+++++++++++++++++++++ See also K2 Matched Filter Crystals2 +++++++++++++++++++++ Date: Mon, 28 Oct 2002 14:38:52 -0800 From: Eric Swartz WA6HHQ - Elecraft Organization: Elecraft To: elecraft at mailman.qth.net Subject: Re: [Elecraft] New Crystals or Not As a follow on to my earlier email, we have been shipping the latest CW and SSB filter crystals since about March 19th, 2002. Approximately from K2 serial number 2570 on. 73, Eric ========= Date: Mon, 28 Oct 2002 15:27:35 -0800 From: Eric Swartz WA6HHQ - Elecraft Organization: Elecraft To: elecraft at mailman.qth.net Subject: Re: [Elecraft] New Crystals or Not Some more clarification: Over the lifetime of the K2 we have made several incremental improvements to our filter crystal matching. When we went to a tighter crystal motional inductance (Lm) specification around 3/29/02, we first received crystals sorted at the vendor with with the older 4.91-20 label, as opposed to the 4.91-0195 that we were using just previously. We then had them custom labeled as 4.9136-S on subsequent shipments to us from the vendor. Here is the breakdown of K2 filter crystal versions: 1) 4.91-20 used on early K2s 2) 4.91-0195 used on more recent K2s and SSB options sold -before- approximately s/n 2570, 3/19/2002. ------ 3) 4.91-20 (sorted to tighter Lm criteria at manufacturer) used from about s/n 2570 (3/19/2002) and for a short time later until we received the remarked crystals. 4) 4.9136-S (remarked and sorted for Lm at the manufacturer) used on K2s after s/n 2570 after those in #3 above were used up. These are what we are shipping for all K2s and KSB2s today. ------ The crystals used in #3 and #4 above are equivalent. The tighter Lm specification results in slightly less filter loss in the CW filter and a slightly wider bandwidth for the SSB filter. So if your K2 is in group #1 or #2, before s/n 2570 and it has the 4.91-0195 crystals in its CW or SSB filter or if it is a much earlier unit with the 4.91-20 crystals, you will probably see a small improvement from using the newer crystals. They are available at: http://www.elecraft.com/order_form_parts.htm Sorry for the confusion! 73,Eric WA6HHQ +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Date: Sun, 20 Oct 2002 20:13:12 -0500 (CDT) From: Paul Jensen To: Subject: Re: [Elecraft] Matched Filter Crystals > This may be na=EFve, but..... on the Elecraft site at 'K2 PARTS AND MOD > KITS' I saw "K2KSB2XTLS Matched Filter Crystals (14) For existing K2 and > KSB2 combinations". I have a long stalled K2 kit that I am 'building', These new crystals replace the 7 in the cw filter and 7 in the ssb option board (KSB2). It makes a huge difference! The crystals are better matched than the previous crystals. I do not see the big drop in signal strength when switching to a narrower bandwidth. The passband ripple is also less, thus improving the audio quality. There is no difference between USB and LSB sound now. This is a major upgrade and would recommend everyone do it. For the $15 cost and 30 minutes of work (with a hakko 808 desoldering tool), this is a no-brainer. I also removed c180 (as part of the 2cd Xtal mod). Paul Jensen AD5IW org msg.. From: "Terres Family" To: Date: Sun, 20 Oct 2002 19:40:38 -0400 Subject: [Elecraft] Matched Filter Crystals Hi guys,=20 This may be naive, but..... on the Elecraft site at 'K2 PARTS AND MOD KITS' I saw "K2KSB2XTLS Matched Filter Crystals (14) For existing K2 and KSB2 combinations". I have a long stalled K2 kit that I am 'building', got stalled when I got what must have been a bad optical encoder, while trying to sort that out got and put together a SSB board, which has never been tried. So I have been out of the loop as it were for quite a while.=20 Are these crystals any different than what came in a stock K2 (serial number <1000) and/or what came in a separate stock SSB kit? Thanks, Jerry Terres aa1of Franconia NH ++++++++++++++++++++++ Date: Sun, 20 Oct 2002 21:28:05 -0400 From: "Mark J. Dulcey" To: Paul Jensen Cc: Elecraft at mailman.qth.net Subject: Re: [Elecraft] Matched Filter Crystals Paul Jensen wrote: >>This may be na=EFve, but..... on the Elecraft site at 'K2 PARTS AND MO= D I thought that if you have a recent K2 and KSB2, you already have crystal= s that are matched as well as the ones in the kit, so it's not useful at = all. Perhaps Elecraft can offer an opinion on which serial numbers are li= kely to be helped by the upgrade, and which ones don't need it. Checking your filter shape with Spectrogram or similar software may also = help. If your filter shapes are already good, regardless of serial number= , the upgrade probably isn't called for - although the early crystals wer= en't matched as carefully, some builders may have gotten a good set by lu= ck of the draw. ++++++++++++++++++++++ Date: Sun, 20 Oct 2002 22:04:49 -0500 (CDT) From: Paul Jensen To: Subject: Re: [Elecraft] Matched Filter Crystals > > This is a major upgrade and would recommend everyone do it. For the $15 > > cost and 30 minutes of work (with a hakko 808 desoldering tool), this is a > > no-brainer. I also removed c180 (as part of the 2cd Xtal mod). > > I thought that if you have a recent K2 and KSB2, you already have crystals that are matched as well as the ones in the kit, so it's not useful at all. Perhaps Elecraft can offer an opinion on which serial numbers are likely to be helped by the upgrade, and which ones don't need it. Bought my K2 in April - #2592. They fixed this problem in May or June. What are your chances of getting 14 perfectly matched crystals? The K2 now has more gain as well - the volume control is at 8 o'clock and the rf gain at 3 o'clock for room filling sound. > Checking your