+++++++++++++++++++++ See also K2 Matched Filter Crystals +++++++++++++++++++++ Reply-To: From: "Ron D'Eau Claire" To: "'Parker Buckley'" , Subject: RE: [Elecraft] Questions about new crystals Date: Sat, 14 Dec 2002 12:54:48 -0800 I have K2 #2636. Now that I've ordered new crystals as part of the upgrade package, please tell me once again why I'm doing this?! Are these better matched than what came with the kit? ------------------ Newer K2's do NOT need new crystals from what I've seen. It all started because, over the years, Elecraft has discovered that the spex on the crystals were not tight enough to ensure that they would all produce the desired filter performance. The filters in MOST K2's were fine, but a few had problems. So they have progressively tightened up the spex. Those who had older K2's SOMETIMES saw an improvement by changing the crystals. I had a mis-matched set for the SSB OPT1 filter in my 2+ year old K2. A new set of crystals fixed that, but even then Wayne/Eric were very surprised that I had a mis-matched set. By then (2 years ago) they thought they had replaced all of the older crystal sets. I, too, have seen a few comments about the crystals "fixing" low gain situations. My K2 has always had plenty of gain, so I can't comment on that. My problem was a too-narrow SSB filter (OPT1) on the SSB module. Fixing that with new crystals also required me to replace all of the CW filter crystals on the r-f board too, in order to have a matched set of filters when I was done. Changing the crystals for the CW filters changed their characteristics, but did not offer any improvement. Nor was any needed. The reference that you've seen to removing a crystal has to do the a recent mod to improve the stability of the K2. The K2 uses parallel crystals in VXO circuits and it has been found that with better spex on one crystal, one crystal can be removed. That yields better overall stability. If you order the BFO/PLL stability mod from Elecraft you will get the proper crystal and other parts to change that will improve the stability. I THINK (check their info on the reflector) that this only applies to K2 BEFORE S/N 3000. I believe that these changes were incorporated in newer K2 kits. So your would probably benefit from adding the BFO/PLL stability mod kit. If I recall correctly, it'll set you back about $10. It's a bargain. Ron AC7AC K2 # 1289 ++++++++++++++++ From: "Rich Lentz" To: "'Parker Buckley'" , Subject: RE: [Elecraft] Questions about new crystals Date: Sat, 14 Dec 2002 15:19:07 -0600 I have 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 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. The display in Spectrogram is significantly flatter and now exceeds the specified 2.2 = kHz bandwidth. Like Eric/Wayne says it is suitable to all rigs before #3000, doesn't cost that much, and you get to heat up the soldering iron again. = I was surprised as to how much of the frequency error was actually the BFO drift error. After completing the above mods and then doing Steve GU3MBS frequency calibration posted on 29 Nov 2002, my frequency + BFO drift error is = less than 20 Hz after several hours (and in between.) =20 Rich, KE0X +++++++++++++++++ Date: Mon, 16 Dec 2002 22:38:59 -0500 To: "Brent Sutphin" From: Dave Gingrich K9DC Subject: Re: [Elecraft] Filter Crystals Cc: At 19:04 12/16/2002 -0500, Brent Sutphin wrote: >I have K2 # 2571. I am one of those people who want my rig to work as >well as possible. I am having trouble with the decision whether or not to >replace my filter crystals. The filters are set up for a pass band of >1.5khz, 700hz, 400hz and 100hz. Here is the symptom I would be trying to >eliminate. I loose 10-12db of signal strength when I switch to the narrow >100hz filter. Is this normal? I set my filters using Spectrogram and the >signal loss was measured with this software. Any help would be appreciated. I to was one that waffled on the crystal replacement for my K2 (S/N 2211) Mainly because I thought my rig sounded pretty good, and the filter traces, though humped somewhat, were not as bad as the examples. BUT, this weekend, I did the BFO mod, and the 14 filter crystals. What an enormous difference. The filter is as flat as a table on top, and with just a slight adjustment of L34, is identical for LSB and USB. Unless you can confirm that your K2 was shipped with a matched set of 14, I would highly