From majordomo-owner@berlioz.nsc.com Mon Mar 3 15:53:58 1997 Date: Mon, 3 Mar 97 15:53:58 PST To: jmoss From: majordomo@berlioz.nsc.com Subject: Majordomo file: list 'laser' file 'laser.9604' Reply-To: majordomo@berlioz.nsc.com Content-Length: 53333 -- >From owner-laser Tue Apr 2 16:32:07 1996 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA07207; Tue, 2 Apr 96 16:32:07 PST Date: Tue, 2 Apr 96 16:32:04 PST From: jmoss (Jim Moss) Message-Id: <9604030032.AA07196@berlioz.nsc.com> To: laser Subject: passive repeaters Sender: owner-laser@berlioz.nsc.com Precedence: bulk >From what I have been reading on the VHF reflector it seems reasonable for us to consider placing a corner reflector on a hilltop to aim at, with a lense collector in the "middle" or near, into fiber (amplification would be better perhaps than passive), but.. for transmitting wide area what would be done? fibers pointing at each station? a hemispherical lense in the middle? Broad high power non-laser light (and count on RX to pick it up?) I'm generally thinking of a passive device we could use for aiming practice, and yet allow 2 way contacts. Jim, WB9AJZ/6 CM87xi Sunnyvale, CA >From owner-laser Wed Apr 3 01:33:33 1996 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA21938; Wed, 3 Apr 96 01:33:33 PST Date: Wed, 3 Apr 96 01:33:14 PST From: root (Operator) Message-Id: <9604030933.AA21924@berlioz.nsc.com> To: laser, outscr, standard, stream, tp4410sc, tpcsch, ts3040, usageman Subject: krueger: disk warning Sender: owner-laser@berlioz.nsc.com Precedence: bulk Please remove any unnecessary files. Disk /home/telstd (/dev/sd6c) is 99% full. The top users are: 363830 /home/telstd/standard 303095 /home/telstd/laser 189812 /home/telstd/outscr 166879 /home/telstd/stream 63563 /home/telstd/tpcsch 31057 /home/telstd/ts3040 8 /home/telstd/lost+found 2 /home/telstd/tp4410sc >From owner-laser Wed Apr 3 04:36:56 1996 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA25224; Wed, 3 Apr 96 04:36:56 PST Message-Id: <199604031235.AA025094931@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: Wed, 03 Apr 1996 12:35:15 +0000 To: laser@berlioz.nsc.com From: "Art Allen, KY1K" Subject: target practice.. Sender: owner-laser@berlioz.nsc.com Precedence: bulk Hi Everyone, I've been testing my modified bore sights in the front yard at about 150 feet range with good results. Indoors, I have been using about a 22 foot long test range with good results too. The advantage of the short distance outdoor range is that I can use a simple tin can, placed flat side facing the laser for a 'target'. I put an LED in the middle of the tin to give me something to aim at, when I hit it, believe me, it will leave no doubt! Ive been setting the laser up in front of the window, then cracking open the bottom of the window, so that the laser can get a direct shot without going thru the window glass..so, I even can stay warm and comfy. Works OK for 'target practice'. OK, last week I promissed a report on my modfoed bore sight design. Since we have alot of new users, I'll summarize slightly... Some discussion amongst group members have pointed out the short comings of using low power rifle scopes for aiming. Also, it appears no one was using simple bore sighting either. My tests revealed the problem with bore sights is that u need to be able to see the front edge of the sight and the rear edge in order to make sure they are inline...not easy to do in darkness. So, I came up with a 1X power alignment system using 'floating dots' in a tube-the dots are lighted and one is on each end of the tube. This is not without problems... In order to use it, your eyes must be able to FOCUS on the 2 sets of dots without blurring, even at 1 foot distance, this is no simple matter. If you stand back 3 feet, u can resolve the dots OK, but they are so far away that u can't align the dots with absolute certainty.... The answer, of course is to make the dots larger, so they can be seen at a greater distance, or perhaps to use simple optics to allow the eyes to focus on the dots at shorter ranges... Haven't tried either method... I glued some small corner brackets to the outside of the laser body and laid the modified bore sight in those brackets and secured them with rubber bands. To align, I cut various thickness 'shims' out of mylar and that works well. I can totally realign the thing in about 10 mins. I would like to report that with a 15 cm distance between the front sight and the rear sight, that I am able to place the laser reliably within 7 mrad (+/- 3.5 mrad). This is probably very usable for those running solid state lasers which dont have the tight beams that the HENE lasers do. At this tolerance, a solid state laser would probably have a 50-50 chance of hitting the target by aiming, then activating the tx, not to shabby.... A longer tube with increased distance between the front and rear sights would give more resolution, but of course it would be bulkier and heavier. ---------------------------------------------------------------------------- Hey, we have many new users! I'd like to welcome them all and invite them to introduce themselves and tell the group about their laser experiences.. 73 and GL...Art.... >From owner-laser Wed Apr 3 09:02:43 1996 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA04622; Wed, 3 Apr 96 09:02:43 PST Date: Wed, 3 Apr 96 09:02:36 PST From: jmoss (Jim Moss) Message-Id: <9604031702.AA04616@berlioz.nsc.com> To: laser Subject: re: passive repeaters Sender: owner-laser@berlioz.nsc.com Precedence: bulk Kent, I've been doing a lot of reading on the web about the various satellites that are used for laser ranging (SLR). Also found one site talking about MLR (moon). Seems most are using 7" or so telescopes with YAG lasers. Your note on a EME beam from Arizona... refers to amateur work? (not research lab/gov't?) What kind of power? There is a Japanese satellite up that apparently is "covered in mirrors" plus has many corner cube reflectors. Sounded like a good visible target. But of course we keep coming back to the aiming issue. Obviously a good telescope system with computer control will work, as that appears to be what is being used. There was also a description of "unmanned" operation sites for SLR. I can put together a list of