The ATU in the KPA1500 alone will achieve the 1.2:1 match with the 2.09 firmware, now in beta. The external tuner is not necessary, unless the antenna SWR is very high.
73, Scott K9MA ---------- Scott Ellington --- via iPad > On Mar 12, 2019, at 10:24 PM, Peter Dougherty <[email protected]> wrote: > > Thanks, Scott! > I'm going to change the way I do things so that ATU is always in, and the > Palstar HF-Auto switches to AUTO mode rather than Manual to keep the match > seen by the KPA below 1.2:1 > > - pjd > > -----Original Message----- > From: K9MA <[email protected]> > Sent: Tuesday, March 12, 2019 1:53 PM > To: Peter Dougherty <[email protected]> > Cc: Reflector Elecraft <[email protected]> > Subject: Re: [Elecraft] KPA-1500 tuner questions > > Just a general comment on the KPA1500: My experience with it shows that the > SWR has to be below 1.2:1 at the amplifier output (ATU input) to run > reliably at full power. If the SWR is higher than that, the amp will often > fault due to excessive current or drive power before reaching 1500 W. (And > may splatter on SSB.) Elecraft recently updated the ATU firmware to > consistently find a better match, and it really helps. > > 73, > Scott K9MA > > ---------- > > Scott Ellington > > --- via iPad > >> On Mar 11, 2019, at 8:49 PM, Peter Dougherty <[email protected]> wrote: >> >> I have a couple of questions about the KPA1500's internal tuner. >> >> For the most part, I leave the tuner inline. Except for two sub-bands >> (SSB on both 40 and 80m) I am well below 2:1, and maybe 2.5:1 at the >> top end of 160m. The KPA does a good job throughout. >> >> The problems/questions arise when I need to transition between the >> KPA's internal tuner on the bottom ends of both 40 and 80, and the >> external Palstar HF-Auto tuner, which I need to wrangle very high SWRs >> on the phone portions of those bands. Obviously I don't want both >> automatic tuners inline at the same time. The situation is most acute on > 40. >> >> The HF-Auto (external automatic tuner) is bypassed everywhere except >> the range of 3650 to 4000, and 7100 to 7300. I would like to >> automatically have the KPA1500's tuner go into bypass at the above >> ranges, just as the Palstar auto-tuner bypasses outside of those >> ranges. Is this somehow possible, or must I manually switch the tuner >> in and out when I cross the appropriate thresholds? >> >> Second question, and I think this relates to the whole "bins" thing, >> which I don't understand, relates to having different tuning solutions >> on the same band segment. This could be handy for me on 80m. Unlike on >> 40, for 80 I have an inverted vee, and it's easy for me to drop the >> ends and change the length of the antenna, so that instead of being >> resonant at 3550 I could make it 3700. I did this for the ARRL-SSB >> contest and it worked pretty well. Is it possible to have two >> different sets of memorized tuning solutions in the KPA-1500, in the >> event I have the vee set for CW (normal) or SSB (for phone contests only)? >> >> >> --------------------------------------------- >> 73 and Good DX >> Peter, W2IRT >> >> >> >> President, North Jersey DX Association >> >> DXCC Card Checker >> Letter O Manager, ARRL Incoming 2nd District QSL bureau >> >> >> >> ______________________________________________________________ >> 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 > > ______________________________________________________________ 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