filter shape with Spectrogram or similar software may also help. If your filter shapes are already good, regardless of serial number, the upgrade probably isn't called for - although the early crystals weren't matched as carefully, some builders may have gotten a good set by luck of the draw. Used the Spectrogram both before and after - it definitely has a flatter passband now. Thanks to Elecraft for making this fix available. Paul Jensen AD5IW +++++++++++++++++++ Date: Sun, 27 Oct 2002 10:40:26 -0600 From: "George, W5YR" Organization: AT&T WorldNet Service To: "elecraft at mailman.qth.net" Subject: [Elecraft] New Crystals I have received - very promptly, I might add - the set of 14 new matched crystals to replace the CW and SSB filters in my K2. I intend to connect case ground wires to both sides of the CW filter crystals at the very bottom of each side *before* installing them. So each crystal will go in with two signal leads and two ground leads already in place. Similarly, I intend to attach case ground wires to the SSB crystals very low on the cans and to route them to the existing ground through-holes with the shortest lead lengths. Thus these crystals will have three wires on each prior to installation. I think that this procedure will not only allow for much lower inductance case ground connections but will greatly facilitate installing the crystals and their case grounds. as well as allowing a better and quicker soldering job on the cases. Any comments or ideas? 73/72, George Amateur Radio W5YR - the Yellow Rose of Texas +++++++++++++++++ From: "Mike McCoy" To: "George, W5YR" , Subject: Re: [Elecraft] New Crystals Date: Sun, 27 Oct 2002 22:22:53 -0600 > I intend to connect case ground wires to both sides of the CW filter > crystals at the very bottom of each side *before* installing them. So each > crystal will go in with two signal leads and two ground leads already in > place. hmm... the thru holes for the xtal ground wires are not right up next to the xtal can. If you solder the wire close to the very bottom you might not have enough 'play' in the wire to allow mounting the xtal flush against the board. Just today I finished replacing both the CS & SSB xtals. I'd put it off for a long time (months) because I wasn't looking forward to disassembling my K2 down to the RF board. Or so I thought... blazing ahead I (fortunately) discovered you only need to remove the bottom and one (right) side cover to gain access to the CW xtals. Still, because it was a 'retrofit' things are pretty darned cramped. The SSB was tight enough to assemble in the first place... Removing the SSB xtals was easy... replacing them *and their grounds* presented a bit of a challenge. After removing all the orig xtals/grounds, I decided the easiest way would be to solder short 'stubs' of ground wire in the PCB first. After they were all in place I then soldered the xtals making sure they were flush against the PCB. Once everything was in place I then bent/formed the wire 'stubs' flush against the cans and soldered them last. All in all it worked out really well and you can't even tell any 'surgery' was done at all. > > Similarly, I intend to attach case ground wires to the SSB crystals very > low on the cans and to route them to the existing ground through-holes with > the shortest lead lengths. Thus these crystals will have three wires on > each prior to installation. You might want to reconsider incorporating the CW xtal 'mod' to the SSB xtals. At least read this first: http://www.rt66.com/~hypoxic/K2stuff/ssbfilterquiry.html Mike - K5PU ++++++++++++++++ Date: Mon, 28 Oct 2002 13:33:17 -0600 (CST) From: Paul Jensen To: Subject: Re: [Elecraft] New Crystals or Not > Has anyone who has replaced their crystals taken any before & after pics of > filter shapes? They would somehow have to find their way to a web site. > Using spectogram, I'm not sure if I could recognize a shape that could be > improved upon if I saw one. Or should I do as the tee shirt says - "just do > it" and be done with it. My K2 is well over a year old. I did not take pictures before and after the crystal change out (probably should have) - but all I noticed was less passband ripple and a fairly dramatic increase in receiver gain. Before I had the volume typically at 2 o'clock for average listening, now it is at almost full counter-clockwise at 8 o'clock. This weekend, I could hear a cw signal 20 feet away even though the volume control was full off! The agc is kicking in a lot more also. "Just do it" Paul Jensen AD5IW ++++++++++++++++ Date: Mon, 28 Oct 2002 11:54:10 -0800 From: Eric Swartz WA6HHQ - Elecraft Organization: Elecraft To: David Schornak Cc: elecraft at mailman.qth.net Subject: Re: [Elecraft] New Crystals or Not All new K2s and SSB adapters are shipping with the latest filters crystals. You can recognize them by their unique marking: ECS 4.9136-S. 73, Eric WA6HHQ ----------- David Schornak wrote: > > since I ordered my k2 and am still waiting for it will it come with matched > crystals or will I need to order them? > KG4LSK +++++++++++++++ Date: Mon, 28 Oct 2002 14:38:52 -0800 From: Eric Swartz WA6HHQ - Elecraft Organization: Elecraft To: elecraft at mailman.qth.net Subject: Re: [Elecraft] New Crystals or Not As a follow on to my earlier email, we have been shipping the latest CW and SSB filter crystals since about March 19th, 2002. Approximately from K2 serial number 2570 on. 73, Eric ========= +++++++++++++++++ Reply-To: From: "Ron D'Eau Claire" To: "'Elecraft List'" Subject: RE: [Elecraft] New Crystals or Not Date: Mon, 28 Oct 2002 15:28:07 -0800 They MIGHT. It's a matter of the "luck of the draw". They didn't CHANGE the