web sites if there is interest. Jim WB9AJZ/6 ---- included below ---- >From kent.e.britain@bangate1.tek.com Wed Apr 3 07:56:40 1996 From: kent.e.britain@bangate1.tek.com Date: Wed, 3 Apr 96 5:52:17 CST X-Priority: 3 (Normal) To: Subject: re: passive repeaters Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Length: 423 Hello Jim: There have been some experiments illuminating a polished sphere to distribute modulated Laser energy, but it takes a lot of power. A retro reflect returns the energy to the uses. 8 years ago KY7B and I expored the possiblities of Laser EME. We got the specs on the Laser retros left behind by the Apollo astronauts. Those retros were so good, a beam from Arizona was returned to Arizona.!! Kent WA5VJB >From owner-laser Wed Apr 3 17:43:56 1996 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA22224; Wed, 3 Apr 96 17:43:56 PST Message-Id: <3163260B.2059@pcix.com> Date: Wed, 03 Apr 1996 20:29:47 -0500 From: Merv Organization: pcix X-Mailer: Mozilla 2.0GoldB1 (Win95; I) Mime-Version: 1.0 To: Laser group server Subject: SLR satellite info... Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: owner-laser@berlioz.nsc.com Precedence: bulk Re. SLR Satellites, a quick search using "AltaVista" and 'slr;satellite' returned 41 fascinating papers to read. Satellites orbits are being determined to better than one inch accuracy ! Apparently a couple of GPS satellites have retro-reflectors also. Merv, NC1K. >From owner-laser Thu Apr 4 01:39:59 1996 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA13865; Thu, 4 Apr 96 01:39:59 PST Date: Thu, 4 Apr 96 01:39:45 PST From: root (Operator) Message-Id: <9604040939.AA13836@berlioz.nsc.com> To: laser, outscr, standard, stream, tp4410sc, tpcsch, ts3040, usageman Subject: krueger: disk warning Sender: owner-laser@berlioz.nsc.com Precedence: bulk Please remove any unnecessary files. Disk /home/telstd (/dev/sd6c) is 99% full. The top users are: 363830 /home/telstd/standard 303095 /home/telstd/laser 189812 /home/telstd/outscr 166879 /home/telstd/stream 63563 /home/telstd/tpcsch 31057 /home/telstd/ts3040 8 /home/telstd/lost+found 2 /home/telstd/tp4410sc >From owner-laser Thu Apr 4 08:58:46 1996 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA25024; Thu, 4 Apr 96 08:58:46 PST Date: Thu, 4 Apr 96 08:58:43 PST From: jmoss (Jim Moss) Message-Id: <9604041658.AA25016@berlioz.nsc.com> To: laser Subject: krueger: disk warning Sender: owner-laser@berlioz.nsc.com Precedence: bulk No problems... Our disk is not the one listed. There is another user with the same name on a different node. Just ignore it. Sorry for the confusion. Jim WB9AJZ/6 BTW... The archive feature is enabled. You can retrieve a full list of all the emails sent (guess it saves them all as a single file). For more info on this: send an email to majordomo@berlioz.nsc.com and put HELP in the body. A list of all commands was sent to you automatically when you subscribed, but you may have trashed it so... HELP. Jim ----- Begin Included Message ----- >From sjnoll@ix.netcom.com Thu Apr 4 05:46:41 1996 Date: Thu, 4 Apr 1996 05:46:07 -0800 From: sjnoll@ix.netcom.com Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Subject: krueger: disk warning To: jmoss@berlioz.nsc.com X-Mailer: SPRY Mail Version: 04.10.06.22 Content-Length: 971 Jim: Do we have a problem here? I'd like to announce this listserv in my West Coast VHFer column, but I'm not sure if it's stable yet? What do you think? <---- Begin Forwarded Message ----> Return-Path: Date: Thu, 4 Apr 96 01:39:45 PST From: root@berlioz.nsc.com (Operator) To: laser@berlioz.nsc.com, outscr@berlioz.nsc.com, standard@berlioz.nsc.com, stream@berlioz.nsc.com, tp4410sc@berlioz.nsc.com, tpcsch@berlioz.nsc.com, ts3040@berlioz.nsc.com, usageman@berlioz.nsc.com Subject: krueger: disk warning Please remove any unnecessary files. Disk /home/telstd (/dev/sd6c) is 99% full. The top users are: 363830 /home/telstd/standard 303095 /home/telstd/laser 189812 /home/telstd/outscr 166879 /home/telstd/stream 63563 /home/telstd/tpcsch 31057 /home/telstd/ts3040 8 /home/telstd/lost+found 2 /home/telstd/tp4410sc <---- End Forwarded Message ----> Steve J. Noll | Ventura CA | WA6EJO | IEEE | AVS | sjnoll@ix.netcom.com ----- End Included Message ----- >From owner-laser Fri Apr 5 01:37:12 1996 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA19165; Fri, 5 Apr 96 01:37:12 PST Date: Fri, 5 Apr 96 01:36:59 PST From: root (Operator) Message-Id: <9604050936.AA19152@berlioz.nsc.com> To: laser, outscr, standard, stream, tp4410sc, tpcsch, ts3040, usageman Subject: krueger: disk warning Sender: owner-laser@berlioz.nsc.com Precedence: bulk Please remove any unnecessary files. Disk /home/telstd (/dev/sd6c) is 99% full. The top users are: 363830 /home/telstd/standard 303095 /home/telstd/laser 189812 /home/telstd/outscr 166879 /home/telstd/stream 63563 /home/telstd/tpcsch 31057 /home/telstd/ts3040 8 /home/telstd/lost+found 2 /home/telstd/tp4410sc >From owner-laser Fri Apr 5 07:15:29 1996 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA01466; Fri, 5 Apr 96 07:15:29 PST Message-Id: <199604051514.AA258837240@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: Fri, 05 Apr 1996 15:13:46 +0000 To: laser@berlioz.nsc.com From: "Art Allen, KY1K" Subject: misc Sender: owner-laser@berlioz.nsc.com Precedence: bulk Hi Everyone, Hey, I had a serious reality check yesterday and wanted to share the results with everyone. I did pass the word to Merv and Dave about this topic last month, but now I think its time for everyone to be made 'aware'. This probably doesn't apply to those outside the US. Yesterday, I visited my neighbor to do some tower installation related machine shop work. As I was walking down the stairs to his basement, I spotted 3 Hamamatsu R268 PM tubes laying atop a pile of junk at the base of his stairs. In talking to him about them, he said he didnt even know what they were, but that he had the PS for them and all the misc related electronics. He told me he paid 50 bucks for a pickup truck sized 'gamma ray detector' from the local VA hospital thru the Government surplus auction. He put in a bid of 50 dollars and was later told by the girl in the office that his was the only bid, and that a 5 dollar bid would have gotten him the same results! The