recommend the mod. I also bought the parts kit for older 2nd filter mod (the one that switches in and out on rcv to xmt). Completely unnecessary with the new crystal set. ================================================ Dave Gingrich, K9DC - Indianapolis, Indiana USA K2 #2211, K1 #931, QRP-L #2376, ARS #1109, FPQRP #389, IRLP 4730, k9dc.ampr.org ================================================ ++++++++++++++++++ Date: Mon, 16 Dec 2002 20:05:23 -0800 From: "John, KI6WX" Subject: Re: [Elecraft] Filter Crystals To: Elecraft Mailing List The 2nd Xtal Filter Mod is necessary if you want a flat response on SSB. The new Xtals do not fix that problem. An improved version of the 2nd Xtal Filter Mod is included in the Rev B update. -John KI6WX > > BUT, this weekend, I did the BFO mod, and the 14 filter crystals. What an > enormous difference. The filter is as flat as a table on top, and with just > a slight adjustment of L34, is identical for LSB and USB. > > Unless you can confirm that your K2 was shipped with a matched set of 14, I > would highly recommend the mod. I also bought the parts kit for older 2nd > filter mod (the one that switches in and out on rcv to xmt). Completely > unnecessary with the new crystal set. > +++++++++++++++ Date: Mon, 16 Dec 2002 21:25:17 -0800 From: "John, KI6WX" Subject: Re: [Elecraft] Filter Crystals To: Elecraft Mailing List Dave; I developed the changes to the original modification and they are posted on my web site at http://home.pacbell.net/johngreb/KI6WX.html . Go to the section on "Improving the Performance of the KSB2". I need to re-post that article to note that the Improved 2nd Xtal Filter Flatness Mod is now included as part of the Rev B board. -John KI6WX John: I note that the "K2 from Revision A to B Upgrade" manual does not include the actual instructions for the 2nd Xtal Filter Mod, but simply indicates to follow the instructions with the XFILMDKT kit. For those who don't need the parts, but would like the new instructions, do you know where they are available for download? thanks, dave belsley, w1euy ++++++++++++++++ From: "Don Brown" To: "Todd Gahagan" , Subject: Re: [Elecraft] Questions about crystal replacement in K2 and SB board Date: Thu, 2 Jan 2003 09:55:10 -0600 Hi The X5-X11 and the SSB crystals are all the same and a matched set. X3-X4 are different even though they are the same frequency. They are series mode crystals while the others are parallel mode. Some of the earlier reference oscillator crystals would not pull enough with one crystal so 2 in parallel were used to de-Q each other so the varactors could change the frequency enough. The newer crystals have been selected to have enough range with only one crystal giving the benefit of much reduced drift in the reference oscillator thus the VFO drift is reduced by more than 50% The change of the BFO toroid reduces the BFO drift but two crystals are required to get enough range in the BFO that is why X3 and X4 are in parallel. Don Brown KD5NDB ----- Original Message ----- From: "Todd Gahagan" To: Sent: Thursday, January 02, 2003 9:34 AM Subject: [Elecraft] Questions about crystal replacement in K2 and SB board > In the process of doing all the mods here (must be what its like to do brain > surgery on your own child) and have now reached the point where I need to > swap out the crystals. Guess I'll risk showing my ignorance but wanted to > make sure that in the K2 this means replacing x5-x11 and not x3 and x4? > Also, replace all the crystals on the SSB board. From what I can tell it > now looks like Elecraft recommends using two grounds for each crystal and > grounding them near the base?? > > One other question: Why are we able to go to only one PLL crystal (X1) > instead of the original 2? > > Thanks, Todd +++++++++++++++ Date: Mon, 13 Jan 2003 13:46:00 -0800 (PST) Subject: Re: [Elecraft] Tips on safely Soldering X7 - X11 Grounding wires on K2 RF Board From: "Martin AC6RM" To: Cc: Reply-To: elecraft at ac6rm.net Mike; Here's what I did to ground these. Construct a picture in your mind of how this is going to go before you actually do it: 1. Install the crystals as instructed in the manual; 2. Select ten of your best excess snipped-off component leads. You need them to be at least a little longer than the crystals are tall. Straighten them out so there are no kinks and no excess solder blobs on them, etc. 3. Turn the RF board upside down and rest it on a non-flammable table or bench top. If you are using a vise to hold the board during this kit-building process, you'll need to remove the RF board from the vise and get it flat on to the non-flammable surface (such as glass, or a flat baking tin, etc.). 