I've seen some gain drift with temperature, too. I've wondered if there might be a way to feed back drive power change requests to a K3, or other radio with adequate command capabilities, to maintain a target output power (say, 1500w) as the amp warms and cools. This should be done slowly - on the order of seconds, not milliseconds like ALC. KPA1500 Utility knows its output power and could be programmed to generate the requests. I don't know how to get commands into a K3 that has its serial port connected to a logging program. There are some port-sharing tools out there that might work, but I'm not familiar with them. In any case, it would require some engineering at Elecraft. In the meantime, I keep an eye on output and tweak the drive manually to stay both powerful and legal.
/Rick N6XI Rick Tavan Truckee, CA On Thu, May 31, 2018 at 10:01 AM, [email protected] <[email protected]> wrote: > My KPA500 also has slightly inconsistent output. If I recall output drops > a little after the first few seconds of key down. Perhaps it is normal for > solid state amps as I have never noticed this with a tube amp. This may be > more of a concern with a legal limit amp if you want to keep it as close > to 1500 watts without going over. > > John KK9A > > Bill Stravinsky k3wjv wrote: > > Yup, as the temp climbs the output drops some. Even though I'm glad I > got the solid state amp I still prefer tubes, hi. The drop is anywhere > between 100 to maybe 300 watts.I never really noted the exact numbers. > BillK3WJV > p.s. I'm thinking its a normal solid state thing. > > On Wednesday, May 30, 2018, 4:23:47 PM EDT, K9MA <k9ma at > sdellington.us> wrote: > > I'm using the K3 with the Elecraft interface cable. I've noticed the > the CW drive power required by mine varies considerably, both with > temperature and SWR. If I set the K3 output for a KPA1500 output of > 1500 W output initially, the output will drop to perhaps 1100 W when the > temperature stabilizes at around 65 C. (I've ruled out any change in > antenna impedance, etc.) A similar change occurs if the SWR goes from > 1:1 to 1.2:1 when changing frequency or switching antennas. I haven't > changed the ALC from the default setting. Has anyone else noticed this? > > 73, > > Scott K9MA > > -- > Scott K9MA > > k9ma at sdellington.us > > ______________________________________________________________ > 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 > Message delivered to [email protected] > ______________________________________________________________ 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 Message delivered to [email protected]
