Are you sure that it is not the K3(s) itself that has unstable output power. I see this occur on my KPA500 and it is not getting hot.
Michael Blake [email protected] <mailto:[email protected]> > On May 31, 2018, at 4:09 PM, K9MA <[email protected]> wrote: > > I agree with Rick: A way to slowly adjust the drive power automatically to > maintain constant peak output would solve the problem. I'd think the KPA1500 > firmware could do this with the K3 via the accessory cable. Probably the K3 > should revert to its original output when the KPA1500 is cold, or power would > initially overshoot. Better yet if the amp could remember drive power for > each band as a function of temperature. > > While it's annoying to have to keep fiddling with the power control, I can > understand that there are higher priorities now. > > 73, > Scott K9MA > > > > ---------- > > Scott Ellington > > --- via iPad > >> On May 31, 2018, at 1:06 PM, Rick Tavan <[email protected]> wrote: >> >> 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] > > ______________________________________________________________ > 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]
