++++++++++++++++++ Reply-To: From: "Sverre Holm - LA3ZA" To: "Elecraft at Mailman. Qth. Net" Date: Sun, 9 Jun 2002 01:19:32 +0200 Subject: [Elecraft] Latest K2 mod's The latest modifications on "the unofficial guide to K2 modifications" are: - Two ways to put the KPA100 100 Watt option in the EC2 enclosure (KK7B and KI6WX) - Simple fix for making current measurement more stable on 80/160 m - Improved version of 2nd stage crystal filter mod (KI6WX) - Replace optical encoder for more steps per revolution and faster tuning (N6TR) The list now also includes mods from K2 manuals: - Improved Tx efficiency at QRP (< 5 W) levels - Auto-detect diodes for keyer - Higher bandwidth in permanent audio filter of KAF2 - Higher audio gain in KAF2 - Intermodulation fix for Lo threshold setting of KNB2 See all 46 modifications on www.qsl.net/la3za/K2/mod.html 73 and happy soldering! Sverre Sverre Holm, LA3ZA Asker, Norway (59.8N, 10.4E) --------------------------------- www.qsl.net/la3za ++++++++++++++++++ Date: Thu, 22 Nov 2001 19:42:04 +0100 From: "Sverre Holm - LA3ZA" Subject: [Elecraft] Beginning of "Unofficial Guide to K2 Modifications" I was inspired by the recent discussion on K2 modifications and whether one needs to modify one's K2 to get full performance so I started to put together a guide to the modifications. At this point it is far from complete, and just shows one way that this can be done. Take a look at: http://www.qsl.net/la3za/K2/mod.html and see what you think. I have included the categories that I think are most relevant. Initially, I would like to get some comments on these categories, and how to give advice on important and not so important mod's. Also, I am thinking about sorting the categories, e.g. listing all front-end filter mod's together and so on. Probably, the disclaimer is in lousy English, as this is not my native language and in addition I am not a lawyer. Input on a proper formulation of the disclaimer is much appreciated. At this point in time, the guide is mainly influenced by the mod's that I have either done myself or looked at. Therefore it is far from comprehensive. Please do not comment on which mod's to include now. Later, and if this guide should create interest, I would like that kind of input. 73, Sverre, LA3ZA - ----------------- www.qsl.net/la3za ++++++++++++++++ From: owner-elecraft at qth.net [mailto:owner-elecraft at qth.net] On Behalf Of Ron D' Eau Claire Sent: 22. november 2001 22:24 To: Elecraft reflector Subject: RE: [Elecraft] Beginning of "Unofficial Guide to K2 Modifications" Sverre, LA3ZA, wrote: > I was inspired by the recent discussion on K2 modifications and > whether one needs to modify one's K2 to get full performance so I > started to put together a guide to the modifications. At this point it > is far from complete, and just shows one way that this can be done. > Take a look at: > > http://www.qsl.net/la3za/K2/mod.html > > and see what you think. That's a nice effort Sverre! I see two levels of mods. One level of mods are those that will become part of the basic K2 when it makes sense to update the circuit and redo the PCB's. These are mods that one would want to make to have a current 'factory designed' version of the rig. The other mods are improvements and enhancements that one might like to make independently but which will probably never be incorporated into the factory-supplied version of the rig. These are the sort of modifications a tinkerer trying to squeeze a little better performance out of their rig would want to try. They appeal to someone who enjoys having the rig on the bench as much as they enjoy having it on the air. I'd guess that most of us who hang around the reflector are in that category. The only mod in the first category that I've seen announced on here is the filter flattening mod for the K2. I don't know if that's been done yet, but Elecraft said it would be incorporated into the r-f PCB at some point. I wonder if any of the other modifications are slated to become a part of the 'factory supplied' rig. I'd expect the K2 volume control mod to fall into that category too, but I don't recall any announcement from Elecraft about that. Ron AC7AC K2 # 1289 ++++++++++++++++++ Date: Fri, 23 Nov 2001 08:57:41 -0500 From: "Don Wilhelm" Subject: Re: [Elecraft] Beginning of "Unofficial Guide to K2 Modifications" Ron and all, I too believe that the only two important mods are the filter flattening mod and the AF pot mod. All other mods and the wealth of information about setting up the K2 are there for the user who is particularly interested in making it 'just a bit better' (i.e. those who want to tinker with it) - a better example - the bandpass filter mods may be important to some folks in Europe, but may limit others who want to listen outside the ham bands.. That being said, I would like to inject that the K2 is a great performer without any mods at all, and everything critical to the performance is already in the base unit. The filter flattening mod is only important once the SSB option is added, and most K2s out there will operate just fine with the unmodified AF pot wiring. So IMHO, there are no critical mods at this time. Still, it would be nice if the folks at Elecraft would provide an errata sheet dealing with these mods until the changes can be incorporated into the board layout. Wayne and Eric - any plan to do this? 73, Don W3FPR +++++++++++++++++ Date: Fri, 23 Nov 2001 08:00:25 -0800 From: Vic Rosenthal Subject: Re: [Elecraft] Beginning of "Unofficial Guide to K2 Modifications" Don Wilhelm wrote: > > I too believe that the only two important mods are the filter flattening mod > and the AF pot mod. I would add the KI6WX crystal grounding mod to improve filter performance. In fact, being a CW operator, I didn't bother with the filter flattening -- but the crystal grounding made a BIG improvement in my K2. Second on my list is the sinewave sidetone mod; it makes zero-beating much easier. 