4. Drop the snip-offs into the ground holes next to the crystals. Get them as verticle as possible, and then solder them in to place. The non-flammable surface is needed because the hot wires will mark up your mother's oak dining room table, or melt through your anti-static mat (this, from experience). 4. Turn the board back over. 5. Clip off these new ground wires about half-way up the crystal cans. Use a pair of small needle-nose pliers to bend each wire such that it makes contact with the crystal about a quarter of an inch up the crystal can. (I sorta "dog-legged" the bends so that about 1/8th of an inch of the ground wire layed flat against the side of the crystal can). 6. Using your vise, or some other mechanical means, rest and secure the RF board on its left edge, such that -- now, as you look DOWN at the crystals and the outside five new ground wires, the wires are oriented ABOVE the crystal can. 7. Following earlier precautions regarding overheating the cans, solder the wires to the cans. 8. Flip the board on to its other edge and then solder the other five. I am sure there are other creative ways to accomplish this task. This worked for me. 73 ES GL, Martin AC6RM K2 #3021 ("It's Shake'n'Bake and Ahh Healped!") > Hi, > > I am a first time K2 builer, and just joined the list. I am greatly > enjoying my kitbuilding experience so far, but I have a little > trepidation in performing the crystal grounding steps for the 5 crystals <...snip...> > So I was wondering at what techniques people had found for this that had > produced good results. <...snip...> > Tnx es 73 de KE0MF > Mike +++++++++++++++++ From: "David A. Belsley" To: elecraft at ac6rm.net, michaellewis at qwest.net Cc: elecraft at mailman.qth.net Subject: Re: [Elecraft] Tips on safely Soldering X7 - X11 Grounding wires on K2 RF Board Michael's description of his work is fine. Something you might want to consider, however, is to pre-tin the spots on the side where you are going to attach the ground wires before you install the xtals. Some of the spots are difficult to access once the xtal is installed. Tining the xtals is easily done: using your iron (700F is plenty adequate), heat the spot by rubbing the iron back and forth a few times a short distance (maybe 1/4" at most). Then bring the solder to the point of contact between the iron and the xtal case. Once it starts to melt, continue dragging the solder blob back and forth, scraping it into the case. You will shortly see it start to stick to and tin the case. Stop. best wishes, dave belsley, w1euy ++++++++++++++++++ From: "Dave" To: "Mike Lewis" Cc: Subject: Re: [Elecraft] Tips on safely Soldering X7 - X11 Grounding wires on K2 RF Board Date: Mon, 13 Jan 2003 22:40:29 -0000 Mike There are several places where components are quite tight in the K2, especially around the PA. In those tight areas it really does help to pre-plan which side you are "going in" with the soldering iron and solder. Consider rotating the board and do a mental check of what is at risk of being burnt by that soldering iron. An old tip (excuse the pun) is to not use a fine soldering iron tip when you have some space and need a quick job. There is nothing worse than messing around with a fine tipped iron taking several seconds trying to heat something larger than the bit was intended for. On Weller TCP irons, those conical (pencil) tips fall into that category. I built my K2 (and K1 and dozens of other projects) with a 25 Watt conventional iron with a variety of bits, even when I had a TCP1 available. Dave, G4AON ++++++++++++++++ Date: Mon, 13 Jan 2003 17:36:50 -0600 To: "Mike Lewis" , elecraft at mailman.qth.net From: Tom Hammond =?iso-8859-1?Q?N=D8SS?