crystals, but changed the matching specifications so sets are more consistent. You may have a good set, you might not. Mine weren't good. The OPT1 bandpass at the -6dB points was less than 2 kHz, and there was no setting of the BFO frequency that was going to make the audio sound good. Be assured that however bad your K2 sounds in receive, it sounds no better in transmit if you have a bad set of crystals. But FIRST, have you done the "SSB Filter Flattening Mod" described on www.elecraft.com under "Builder's Resources"? That affects the received signal quality. It has no effect on the OPT 1 filter or the transmitted signal. It flattens the response of the "cleanup" filter at the output of the IF amplifier. The original design of that filter had quite a "tilt" to the bandpass, making SSB audio sound overly "bright" with way too much high frequency response on one sideband and bassy and muffled with too much low frequency response on the other sideband. If you haven't done this mod yet, do it FIRST, then evaluate whether you think you want new crystals for the filters. Ron AC7AC K2 # 1289. Fred N9TA wrote: What will the new xtals do for the performance?? I've always thought my K2 (Ser#242) sounded like crap on SSB (RX side), but seeing as I rarely work SSB I didn't really care. Will the new xtals "open" up SSB somewhat ??? +++++++++++++++++ From: "Mike McCoy" To: "Paul Jensen" , Subject: Re: [Elecraft] New Crystals or Not Date: Mon, 28 Oct 2002 18:03:02 -0600 I just completed the xtal replacement and I can pretty much echo Pauls observations. Not sure about the ripple but it's definately flatter, i.e.there is less slope across the passband (previously the filter 'fell off' about 6-8 db toward the high end). However, I now seem to have a -4 to -5 db 'notch' about 400 hz wide smack in the middle though (now two big 'ripple bumps' ? ;) Even so it's no biggy... having an overall flatter response across the passband is a good thing. More importantly (at least in my case) the SSB passband is wider. The SSB passband with the xtals I received with my kit was only about 1400-1500 hz wide ( at -10 db) which made SSB sound umm.. 'pinched' (even after the SSB filter mod). After installing the new matched SSB xtals it's about 2.5Khz wide at 0 db and 1800-2K wide now. -10 db. That improvement alone made it worth the effort for me. But that's not all... It's appears my problem of 'low audio' is gone. I can only presume it's due to an increase in receiver gain. Prior to the replacement I had to turn my audio gain pretty much fully clockwise (or use headphones) to hear anything. Now it's about 9 o'clock to achieve the same level. As a point of reference my original xtals were labled ECS 4.915-0195 (K2 sn # 2602, ordered 4/15 and finished about 5/30) Bottom line, this retrofit certainly has my vote. While I felt the K2 was pretty darn decent before, I now feel like I have the K2 everyone has been raving about. Mike - K5PU ++++++++++++++++ Reply-To: From: "Ron D'Eau Claire" To: "'JAKidz'" , Subject: RE: [Elecraft] Re: New Crystals (K7JG) Date: Mon, 28 Oct 2002 20:35:10 -0800 The crystals are a matched set. Change one and you need to change them all if you want good predictable performance. That includes both the CW filter crystals on the r-f board and the OPT1 crystals on the SSB board. Otherwise you will more likely end up with more problems than you started with. What do you mean that "calibration settings are by the book"?. Do you mean the BFO frequency settings are those suggested in the manual? If so, then your problem is a mis-aligned filter, not necessarily a bad crystal. On the narrower bandwidths especially, the "book" values are likely to be well off the mark. Use Spectrogram and align those filters and see how it sounds. SOME ops report an improvement in the audio level after changing the rocks. SOME others report better SSB bandwidth out of the OPT1 filter with new crystals. Your symptoms sound like the BFO isn't on frequency for FL3 and FL4. Ron AC7AC K2 # 1289 John, K7JG ... 14 new crystals are in hand but now what. SSB audio volume is okay on OP1 and OP2; the big drop in audio occurs on FL3 and FL4. This weekend it was sufficient to pickup a LU and LO, T32, ZD8, ZK1 with AF1 on and OP1 or OP2. So if it isn't broke I don't want to break it fixing it. Calibration settings are according to the book. ... it looks like X7 - X11 might be the culprits. So changing those 4 out should do it, right? +++++++++++++++++ Date: Tue, 29 Oct 2002 00:34:30 -0500 To: "Mike McCoy" From: Charles Greene Subject: Re: [Elecraft] New Crystals or Not Cc: Mike and All, I have a question about the new xtals and the transmit bandwidth. Do they do anything for it? I really don't have any problems with receive sensitivity or receive bandpass aligned using Spectrogram; however, I don't use SSB much but I do use PSK31. The transmit bandwidth varies a lot from LSB to USB on transmit. Also, I have to reset the level control either on the computer or using an external pot when I go from a transmit signal of say 800 Hz to 2000 Hz. It is particularity annoying as the K2 doesn't have a mike gain control to help in this regard. For example, if I adjust the audio level for a power output of 5 watts at 800 Hz, it drops down to between 1 and 2 watts at 2000 Hz and is unusable above. (You can't touch the power output control, as this introduces non-linearity which is fine for SSB but introduces unacceptable IMD for the digital modes). Actually, the K2 has the best IMD of any transmitter I have seen, but the transmit bandpass drops off too much at the high end. At 06:03 PM 10/28/2002 -0600, Mike McCoy wrote: >I just completed the xtal replacement and I can pretty much echo Pauls >observations. Not sure about the ripple but it's definately flatter, >i.e.there is less slope across the passband (previously the filter 'fell >off' about 6-8 db toward the high end). However, I now seem to have a -4 >to -5 db 'notch' about 400 hz wide smack in the middle though (now two big >'ripple bumps' ? ;) Even so it's no biggy... having an overall flatter >response across the passband is a good thing. > >More importantly (at least in my case) the SSB passband is wider. The SSB >passband with the xtals I received with my kit was only about 1400-1500 hz >wide ( at -10 db) which made SSB sound umm.. 