73, Vic, K2VCO Fresno CA ++++++++++++++++++= Date: Fri, 23 Nov 2001 18:28:23 +0100 From: "Sverre Holm - LA3ZA" Subject: [Elecraft] Unofficial Guide to K2 Modifications The guide seems to be helpful for people to find their way through all the modifications suggested over the years, so I have kept on updating it. I have soon reached the point where I cannot think of any more modifications to add, but I am sure I have forgotten several. So please send me your suggestions. Also, I am particularly interested in getting some feedback from those whose work I am referring to, and that they make sure that what I have written is correct. The list is at: http://www.qsl.net/la3za/K2/mod.html 73 Sverre, LA3ZA - ----------------- www.qsl.net/la3za ++++++++++++++++ ---------------------------------------------------------------------- Date: Fri, 23 Nov 2001 09:54:47 -0800 From: lhlousek Subject: Re: [Elecraft] Beginning of "Unofficial Guide to K2 Modifications" Another K2 mod that might go on the list is increasing QSK speed by reducing the value of R17 on the control board. I haven't tried this myself yet but it is in the queue. Lou W7DZN +++++++++++++++++ Date: Sun, 25 Nov 2001 12:06:42 -0800 From: lhlousek Subject: Re: [Elecraft] My List of K1 Mods Here's another good K1 mod I posted on the reflector a couple of months ago: There is a loud pop in the headphones whenever you switch the ATTN in or out. Putting a 100 uH choke across pins 3 and 8 of relay K1 on the RF board completely eliminates it. The pop is due to the fact that the network that the RX switching-diode current flows through changes when the ATTN relay opens or closes causing a transient in T1. The added choke provides continuity for the switching current so no transient is generated. With ATTN off the contacts are closed shorting across the choke so it has no effect. With ATTN on the contacts are open and the RF flows through the attenuation pad (like it used to) because it can't flow through the choke. Lou W7DZN +++++++++++++++++ Date: Sat, 8 Dec 2001 23:04:20 +0100 From: "Sverre Holm - LA3ZA" Subject: [Elecraft] Unofficial Guide to K2 Modifications - update The guide at http://www.qsl.net/la3za/K2/mod.html has now been updated so it should be more or less complete for all but the earliest modifications for: - - The basic K2 - - The SSB option KSB2 - - The audio filter/real time clock KAF2 - - The noise blanker KNB2 As always, I would appreciate your input on additional topics that should to be included. Sverre, LA3ZA - ----------------- www.qsl.net/la3za +++++++++++++++++++ To: Bill Coleman Cc: elecraft at mailman.qth.net Subject: Re: [Elecraft] K2 On the Way -- Planning for Mods? From: "Steve Lawrence" Date: Thu, 7 Mar 2002 13:25:29 -0500 Bill, I too have been confused concerning "official" vs. "user" vs. "general interest amateur technical stuff" changes and modifications as expressed on the Elecraft site. Late last year, I even proposed a better site arrangement to help the user sort through the wealth of resources there. These evidently are still on the "to do" list. In the mean time, another site has an interesting summary, listed in a straight forward table: http://www.qsl.net/la3za/K2/mod.html You might check this out. 73, and welcome to the Elecraft community. Steve aa8af Bill Coleman Sent by: elecraft-admin at mailman.qth.net 03/07/2002 12:47 PM To: cc: Subject: [Elecraft] K2 On the Way -- Planning for Mods? Last week I couldn't wait any longer, and I broke down and ordered a plain jane K2 kit. (I'll order options when I get the K2 mostly assembled) I've browsed the Elecraft site, and I'm a little bit confused about the modification listings there. It's a bit hard to tell what's an "official" modification, what's a "recommending" modification and what's a special purpose or an experimental modification. >From my reading, about the only mod that appears to relevant to the plain K2 are changes to the crystal case grounding and bypassing to reduce filter blow-by. Is there something I missed? What other modifications are recommended out there? Bill Coleman, AA4LR, PP-ASEL Mail: aa4lr at arrl.net Quote: "Not within a thousand years will man ever fly!" -- Wilbur Wright, 1901 ++++++++++++++++ Reply-To: From: "Ron D' Eau Claire" To: Subject: RE: [Elecraft] K2 On the Way -- Planning for Mods? Date: Thu, 7 Mar 2002 10:39:05 -0800 > It's a bit hard to tell what's an "official" modification, what's a > "recommending" modification and what's a special purpose or an > experimental modification. > > >From my reading, about the only mod that appears to relevant to > the plain > K2 are changes to the crystal case grounding and bypassing to reduce > filter blow-by. > > Is there something I missed? What other modifications are recommended out > there? > > Bill Coleman, AA4LR, PP-ASEL You touch on a point that has come up recently Bill: "official" vs. "unofficial" mods. IF we define as "official" mods those furnished by or personally recommended that everyone make by Wayne or Eric at Elecraft, the only ones that I know of are the following: "K2 2nd Stage Xfil Mod, for 'Flatter' SSB Filter Response" that fixes an annoying tilt in the i-f output filter. This involves adding a transistor switch that changes a capacitor value in SSB. It is only needed if/when you want to listen to AM/SSB. According to a recent note from Wayne, this mod will eventually be incorporated