Misc. K2 Notes ++++++++++++++++++++ Date: Sun, 19 Aug 2001 10:03:02 -0700 From: Vic Rosenthal Subject: Re: [Elecraft] K2 Improving QSK Performance? Dave Gingrich wrote: > > Has anyone been successful in improving the QSK performance of the K2? I was slightly disappointed with not being able to hear between the dots at 25 wpm. The release notes for the new firmware suggest changes to control board R17 may improve things. Has anyone played with this? I have not installed the new firmware yet, but at Wayne's suggestion I did try reducing the value of R17. While sending dits with the QSK parameter set to 001, I found that I could go as far as putting a 1 M resistor across the original 3.3 M resistor before I started hearing clicks. This did improve QSK speed, but it still isn't fast enough to hear between dits at 30. Wayne indicated that the new firmware would improve the speed some more. 73, Vic, K2VCO Fresno CA +++++++++++++++++++++++ Date: Mon, 20 Aug 2001 22:29:33 -0500 From: Dave Gingrich Subject: Re: [Elecraft] K2 Improving QSK Performance? I fiddled around with changing control R17, trying values as low as 470k. At the low end I began to get nasty clicks on receiver recovery, so I settled in on 1.0M. Pretty significant improvement in QSK speed. (version 2 firmware). - -Dave ===================== Dave Gingrich, K9DC Indianapolis, Indiana Dave at dcg.org ++++++++++++++++++++++ Date: Fri, 21 Sep 2001 08:12:44 -0600 From: "Rod Cerkoney, N0RC" Subject: Re: [Elecraft] Power Connector for K2 Chas, Are you asking about the plug that fits the connector in the radio? Or, the connector in the radio? The plug is 5.0/2.1mm OD/ID respectively. RS has them, but I don't have the P/N. In store packages have size marked on them. The part Elecraft supplies is from Switchcraft and is available from Digikey part number: SC-1052-ND (I think the Switchcraft item is of superior quality) The Connector in the radio (probably Switchcraft) is Digikey item: SC1155-ND Digikey online page for these items is: http://info.digikey.com/T013/V5/177.pdf GL 73, Rod N0RC Ft Collins, CO +++++++++++++++++ Date: Fri, 21 Sep 2001 10:19:20 -0500 From: Tom Hammond =?iso-8859-1?Q?N=D8SS?= Subject: [Elecraft] K2 Coaxial Power Connector - More info Rod Cerkoney, N0RC, wrote: >The plug is 5.0/2.1mm OD/ID respectively. RS has them, but I don't >have the P/N. In store packages have size marked on them. The part >Elecraft supplies is from Switchcraft and is available from Digikey >part number: SC-1052-ND (I think the Switchcraft item is of superior >quality). > >The Connector in the radio (probably Switchcraft) is Digikey item: >SC1155-ND > >Digikey online page for these items is: > > http://info.digikey.com/T013/V5/177.pdf More info: Switchcraft #S760, Mouser part #502-S-760 Technical specs: ID .080" (2.03mm), assume 2.1mm OD .218" (5.5mm) See NOTE below Barrel Length .375" (9.52mm) Note: Switchcraft does not list a 5.1mm (0.20") diameter barrel coaxial power connector. It appears that ALL of their coaxial pwr connectors are 5.5mm (0.218") in diameter. I used a caliper to confirm the outside diameter of the barrel of the plug I'd received from Elecraft. 0.218" (5.5mm) on the button. For more info on this Switchcraft connector, go to: http://www.switchcraft.com/ and search for "S760". The plug dimension specs are at the bottom of this page, and if you click on selection #2 (760/S760) from the list at the top of the page, you can download a single-page PDF which shows to detailed engineering drawing of the plug, with references which will match to the specs on the page noted above. I believe this to be the power plug which we are using on our K2s and K1s. They ARE better quality than the plugs available from R/S, if for no other reason that the fact that the center cunductor of the Switchcraft plugs is slightly recessed within the insulator, thus making it more difficult to accidently short the positive lead to ground. The apparent R/S equivalent (at least with regard to dimensions, NOT quality) is their 274-1569 (5.5 x 2.1 mm). The apparent DigiKey part #'s are: Plug SC-1052-ND (as Ron has stated) Socket SC-1153-ND (the SC-1155-ND is SMT) NOTE that the 1998 DigiKey catalog from which I got this info had the Switchcraft part #'s for the plug and jack SWITCHED. However the DigiKey web site (www.digikey.com) had everything listed correctly. Users are urged to RETAIN this information for the future when you will surely need it. And WILL eventually need it... almost guaranteed! Thanks Ron, Tom Hammond N0SS +++++++++++++++ Date: Mon, 24 Sep 2001 21:53:19 -0600 From: "Len Koppl" Subject: Re: [Elecraft] K2 Sticking T/R operation You might try re-seating the micro-controllers in the rig. A friend of mine had a problem where keying the rig at less than 2 w worked fine, but keying it at over 2 w reset the computer chips in the rig. The cure was to carefully remove (observing static mitigation practices) the microcontroller on the RF board and reseat it. This may work for you, and if needed, you may want to try the microcontrollers on the control and front panel boards as well. 73, Len, KDØRC ++++++++++++++++++ Date: Fri, 26 Oct 2001 21:46:09 -0500 From: "Rich Lentz" Subject: