floor? No, we're not using a gated pmt. In our operational system we do something called "range gating" but we apply anything to the pmt. We apply gating after the tube, in the follow-on electronics. Basically, we detect the exiting pulse, and use that signal to "start" a one-shot circuit which times-out just above the surface we're interested in. When it times out, we then simply trigger on the first pulse that crosses our threshold. We do all this triggering on the "on wavelength" channel. That's the channel with a pmt/filter which pass the laser wavelength. The signals in that channel are extremly strong. The signals we're interested in are weak. They are water-raman, choloryphy and other fluorosence signatures. Some of my PMTs do have a noise gate electrode but it's biased so > that it's on all the time. Yes, I've worked with gated tubes. You can generate a signal right out of noise with it. I don't think it has much application in cw work. You might be able to use it as a gain control if you don't like turning the hv up/down. :-) > I don't do any type of processing (other than some gain stages) between > the PMT and the A/D converter which feeds the computer. The VLF > convertor takeoff is just before the A/D converter. What freq. is your vlf? > PS - Where are you located? Any thoughts about some over the horizon > laser scatter tests? If so you might want to check out VE2IQ's software > for weak signal work... My house is in the woods, though I might have a narrow shot to the west - north west. I would be looking across the city lights of Salisbury Md at a low angle and I think that would be very noisy. I am interested in what's going on though. I did the fft stuff abt 10 years ago using a pmt and a digital scope with builtin fft software. It worked quite well, and produced nice signals. Best of all is the low cost, low bandwidth electronics needed. -Wayne >From owner-laser Wed Jun 25 17:52:57 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA07834; Wed, 25 Jun 97 17:52:57 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f Message-Id: <33B1BB63.3F7E@prodigy.net> Date: Wed, 25 Jun 1997 19:44:19 -0500 From: KC5AN Organization: Prodigy Internet X-Mailer: Mozilla 3.0 (Win95; I) Mime-Version: 1.0 To: Laser Reflector Subject: [LASER] Subcarrier modulation Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Reply-To: KC5AN Sender: owner-laser@berlioz.nsc.com Precedence: bulk On my next laser transmitter, I plan to use a 25 kHz sucarrier for voice. I picked 25 because it seems to be (just slightly) the most often frequency I have heard mentioned for this, and I am trying to be as "standard" as possible. For this reason I would like to know the more common modulation method for such a subcarrier among current laser oprators..... AM or FM? Many thanks, John KC5AN North Texas >From owner-laser Thu Jun 26 12:36:17 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA23338; Thu, 26 Jun 97 12:36:17 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f Date: Thu, 26 Jun 1997 12:25:31 -0700 (PDT) From: Clifford Buttschardt To: KC5AN Cc: Laser Reflector Subject: Re: [LASER] Subcarrier modulation In-Reply-To: <33B1BB63.3F7E@prodigy.net> Message-Id: Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Reply-To: Clifford Buttschardt Sender: owner-laser@berlioz.nsc.com Precedence: bulk Hi all and John. Regarding the freuquency to use for subcarrier generation, I've heard of two other popular frequencies: 40 and 65 KHz. 40 Khz is in use simply because piezioelectric transducers are widely available a tuned circuits! They are used in TV remotes and "bug chasers" and of course, small mechanically. 65 KHz was used in the optical communicator published first in Jan 94 "Practical Wireless". This approach was again used and circuits included in the "Communications Quarterly" for Spring 1995. At best this selection is a good guess between the one over F noise on the low freq end and the wider bandwidth noise of a higher freqeuncy. With due respect to the progress already made in baseband modulation, we should select some subcarrier to standardize upon. Cliff Buttschardt K7RR On Wed, 25 Jun 1997, KC5AN wrote: > On my next laser transmitter, I plan to use a 25 kHz sucarrier for > voice. I picked 25 because it seems to be (just slightly) the most often > frequency I have heard mentioned for this, and I am trying to be as > "standard" as possible. > > For this reason I would like to know the more common modulation method > for such a subcarrier among current laser oprators..... AM or FM? > > Many thanks, > John > KC5AN > North Texas > >From owner-laser Thu Jun 26 15:37:06 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA27513; Thu, 26 Jun 97 15:37:06 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f Date: Thu, 26 Jun 97 15:29:06 PDT From: jmoss@berlioz.nsc.com (Jim Moss) Message-Id: <9706262229.AA27331@berlioz.nsc.com> To: laser@qsl.net Subject: [LASER] subcarriers Reply-To: jmoss@berlioz.nsc.com (Jim Moss) Sender: owner-laser@berlioz.nsc.com Precedence: bulk I recently built a FM subcarrier system using 30KHz +/-5 seems to work fine. The PLL adjusts to the RX carrier and then locks. Jim WB9AJZ/6 CM87xi >From owner-laser Fri Jun 27 17:08:24 