machine was in working order, but just wasn't as accurate and precise as newer equipmet was, so they tossed it! Anyway, he got 3 PM tubes and power supplies along with all the electronics and a really big (heavy) gamma ray source. All of the tubes had consecutive serial numbers and a 1984 date of manufacture on them, I bet they are all in great shape! So, if u are looking for electronic parts and optics, the government surplus sealed bid auctions are probably a great source. I know they have them for different 'regions'. Incidently, he spent an entire day stripping the thing down, then took the aluminum to a scrap yard and sold it for 30 dollars! Scrap aluminum is a big high ticket item, esp'ly if its 'pure', meaning not mixed with other materials. -------------------------------------------------------------------------- OK, I've read the recent posts regarding the lunar reflectors and various man made earth orbiting satellites with mirrors on them. WOW, talk about the ultimate target practice! Years ago, there was a 12 foot diameter tin foil balloon in orbit, and various hams tried to make microwave QSO's by bouncing signals off of it. But, these special 'light only mirrors', although smaller than the balloon, should be FB since they are for 'light' only. Im not ready to undertake a wide range az/el laser aiming project....but, we might learn alot about developing aiming strategies if we did undertake such a project. Perhaps, with a wide range az/el system, you dont care about aiming at a specicic target, or even being able to 'see' that target. Maybe u just align your system to a 'local' hilltop, where u know the height, longitude and latitude.. Then just push a button and have your system rotate itself to the 'remote' target based on the previous 'benchmark' info?? Probably won't happen soon, but the ability to target a distant site without actually being able to 'see' it might be usefull, esp'ly for invisible IR laser Q's. Has anyone actually tried to hit any of these reflectors in orbit ??? It should be possible to see the reflection with the naked eye, and possibly you could mount your laser on a crude az/el setup and hand aim it, which would sweep it across the sky rather nicely. I'm not sure u could get a qso, but u should be able to atleast detect when u hit the satellite. Although the round trip distance would be atleast 250 miles, I dont think this is a problem as the Earths atmosphere is only 5 or 6 miles thick, after that, u have no attenuation and no scattering. The ultimate laser tag game I would say! ------------------------------------------------------------------------ Anyone know of a good windoze based satellite tracking program ??? 73 and GL...Art... >From owner-laser Mon Apr 8 08:46:06 1996 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA03229; Mon, 8 Apr 96 08:46:06 PDT Message-Id: <199604081541.AA11171@personal.eunet.fi> X-Sender: oh2aue@personal.eunet.fi Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Date: Mon, 08 Apr 1996 18:41:33 +0300 To: laser@berlioz.nsc.com From: oh2aue@personal.eunet.fi (Michael Fletcher) Subject: List newby... X-Mailer: Sender: owner-laser@berlioz.nsc.com Precedence: bulk Hi Chaps ! I exchanged a few words with Art, who mailed me after seeing 474 THz on my sig. I've been on the laser list for a couple of weeks now, but have not taken particular part in discussion, interesting as it all has been. I am pretty busy nowadays ( work - what else ), but I manage to spend some time on my other interests which include working on hardware for the up coming P3D satellite ( AMSAT-OH is delivering the 10 GHz transmitter ), microwave hardware construction and other interesting scientific gadgets - such as laser stuff ! I haven't got very far ( even QRB-wise ), but what I have right now is: - a couple of HeNe lasers 25 - 35 mW - three tweaked semiconductor lasers ( from laser pointers ) - a 10.5 cm refractor telescope ( last used on Hyakutake ... ) - a box of prisms, lenses, photodiodes, CCD's and like - a couple of fan modulators ( used for a two way QSO with OH6EH ) - a 5 MHz PWM modulator test circuit for a semiconduntor laser What I am keeping my eyes peeled for ( in addition of 5, 10 and 24 GHz TWT's ) are: - a PMT with PSU for the telescope - overhead projector surplus Fresnel lenses ( available from Edmund ) - spare time... - optoelectric modulators for about 5 - 10 MHz ( PAL video ) - a Bragg element ( on Lithium Niobate ) for a spectrum analyser - a neat collimator for the 35 mW HeNe-laser ( Yeah - Edmund have them ) The semiconductor lasers are dirt cheap. The majority ( at least here in Finland ) seem to come from the Far East. The most common type has a modulation pin input that is not used ( ! ) and a power adjustment ( a pot ), presumably for setting the output level to comply with the local authorities power restrictions ? The output level of these pointers is usually less than 0.5 mW, but this output can be increased considerably ( observations based on visible intenstity increase ). The operation voltage is typically 3 Volts. The laser units have a built-in focusing lens ( adjustable ). Michael OH2AUE P.S. Anybody going to NAB ? _\\///_ _ _ _ (' O O ') (_()_()_) I.O.O.F. *------------ooO-(_)-Ooo---------------------------* * Michael Fletcher OH2AUE: * * Vanhaistentie 4 C 43 50 MHz * * FIN-00420 Helsinki 144 MHz * * 432 MHz * * Phone/Fax + 358 0 566 62 63 home 1.296 GHz * * Cellular + 358 50 5505 293 2.304 GHz * * Phone + 358 0 1480 7521 work 5.760 GHz * * http://personal.eunet.fi/pp/oh2aue/ 10.368 GHz * * 24.092 GHz * * Life is above 1 GHz; 474 THz * * >99.9 % of the ham bands are there..... * *--------------------------------------------------* >From owner-laser Fri Apr 12 08:47:44 1996 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA07663; Fri, 12 Apr 96 08:47:44 PDT Message-Id: <199604121546.AA127813968@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: Fri, 12 Apr 1996 15:45:59 +0000 To: laser@berlioz.nsc.com From: "Art Allen, KY1K" Subject: SLR ideas? Sender: owner-laser@berlioz.nsc.com Precedence: bulk Hi Everyone, Hey, are you guys still alive out there ???? I've read the recent posts on Satellite laser ranging, and the idea sounds great, if nothing else, it should provide the ultimate in target practice..if we can hit a moving satellite in earth orbit, then a stationary ground target should be a piece of cake. Just the EXPERIENCE of trying to do SLR would probably advance our aiming techniques by several orders of magnitude. Some number of weeks ago, I did alot of research into methods of aiming using various 'hands off' techniques. All the basic concepts seemed to be usable and it looked like hands off techniques allowed a (normally sloppy) aiming platform to to perform rather nicely-it was amazing how much slop could be tollerated if the human never touched the platform! One of the most dependable and simplest methods I came up with was to simply mount a mirror on the shaft of a stepper motor and aim the laser at the mirror. 