= Subject: Re: [Elecraft] Tips on safely Soldering X7 - X11 Grounding wires on K2 RF Board Hi Mike: I can appreciate your concern. Though I don't think you'll have any problems. Soldering the ground wires to the Xtal cane BEFORE you install them can be accomplished as follows: 1) Tin the end of ALL the wires you'll be using for the ground lead. Note that it's OK to leave a small amount of extra solder on the end of the wire. 2) Hold each xtal so it's on its side with one of the narrow sides facing up. If you have a small vise, use it. 3) Using your T/C iron (a wider tip if you happen to have one) at 700-725 F, clean the tip and apply a small amount of solder to the tip to ensure that it's well tinned. Tin the bottom edge of the xtal can, about 1/8" up from the bottom bead going around the can. This should take only 4-5 seconds, max. Repeat for the other side of the xtal can. Pre-tinning the can ensures that the solder will 'take' quickly in the next step AND it means that you didn't have to mess with a wire AND solder at the same time when trying to attach the wire itself. 4) With the Xtal still held in place, lay one of the tinned wired up against the tinned spot on the xtal case and touch BOTH the wire and the xtal can with the iron. You should see the solder from both tinned spots melt and 'sweat' the joint together. DONE. 73, Tom Hammond N0SS PS It works well for me... of course, YMMV. >I am a first time K2 builer, and just joined the list. I am greatly >enjoying my kitbuilding experience so far, but I have a little trepidation >in performing the crystal grounding steps for the 5 crystals that are >grounded on the sides of the case. I do have a temp controlled iron, and >have been running it at 700 degrees so far. I used a small amount of >liquid solder flux (only a small drop) on the tops of the crystal cans for >the previous crystals I have grounded, and the results seemed to be pretty >good, and did not require me to leave the iron on the crystal case for an >appreciable amount of time. I had also soldered the ground wires in before >the crytals in these earlier steps - that seemed to make life easier. I >guess I am a bit more jumpy on these last crystals because: > >1) Extra warnings in manual about excessive heat > >2) added complexity of soldering to both sides of crystal > >3) More awkward access, due to mount point on edge, and potential >interference from R pack SIPs on one side of crystals > >4) Extra difficulty in getting ground wires to lay close to the case > >So I was wondering at what techniques people had found for this that had >produced good results. Does it possibly make sense to try somehow to >solder the wires to the crytal case before the crystals are soldered into >the board? If not, is soldering the wires into the board first still seem >like a good approach? Is there some nice trick for getting the grounding >wire to lay against the side of the case prior to soldering? Any insights >would be appreciated. > >Tnx es 73 de KE0MF >Mike +++++++++++++++ From: "Bob - AG5Q" To: "Bruce D. McLaughlin" , Subject: Re: [Elecraft] Grounding crystal filters Date: Fri, 14 Mar 2003 17:34:01 -0600 Hi Bruce, You can do it before or after putting the xtals on the board. Perhaps easiest is to put the wires in the holes on either side of the xtal and solder them first and tin the upper end of the wires. Bend the wires so the xtal can be easily inserted. It may be easier to tin the sides of the xtal before putting it on the board, depending on the surrounding components. One tool I've found handy for holding small parts for soldering is to put a rubber band around the handles of regular pliers. This makes a nice little vise and you can adjust the holding force by winding the rubber band around the handles. After putting the xtal on the board, bend the leads into position and solder them quickly. The alternative is to put the leads on the xtal first, but then you have to wiggle four leads into position at the same time. If the xtal is close to a tall component, you may have to do it this way. 73/ Bob - AG5Q ----- Original Message ----- From: "Bruce D. McLaughlin" To: Sent: Friday, March 14, 2003 5:06 PM Subject: [Elecraft] Grounding crystal filters > Does anyone have a good suggestion or two as to how best to handle the > crystal grounding? > Bruce - W8FU ++++++++++++++++++ Reply-To: "Indy" From: "Indy" To: Date: Fri, 14 Mar 2003 21:33:14 -0700 Subject: [Elecraft] crystal grounding How i DID it!!! by young Frankenstein ;-) Your mission, ground them twice with the thickest and shortest wire = possible while not destroying the crystal in the process. this is how I = did it, no guarantees if anyone else were to do it... no vises, no fancy = tools, just a little thought 1) 600 grit sand paper, sanded the side of the crystals. i did not tin = them. Once scruffed up they tin instantly anyway. 