into the basic K2, but it must await the next rework of the r-f board. "K2 AF Pot Application Note" that fixes a problem with the audio gain control that bothered many, but not all, users. The original design has the audio gain control acting as a 'shunt' literally shorting out the audio at the input to the audio amp. This worked well enough for most users, but many of us noticed that we were always running the audio gain control down near the minimum gain point. Also, our audio gain controls became very 'noisy' with the level jumping around when the control was touched. Apparently this was the result of the audio channels in some K2's having a lot more gain than others. The fix re-wires the audio gain control so that it behaves more like a normal 'audio taper' control and so it is no longer used right at the minimum point. It greatly improves the 'feel' of the audio gain and eliminated the 'noise' problem. I can't say that Elecraft has recommended that those who are not bothered by the way their K2 audio gain works make this change, but they HAVE recommended it to anyone finding the audio gain control touchy or noisy. Finally, there is a new mod from Wayne that is not on the Elecraft site yet as far as I know. Some K2's exhibit a tendency to start QSY-ing at random during a transmission. They would always increment upward in frequency as the rig was keyed in CW (it might happen whenever the PTT is pushed in SSB as well, but that would be a lot less apparent). The problem is that the optical encoder is reporting tuning control knob movement during transmit when in fact it has not been moved. It only happens if the encoder is sitting right on the transition of an optical segment, so it happens rarely and is almost impossible to do on purpose. The mod changes how the encoder is used slightly, so this problem will not occur. Wayne posted it in an e-mail to everyone, but I don't see it elsewhere yet. Those are the ONLY "Official" mods that I know of. There may be others. That's not to say that there aren't a LOT of GOOD mods out there that will enhance your K2. But, you are right. It's darn near impossible to see which ones Elecraft recommends be made and which ones they have not specifically recommended. Those listed above are the only ones that I know of that Wayne or Eric have specifically recommended. Some mods, such as the grounding of the crystal cans at the bottom, have not been recommended by Elecraft as far as I can see. I seem to recall that the reason for not recommending it was that it is easy to ruin a crystal with a tad too much heat when soldering at the bottom of the can. Ron AC7AC K2 # 1289 +++++++++++++++++ Date: Thu, 07 Mar 2002 13:02:49 -0600 To: Bill Coleman , elecraft at mailman.qth.net From: Tom Hammond =?iso-8859-1?Q?N=D8SS?= Subject: Re: [Elecraft] K2 On the Way -- Planning for Mods? Hi Bill: > From my reading, about the only mod that appears to relevant to the plain >K2 are changes to the crystal case grounding and bypassing to reduce >filter blow-by. > >Is there something I missed? What other modifications are recommended out >there? Definitely the xtal grounding mod! Consider adding the CW Sidetone mod as well... it makes a fairly significant improvement in what you're gonna hear for hours on end while contesting. As a preventive measure, e.g. easier to do now than later, add the AF GAIN MOD. When you build your K2, NOTE that T2 should be elevated avobe the PC board about 1/8" in order to provide a bit more output on 10M/12M. Finally, be sure to install the VFO "Walk" mod. I can provide any/all of these mods in PDF format. If you can't find them on the Elecraft site. Please check there first. 73 - Tom Hammond N0SS +++++++++++++++++ Date: Thu, 07 Mar 2002 19:34:35 -0600 To: Bill Coleman , elecraft at mailman.qth.net From: Tom Hammond =?iso-8859-1?Q?N=D8SS?= Subject: Re: [Elecraft] K2 On the Way -- Planning for Mods? Bill AA4LR wrote: > >Definitely the xtal grounding mod! > >OK. I think you offered some chip caps for this mod as well, no? Actually, I recommended nothing. The original idea for the mod came from KO0B (if I recall), and subsequent to that, KI6WX did a much more detailed write-up on the mod, and produced a PDF of it. There was a suggestion of adding chip caps, however, if memory serves, it was also mentioned that any improvement due to the addition of the chip caps was minimal and probably not worth the added effort/cost. > >Consider adding the CW Sidetone mod as well... it makes a fairly > >significant improvement in what you're gonna hear for hours on end while > >contesting. > >I hadn't heard about this one. This one comes courtesy of Randy Hargenrader, WJ4P. From: "Randy Hargenrader" To: Subject: [Elecraft] SINEWAVE SIDETONE Date: Sat, 26 Feb 2000 02:26:53 -0500 MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 4.72.3110.1 X-MimeOLE: Produced By Microsoft MimeOLE V4.72.3110.3 K2'ers, Tonite I finally cracked the sidetone "nut"! I now have a pure sinewave from the sidetone circuit working in serial numbers 183 and 661. It's VERY easy. Here's the modification to the control board... 