1.8 degreee per step motors that run on 5 volts are common surplus items. 1.8 degrees = 30 milliradians, so, with a 1 mrad beam, u would need to gear the stepper motor down to a 30 to 1 ratio in order to get full coverage between the steps. For a more typical 4 mrad solid state laser, u would only need to gear the motor down to a 7 to 1 ratio to get full coverage between the steps. Those using solid state lasers could actually mount the laser diode right on the shaft of the gearing mechanism. Sounds like a fairly easy way to get AZ or EL.... I wanted a more direct approach, one that didnt require external gearing tho. I tried several methods to 'damp' the mirror, so that the stepper could hold the mirror in any position between the steps... I tried various methods including fluid damping and magnetic damping, but just couldnt get the mirror to 'stop', except at the ends of the 1.8 degree steps. I was driving the stepper motor with a free running oscillator and a variable one shot multivibrator, in order to vary the duty cycle of the stepper motor drive, it appeared to be working, but, no matter what I did, I couldnt get the mirror to stop moving... I tried driving the stepper motor clock input at 10 khz and at 1 khz, and fixed the duty cycle at 50 percent, my hope being to have the mirror stop at about half way between the steps. Best I could do was to have the beam sweep about 7.5 mrad, I could NEVER get the blasted beam to stop. Any ideas ???? Towards this end, I've recently seen megabuck controllers for stepper motors advertised. They claim to use 'proprietary' techniques, but they can do 'partial steps', up to 50,000 descrete positions can be selected per revolution of the motor. The only hints they give are that the drive speeds are arout 100 khz. Certainly, they aren't varying the duty cycle between the steps as I tried to do, they must be doing it some other way. It appears that they use standard old regular 'off the shelf' stepper motors. Does anyone have any idea how these megabuck controllers work ??? Also, has anyone actually tried hitting a satellite and watching for a beam to be refelected ?? 73 and GL...Art.. >From owner-laser Fri Apr 12 10:10:19 1996 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA10832; Fri, 12 Apr 96 10:10:19 PDT Date: Fri, 12 Apr 96 10:10:15 PDT From: jmoss (Jim Moss) Message-Id: <9604121710.AA10826@berlioz.nsc.com> To: laser Subject: steppers Sender: owner-laser@berlioz.nsc.com Precedence: bulk Great info avail able on www.cs.uiowa.edu/~jones/step/index.html see also zebu.uoregon.edu/~mbartels/altaz/altaz.html I've got a bunch more too. Been researching this on internet for the last week and a half. These telescope guys have stuf well under 1mR. another good site (but slow) www.newport.com/tutorials/Motorized_Actuators.html I bought 2 sets of motors: a pair of bipolar steppers 1.8 degree. These need an H driver, looking for a chip to do it. NSC makes one but have to find it. a pair of unipolar steppers 7.? degree. These are simpler to control. from old floppy disks. Haven;t started bench work yet. I have next week off!!! Hmmm. If only I didn't have to paint the house, sheet rock, texture, paint the garage, and then build organizers! Jim WB9AJZ >From owner-laser Sat Apr 13 04:06:57 1996 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA09704; Sat, 13 Apr 96 04:06:57 PDT Date: Sat, 13 Apr 1996 04:04:22 -0700 (PDT) Message-Id: <199604131104.EAA27959@valleynet.com> X-Sender: n7stu@mail.valleynet.com X-Mailer: Windows Eudora Version 1.4.4 Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" To: laser@berlioz.nsc.com From: n7stu@valleynet.com Subject: using surplus laser diodes Sender: owner-laser@berlioz.nsc.com Precedence: bulk Hi all, I have several laser scanner diodes and power supplies? that I would like to try out. Can anyone provide me with info on safely powering these up and specifications? Power supplies Scan-A-Matic 0284-3 T32001 5vdc " 1083F09 t32002 12vdc These have a seven section terminal strip for connections, a led and a small screw on the top. Diodes, Skan-A-Matic P33014 0585F 90 about 1" long x 1/4" dia. threaded, two nuts holding on an alum. plate (heat sink?) S3?22-3 ????83F53 (can't read it very well) blue block about 2" long with 1" of it about 3/16" dia. threaded. These appear to have some focusing optics built in, but not adjustable. Also have one laser diode assembly removed from an HP Laserjet IIID and several reject computer mice with IR diode pairs and chopper wheels. Any info/pinouts on these? Would like to get a pair going before the June contest. 