'pinched' (even after the SSB >filter mod). After installing the new matched SSB xtals it's about 2.5Khz >wide at 0 db and 1800-2K wide now. -10 db. That improvement alone made it >worth the effort for me. > >But that's not all... It's appears my problem of 'low audio' is gone. I can >only presume it's due to an increase in receiver gain. Prior to the >replacement I had to turn my audio gain pretty much fully clockwise (or use >headphones) to hear anything. Now it's about 9 o'clock to achieve the same >level. > >As a point of reference my original xtals were labled ECS 4.915-0195 (K2 sn ># 2602, ordered 4/15 and finished about 5/30) > >Bottom line, this retrofit certainly has my vote. While I felt the K2 was >pretty darn decent before, I now feel like I have the K2 everyone has been >raving about. 73, Chas, W1CG K2 #462 ++++++++++++++++++ From: WA9GQT at aol.com Date: Tue, 29 Oct 2002 08:28:17 EST To: elecraft at mailman.qth.net Subject: [Elecraft] Re:New Crystals or Not Hello to All! I think we need to determine a good method of checking the spec's on our various K2's before we get the soldering stations hot and risk component damage. I have K2 SN 1900 which has the 4.91-0195 crystals in it. I have done the 2nd XFil SSB mod(with 100pF & 5.6K resistor update) and the KO0B CW filter ultimate rejection mod. I was also one of the initial K2's with the AF Gain Mod. I use my K2 on both CW & SSB, almost 50/50. I seem to have enough audio and am very pleased with CW & SSB. I get wonderful reports on both modes. I wonder just how much my K2 would benefit by replacing all my SSB and CW crystals. We need good spectrogram parameters to be able to determine just how much improvement our K2's will receive from replacing all of the crystals. Thanks for the info. 73, Rod WA9GQT K2 SN 1900 ++++++++++++++++++ Reply-To: From: "Ron D'Eau Claire" To: , Subject: RE: [Elecraft] Re:New Crystals or Not Date: Tue, 29 Oct 2002 07:47:04 -0800 I would guess that you'll find no improvement by changing the crystals, Rod. Many (most?) early K2's had crystal sets that were just fine. Elecraft has NOT "improved" the crystals. All that's changed is that they are ensuring that every crystal set shipped behaves more like they expect them to. They did that by tightening up the parameters they are using to identify "matched" sets. The problem was that the sets were not consistent enough, and some ops got crystals that produced very poor results on SSB. And by poor, I mean POOR! Some K2s sounded awful trying to transmit with a bandwidth of well under 2 kHz. Others have had very low audio that new crystals seem to have fixed. You say that you aren't experiencing any of this. I still believe in "if it isn't broken, don't fix it!". And, yes, it's a bit of a job changing out all of the crystals - especially on the very delicate little solder pads used on the SSB board. I was one of those with a bad set. I didn't need Spectrogram to tell me that they were bad and the new ones were good, only my ears. The difference was DRAMATIC. Ron AC7AC K2 # 1289 Rod WA9GQT wrote: I use my K2 on both CW & SSB, almost 50/50. I seem to have enough audio and am very pleased with CW & SSB. I get wonderful reports on both modes. I wonder just how much my K2 would benefit by replacing all my SSB and CW crystals. ++++++++++++++++++ Date: Tue, 29 Oct 2002 12:32:33 -0600 From: "George, W5YR" Organization: AT&T WorldNet Service To: WA9GQT at aol.com Cc: elecraft at mailman.qth.net Subject: Re: [Elecraft] Re:New Crystals or Not You will have them after I do my crystal installation and run a new set of SpectroPRO spectra to compare with the original set for all filter settings and modes. This is a professional audio analysis program suite that provides much higher resolution and spectral detail than SpectroGram, so quantitative comparisons should be available and useful. My K2 is #489 with the original -20 xtals so I expect substantial improvement. Some mods have been made but everything will be brought up to current "standards" as part of the filter crystal replacement. On the other hand, anyone pleased with the current performance of his/her K2 should weigh the pros and cons of making the mod: time, cost, potential damage, etc. My take is that based upon my baseline spectra, even though my K2 superficially sounds "good" and is acceptable as it is, I expect that the new filters will make it much better, especially for SSB operation. Thus, I am willing to accept the cons in anticipation of the pro's! <:} 73/72, George Amateur Radio W5YR - the Yellow Rose of Texas In the 57th year and it just keeps getting better! Fairview, TX 30 mi NE of Dallas in Collin county EM13qe K2 #489 Icom IC-765 #2349 Icom IC-756 PRO #2121 WA9GQT at aol.com wrote: > > Hello to All! > -- snip -- > We need good spectrogram parameters to be able to determine just how > much improvement our K2's will receive from replacing all of the crystals. > Thanks for the info. > > 73, > > Rod WA9GQT K2 SN 1900 > +++++++++++++++++ From: "Mike McCoy" To: Subject: Re: [Elecraft] Re:New Crystals or Not Date: Tue, 29 Oct 2002 16:12:56 -0600 OK, I have thrown together a website displaying the Spectrogram filter plots using the new xtals labled ECS 4.9136-S. I included plots for CW filters FL1-4 and LSB/USB Op1 Nothing fancy, just a quick & dirty introduction, the plots & some observations. It is best viewed with IE5 at 1024x788 (Sorry, I didn't test for netscape users) You can view them at http://home.austin.rr.com/cofr/ Please feel free to ask any questions and/or comment on my results (good or bad ;) 73, Mike - K5PU +++++++++++++++++ Date: Wed, 30 Oct 2002 16:50:00 -0600 From: "George, W5YR" Organization: AT&T WorldNet Service To: Don Brown Cc: Bob - AG5Q , Elecraft Subject: Re: [Elecraft] Gain calibration I built two 45 dB pi-network resistive attenuators in a small project box with double-sided PCB stock for shielding between sections. Actual attenuation checks out at 91 dB at 20 KHz. This device is placed on the output of the Icom 756 PRO set for minimum output of about 1.55 watts. At that level, the signal delivered through the attnuator to the K2 is S5 on the meter. Using that as a "standard input signal" I can compare the output audio level before and after the crystal changes. I also have a noise generator I use for alignment and spectral plotting that will make a good standard input signal for comparison. In fact, I used it to plot all the spectra for all modes and filters prior to the crystal installations, and will do so again after the mods are complete. Now if I can just make enough time to do this and 20 other things! <:{ I think that we need to keep in mind that all of our K2's differ to varying degrees in several respects. So, I am not terribly confident that my measurements would indicate a great deal numerically for another K2. So, the outcome is likely to be largely subjective. 73/72, George Amateur Radio W5YR - the Yellow Rose of Texas In the 57th year and it just keeps getting better! Fairview, TX 30 mi NE of Dallas in Collin county EM13qe K2 #489 Icom IC-765 #2349 Icom IC-756 PRO #2121 ++++++++++++++++++ Date: Wed, 30 Oct 2002 16:35:23 -0800 From: "John, KI6WX" To: Elecraft Mailing List Subject: [Elecraft] New Crystals or Not Steve; I worked with Elecraft on measuring the crystals, both the original ones and the new ones. The original test procedure for selecting crystal sets did not always select ones with the same series resonant frequency. A second problem was that the motional inductance of the original crystals varied more than desired. Both of these effects can create suboptimal response of the SSB and CW filters. Many K2's are fine, but in some the variation became great enough that the filter response is not as good as it should be. In some cases this could easily be heard by listening to the radio. The best way to determine if you would benefit from replacing your crystals is to measure the filter response using Spectrogram on the audio output and an RF noise generator at the RF input. Details on using the earlier versions of Spectrogram can be found at my web site, http://home.pacbell.net/johngreb/KI6WX.html . I will publish a note on using Spectrogram 7 in the near future, but you can still use it for filter response measurements since it is similar to the earlier versions. SSB Filter - The correct filter response should have a width of about 2.0 to 2.2 kHz. There will be some ripple in the passband and a more prominent dip of 3-4 dB in the middle of the filter passband. The response of the SSB filter can be seen in "Improving the Performance of the KSB2" which is posted on my web page. If the filter response is narrower than 2.0 kHz, replacing the SSB crystals will widen its bandwidth. If the ripple is larger or one side of the passband seems to fall off slowly, the crystals should be replaced. CW Filter - For bandwidths less than 700 Hz, the filter should show a single peak. As the filter bandwidth is narrowed, this peak will narrow and the amplitude may drop slightly, particularly at a 100 Hz bandwidth. The CW crystals should be replaced if the filter response shows multiple peaks or the amplitude drops off sharply with decreasing bandwidth. This includes all 5 crystals in the CW filter and the 2 crystals in the second Xtal filter. Your current set of crystals is fine if you don't see these types of problems in Spectrogram. -John KI6WX +++++++++++++++++ From: "Allen C. Ward" To: "elecraft reflector" Date: Fri, 1 Nov 2002 13:02:55 -0600 Subject: [Elecraft] Matched Crystals worth the effort!!! Today I finished installing, re-caling and testing 14 new matched crystals. My K2 is serial #1107, so not a field test or real early unit, but still about two years old. I had previously done the mods (KI6WX etc.) to flatten response but I still wasn't happy with the filter response. The original crystals were marked 4.91-0195 for the standard filter and 4.91-20 for the K2SSB. I also opted for the toroidal L33 BFO choke. I first recorded (using Spectrograph) the original responses and then replaced the CW filter crystals grounding them low on the can sides. I then recaled the BFO settings and recorded the results. Now the beat note does not change when selecting different bandwidths and the response stays the same or increases slightly as bandwidth is decreased. This is a GREAT improvement! I then changed the K2SSB crystals. The improvement was not nearly as great. After testing I then did the BFO mod (C174 and L33 replaced). I then had to recal the BFO for all filter modes and bandwidth. I have a new receiver!! The SSB response is almost identical for LSB and USB and instead of looking like a hock shop western saddle, the