[Elecraft] KPA-1500 tuner questions

[Dave]

The issue with the internal tuner in Peter’s case is SWR will be high enough to cause necessary power reduction. (Max power will be reduced. )

The HF Auto allows for slightly higher power at same SWR presented to tuner. 

Dave wo2x

Sent from my waxed string and tin cans. 

> On Mar 13, 2019, at 11:02 AM, K9MA <k9ma at sdellington.us> wrote:
> 
> 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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