[Elecraft] KPA-1500 tuner questions

[K9MA]

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
>> 
>> 
>> 
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