I will give it a try, thanks again for all the help! Ken ----- Original Message ----- From: "Don Wilhelm" <[email protected]> To: "Ken Cannaday" <[email protected]> Cc: <[email protected]> Sent: Tuesday, August 31, 2010 9:11 AM Subject: Re: [Elecraft] K2 KPA/100 excessive power issue, SSB mode, some bands
> Ken, > > This is behavior that is typical after the KI6WX SSB RF Gain mod has been > installed. > Whether or not you have installed that mod, try the following changes to > the KSB2 board: > 1 - Change R9 to 15k > 2 - Cut the trace (on the top of the board) between P1 pin 6 and the base > of Q1 and insert a 1k resistor between those two points. You will have to > orient the resistor vertically, or use an SMD resistor. > > That should calm the ALC overshoot when operating into a dummy load. > > The question still remains about the original problem which was an > overshoot problem on 40 meters. If that persists when operating into an > antenna, the KPA100UPKT is the solution. > > 73, > Don W3FPR > > > On 8/31/2010 6:54 AM, Ken Cannaday wrote: >> Thanks much for the comments, all were very helpful and are much >> appreciated. I did some further testing along the lines suggested with >> the >> following results: >> >> Settings: SSBA = 1; SSBC = 3 to 1; requested power QRP = 2, QRO = 20; >> transmitting into a dummy load; microphone = Heil HC4 (but similar >> results >> have generally been experienced with Icom electret hand mike, HM 36); all >> bands tested in both TUNE and SSB modes . >> >> Generally in QRP on TUNE mode, I saw anywhere from 2.8 to 2.3 watts after >> the ALC had time to settle in (the ALC seems to start over with any >> change >> in band or certain other settings). In particular, I saw 2.8 watts on >> 160, >> 2.3 on 10 meters, with the other bands somewhere in between. In SSB, I >> generally saw peaks at one or two bars, with an occasional third bar, for >> ALC; and two bars with an occasional third bar for RF. The exceptions >> were: >> 80 meters, where there was a very brief initial surge up to 4 or 5 bars >> before settling in at 1 to 3 bars for ALC, and 2 to 3 bars for RF; 40 >> meters, where again there was the initial surge in reading before >> settling >> at 3 to 4 bars for both ALC and RF; 30 meters where the results were >> similar >> to 40 meters except that RF eventually settled to only 2 to 3 bars. >> >> Then switching to QRO, on Tune mode, I saw 19, 20, or 21 watts on all >> bands >> except on 80 meters where the ALC never seemed to settle in and kept >> bouncing around between 18 and 22 watts, with 19 being the most stabile >> eventual reading. In SSB, I generally saw peaks at 1 (10 and 12 meters), >> 1 >> to 2, or 2 to 3 (160) bars for ALC and 2 to 3 bars for RF. On 80 meters, >> however, there was again an initial surge, lasting a little longer and >> settling in a little slower to an eventual 2 to 3 bars for ALC and a >> solid 3 >> bars of RF; on 40 the initial surge was more extreme with the ALC kicking >> up >> as high as 6 bars before settling in at 3 to 4 bars, 2 to 3 bars for RF. >> The most extreme results were on 30 meters where I saw readings as high >> as 5 >> to 6 bars for ALC and 7 to 10 bars for RF. After a much longer period of >> speaking into the microphone, eventually readings settled respectively to >> 3 >> to 4 bars with a rare 5th bar and 2 to 3 bars with an occasional 4th bar. >> >> I should add that I can generally get a bit higher readings by screaming >> into the microphone, but the results summarized above were obtained by >> speaking just a bit louder than normal, as if I am excited on the verge >> of >> working a new, rare DX entity. >> >> Generally a higher RF reading was supported by a higher ALC reading. >> Does >> this indicate that any excess in power output is not likely to be an ALC >> problem rather than a KPA/100 problem? How necessary do you think it is >> to >> install the KPA100UPKT given these results? Any observations or >> suggestions >> would be appreciated. >> >> 73 >> >> Ken >> ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
