The issue with the internal tuner in Peter’s case is SWR will be high enough to cause necessary power reduction. (Max power will be reduced. )
The HF Auto allows for slightly higher power at same SWR presented to tuner. Dave wo2x Sent from my waxed string and tin cans. > On Mar 13, 2019, at 11:02 AM, K9MA <[email protected]> wrote: > > 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 ______________________________________________________________ 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
