http://elecraft.85.s1.nabble.com/KPA-1500-tuner-questions-tp7649648p7649696.html
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.
> On Mar 12, 2019, at 10:24 PM, Peter Dougherty <
[hidden email]> 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 <
[hidden email]>
> Sent: Tuesday, March 12, 2019 1:53 PM
> To: Peter Dougherty <
[hidden email]>
> Cc: Reflector Elecraft <
[hidden email]>
> 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 <
[hidden email]> 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:
[hidden email]
>>
>> This list hosted by:
http://www.qsl.net Please help support this email
>> list:
http://www.qsl.net/donate.html>
>