73, Robert N7STU/YB2ARO, DM07aa/OI52ee n7stu@valleynet.com http://www.valleynet.com/~n7stu (WSWSS mirror & N7STU/YB2ARO homepages) >From owner-laser Mon Apr 15 08:19:26 1996 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA04907; Mon, 15 Apr 96 08:19:26 PDT Message-Id: <199604151518.AA059021483@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, 15 Apr 1996 15:18:02 +0000 To: laser@berlioz.nsc.com From: "Art Allen, KY1K" Subject: which sats have retromirrors? Sender: owner-laser@berlioz.nsc.com Precedence: bulk Hi everyone, Thanks to Jim, I got alot of info about stepper motors, a subject I wouldn't even have thought to look for on the WWW. The astronomy people have wide range stepper motor controlled mirror drives, which appear to meet our accuracy requirents for slr applications-90 degree EL and 360 AZ, with accuracy and reproducability in the arc second range. I'm curious about which satellites actually are used for slr? There was a mention of a JA satellite covered in mirrors, and that some GPS sats have retroreflecting mirrors on them. I wanted to look at some of these satellites orbits, and I've imported a high accuracy satellite tracking program. But I need to know which satellites have mirrors or retroreflectors on them. Anyone have this info??? Also, how big are the mirrors?? I did spend some time looking for this on the www, and found some slr info, but no satellite names or details of the retroreflectors themselves. HHHEEEELLLLPPP...... Art... They have software that can move stepper mot >From owner-laser Mon Apr 15 11:14:03 1996 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA12275; Mon, 15 Apr 96 11:14:03 PDT Date: Sun, 14 Apr 1996 11:43:00 -0700 From: sjnoll@ix.netcom.com Message-Id: <199604141843.LAA16867@dfw-ix2.ix.netcom.com> Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Subject: Laser Communication Range To: laser@berlioz.nsc.com X-Mailer: SPRY Mail Version: 04.10.06.22 Sender: owner-laser@berlioz.nsc.com Precedence: bulk Greetings Fellow Laser Cadets: Laser Communication Range I began writing this several weeks ago and soon became overwhelmed! There are _so_ many factors to consider in just trying to calculate the distance a given laser and receiver can communicate over. Looking at the range equation... 1 /4 * TX Power * RX lens area * Optics xmission * Ta \ - Range =| -------------------------------------------------- | 2 \ Pi * RX sensitivity * ((Laser divergence)^2) / Range = Kilometers TX Power = Watts RX lens area = square kilometers Optics transmission (1 = perfect. A single lens = 0.92) Ta = Transmittance of Atmosphere (/km). RX sensitivity = Threshold sensitivity in Watts Laser divergence = radians The 4 and the Pi are sometimes left out. Well, the TX Power is pretty self-explanatory. By the way, a "5 mW" label on a laser doesn't mean it puts out 5 mW. It means it doesn't put out _more_ than 5 mW - otherwise it fits into a different laser hazard class. The receiver antenna area is simple too. It's probably a round conventional lens or a round or rectangular fresnel or a curved mirror. The optics transmission would be 1 for perfection. Deduct 4% for each lens surface, about 0.92 for a single lens. A mirror is more like 0.9 according to Edmund. Multiple lenses/mirrors have to be treated correctly mathematically. Now, I expect that a fresnel lens is significantly less efficient that a "standard" convex lens. It is kind of a synthesized trade-off lens. But so far I haven't found an actual efficiency figure. I talked to Edmund Scientific about this and was surprised to find out that they really don't have a clue! Rolyn Optics had no figures. Fresnel Technologies is supposed to have a catalog with such info in it, but after several weeks nothing has shown up. The second time I called them for a catalog the sales guy said that he has to have all catalog requests approved by their president! Found nothing in several optics books I've read, or on the sci.optics group. I'll search further - there's more optics books at work. Also - I don't believe that a typical fresnel will produce a small a spot as a conventional lens - but again I don't have any figures on this yet. The spot size is crucial especially if you're using a small-area detector (like if you were trying for high speed or low noise with a solid-state detector.) The inefficiency might be very significant. This can't be ignored for any kind of optical antenna - it every bit of the light you gather being focused within the active area of the detector? Not likely - unless you are using a photomultiplier with its typical large area, or a large photodiode. Some photodiodes and all(?) phototransistors have rather small active areas. The laser divergence is usually approximately known. Do try this - aim an average HeNe and a pen-pointer at a white surface 100' away and compare the spots. You might be surprised. My pen-pointers look more like the Mark of Zorro than the nice fuzzy HeNe spot. Now things get real difficult. Ta, the Transmission of the Atmosphere: (-a * R) Ta = exp Or, Transmittance of the Atmosphere equals 2.72 raised to the power of the negative product of the Atmospheric Attenuation Coefficient times the Distance. A perfect Transmittance equals 1. The Atmospheric Attenuation Coefficient is a factor you can get from a graph from the RCA Electro-Optics Handbook. The graph was derived from data in the Handbook of Geophysical and Space Environments, 1965, McGraw-Hill. R, the distance, is in kilometers. Again, the Atmospheric Attenuation Coefficient can be found on a graph, commonly called "Calculated Atmospheric Attenuation Coefficients for Horizontal Transmission at Sea Level in a Model Clear Standard Atmosphere" that covers 0.2 um to 4 um and factors in ozone absorption, Rayleigh and aerosol scattering. I'll attempt to read some numbers off of the graph: Wavelength Coefficient 400nm 0.245 500nm 0.18 600nm 0.16 700nm 0.14 800nm 0.13 900nm 0.12 1000nm 0.115 This standard graph does not take into account the various suck-outs due to water vapor, oxygen, and carbon dioxide. These suck-outs are approximately: Transmittance is 12% down at about 770nm 9% down at about 850nm 12% down at about 915nm 60% down at about 955nm I'll assume we're not interested in longer wavelengths due to lack of affordable lasers and detectors. There are no significant effects in the visible. Lets' run some numbers through. Laser Source Wvlngth Atten Coeff Ta nm (Std Clear) 10 miles 100 miles Helium Cadmium 442 0.21 0.034 2.1^-15 HeNe/Vis Diode 634 0.15 0.089 3.3^-11 Cheap Pen Point 670 0.14 0.105 1.6^-10 CD Player Diode 780 0.13 0.109* 7.3^-10* AlGaAs Diode 815 0.125 0.133 1.8^-9 Pulsed IR Diode 905 0.12 0.131* 3.7^-9* * -10% suck-out correction applied. Note the situation that the range is in two places in the range formula. It's the answer you may be seeking, but it's also needed to get Ta. Rats! Well, 'cause I was asleep or on drugs that day in math class I haven't come up with a nifty solution for that problem... except, in grinding several scenarios through the range equation I found it all too easy to make a math mistake and get non-repeatable answers. This has prompted me to begin to write a computer program to figure