2) soldered vertical bare wires in the circuit board ground holes 3) soldered crystals in place on circuit board 4) pushed top of wire toward crystal until it touched, but it won't = stay against the crystal, springs back a little 5) slid screw driver down wire from the top, while pushing it against = crystal, now it stays in contact with the crystal. made sure that the = grounding wire on the SSB board side is at least an eighth of an inch = down from the top of the crystal, then it won't interfere with SSB board 6) solder the top of the wire to the crystal 7) then, in one swift motion, draw iron and solder down the side of the = crystal along wire and off of it. iron is in contact low on the crystal = for tenths of a second at most. grounding wire ends up well shorter than a quarter of an inch. this is a high point of the entire build. My filter skirts are straight = down to the noise floor, no convex dish at all, and thank you to the two = engineers who pioneered this approach to get rid of the blow-by, KI6WX = and the other was Kevin, but I forget his call, thank you guys for so = improving the performance of these filters! they deserve the credit GL Fred KT5X W5YA/qrp K2 # 700 +++++++++++++++++ From: "Don Brown" To: Subject: Re: [Elecraft] K2 14 Xtal Replacement Answer Received Date: Mon, 19 May 2003 11:42:27 -0500 Sorry, I didn't post to the reflector Yes you replace X5 and X6 NOT X3 and X4. They are different. Don Brown KD5NDB +++++++++++++++++++ Date: Fri, 23 May 2003 19:23:31 -0700 From: Phil Wheeler Organization: Outstanding To: George Winship Cc: support at elecraft.com, elecraft at mailman.qth.net Subject: Re: [Elecraft] KPA-100, etc. -- snip -- With S/N 2217, I'm not sure whether you need the matched xtal mod. At some point the xtals in the kits became matched as well as they are now. I just don't know when S/N-wise. Ah .. here is a posting from Eric: > +++++++++++++++++++++ > 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 It looks like you might benefit from the matched xtal mod. On the other hand, have you used Spectrogram to align your filters? Info on this at the website. I suspect if it sounds "tinny", aligning the filters well might improve things more than changing the filters.. YMMV. 73, Phil ++++++++++++++++ Date: Sat, 24 May 2003 11:29:07 -0700 From: Phil Wheeler Organization: Outstanding To: Elecraft Subject: [Elecraft] K2 Filter Alignment with Spectrogram An old subject, to be sure. I did the matched xtal mod, BFO mod and PLL thermister temp stabilization mod and set the filters at the default settings for the xtals (3.7 on envelope). Sounded pretty good. But since I had some free time, I finally build the noise generator kit I had on hand last night. This am I used it and Spectrogram to fine tune the filters in all modes. It took only an hour and I did not change things all that much, but it made a world of difference .. particularly for the narrower filter settings.. Info on all of this is available at the Elecraft website. 73, Phil +++++++++++++++ Date: Wed, 04 Jun 2003 13:25:09 -0400 To: elecraft at mailman.qth.net From: Kevin Cozens Subject: Re: [Elecraft] 14 Matched Crystals for K2 At 07:55 PM 06/03/2003 -0400, Daniel L Brinneman wrote: >I got my 14 matched crystals today for the K2 with no instructions. >Where do I install them on the boards? The K2KSB2XTLS is one envelope containing 14 crystals used to replace X5 through X11 inclusive on the RF board of the K2 and the seven crystals on the KSB2. Take the 14 new crystals, put them in their little envelope and put the envelope somewhere safe. Get two little bags and put them on your work bench. Take out the 7 crystals on the RF board, put them in one of the little bags. Label the bag as the RF board X5-X11 crystals and put the bag somewhere safe (other than where you put the new crystals. Remove the 7 crystals on the KSB2, store them in the other bag, label the bag as KSB2 crystals, and put the bag near where you put the other bag of 7 crystals. Now that all the old crystals are out of the way, you can open the container of new crystals and start installing them. By doing this, you avoid any possibility of mixing up the different sets of crystals. Its basically what I did when I changed the crystals on my K2. Cheers! Kevin. (http://www.interlog.com/~kcozens/) +++++++++++++++