Tell us a bit more about the antenna. How is it fed? Is it properly choked to eliminate RF shield current (this is current flowing on the outside of the shield. It is a bit early to remember the proper term…)? And, do you have chokes on the coax at the KAT500 or KPA500?
I think we need a bit more info to determine what is going on here. RF return currents flowing back into the station and combining at the KAT500 connector could account for something like this. Note that I don’t discount that the 20m LPF is noticeably less efficient than those on the other bands. Each KPA is unique in this sense - we tune the LPFs for best efficiency for each band. I suspect your KPA is just fine, but the more info we get from you, the more we can tell what is going on. In any case, welcome to Elecraft products! We work hard to bring delight to your radio experience. 73! Jack, W6FB > On Aug 2, 2019, at 4:03 PM, W4HWD <dullha...@gmail.com> wrote: > > HI, > > I'm new here and new to Elecraft. I have to KPA/KAT500 combo and love it! I > do have a question about PA current though... > > On all bands except 20, when running full power out, my HV sits around 64v > and PA current is stable between 10 and 12A. FAn takes it's time coming on > and amp just loafs along. On 20, however, even at lower power output levels, > the PA current is high and the fan comes on and steps up quickly! At full > 500W out on 20, HV is 62v and current runs as high as 16A! Even at 300w out > the current runs around 13A, higher than any other band at full 500w out. > > Question is, is this just how it is or do I have something amiss on 20m? > Antenna is doublet 60' in the air and this antenna is the one I use on 80, > 40 and 20, so don't think I can blame the antenna. Tuner loafs along during > all this, and SWR is no worse than 4:1 on any of these three bands. > > Harry W4HWD > > > > > > -- > Sent from: http://elecraft.365791.n2.nabble.com/ > ______________________________________________________________ > 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 > Message delivered to jackbrin...@me.com ______________________________________________________________ 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 Message delivered to arch...@mail-archive.com