range - including Ta, lens losses, everything - so it might as well do an iterative process using a number of distances to calc Ta, and then pick the closest range answer that equals that distance. It may take a while to finish that software. Meanwhile, back at the ranch... I'll tell you now without going further that initial calc's with some of these figure looked bogus - like the predicted range seemed too short. Like, how was it possible to go 100-and-something miles with a 20mW HeCd or why have I had no problem with 58 miles & 2 or 3 milliwatt HeNe. The answer may be in the Atmospheric Attenuation Coefficient taken from the data based on a "Standard Clear Atmosphere." What's a Standard Clear Atmosphere? Well, there's also a "Very Clear" designation as well as an "Exceptionally Clear" designation. How do we know how clear it is? Dig this: Atmospheric Attenuation Ta Designation Coefficient 10 miles 50 miles 100 miles @670nm Standard Clear 0.14 0.105 1.2E-5 1.6E-10 Very Clear 0.082 0.267 1.4E-3 1.9E-6 Exceptionally Clear 0.054 0.419 1.3E-2 1.7E-4 Wow! Look at the tremendous improvement at _long_ distances from assuming "Exceptionally Clear." Range is proportional to the square-root of Ta, so is it true that we see something like a 1031 times improvement in range by choosing the Exceptional model over the Standard model? Stop here a moment and consider that the math shows that haggling over stuff like the difference in area between a 3" lens and a 4" lens is so pointless compared to the tremendous variable of atmospheric clarity. Well, we're not done yet! Notice I skipped the receiver sensitivity. I didn't think this parameter was a big deal until we began discussing it at work. The receiver sensitivity is measured in Watts per root hertz and is usually designated Equivalent Noise Input (ENI) or Noise Equivalent Power (NEP) in detector specifications. Typical figures: 10E-13 to 10E-14 for silicon photodiodes This is wavelength sensitive, of course. But, this is not including the necessary amplifier - which will contribute significantly to the noise. All sorts of things come into play here - If you need speed, like for video, you want a high speed photodiode and amp. The bandwidth adds noise, the small area of the photodiode needed to reduce capacitance reduces noise, if you bias the photodiode to increase its speed that adds noise, and on and on. And if you use junk amps like 741's, who knows what you'll get. But all of this is calculatable from the amplifier specs, the photodiode capacitance, and other parameters. By the way, construction techniques count as much here in nanoamp-land as they do in microwaves. Don't forget now to multiply the NEP by the square root of the bandwidth. If it's standard audio, 300-3000 Hz, then times 52. We can cheat a little here and grab a NEP figure from a Burr-Brown OPT-201 hybrid photodiode/amplifier. As the important amp and its effects are included in the specs: about 6E-11 Watts @ 3 KHz bandwidth. Now, going back to the range equation with: 2 milliwatt TX power (0.002 W) 2 milliradian divergence (0.002 R) 4" receive lens (2.116E-4 sq-km) 0.92 receive lens transmission (0.92) 6E-11 NEP @ 3 KHz bandwidth 1:1 SNR (6E-11 W) 670 nm atten coeff "Standard Clear" = (0.14 /km) "Except. Clear" = (0.054 /km) After several iterations... Standard Clear Atmosphere = 42.5 km / 26.5 mile range Exceptionally Clear Atmosphere = 97 km / 60.6 mile range These figures seem too low to me. I have easily done 48 km with a similar setup (2-3mW HeNe, 931A PMT RX). I'm feeling that the Standard Model Atmospheres are the problem, specifically their aerosol contents. And it seems that the models were developed based on a clear atmosphere corresponding to a visibility of 23 km. Well, "visibility" itself is a whole can of worms. It's defined as the perception of a 2% contrast. Obviously, this is all dealing with daylight observations. How do you relate 2% contrast to looking at a laser beam in pitch dark? The basic models are based on sea-level too. If you go up just a little in altitude the aerosols drop off significantly. >From the Handbook of Optics: Attenuation Coefficient per Kilometer Clear Midlatitude Summer model at 6328A (HeNe) 0 km % of Total 1-2 km % of Total Molecular Absorption <10-3 <10-3 Molecular Scattering 6.44E-3 4 5.5E-3 10 Aerosol Absorption 9.14E-3 6 2.72E-3 6 Aerosol Scattering 1.37E-1 90 4.08E-2 83 Total 0.1526 0.04902 Note how a little elevation divides the attenuation coefficient by 3, and that the bulk of the coefficient is aerosol scattering. Again, the models seem to be based on sea-level day visibility of 23 km. I don't know how they came up with 23 km. I think you can see a lot farther than that, day, and especially night, in a "clear" atmosphere. I'm guessing that we should use the "Exceptionally Clear" model for our uses - that is, prediction laser communication range on a clear dark night without haze. What do you think? 73, Steve J. Noll | Ventura CA | WA6EJO | IEEE | AVS | sjnoll@ix.netcom.com >From owner-laser Mon Apr 15 13:48:58 1996 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA18546; Mon, 15 Apr 96 13:48:58 PDT Date: Mon, 15 Apr 96 13:48:55 PDT From: jmoss (Jim Moss) Message-Id: <9604152048.AA18540@berlioz.nsc.com> To: laser Subject: Satellite Targets Sender: owner-laser@berlioz.nsc.com Precedence: bulk Targets are listed at http://gauss.crl.go.jp/targets.html The japanese one with mirrors is Ajisai, launced in 1986 Jim >From owner-laser Thu Apr 18 10:51:44 1996 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA06566; Thu, 18 Apr 96 10:51:44 PDT Date: Thu, 18 Apr 1996 06:32:02 -0700 From: sjnoll@ix.netcom.com Message-Id: <199604181332.GAA03503@dfw-ix5.ix.netcom.com> Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Subject: Retro-reflectors To: laser@berlioz.nsc.com X-Mailer: SPRY Mail Version: 04.10.06.22 Sender: owner-laser@berlioz.nsc.com Precedence: bulk Retro-reflectors... I have a 1" dia cube-corner prism that I got from Edmund years ago and a 2.75" dia one that I picked up surplus somewhere. Frankly, I haven't found much use for them. I'm located in the middle of a housing tract with no good place to plant one for atmospheric transmission studies, etc. Another problem is backscatter. If you bore-sight down a beam you see a lot of backscatter, so if you don't have a chopper or eqiv at the retro-reflector end of a long shot I think the backscatter is going to interfere with the return. RE: building mirror-type retro-reflectors from silicon wafers. I don't understand. Silicon wafers are not very reflective at all. They absorb light - otherwise there would be no silicon-based detectors! You can coat them - like slow sputtered aluminum - to get them shiny, but a glass mirror will work just as well. Plus, they flex. Their round shape is not optimum for building a cube-corner mirror - you need triangles for that - and they aren't going to cleave that way. The inexpensive surveyor's retros sound like a great idea! For the lowest cost per square foot how about building retro-reflectors from "mirror-tile"? 