1) Add a 47 K ohm resistor to the position of C24, a .0027uF capacitor. Pull up one side of C24. It doesn't matter which side. I had to completely remove it first then extend one lead out from the body of the capacitor so that it would have one lead in a hole and one lead up in the air for a "flying connection". Add the 47K ohm resistor to the other hole, also standing on end. Tack solder the top of the 47K ohm resistor to the "top" lead of C24, making a "flying" connection. Note: If the only modification you make is to add the 47K resistor, the tone will smooth out enough that you WILL notice a difference (for the better) but the tone will not be a clean sine wave. The next step will give the sine wave. 2) Make sure C33 is a 2.2uF electrolytic capacitor. (If you made the previous modifications to the sidetone I suggested some time ago, you might want to use these new values.) Solder a 47mH inductor across pins 7 and 10 of RP5. Do not remove RP5, and there is no need to cut any traces. Just tack solder the 47mH inductor across pins 7 and 10 of RP5. Note: For those of you who prefer to run low frequency sidetones, the sidetone begins to become slightly distorted below 530Hz and loses the nice sinewave shape below that. To compensate, use a 4.7uF cap at C33 or tack a 2.2uF cap across it on the back of the board. The higher frequency side-tones will be nice but at a slightly lower amplitude which isnt really a problem since you can reset the level at will. Your done! Put your K2 back together and start enjoying the sweet sound of a sine wave sidetone! BTW, miniature 47mH chokes are available from Mouser Electronics - part number: 434-03-473J, at 800 346 6873. Approximate cost $1.36 each. Usual disclaimers... 72, Randy WJ4P > >As a preventive measure, e.g. easier to do now than later, add the AF GAIN > >MOD. > >I remember reading about this one. However, I thought Elecraft found the >problem and would have incorporated the change into recent K2 kits. I >just ordered my kit last week, so wouldn't it have this fix? Could be, but I suspect it'll see the light of day inn the next iteration of the RF board, which is only about to hit Wayne's drawing board. Until that time, I'd plan on installing it myself. > >Finally, be sure to install the VFO "Walk" mod. > >That was just discussed recently. I didn't realise there was a mod for >this as well. Wayne posted it a couple weeks ago. I wrote it up for them, and it's now on Eric's PC (somewhere) awaiting it appearance on the Elecraft Web Site. >You have URLs for these? I'll download them and put them in my file. I'm only familiar with the URL for the 2nd Xfil SSB Mod: http://www.elecraft.com/Apps/new_fil_docs/k2_2nd_xfil_ssb_mod.pdf (Note, ALL spaces in the URL shown above are underscores "_", even though the auto-underlining of the link may tend to obliterate them) I believe there are several of them awaiting being put up on the web site. Go to the Elecraft web site, and take a look... there probably are others that I'm not remembering being listed there. I'd put them up on my web site, but I have limited download volume and I'm pretty certain that it's disappear once I announced that they were there and available for download. I know there are several folks here who have their own servers. If they'll drop me a note, I'll be happy to send them all of the mods I have IF they will make them available to users. I'd prefer to do it ONLY ONCE, and to several servers at one time, rather than piecemeal and repeatedly. What I'll probablt do is try to gather several takers over a couple days and then send them all at one time. 73, Tom N0SS +++++++++++++++++ Date: Thu, 07 Mar 2002 19:20:30 -0600 To: Tsachy Lindenbaum , elecraft at mailman.qth.net From: Tom Hammond =?iso-8859-1?Q?N=D8SS?= Subject: Re: [Elecraft] K2 On the Way -- Planning for Mods? Tsachy: >Always happy to read ur mail. >What's the "walk" mod? Don't remember seeing it. That's my 'label' for the most recent mod Wayne came up with and I did the write-up on. The 1-wire jumper on the CONTROL board to prevent the K2's VFO from 'walking' up/down the band under certain INfrequent tuning conditions of the VFO optical encoder. ++++++++++++++++++ Date: Thu, 07 Mar 2002 19:35:37 -0600 To: elecraft at mailman.qth.net From: Tom Hammond =?iso-8859-1?Q?N=D8SS?= Subject: [Elecraft] Fwd: K2 Alert 16, VFO Walk Fix, on web page Just received from Eric --- Thanks E. Tom >Date: Thu, 07 Mar 2002 12:24:10 -0800 >From: Eric Swartz WA6HHQ - Elecraft >Organization: Elecraft >To: Wayne Burdick >Subject: K2 Alert 16, VFO Walk Fix, on web page > >K2 Alert 16 is now on the Builders Resource Page. Wayne - feel free to >repost a >note to the list. Reference Alert 16 for more details. (It includes Tom's >excellent pics of the mod.) > >Tom - Thanks for the write up!! +++++++++++++++++++++ Date: Sat, 09 Mar 2002 10:02:46 -0600 To: David Pratt , elecraft at mailman.qth.net From: Tom Hammond =?iso-8859-1?Q?N=D8SS?= Subject: Re: [Elecraft] K2 On the Way -- Planning for Mods? Dave: > >When you build your K2, NOTE that T2 should be elevated avobe the PC board > >about 1/8" in order to provide a bit more output on 10M/12M. > >I have not noticed that one before, Tom. My T2 is flat on the board but >I am getting 9.6W on 28MHz and 12.6W on 24MHz. Are you saying that it >would be even higher if I spaced it up a bit? I believe there were posts from Gary Surrency a while back which indicated that if one experienced marginal output on 10M/12M, this problem could (possibly) be reduced by raising T2 (I'm pretty certain it was T2 anyway) just a bit above the PC board. Maybe someone can either confirm or deny my failing recollections. Tom ++++++++++++++++++++++ From: "Mike Lyness, AF4LQ" To: , Subject: Re: [Elecraft] K2 On the Way -- Planning for Mods? Date: Sat, 9 Mar 2002 19:32:48 -0500 It (the T2 mod/application note) dealt with winding T2's primary correctly. Below is pasted the Apllication Note that I saved when I was building mine.....there was a picture (guess it's still on the Elecraft site) of a corrrectly wound T2, not included here: --------------paste-------------------- Elecraft K2 Application Note Winding T2 for Maximum Power Output on 12/10M by Gary Surrency, AB7MY ( gary at