On 9/22/2012 3:05 PM, Bill K9YEQ wrote: > Fred, > > More than likely you are changing freqs and the amplifier/K3 are folding > back power based on detected antenna complex loading issues. Until the > KAT500 becomes available, you don't need 100 watts on any band to get 500W > out! Back off your per band settings and test. Whatever you are using for > your tuner, I would suspect it is not matching.
I think I wasn't clear Bill, and unfortunately, it's not the first time. :-) The KPA500 wants between 25 and 30 watts, depending on band for 500 watts out. The irreproducible "problem" I described seems to be in the dual-power memories in the K3. The most common manifestation is: 1. KPA500 --> STBY, usually because I punched up a new band on it. 2. K3 TUNE: Mine is 5W. I tune up the antenna coupler [MFJ 989-C], SWR=1:1 3. KPA500 --> OPER, because I pressed the switch 4. K3 TUNE: SWR still 1:1, but now into the KPA500 of course, output power around 60W [still 5W tune power from the K3] 5. Tap K3 TUNE, now I'm receiving and ready to TX. KPA500 is in OPER. K3 should have gone to 25-30W depending on the band. Start to send, KPA500 output is still around 60W [and the DX calls someone else], and when I move the K3 PWR knob to check the setting, it is still at 5W. The only way I've found to get it back to the 25-30W range is to turn the PWR knob. This only happens every now and then, more often then than now, nearly all the time it works as expected ... ending TUNE on the K3 sets the power to 25-30W if the KPA500 is in OPER, 100W if it isn't. If I had to guess [hardly ever a productive troubleshooting technique], it looks like the power memories are fine, the K3 is just missing some signal to tell it to go into normal operate mode with an active KPA500. The reverse problem ... running barefoot at 100W and I put the KPA500 into OPER [using the front panel switch] because the DX isn't answering me [and I'm going to show these clods in the pile!] and the K3 stays at 100W [lighting up the 500 :-)] has happened a few times, not nearly as often as the reverse problem described above. I've tried re-seating the big cable between the KPA500 and K3 several times, once with a drop of DeOxit into the contacts, with essentially no change. Since I can't make it happen on command, I'm loath to do much more than mention it here, and maybe should stop that. I sent my K2 to Don once with what I perceived as a clear problem, he spent a lot of time for which I'm sure he did not charge me, and couldn't make it fail. It's never happened again, in fact I managed NH8S just before QRT with K2 @ 5W to my new AlexLoop out on our deck. 73, Fred K6DGW - Northern California Contest Club - CU in the 2012 Cal QSO Party 6-7 Oct 2012 - www.cqp.org ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