response is very flat from 500 to 2000 Hertz. Tuned to a CW signal the frequency readout change from SSB to CW is 600 Hz (the sidetone frequency). Sideband sounds more natural. This change and the other mods mentioned in the Elecraft webpage are easy to do and are worth the minimal cost and effort if you need them. Allen KA5N +++++++++++++ Date: Tue, 05 Nov 2002 13:28:17 -0500 From: Larry - WA2DGD To: Elecraft Reflector , Gary Surrency Subject: [Elecraft] Re: WA2DGD: RE: New xtals Hi Gary, Thanks for the reply. Keep in mind this is a fully functioning K2 with the old xtals. I removed the SSB module and shorted the appropriate pins. Now the CW filters work great, no attenuation and a great shape. CW and CW rev look and sound excellent. I was easily able to run spectrogram. I put the SSB module back in and.....everything works great...go figure. Maybe I didn't have the SSB module seated well. Thanks for all the help. 73 Larry WA2DGD K2 #1672 ARCI QRP #11215 NJ-QRP# 395 ----- Original Message ----- From: "Gary Surrency" To: "'Larry - WA2DGD'" Cc: "CSinfo (E-mail)" Sent: Tuesday, November 05, 2002 12:43 PM Subject: WA2DGD: RE: New xtals > What filter is FL2-FL4 set to? These are often the CW variable filter on the > RF PCB, and not the OP1 fixed filter on the SSB option. > > If this is the case, then you may have a problem with the CW variable > filter, or the PIN diode switching on the SSB option that selects either > filter. > > It could also be just a poor alignment on the CW variable filter too. When > CAL FIL BFO settings are correct, there is only a 3-6dB loss at the narrower > CW filter bandwidths. > > Be sure the T1, T2, RFC1, RFC2 toroids on the KSB2 option are correctly > built and installed, and there are no poorly tinned toroid leads or short > circuits in those areas. A close inspection of the SSB option should show if > there is a problem. > > Place jumper wires in the 3 pin connectors, and a .001uF cap across P1 pins > 7 & 12. See if the rig then works normally, and if you can get CAL FIL done > well for the CW filter. > > -- > 73, Gary AB7MY > ========= > gary at elecraft.com > Elecraft Technical Support > > -----Original Message----- > From: Larry - WA2DGD [mailto:wa2dgd at comcast.net] > Sent: Tuesday, November 05, 2002 9:44 AM > To: Elecraft Reflector; Elecraft Support > Subject: New xtals > > > Hello all, > > I just finished replacing xtals X5 - X11 and the 7 xtals on the ssb board. > I'm trying to use Spectrogram and the noise generator to realign the filters > (cal fil). I'm finding that FL2 and FL3 are down at least 20db and FL4 is > down over 30db compared to FL1. I get similar results on SSB. Am I > forgetting to do something else? > I've rechecked the xtals under magnification and all connections are fine, > no shorts, etc. I grounded the xtals at the bottom on both sides (just like > the original xtals). > What's happening here? Your help will be greatly appreciated. > 73 > Larry > WA2DGD > K2 #1672 > ARCI QRP #11215 > NJ-QRP# 395 +++++++++++++++ From: "Lyle Johnson" To: "Elecraft" Subject: RE: [Elecraft] Removing Crystals Date: Tue, 5 Nov 2002 12:26:19 -0800 Hello Steve! > I wonder what most are using to remove the old crystals? Most > components you can cut out on the top and then use a solder > pullit or solder wik (I prefer solder wik) unfortunately the > crystals cannot be cut off, like a resistor or cap. The most important thing is to preserve the PC board - so plan to sacrifice the old crystal. I have used solder wick for this. Just use the right temp on the iron (700 degrees F is fine, but NOT 800!). Once you have the solder removed from the hole, clip the ground lead and see if the crystal comes out. If it does, proceed to the next one :-) If it doesn't, heat one of the two pins and push the crystal away from the heated pin. Then repeat from the other side on the other pin, back and forth, rocking the crystal until it comes free. +-----+ <-- push here | | | | | | +-----+ Crystal ========|===|=== PCB \<---- heat here If you keep the iron temperature low enough (and high enough!), and don't apply heat too long, you'll preserve the board and the crystal will come out easily. If you use too much pressure and not enough heat, the lead may pull out the plate-through in the PCB or lift a pad. If you use too high a temperature, you're likely to lift a pad. Neither problem is unrepairable, but both are avoidable. 73, Lyle KK7P ++++++++++++++++ From: "Mike McCoy" To: "Steve & Anne Ray" , "Elecraft" Subject: Re: [Elecraft] Removing Crystals Date: Tue, 5 Nov 2002 14:41:45 -0600 Steve, I simply used my 40w soldering pencil and a 'solder sucker' desoldering pump. I took the bottom cover (not the heat sink) off, turned the K2 upside down and desoldered the xtals until they basically fell out on their own. Same with the (removed) SSB board but I held it upside down in my PC board vise. Using some needlenosed pliars I applied some slight 'pull' on the ground wires during desoldering to remove them then cleaned up the excess solder in the thru holes with the desoldering pump. Just be quick with the heat on the SSB board though... those are some tiny pads and they could 'cook off' easily. Actually *replacing* the xtals/grounds is harder. To reinstall the grounds at the base of the xtals on the RF board was a bit challenging (the resistor pacs are in the way on one side) I decided to replace the ground leads first with short, bare 'stubs' of left over clipped leadwire. Once they were all in I trimmed them all to the same length (about 1/2" or so). I then soldered the xtals in place making sure they were firmly pressed against the PC board. Then I bent the ground 'stubs' up against