elecraft.com ) For highest output on 10m/12m, it is especially important to wind T2's primary with 80-85 % of the core covered, and the secondary well spaced around the core as much as possible. Bring the secondary leads down and under the core, and then route them back to the # 3&4 pads. This allows the leads to come off of the core further apart on the core, and makes for easier connection without having the sec. leads come off the core too close together. The slightly longer lead length of T2's secondary when wound this way is not significant. It also helps to slightly space this transformer about 1/16" off of the PCB surface to minimize any losses that may reduce the output on 10m/12m. ----------------------------------------- 73, Mike AF4LQ ++++++++++++++++++++ Reply-To: From: "Sverre Holm - LA3ZA" To: "Elecraft at Mailman. Qth. Net" Date: Mon, 6 May 2002 10:14:19 +0200 Subject: [Elecraft] More ideas for K2 modification The rate at which modifications to the K2 appear seems to have been slowing down lately, so I sat down and wrote down everything I thought would be interesting, or possible to modify and put it into: http://www.qsl.net/la3za/K2/ideas.html Some of these ideas are unrealistic or nearly impossible, but that is of no concern here. I am sure there are many more ideas out there, so please send your input and then I will add them to the list. Maybe that could trigger someone with a hot, but idle soldering iron to try out something? 73, Sverre Sverre Holm, LA3ZA Asker, Norway (59.8N, 10.4E) --------------------------------- www.qsl.net/la3za +++++++++++++++ Reply-To: From: "Sverre Holm - LA3ZA" To: "'Kevin Cozens'" Cc: "Elecraft at Mailman. Qth. Net" Date: Thu, 9 May 2002 11:32:01 +0200 Subject: [Elecraft] RE: RFC11 toroid (was K2 for sale) This is a mod which is mainly of use in the crowded air waves of Europe, see www.qsl.net/la3za/K2/mod.html 73, Sverre Sverre Holm, LA3ZA Asker, Norway (59.8N, 10.4E) --------------------------------- www.qsl.net/la3za -----Original Message----- From: elecraft-admin at mailman.qth.net [mailto:elecraft-admin at mailman.qth.net] On Behalf Of Kevin Cozens Sent: 9. mai 2002 04:35 To: elecraft at mailman.qth.net Subject: Re: [Elecraft] K2 for sale At 09:24 PM 05/08/2002 +0300, Jimmy wrote: >3. Intermodulation mod (Toroid at RFC11) I thought I was aware of all the key mods for the K2. I wonder how I seemed to have missed hearing about this one? Anyone have the pointer to the information about this mod? Cheers! Kevin. (http://www.interlog.com/~kcozens/) Owner of Elecraft K2 #2172 |"What are we going to do today, Borg?" E-mail:kcozens at interlog dot com|"Same thing we always do, Pinkutus: Packet:ve3syb at ve3yra.#con.on.ca.na| Try to assimilate the world!" #include | -Pinkutus & the Borg ++++++++++++ Reply-To: From: "Sverre Holm - LA3ZA" To: "'Dimitris Vitorakis'" , Subject: RE: [Elecraft] K2 for sale Date: Thu, 9 May 2002 11:41:03 +0200 -----Original Message----- From: elecraft-admin at mailman.qth.net [mailto:elecraft-admin at mailman.qth.net] On Behalf Of Dimitris Vitorakis .... Right after i got it i sent it to Martin Wilschke DK8ZJ , who performed in a clearly professional manner all the "elecraft recommended modifications" in March-April 2002:These are: 1. Grounded crystal mod 2. "2nd Stage Crystal Filter mod" 3. Intermodulation mod (Toroid at RFC11) 4. Increased blanking time on NB2 for long duration pulses --------------------- The grounded crystal mod (# 1) is, as far as I know, not a an 'Elecraft recommended mod'. But it is recommended by many K2 owners. Actually I think that indirectly there is a warning against it in the manual. This mod is clearly a mod that enhances performance, but also one that increases the risk of damaging a crystal or two. Being involved in several companies myself, I can understand that Elecraft cannot recommend doing that, but on the other hand I wouldn't be surprised if there are some K2's at Elecraft with this mod! 73, Sverre ++++++++++++++++++ Date: Thu, 09 May 2002 09:21:37 -0500 To: "Joe Randle" , elecraft at mailman.qth.net From: Tom Hammond =?iso-8859-1?Q?N=D8SS?= Subject: Re: [Elecraft] Three Questions? -- snip -- >2. How many mods for SSB are actually recommended by Elecraft? The 2nd Xfil SSB Mod certainly is. Other mods not necessarily 'recommended', but probably worthwhile to consider: If you have marginal-to-low mic gain, change KSB2-R14 from 1K to 10K. ___ Here's a mod from KI6WX which helps flatten the response of the 2nd Xfil a bit more. I have installed it in my K2 and it has produced a somewhat flatter passband when using my OP1 filter on SSB receive. Quoting KI6WX: The change may be installed with the following steps: 1. Install the 2nd Xfil Mod described in http://www.elecraft.com/Apps/new_fil_docs/k2_2nd_xfil_ssb_mod.pdf 2. Replace the 120pF capacitor in the above mod with a 100pF capacitor 3. Install a 5.6k resistor from pin 1 of U11 to pin 2 of U11 on the RF board 4. Check the adjustment of L34. In CW mode, tune to the weak birdie heard at 7 MHz. Set the filter bandwidth to 0.1 kHz and tune L34 for maximum signal relative to the background noise. Your K2 now has a much flatter response when receiving SSB signals through the OP1 filter. -- snip -- 73, Tom Hammond N0SS +++++++++++++++++ Reply-To: From: "Sverre Holm - LA3ZA" To: "'Kevin Cozens'" , Subject: RE: [Elecraft] K2 Cal Cur Modification Date: Wed, 19 Jun 2002 08:22:48 +0200 > -----Original Message----- > From: elecraft-admin at mailman.qth.net > [mailto:elecraft-admin at mailman.qth.net] On Behalf Of Kevin Cozens > Sent: 19. juni 2002 00:51 > Oops...my mistake. I should have checked the printouts I made > from the web site. I