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" <[email protected]>
To: "'K9MA'" <[email protected]>
Cc: "'Reflector Elecraft'" <[email protected]>
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 <[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
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