the xtals and soldered them in place. Worked like a charm. Mike - K5PU ++++++++++++++++ From: "Rick" To: Date: Wed, 6 Nov 2002 11:21:08 -0600 Subject: [Elecraft] removing old crystals I have replaced the IF xtals in my K2 and have a tip on how to remove the old xtals. Begin by unsoldering the makeshift ground lead from the top of the xtal. From below, heat one of the xtal leads while applying *mild* force to attempt to lift that side of the xtal SLIGHTLY away from the board (not all at once). If it doesn't move, heat the other xtal pin and apply some force to lift it. One or the other lead will permit the xtal to lift up slightly. When you have managed to lift one side the xtal a tiny bit, heat the opposite lead and lift. Repeat this procedure until you have "walked" the xtal out of the board. The walking process takes about two or three "heatings" on each xtal lead before the xtal is free from the board. Use a "solder sucker" or solder wick to clean the holes on the board afterwards. I don't believe there is a significant need to solder the xtal can gnd lead to the bottom of the xtal body since the inductance of a 1/2" long wire at 4.9 mHz is miniscule. Nonetheless, I soldered the gnd leads at the bottom of each xtal can then hurriedly placed them on the wet sponge of the soldering station to cool! You have to plan ahead when soldering the gnd leads to the bottom of the xtal cans since, if improperly placed, the xtals won't seat nicely on the board. (Another reason to solder the gnd lead to the top of the xtals!) I bought the new set of xtals because they were inexpensive and it offered the possibility to improve a very good radio. They did improve the quality of the SSB audio. There is no longer any difference in the sound of the white noise between USB and LSB. (I made the transistor-switched cap mod before and that helped, but the new xtals (with the transistor-switched cap mod) work better. However, attempts to narrow the filter to 2.2 kHz (OP2) resulted in less than equal performance between USB and LSB. However, SSB filter bandwidths of 1.5kHz and 200 Hz were USB/LSB symmetrical. Hope this helps someone. If your rig has the older xtals, a set of new ones is worthwhile. Besides, it's fun to play inside the radio again! 73's Rick KC0OV K2 1360 ++++++++++++++++ Date: Fri, 08 Nov 2002 21:30:12 -0800 From: Phil Wheeler Organization: Outstanding To: Joe Malloy Cc: Mike , Elecraft Subject: Re: [Elecraft] K2KSB2XTLS Crystal Mod Kit Joe Malloy wrote: >Mike, I probably wrote that message; having mislaid the instruction sheet >for the 14 crystals (or so I thought), I asked which crystals were to >replaced on the RF board besides the obvious 5. Well, in thinking about it, >I'm not sure there *was* an instruction sheet. > I think there was not. Phil +++++++++++++++++++ From: "Mike McCoy" To: , Subject: Re: [Elecraft] K2 14 crystal replacement results. K2 system gain results Date: Sat, 9 Nov 2002 16:42:54 -0600 Ron said: > Like Larry, W2BVH, I found it hard to judge the OPT-1 filter performance > by looking at Spectrogram, but the difference in the "sound" of the > filter when monitoring my own SSB transmission was tremendous! > > Keep in mind that the problem is NOT "bad crystals" in general, but SOME > kits with SOME "bad crystals" that produce filters with either too much > insertion loss or too narrow of a bandwidth for SSB. So even with kits > with adjacent serial numbers, one may see a big improvement and the next > one will see none at all. > > Mine had no insertion loss problems, but my OPT 1 filter was way too > narrow for decent SSB quality. I had to change all of the crystals, of > course, so I'd have a "matched set" after putting in the new ones for > the OPT-1 filter. > > Ron AC7AC > K2 # 1289 I had *exactly* the same issue/results here. I guess I was a victim of the odds and my previous xtals (-0195's) made my SSB xmit audio 'pinched' &/or thin sounding and thus too bad to even bother. Since I replaced the xtals (right after the surprise that I'm only running 10w) I've had a couple QSO's in the last day or so *volunteer* how good the audio sounded! I am ONE HAPPY CAMPER! Mike - K5PU K2 # 2602 ++++++++++++++++ Reply-To: From: "Ron D'Eau Claire" To: Subject: RE: [Elecraft] IF xtal replacement mod Date: Thu, 14 Nov 2002 09:29:58 -0800 Several months ago when I replaced my filter crystals I saw a message that caught my eye. I believe that it was from Eric or Wayne, pointing out that with good i-f filter crystals the attenuation increases sharply down near 200 Hz. That was why they recommended 400 Hz as the "narrow" CW filter bandwidth. I haven't saved the message so I must work from memory. It raised some questions because, apparently, somewhere in the Elecraft documentation an example of 100 Hz for the narrow filter is mentioned. I noticed the message because I had used my FL4 at 200 Hz until I replaced the crystals, but found that I did not like the sound of the filter at that bandwidth with the new crystals installed. It wasn't so much the attenuation, although I did notice that, but more the "sound" of the filter. QRN and signals near the edge of the bandpass had a "harsh" quality that I attributed to the distortion produced by the steeper slopes at the edges of the passband. In my experience, there really IS a place in this world for filters whose sides are not vertical. It didn't matter to me since I normally operate CW with a bandwidth of 1 or 1.6 kHz or greater and do the filtering in my head. I just set my "narrow" filter to 400 Hz. Ron AC7AC K2 # 1289 "David A. Belsley" wrote: > > Well, I replaced the 7 IF xtals and redid CAL FIL with spectrum > analyzer. I guess the results are good, although I didn't do any > before and after measurements. The only negative is that my FL4 > position, at 100Hz, is now much more attenuated relative to the other > BPs, roughly one S unit. It was somewhat less than the others before > the mod, but not that much. Any thoughts out there? ++++++++++++++++++ Date: Fri, 15 Nov 2002 17:48:08 -0600 To: elecraft at mailman.qth.net From: Tom Hammond =?iso-8859-1?Q?N=D8SS?