should have said the Cal Cur mod was found from the > LA3ZA web site which lists K2 mods. > The K2 mods page has been generated from Word, and the capacitor value for the Cal Cur mod was written with a greek mju in the Symbol font followed by F (0.1 microFarad). I have noticed that this displays correct in Internet Explorer, but Netscape does not seem to recognize the symbol font and puts an 'm' instead, I haven't checked with Opera or other browsers. I don't really know how to resolve this, except to write microFarad. (PS! No intention to start a discussion on which browser is best here, then of course I should have supported Opera which is developed only 20-30 km from where I live! ) 73, Sverre www.qsl.net/la3za/K2/mods.html +++++++++++++++++ Reply-To: From: "Sverre Holm - LA3ZA" To: "Elecraft at Mailman. Qth. Net" Cc: Date: Wed, 19 Jun 2002 09:16:20 +0200 Subject: [Elecraft] mu ( was K2 Cal Cur mod) -----Original Message----- From: David Pratt [mailto:david at kippax.demon.co.uk] >You could edit the HTML code, Sverre. Putting µ in place of the >mu should reproduce the mu in any modern browser. Unfortunately, I have >not found a similar way of inserting the capital omega symbol. Thanks David, I put in your suggestion and now the mu seems to be fine. It is both in the Cal Cur mod (mod # 6 from top) and in the 'DC blocking capacitor for the aux RF connector' mod (search for 'connector'). BTW: This mod should be a must for everyone who uses the K2 from internal batteries, it might save you a relay! 73, Sverre http://www.qsl.net/la3za/K2/mod.html ++++++++++++++++++++ See also "Internet Browser Special Characters" dwn ++++++++++++++++++++ From: "Dan Barker" To: "Elecraft" Subject: FW: [Elecraft] mu ( was K2 Cal Cur mod) Date: Wed, 19 Jun 2002 07:18:01 -0400 See my other post. µ is very dangerous. It depends on the fonts = installed clientside. Use µ as stated. Dan ... Putting µ in place of the mu ... +++++++++++++++++++ Reply-To: From: "Sverre Holm - LA3ZA" To: "Elecraft at Mailman. Qth. Net" Subject: RE: [Elecraft] So many mods; so little time Date: Sat, 6 Jul 2002 21:23:04 +0200 > -----Original Message----- [mailto:elecraft-admin at mailman.qth.net] On > Behalf Of phoon.usinet > > 1) When you buy the latest K2 kit, are all the important > mods already incorporated into the intial kit build? > > 2) How do you sort through the "factory recommended mods" vs > "user recommended mods"? Are there lists of each somewhere? > > 3) How do you decide which ones to install? > I would look at the list at http://www.qsl.net/la3za/K2/mod.html and only consider the six modifications under Basic K2: Improved Performance. When you buy a new K2 now, two of those will be included: - Frequency shift mod (assuming you get firmware ver 2.02E or later) - VFO - PLL interaction (7185 kHz) That leaves four to choose between. None of them are required for a good operational K2, so don't think about them before you complete the K2 and have tuned it and made your first contacts. After you get some experience in operating the K2, go back to the list and consider the four mods and start looking at the other ones down the list. Although there are almost 50 mods listed there, none of them are essential, and many of them have been made by people with special needs, or who found building so fun that they could not stop after the K2 was completed! > 4) In order to avoid "K2 overload", is it best to buy just > the basic K2 kit, get it working properly, and then buy the > add-ons gradually, and sequentially, after the basic kit is working? > Yes, highly recommended! Good luck with your K2 (?) ! 73 Sverre Sverre Holm, LA3ZA Asker, Norway (59.8N, 10.4E) --------------------------------- www.qsl.net/la3za ++++++++++++++++ Reply-To: From: "Ron D'Eau Claire" To: "'phoon.usinet'" , Subject: RE: [Elecraft] So many mods; so little time Date: Sat, 6 Jul 2002 18:07:09 -0700 You ask good questions Peter. I'm sure that you are not the only new builder to be worried about that and wonder if you could ever build a complete K2 that works well. You can. It just LOOKS a lot more complicated than it really is... And the great variety of modifications that have been suggested only make it look even worse! For now, IGNORE the Mods! Buy your K2 and build it according to the manuals FIRST. Go ahead and get any other of the accessory modules, like the Noise Blanker, Single Sideband module, Antenna Tuner, etc., that you want. The manuals are very well organized and lead you through the building process step-by-step. FIRST you build the basic K2, and the manuals will take you through tests as you go to be sure you haven't made any mistakes. If you do make a mistake, you will catch it quickly so you don't have to troubleshoot the entire radio looking for it. Once you have the basic 10-watt CW K2 running, you then add the modules one by one in any order that you please, testing each one and the whole K2 with it installed to be sure everything works properly. If you buy the modules when you buy your K2, you will find instructions in your K2 manual telling you when to go get a connector out of the module kit and put it in the K2. Those are the connectors your accessory module will plug into when you get around to building it, and it will make installing the modules a little simpler. But it is not necessary to have them first. It's a small job to go back and install the connectors later when you get the module. The K2 is designed to be disassembled quite easily and quickly to make changes and additions./ A few ops have decided to build one of the smaller accessory modules first to "warm up" to the job. I DO NOT recommend doing that! First, most of the