[Elecraft] KPA-1500 tuner questions

[Peter Dougherty]

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 <lists at 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 <k9ma at sdellington.us>
> Sent: Tuesday, March 12, 2019 1:53 PM
> To: Peter Dougherty <lists at w2irt.net>
> Cc: Reflector Elecraft <elecraft at 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 <lists at 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 at mailman.qth.net
>> 
>> This list hosted by: http://www.qsl.net Please help support this 
>> email
>> list: http://www.qsl.net/donate.html
> 
>