= Subject: [Elecraft] Comparison of New vs Old K2 Filter Xtals Hi Folks: As threatened, I finally got around to comparing the passbands of my New vs. my Old K2 Filter Xtals. that comparison is on PDF format and my be DOWNLOADED from: http://www.qsl.net/n0ss The link is BELOW the 'Welcome', so place don't miss it. 73, Tom N0SS ++++++++++++++++++ Reply-To: From: "Ron D'Eau Claire" To: "'Robert Fanfant'" , Subject: RE: [Elecraft] Can't hear the internal birdie while in CW Date: Sat, 16 Nov 2002 23:52:04 -0800 Completed several mods including the 14 XTAL replacement and I can no longer hear the internal birdie while in CW. Do hear it in either LSB or USB. Where do I start looking for the problem? CW signals seem to be much lower in CW mode then when hearing them in USB or LSB mode. -rob N7QT ------------------------------ I'd check the xtals first and see if you have any continuity between the cases and either lead on each crystal. In the initial build, a lot of ops ran into very low signals that were traced to flowing a bit too much solder into a crystal lead hole. It flowed through, formed a small bump of solder around the lead under the crystal, and touched the case, grounding the signal circuit at that point. It's impossible to see since the short because it is hidden under the crystal. That's assuming that the problem is in your crystal replacement. Your situation is a textbook case for taking the time to reassemble the rig enough to check it out after EACH change. Ron AC7AC K2 # 1289 +++++++++++++++ Date: Wed, 04 Dec 2002 13:27:59 -0500 From: W2AGN To: elecraft at mailman.qth.net Subject: [Elecraft] K2 #023 back up! Well, finished the BFO mod, and replacing the filter crystals. Also even added the speaker grill cloth. Just realigned all the filters with spectrogram. Didn't imagine that the K2 could be any better, but now it seems so. My K2 has always been one of those that you had to run the audio up around 3 o'clock or so. No longer! Now I am sitting here with the audio at 8 0'clock, and getting fine copy with the speaker. Something sure made a difference. I guess it was worth the work! ++++++++++++++++++ Date: Fri, 06 Dec 2002 08:02:27 -0600 From: Randy Moore To: Elecraft Reflector Reply-To: Randy Moore Subject: [Elecraft] Updates to ole #337 Finally got around to applying some long delayed updates to my 3 year old K2 (#337). Late last night I completed the 2nd xtal filter mod, the PSK31 mod, BFO torroid, ref. xtal osc, and replaced all my old filter xtals with a matched set. No, I didn't do all that at once - I did some basic testing between each one, just to make sure nothing bad had happened, but I wanted to wait until it was all done to tweak things up. It was late when I got it all done, so I only ran through a quick CAL PLL and CAL FIL on only CW. Initial observation is - WOW!! I've always had serious attenuation of received signal on CW with progressively narrower filter settings. I had long discussions on the reflector 3 years ago about it. The concensus then was that something was wrong, but no one could tell me what it was. Well, all that's now GONE! Very little attenuation now! An amazing difference! I must have gotten a worst case set of filters xtals! I captured some "before" Spectrogram images before starting this, and this weekend I'll do some "after" shots and make them available somewhere. I am not fond of doing these mods, and there's always a risk of me screwing things up, so I agonized over it for a long time, but it looks like it was well worthwhile! 73, Randy, KS4L +++++++++++++++ From: "Rich Lentz" To: "Elecraft Reflector" Date: Fri, 6 Dec 2002 11:54:23 -0600 Subject: [Elecraft] BFOMDKT & K2KSB2XTLS MODS Just completed the BFOMDKT and the K2KSB2XTLS MODS to K2 #2260. This = has got to be the BEST upgrade Elecraft offers. If you have been thinking = about it, "Just do it," it is well worth the effort and can be completed in = just several hours. The 2940 BFOMDKT has limited my frequency drift to less = than 20 Hz. The K2KSB2XTLS has flattened, slightly widened, and reduced the frequency change between the various XFIL settings. =20 Wayne and Eric are to be commended on providing this inexpensive yet outstanding improvement.=20 Rich KE0X ++++++++++++++++ Date: Tue, 10 Dec 2002 10:47:21 -0500 From: W2AGN Subject: Re: [Elecraft] Tech Note for Crystal Replacment? To: Elecraft List On 10 Dec 2002 at 7:54, Todd Gahagan wrote: > Thanks for the quick reply!! Todd, WA7U > > > > Tech Note for Crystal Replacment? Is this available anywhere on the > > Elecraft site? > > > > No, there is no tech note for this. If you have an older K2, and you > believe > > your filter is not good, you buy the new crystals, remove the old > crystals, > > install the new ones, and run CAL FIL. > > > > 72/73, > > > > Lyle KK7P Incidentally, I did the crystal replacement on my trusty old S/N 023, and it REALLY made a difference. I had the problem often mentioned of seeming low gain (having to to run AF Gain at max). After the replacement,I get good results with AF gain at 9 oclock. Don't know if that's typical, but worked for me. --- +-++-++-++-++-+ John L. Sielke |W||2||A||G||N| http://www.w2agn.net [UPDATED] +-++-++-++-++-+ Ex-K3HLU,TF2WKT,W7JEF,W4MPC,N4JS ++++++++++++++++