12" squares are $1.33 each here. Split them in two from one corner to an opposing corner to make two triangles. Glue three of these triangles together to make one one-half square-foot retro for $2. A bunch of these could be assembled in a planar array for a cheap monster retro-reflector. It would be interesting to erect a large (ten-foot dia) array a mile or so away. It would return most all of the signal from a one or two milliradian laser. 73, Steve J. Noll | Ventura CA | WA6EJO | IEEE | AVS | sjnoll@ix.netcom.com >From owner-laser Fri Apr 19 06:36:33 1996 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA23825; Fri, 19 Apr 96 06:36:33 PDT Date: Fri, 19 Apr 1996 06:29:31 -0700 From: sjnoll@ix.netcom.com Message-Id: <199604191329.GAA23819@dfw-ix6.ix.netcom.com> Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Subject: Extra-terrestrial Retro-Reflectors To: laser@berlioz.nsc.com X-Mailer: SPRY Mail Version: 04.10.06.22 Sender: owner-laser@berlioz.nsc.com Precedence: bulk Extra-terrestrial Retro-Reflectors... Moon retros - I gave up thought of bouncing a laser off of the US & Russian moon retro-reflectors after seeing a TV program on the subject years ago. Even NASA couldn't get a return from every shot of their high power laser. Satellite retros - Those sound interesting. I didn't know there were a lot of them up there. But beyond the novelty, I'm not sure what use it would be. But that idea does bring up a really interesting thought... Shuttle or MIR Amateur Radio Laser Communication - wouldn't that be neat? The 300(?) mile shot might be feasible with Amateur (albeit foaming-at-the-mouth Amateur) equipment? The transmittance of the atmosphere for a straight-up sea-level to outer space shot is great - 80% to 85% for visible light in excellent visibility conditions (see RCA Electro-Optics Handbook). If it was done with a Ham astro/cosmo-naut it would fit into the arena of Amateur Radio too. Now, just how hard is it to keep a beam aimed on a low-orbit spacecraft? What is practical in the area of motorized telecope mounts? 73, Steve J. Noll | Ventura CA | WA6EJO | IEEE | AVS | sjnoll@ix.netcom.com >From owner-laser Fri Apr 19 15:47:49 1996 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA10481; Fri, 19 Apr 96 15:47:49 PDT Message-Id: <199604192246.AA052123975@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: Fri, 19 Apr 1996 22:45:59 +0000 To: laser@berlioz.nsc.com From: "Art Allen, KY1K" Subject: slr info.... Sender: owner-laser@berlioz.nsc.com Precedence: bulk Hey everyone, For those interested in satellite laser ranging, I have some news... I started in this aspect of lasers as a way to fine tune/research aiming techniques. After all, if we can hit a moving satellite in orbit, then hitting a stationary qso partner 100 miles away should be a piece of cake! Also, astronomers do it routinely, so I thought I might get some tips! Well, I've become hooked I think! Some of the astronomy people have stepper motor controllers which appear to allow a satellite to be tracked across the sky (with millirad accuracy and arc second tracking error). There are numerous satellites in earth orbit that should make great targets. Information I have found on the internet refers to these satellites by their Cosper number-our satellite tracking programs use the 'norad' number. In my search 'conversion' info between the 2 designations, I've discovered a whole group of astronomers who look at satellites, and I guess more than a few of them have used slr to determine 'spin rates', which is like a fingerprint as far as actually identifying the satellite in question! I've also discovered that these astronomers have their own mailing list, and I've signed up for it. I'll pass further info on to anyone who wants it. Regarding satellite tracking software, use STSPLUS-a high accuracy no compromise satellite tracking program which runs on super computers only (the noraml ones make rounding errors and other 'assumptions' at the expense of speed and accuracy). Until recently, PC's wern't capable of doing the full blown math required for the 'high accuracy model'. STSPLUS is available via the inet. Hey, thats about it for now-have a great day, Art... >From owner-laser Wed Apr 24 17:20:38 1996 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA22957; Wed, 24 Apr 96 17:20:38 PDT Date: Wed, 24 Apr 96 17:20:34 PDT From: jmoss (Jim Moss) Message-Id: <9604250020.AA22948@berlioz.nsc.com> To: laser Subject: Info sources Sender: owner-laser@berlioz.nsc.com Precedence: bulk In addition to the internet stuff, a good source of info on laser comm is SPIE proceedings for FREE-SPACE LASER COMMUNICATION TECHNOLOGIES. the 6th one (VI) was 26-38 Jan 1994. This proceeding has LOTS of good stuff on acquisition and tracking, not to mention other stuff. From what I was looking at the VI is better than VII. Haven't seen one for VIII (1996) yet. Our tech library was able to borrow one from another library. TK 5103.6.F76 1994 Volume is 2123 from SPIE library of congress cat card # 93-87124 isbn 0-8184-1416-6 Typical reprints are $6 per article. Jim >From owner-laser Fri Apr 26 22:54:07 1996 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA25871; Fri, 26 Apr 96 22:54:07 PDT Date: Fri, 26 Apr 1996 22:47:59 -0700 From: sjnoll@ix.netcom.com Message-Id: <199604270547.WAA16489@dfw-ix7.ix.netcom.com> Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Subject: Commercial Atmospheric Transmission Software Demo To: laser@berlioz.nsc.com