RE: [Elecraft] 3.3 pf caps Check out the K2 errata Sheet. It can be downloaded from the web page if you lost it. It states that C22 AND C23 have several replacement values one of which is 2.7 pF. I believe the 2H7 is a 2R7. At least that is what them used for in my rig and it works. - -----Original Message----- From: owner-elecraft at qth.net [mailto:owner-elecraft at qth.net]On Behalf Of Cady, Fred Sent: Friday, October 26, 2001 8:44 PM To: 'elecraft at listserver.qth.net' Subject: [Elecraft] 3.3 pf caps I'm down to the last components in the K2 and I was not able to find 3.3 pF caps as described in the book. I do have two caps that say 001 AHK (or RHK) on one side and 2H7 A1D (or similar) on the other side. Could these be the missing 3.3 pF caps? Going on the air this weekend! Cheers all, Fred KE7X ++++++++++++++++++ Date: Wed, 31 Oct 2001 21:29:32 -0600 From: "William R. Moore" Subject: [Elecraft] K2 Sidetone mod I've been putting off the sidetone mod because I hate unsoldering stuff. But bolstered by the success of another mod, I ordered the inductor from Mouser and tonight applied the sidetone mod as described on the Elecraft website. Took about 30 minutes. Only had to unsolder one end of one cap; solder in a resistor and the inductor. No sweat! Makes a big difference to my ear, and really makes zero-beating a lot easier. Thanks to Randy and Tom! 73, Randy, KS4L K2 #337 ++++++++++++++++++++++ Date: Sat, 10 Nov 2001 11:03:10 -0500 From: "David A. Belsley" Subject: Re: [Elecraft] KAF2 RTC Accuracy Frank: I have finally been able to tame my RTC and it's taken about 64pf to do the job. I started out with the 33pf (32.26pf) stock cap, and the clock ran about 1 to 1.2 sec/day fast. I'm not exactly sure of this speed because I had not then developed an accurate way to read the clock's delayed display refresh. In several steps, I determined the clock rate was responding to capacitance at a rate of 31.74pf/second/day, and the relation seemed quite linear. This projected to 64pf to bring the clock to proper speed, and this seems to be very close to the case. It has gained a 'just-perceptible-fraction' (the ol' jpf) of one second over one week. I think it is still running fast -- but, to attest to how good things currently seem, I will have to wait perhaps another week to see for sure. I got a 3-50pf mini padder from Mouser to use for this job; it is no bigger than the original 33pf ceramic. My initial projections suggested the 50pf ought be enough, but I was soon shown wrong there. So I ended up simply putting that padder in parallel with a 47pf ceramic. That combination is now at 64pf. You seem to be starting from a faster speed, so your finding that a 75pf capacitor doesn't do the job is not out of line. If you really were 2 seconds/day fast with the original 33pf capacitor, and your clock chip responds to capacitance the same as mine, you might need as much as 90-100pf to calm things down. Note, by the way, that the inherent capacitance between pins 2 and 4 (ground) of U3 is (at least for mine) 23.4pf. Thus, whatever capacitance you are tacking between these pins is going on top of that. best wishes, dave belsley, w1euy (and best wishes particularly to K1JD and N2JZ who, I am sure, are both extremely amused by this posting). - --On Friday, November 9, 2001 5:46 PM -0500 W4FMS at aol.com wrote: > Hi Gang: > > I've been trying to slow down the RTC in my KAF2. With the stock 33pf > cap, the RTC started out at least 2sec/day fast (which might be to spec) > but I found this unacceptable. Knowing it was off, I would be adjusting > the time monthly. Since I didn't have a small variable cap to fit > behind the board with C19, I've been using fixed value caps to adjust > the clock speed. > > I'm up to 75pf and the clock still seems to being gaining almost > 1second/day. This is the highest value that I've heard and I'm suprised > it still appears to need more. For the others on the list that have > done this experiment, does this seem correct or am I overlooking > something? Will I eventually hit a value where the clock will run too > slow? I'm wondering if my clock xtal is way out of tolerance? Any info > appreciated. > > Frank, W4FMS ++++++++++++++++++++ Date: Mon, 12 Nov 2001 14:42:03 -0800 From: Phil Wheeler Subject: Re: [Elecraft] Current Measurements This website has some good measurements for an early build, Tom (not mine). http://www.qsl.net/kw1nd/k2.htm >From the look of it (abt 2.7 W for 10 W on 10 M as I recall), you are OK. 73, Phil Tom wrote: > > Hi all, > I got past the heat sink and fat finger problem, thanks to all. > > I'm drawing 2.56 amps on the K2 at 10 watts. The manual says I shouldn't be > much higher than 2.0 amps. Do you all think I'm OK at this level or should > I pull out all of those transformers and see if that's the problem ( I don't > wanna do that!). I don't anticipate battery life to be a major issue from > my perspective. ++++++++++++++++++++ Date: Thu, 06 Dec 2001 22:55:31 +0100 From: df5rf Subject: Re: [Elecraft] K2 no receive on 14MHz Just for your information: Problem was solved by adding a 12pF capacitor parallel to C23, as suggested by Gary. Thanks! Gernot DF5RF +++++++++++++++++