module boards are actually more densely packed with parts than the main K2, so they are actually a little harder to assemble. Also, you have no way to test your finished module and see if it works okay when you are done until you get the whole K2 running. Also, the K2 manual is a better step-by-step manual for a builder than the module manuals. So do the K2 FIRST, get confidence that you have a nice radio and that you can follow the instructions easily, and then build the accessory modules. Now that you have your K2 and accessories working, take a look at the mods and see what might apply to you. Fortunately, some ops have done a wonderful job organizing and listing the modifications. I recommend the excellent web site by Sverre, LA3ZA at http://www.qsl.net/la3za/K2/mod.html Note that he indicates the source of the mods. I would do the mods from Elecraft first, THEN consider some of the others as you gain experience with the K2. I say that because among those Elecraft mods are some that solve specific problems. Most (all?) of the mods by others provide various degrees of performance improvements. Whether or not you want to pursue them will be up to you. Some of the Elecraft mods only apply to older K2's. Some mods fix particular problems that may or may not show up in your K2. Do any mods that you choose one at a time and check the operation of your K2 after it is done to satisfy your self that it is working properly. Looking at Sverre's list, there is only ONE mod that I would say is a real "must do" and that is only if you are going to use your K2 on Single Sideband. That is the "2nd Stage Crystal Filter Mod", also called the "2nd Xfil Flattening Mod" on the Elecraft Builder's resources. Note that is the ONLY mod that is listed as "Recommended by Elecraft". I greatly improves your SSB reception and Wayne has been adamant about recommending that everyone using their K2 on SSB make. And, of course, you have the resources of all the ops on this reflector to help you out with any question. And you can ask questions directly of Elecraft. As you get started remember two things: 1- There are NO "dumb" questions. 2 - In my experience, the most successful builders take a look at a new project like the K2 when it arrives and say to themselves, "Okay, here we go! I sure hope that I don't mess it up!" That's a sure sign that you will be successful. Ron AC7AC K2 # 1289 +++++++++++++++++++ Date: Thu, 18 Jul 2002 08:19:00 -0500 To: dk4lx , elecraft at mailman.qth.net From: Tom Hammond =?iso-8859-1?Q?N=D8SS?= Subject: Re: [Elecraft] Sidetone mod Holger: >I wanted to implement the sidetone mod by WJ4P the other day, but - >much to my surprise - the parts/values referred to in the mod >description, do not comply with what I have on my pcb. I was able to >spot the numbered caps ok, but neither were they in the audio >section, nor did they have the values specified in the mod. How come? >Do I have to live with my non-sinusoidal sidetone for the rest of my >life? What is the Rev level of the MANUAL for your K2? There should NOT have been ANY component ID changes in any of the manuals, but I will be happy to check and try to give you the proper component IDs. Finally... BE SURE you are referring to the correct PC board. The board Randy is working on is the CONTROL BOARD, not the RF Board. I just checked the component IDs on Revs D & C of the K2 manual, for the Control Board and everything is correctly identified. 73, Tom Hammond N0SS +++++++++++++++++ Date: Thu, 18 Jul 2002 15:44:42 +0100 To: =?ISO-8859-1?Q? "Tom_Hammond_N=D8SS" ?= , elecraft at mailman.qth.net From: dk4lx Subject: Re: [Elecraft] Sidetone mod Thanks Tom - my mistake: overlooked "control board". Sorry about that. 161, Holger Tom Hammond NXSS schrieb am 18.07.2002: >Holger: -- snip -- +++++++++++++++++++++ Reply-To: From: "Sverre Holm - LA3ZA" To: "Elecraft at Mailman. Qth. Net" Date: Wed, 6 Nov 2002 22:29:10 +0100 Subject: [Elecraft] K2 mods list keeping track of Elecraft ... I had a look through the latest version of the K2 Manual and have tried to update the mods list at http://www.qsl.net/la3za/K2/mod.html with status regarding the latest manual and serial numbers 3000+. I am impressed at how many of the mods that have come up over the years that now have been included, but I need help from experts in this group. Would you please comment on my mods list and whether I am up to date on all the changes that are in the latest manual? 73 Sverre, LA3ZA +++++++++++++++ From: "Don Brown" To: "Elecraft" Date: Fri, 8 Nov 2002 14:53:58 -0600 Subject: [Elecraft] K2 Mods nist Hi Gang I just looked over Sverre Holm's list of K2 mods and he has added the = Rev B information. This is a great resource for anyone thinking about = the mods to add to your K2. This list gives you all of the pros and cons = of adding a mod and its all in one place with links in many cases to the = mod instructions. Worth checking out. http://www.qsl.net/la3za/K2/mod2.html Don Brown KD5NDB +++++++++++++++ From: "Don Brown" To: "Elecraft" Subject: Re: [Elecraft] Recent K2 Mods Date: Thu, 14 Nov 2002 22:11:02 -0600 Hi I think you have the 10/12 meter bandpass and ALC mod confused with the 2nd xtal filter mod. The KPA100 comes with the former. There are several more mods in addition to the ones you have installed and the PLL/BFO required to bring your K2 up to "B" status. The kit and instruction will be available soon. I have a "B" schematic and I count at least 19 mods total to bring a Rev A to a Rev B. 1 PLL 2 BFO 3 D10 4 ALC 5 10/12 meter 6 RFC15 7 RFC11 8 add C28,29 9 change value C30,36 10 add C224 11 change value C225,226,227,L25,L26 12 audio pot mod 13 sine wave side