X-Mailer: SPRY Mail Version: 04.10.06.22 Sender: owner-laser@berlioz.nsc.com Precedence: bulk For what it's worth... Check out http://www.ontar.com This outfit makes very sophisticated atmospheric transmission software. While it costs $1000+ they have a demo version available via FTP. I've installed it, and its impressive if not confusing (no Help). Bunch of atmosphere models, etc. I was not able to get their web FTP pointer to work, but got to the FTP site to get the demo by: ftp.shore.net then change directory to: members then change directory to: ontar then transfer file: ontrdemo.exe It's Windows (oh boy.) 73, Steve J. Noll | Ventura CA | WA6EJO | IEEE | AVS | sjnoll@ix.netcom.com >From owner-laser Sun Apr 28 22:17:46 1996 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA04330; Sun, 28 Apr 96 22:17:46 PDT Date: Sun, 28 Apr 1996 22:14:43 -0700 (PDT) Message-Id: <1.5.4.16.19960428221501.214f3ec0@mail.valleynet.com> X-Sender: n7stu@mail.valleynet.com X-Mailer: Windows Eudora Light Version 1.5.4 (16) Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" To: laser@berlioz.nsc.com From: n7stu@valleynet.com Subject: mils to degrees Sender: owner-laser@berlioz.nsc.com Precedence: bulk Ok stupid question here. How many mils = 1 degree? Or is is how many degrees make 1 mils? I picked up a MT-1946/PPS-4 tripod at the local flea market today for future laser/microwave use. This is calibrated in mils|x100 (0-63) azimuth and +3 to -8 mils (or is is +8 to -3, haven't tried it yet) elevation. I would like to make a degrees conversion chart for uwave work. Is this calibration sharp enough for laser work? Obviously it is better than your above average camera tripod and ultra heavy duty. 73, Robert N7STU/YB2ARO, DM07aa/OI52ee n7stu@valleynet.com http://www.valleynet.com/~n7stu (WSWSS mirror & N7STU/YB2ARO homepages) >From owner-laser Mon Apr 29 09:34:31 1996 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA18326; Mon, 29 Apr 96 09:34:31 PDT Date: Mon, 29 Apr 96 09:34:28 PDT From: jmoss (Jim Moss) Message-Id: <9604291634.AA18320@berlioz.nsc.com> To: laser Subject: mils to degrees Sender: owner-laser@berlioz.nsc.com Precedence: bulk If it is milli Radians you can convert: 2*PI RADIANS = 360 DEGREES 1 DEGREE= 2 * PI / 360 = .01745 RADIANS or 17.45 mR 1x100's of mils would equate to 5.73 degrees. >From you calibration I presume azimuth has 360 deg rotation, 360/63 = 5.174 deg. So it seems to be the same. That calibration is not much for lasers. And is probably poor for uWave. Are there sub-calibration marks? Like 10ths between ? Sounds like a good base tripod to work from. I am currently working on a pair of stepper motors that can be mounted on a tripod. You get close by hand, and then use the steppers to fine tune. (will have about 5uR per step versus beam width of about 1-2 mR) Jim ---- Begin Included Message ----- >From owner-laser Sun Apr 28 22:57:19 1996 Date: Sun, 28 Apr 1996 22:14:43 -0700 (PDT) X-Sender: n7stu@mail.valleynet.com X-Mailer: Windows Eudora Light Version 1.5.4 (16) Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" To: laser@berlioz.nsc.com From: n7stu@valleynet.com Subject: mils to degrees Sender: owner-laser@berlioz.nsc.com Content-Length: 643 Ok stupid question here. How many mils = 1 degree? Or is is how many degrees make 1 mils? I picked up a MT-1946/PPS-4 tripod at the local flea market today for future laser/microwave use. This is calibrated in mils|x100 (0-63) azimuth and +3 to -8 mils (or is is +8 to -3, haven't tried it yet) elevation. I would like to make a degrees conversion chart for uwave work. Is this calibration sharp enough for laser work? Obviously it is better than your above average camera tripod and ultra heavy duty. 73, Robert N7STU/YB2ARO, DM07aa/OI52ee n7stu@valleynet.com http://www.valleynet.com/~n7stu (WSWSS mirror & N7STU/YB2ARO homepages) ----- End Included Message ----- >From owner-laser Mon Apr 29 11:10:34 1996 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA21488; Mon, 29 Apr 96 11:10:34 PDT Date: Mon, 29 Apr 1996 11:07:26 -0700 (PDT) Message-Id: <1.5.4.16.19960429110745.22f73240@mail.valleynet.com> X-Sender: n7stu@mail.valleynet.com X-Mailer: Windows Eudora Light Version 1.5.4 (16) Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" To: jmoss@berlioz.nsc.com (Jim Moss), laser@berlioz.nsc.com From: n7stu@valleynet.com Subject: Re: mils to degrees Sender: owner-laser@berlioz.nsc.com Precedence: bulk Hi Jim, At 09:34 AM 4/29/96 PDT, Jim Moss wrote: > >If it is milli Radians you can convert: > >2*PI RADIANS = 360 DEGREES > >1 DEGREE= 2 * PI / 360 = .01745 RADIANS or 17.45 mR > >1x100's of mils would equate to 5.73 degrees. > >>From you calibration I presume azimuth has 360 deg rotation, 360/63 = 5.174 deg. >So it seems to be the same. Like I said, stupid question. I realized this after I sent the msg. Actually I think it should be 360/64 = ~5.6 deg which is very close to your 5.73 deg. > >That calibration is not much for lasers. And is probably poor for uWave. Are >there sub-calibration marks? Like 10ths between ? > I will have to look at that. I was just looking for major markings. > >Sounds like a good base tripod to work from. I am currently working on a pair of >stepper motors that can be mounted on a tripod. You get close by hand, and then >use the steppers to fine tune. (will have about 5uR per step versus beam width >of about 1-2 mR) > Should work out great even if it needs a few improvements. Can't complain for $25. Funny what strange things show up at the local swap meet, bought an HW-9 there last year for $10. Let me know how the motors work out. Are they just el cheapo HSD/REI specials? 73, Robert N7STU/YB2ARO, DM07aa/OI52ee n7stu@valleynet.com http://www.valleynet.com/~n7stu (WSWSS mirror & N7STU/YB2ARO homepages) >From owner-laser Mon Apr 29 11:36:09 1996 Return-Path: Received: by berlioz.nsc.com (4.1/SMI-4.1) id AA22502; Mon, 29 Apr 96 11:36:09 PDT Date: Mon, 29 Apr 96 11:36:05 PDT From: jmoss (Jim Moss) Message-Id: <9604291836.AA22496@berlioz.nsc.com> To: laser Subject: Re: mils to degrees Sender: owner-laser@berlioz.nsc.com Precedence: bulk The motors I am using are from old floppy drives. 1.8 degrees per step (200 per rev). 5 wire.. so easier to control with simple drivers. More as I go along. Jim WB9AJZ/6