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA03801; Fri, 27 Jun 97 17:08:24 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f Message-Id: <33B54326.2DEA@alphalink.com.au> Date: Sat, 28 Jun 1997 10:00:22 -0700 From: Derek Weston Organization: Realtime Control X-Mailer: Mozilla 2.02 (Win16; I) Mime-Version: 1.0 To: laser@qsl.net Subject: [LASER] Laser IrDA links X-Url: http://www.qsl.net/wb9ajz/laser/laser.htm Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Reply-To: Derek Weston Sender: owner-laser@berlioz.nsc.com Precedence: bulk Hi folks, Just joined the mail list. Very interesting things going on. I'm experimenting with laser data comms using IrDA format. (details at http://www.vicnet.net.au/~upnet/status.htm ) Is anyone else on the list playing with laser data comms? Regards, Derek VK3BIJ >From owner-laser Sat Jun 28 15:57:28 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA05614; Sat, 28 Jun 97 15:57:28 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f Message-Id: <33B5949D.1E50@prodigy.net> Date: Sat, 28 Jun 1997 17:47:57 -0500 From: KC5AN Organization: Prodigy Internet X-Mailer: Mozilla 3.0 (Win95; I) Mime-Version: 1.0 To: Laser Reflector Subject: [LASER] Binocular lens cap & opt210 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Reply-To: KC5AN Sender: owner-laser@berlioz.nsc.com Precedence: bulk I'm afaid my only input to this reflector for a while is going to be a series of questions. So, here's the next one. I read a posting a while ago about mounting an OPT-210 to a binocular lens cap. The writer said that this way he could sight through one side of the binoculars & receive on the other side thru the OPT-210. I would like to hear more about this. Especially about the mounting of the OPT-210 & its associated components. Many thanks, John in N. Texas >From owner-laser Sun Jun 29 12:47:15 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA26006; Sun, 29 Jun 97 12:47:15 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f Message-Id: <33B6BBA3.1FD2@regensburg.netsurf.de> Date: Sun, 29 Jun 1997 21:46:43 +0200 From: thoborns X-Mailer: Mozilla 3.01 [de] (Win95; I) Mime-Version: 1.0 To: laser@qsl.net Subject: [LASER] want to be put on your mailing list Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Reply-To: thoborns Sender: owner-laser@berlioz.nsc.com Precedence: bulk I want to be put on your mailing-list in order to get information about laser modulation. Thanks Thomas Bornschlegel thomas.bornschlegel@regensburg.netsurf.de >From owner-laser Sun Jun 29 17:30:50 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA01271; Sun, 29 Jun 97 17:30:50 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f Date: Sun, 29 Jun 1997 17:19:35 -0700 (PDT) From: Clifford Buttschardt To: Bill Rausch , Dave Riley , Bill Lake , Lyle E Koehler , Johan Forrer , Bill DeCarle , Mike Cook Cc: Laser newsgroup , bpsk@qso.net Subject: [LASER] BPSK beacon 187.65 KHz improved Message-Id: Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Reply-To: Clifford Buttschardt Sender: owner-laser@berlioz.nsc.com Precedence: bulk Hi All. As part of field day, we put out four, five hundred foot ground radials under the HDO(nul) beacon. Of course they were not taken up (immediately) so the beacon has been retuned. Yes, I realize summer static might make reception difficult but if you have a moment, you might see if you can lock on with ms1000. The signal strength some ten miles away is more than four times what it was. Another suggestion of merit that just came by was for me to put on a laser modulated with the same information pointed some 16 degrees upward, pointed at the San Francisco Bay Area. If there is to be refraction from a layer some 18 miles up, two signal sources would be available containing similar information. Interesting idea 73 Cliff Buttschardt K7RR >From owner-laser Mon Jun 30 11:36:10 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA24003; Mon, 30 Jun 97 11:36:10 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f Date: Mon, 30 Jun 97 11:26:05 PDT From: jmoss@berlioz.nsc.com (Jim Moss) Message-Id: <9706301826.AA23729@berlioz.nsc.com> To: laser@qsl.net Subject: [LASER] Binocular lens cap & opt210 Reply-To: jmoss@berlioz.nsc.com (Jim Moss) Sender: owner-laser@berlioz.nsc.com Precedence: bulk John, That was me. I took a plastic lens cap and cut a small hole in the center, then mounted it to the OPT210. (put all your circuitry on the back side of the board to allow a good fit.) Lacking a good box and metal/plastic skills, I wrapped the whole thing in black plastic tape! Be sure to have a light tight seal between the 210 and the cap. Also beware of light leakage from behind. (That's why I taped the whole thing up.) It also makes sense to wrap it in Aluminum foil and connect to battery ground to eliminate pickup from RF sources, such as your laser modulator! The light seal on the lens cap to the bino eyepiece is quite good. I also then mounted the laser on top of the binos. My binos have a 1/4" screw adapter on them, allowing mount to a tripod and to mount an L bracket for the laser. I then sight through the open eye piece and align the laser. Works good for getting returns off stuff. Need a fine movement mechanism for the 2 way QSO's! Jim WB9AJZ/6 CM87xi ----- Begin Included Message ----- >From owner-laser Sat Jun 28 18:44:21 1997 X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f Date: Sat, 28 Jun 1997 17:47:57 -0500 From: KC5AN Organization: Prodigy Internet X-Mailer: Mozilla 3.0 (Win95; I) Mime-Version: 1.0 To: Laser Reflector Subject: [LASER] Binocular lens cap & opt210 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Reply-To: KC5AN Sender: owner-laser@berlioz.nsc.com Content-Length: 470 I'm afaid my only input to this reflector for a while is going to be a series of questions. So, here's the next one. I read a posting a while ago about mounting an OPT-210 to a binocular lens cap. The writer said that this way he could sight through one side of the binoculars & receive on the other side thru the OPT-210. I would like to hear more about this. Especially about the mounting of the OPT-210 & its associated components. Many thanks, John in N. Texas ----- End Included Message ----- >From owner-laser Mon Jun 30 17:20:49 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA05116; Mon, 30 Jun 97 17:20:49 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f Message-Id: <33B93BA2.6668@alphalink.com.au> Date: Tue, 01 Jul 1997 10:17:22 -0700 From: Derek Weston Organization: Realtime Control X-Mailer: Mozilla 2.02 (Win16; I) Mime-Version: 1.0 To: laser@qsl.net Subject: [LASER] Laser diode driver setup Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Reply-To: Derek Weston Sender: owner-laser@berlioz.nsc.com Precedence: bulk How do those of you who build your own laser diode drivers set the diode operating current? I'm playing with a driver design which both hard limits the laser diode current, and also regulates it on the basis of feedback from the monitor photodiode. It seems from my position of relative ignorance that the spread between individual ostensibly identical diodes in both the laser diode current and the monitor diode current are both too great to use either of these parameters for setting the operating point. Is using an optical power meter the only satisfactory way? If so, has anyone developed a home-brew power meter and a calibration process which results in useful accuracy? Suggestions would be much appreciated. Cheers, Derek VK3BIJ >From owner-laser Mon Jun 30 20:50:46 1997 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA11980; Mon, 30 Jun 97 20:50:46 PDT X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f Date: Mon, 30 Jun 1997 20:40:20 -0700 (PDT) From: Clifford Buttschardt To: Jim Moss Cc: laser@qsl.net Subject: Re: [LASER] Binocular lens cap & opt210 In-Reply-To: <9706301826.AA23729@berlioz.nsc.com> Message-Id: Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Reply-To: Clifford Buttschardt Sender: owner-laser@berlioz.nsc.com Precedence: bulk Hi all and Jim and John. I thought I would add this to the network regarding optics. The Fair Radio Sales addendum just arrived. They have six power rifle spotting scopes supposedly new for $15. In their view the only drawback is that they do not have crosshairs. Sounds like an advantage to us that do not need that function. Cliff Buttschardt K7RR On Mon, 30 Jun 1997, Jim Moss wrote: > John, > That was me. I took a plastic lens cap and cut a small hole in the center, > then mounted it to the OPT210. (put all your circuitry on the back side of > the board to allow a good fit.) Lacking a good box and metal/plastic skills, I > wrapped the whole thing in black plastic tape! Be sure to have a light tight > seal between the 210 and the cap. Also beware of light leakage from behind. > (That's why I taped the whole thing up.) It also makes sense to wrap it in > Aluminum foil and connect to battery ground to eliminate pickup from RF sources, > such as your laser modulator! > > The light seal on the lens cap to the bino eyepiece is quite good. I also then > mounted the laser on top of the binos. My binos have a 1/4" screw adapter on > them, allowing mount to a tripod and to mount an L bracket for the laser. I then > sight through the open eye piece and align the laser. Works good for getting > returns off stuff. Need a fine movement mechanism for the 2 way QSO's! > > Jim > WB9AJZ/6 CM87xi > > ----- Begin Included Message ----- > > >From owner-laser Sat Jun 28 18:44:21 1997 > X-Authentication-Warning: ns1.qsl.net: majordom set sender to owner-laser@qsl.net using -f > Date: Sat, 28 Jun 1997 17:47:57 -0500 > From: KC5AN > Organization: Prodigy Internet > X-Mailer: Mozilla 3.0 (Win95; I) > Mime-Version: 1.0 > To: Laser Reflector > Subject: [LASER] Binocular lens cap & opt210 > Content-Type: text/plain; charset=us-ascii > Content-Transfer-Encoding: 7bit > Reply-To: KC5AN > Sender: owner-laser@berlioz.nsc.com > Content-Length: 470 > > I'm afaid my only input to this reflector for a while is going to be a > series of questions. So, here's the next one. > > > I read a posting a while ago about mounting an OPT-210 to a binocular > lens cap. The writer said that this way he could sight through one side > of the binoculars & receive on the other side thru the OPT-210. > > I would like to hear more about this. Especially about the mounting of > the OPT-210 & its associated components. > > Many thanks, > John in N. Texas > > > ----- End Included Message ----- > >