tone 14 AGC threshold 15 voltmeter switch 16 added filtering on voltage sense 17 D19,20 and C71 for future 60 meter option 18 change R60 to fixed 100 ohm resistor 19 new crystals for CW and SSB 20 ?? Don Brown KD5NDB ----- Original Message ----- From: "James C. Hall, M.D." To: Sent: Thursday, November 14, 2002 3:02 PM Subject: [Elecraft] Recent K2 Mods > I've been following the recent threads on available K2 mods - if memory > serves, I thought the parts for the 2nd filter SSB mod was included with the > KPA100. I sure remember doing this one - and it works great ! It looks like > the only mod I don't have of the list on the Elecraft site is the newest > one - PLL/BFO mod. Is this not correct. I'm gathering up my Christmas list, > so I have to be sure !! > > Jamie > WB4YDL +++++++++++++++ Reply-To: From: "Sverre Holm - LA3ZA" To: Date: Mon, 18 Nov 2002 19:31:40 +0100 Subject: [Elecraft] Picture of AGC/S1 mod on control board I put a picture of the control board after the serial # 3000+ mods for the AGC threshold pot and the jumper block for the voltage selector. Look at http://www.qsl.net/la3za/K2/K2ctrlB.jpg (162 kbytes) 73 Sverre Sverre Holm, LA3ZA ------------------ www.qsl.net/la3za +++++++++++++++ Date: Sun, 05 Jan 2003 09:57:22 -0600 To: "n3drk" From: Tom Hammond =?iso-8859-1?Q?N=D8SS?= Subject: Re: [Elecraft] confused with all mods k2 Cc: Hi John: Somehow, I just saw this message from you, and I actually saw responses to it before I saw the original... > With all the modifications for the k2 that are out > there i just dont know where to start. I am trying > to keep this rig as close to the original design > as possible so i don't want to put every mod into it. Mod's I'd suggest warranting your consideration: K2 2nd Xfil SSB Mod (KI6WX version), I can supply if you can't find it. K2 Walking VFO mod - But ONLY if you don't have the firmware version which fixes the problem AND if you don't plan to upgrade to that firmware version. Unfortunately, I do't have the info telling which firmware rev. fixes the problem. You might drop a note to Wayne to find out if you already have the required firmware version. If you are a dyed-in-the-wool CW operator, you might want to consider adding the CW Xtal grounding mod. This mod moves the ground wires on the CW filter xtals from the top of the xtal cans, to the bottom, and adds a second ground to each xtal as well. Helps to reduce the amount of signal which 'sneaks' around the xtal filter and shows up as reduced ultimate signal rejection. Dave, G4AON, suggested changes to the capacitors in the higher band filters. This is generally NOT required US-based operators. However, it is suggested for European ops. They have a LOT higher levels of short- wave broadcasting stations over there. If you happen to have what appears to be a dirty AF Gain control... scratchy when you turn it, and especially down toward the low end of the AF Gain range, then the fix for the Noisy AF Gain control is worth adding, but not required if you don't have the problem... it can always be added alter on. > I have k2 s/n 2444 and purchased the kat2 at the same > time. Last week i purchased and received the ksb2 ssb > module and have yet to build it. The KSB2 is a pretty closely packed PC board, so exercise EXTRA care when soldering on this board. > My manual states it is REV C. I am becoming somewhat confused > with all the mods for below s/n 3000 and rev a to b etc. The "Rev C" you see there applied ONLY to the revision version of the MANUAL, not the RADIO itself! You have Rev A PC boards in your K2. > With my equipment what do i need to install (basics) to get it up to par? Hope this helps. 73, Tom Hammond N0SS ++++++++++++++++++ Reply-To: From: "Sverre Holm - LA3ZA" To: "'Ed Tanton'" , "'elecraft'" Subject: RE: [Elecraft] confused with all mods k2 Date: Sun, 5 Jan 2003 20:43:04 +0100 The list at http://www.qsl.net/la3za/K2/mod.html is maybe the closest you can get to what you want? For the new readers on this list, let me do some advertising for the K2 modifications list. It is divided into three categories: 1. Elecraft modifications to bring your K2 up to date with serial numbers 3000+. Here you will find a pointer to Elecraft's 3000+ modifications document + a matrix of the same modifications that also offers some more background than the Elecraft document. 2. Elecraft modifications that took place for various serial numbers prior to 3000. This is a short list of mods that most K2's except the oldest ones already have. 3. General modifications applicable to any K2. This is the section with modifications for special needs or tweeking. All of the mods are listed with a short description and links to more info. For instance the 'extremely strong on-frequency signal' mod that was presented yesterday can be found here, as well as some of the bandpass filter mods that are not in the 3000+ category, and that are useful e.g. in Europe. Hope this helps, 73 Sverre LA3ZA +++++++++++++++++++ Reply-To: From: "Sverre Holm - LA3ZA" To: Cc: "'Stefan Steger'" Date: Mon, 24 Mar 2003 12:23:38 +0100 Subject: [Elecraft] Updated list of K2 modifications The list of K2 modifications on www.qsl.net/la3za/K2/mod.html has been updated. Changes in "3. General mods" are: - Input bandpass filters: Clever way of getting wide and narrow bandwidths in the combined filters, esp. the 10/12 m, 20/30 m filters as well as the 80/160 m filter for EU bandwidths (from DL7MAJ). - Link to interfacing of SGC audio DSP to the K2. - Link to warning from W1CG about _not_ to integrate the NJQRP W1CG balun inside the K2. 73 Sverre LA3ZA Sverre Holm, LA3ZA ------------------ www.qsl.net/la3za +++++++++++++++++