I would be concerned about reducing voltage for SSB and TX IMD. The NXP 1K50H devices are only biased at 1 amp each which is a bit low for optimal IMD as it is. SSB IMD could be improved by increasing bias to 2 amps per device. Since the bias is only present during TX the waste heat increase would be negligible.
The FLex Power Genius XL uses same RF devices and they use 2 amps per device @ 52 volts on SSB. IMD at that spec on PG. L is very acceptable. I am sure there is a reason I am overlooking for the Elecraft engineers to adjust bias to 1 amp per device. Dave wo2x Sent from my waxed string and tin cans. > On Nov 13, 2020, at 10:28 AM, Roy <k...@ncn.net> wrote: > > Yes, I read the same. Lowering the PA voltage might be a bit difficult... > > 73, Roy K6XK > >> On 11/13/2020 8:27 AM, Howard Sherer wrote: >> Reading the display on the KPA 1500 at various RF output levels shows an >> efficiency as follows on 40M into a dummyload: >> >> >> 300W 23% >> 500W 27% >> 1000W 42% >> 1300W 48% >> 1500W 52% >> 1600W 54% >> >> Have other owners seen results like this? Do you think a firmware and menu >> item could be developed to increase the amps efficiency at lower power >> levels by lowering the voltage to the PA? >> ______________________________________________________________ >> > > ______________________________________________________________ > 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 rocke...@gmail.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
