Well that's just it, the SWR is very, very high in the phone portions of both 40 and 80.
I can't see any other way to accomplish full automated operation without the second tuner. I am loathe to have two of them together, but I just can't see any other way. I occasionally remote my own station, and even when not, I can't risk another high power/high-SWR error, so on QSY I have no alternative but to pre-tune before keydown. 40m is below 2:1 until around 7090ish, then rises very rapidly above that. It's 8:1 at 7295. 80m is below 2:1 from 3500 to 3700ish, then rises to 10:1 by 4000 (although it's closer to 5.5:1 at 3850, as high as I'll ever go. - pjd -----Original Message----- 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 <li...@w2irt.net> 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 <k...@sdellington.us> > Sent: Tuesday, March 12, 2019 1:53 PM > To: Peter Dougherty <li...@w2irt.net> > Cc: Reflector Elecraft <elecraft@mailman.qth.net> > 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 <li...@w2irt.net> 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:Elecraft@mailman.qth.net >> >> 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:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
