[Elecraft] KPA-1500 tuner questions

Thu Mar 14 05:36:22 EDT 2019

Peter,

Could you use a fancy Band Decoder that provides auxiliary outputs based 
on operating frequency (not band)? Use the auxiliary outputs to 
automatically enable/disable the Palstar tuner when your 40 and 80 
operating frequencies require. Otherwise keep the Palstar out of 
circuit.

See: www.hamprojects.info/FreqEZ

-larry (K8UT)

------ Original Message ------
From: "Peter Dougherty" <lists at w2irt.net>
To: "'K9MA'" <k9ma at sdellington.us>
Cc: "'Reflector Elecraft'" <elecraft at mailman.qth.net>
Sent: 2019-03-14 01:45:28
Subject: Re: [Elecraft] KPA-1500 tuner questions

>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
>>>
>>>
>>>
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>>
>>
>
>
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