http://elecraft.85.s1.nabble.com/KPA-1500-tuner-questions-tp7649648p7649697.html
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.
Sent from my waxed string and tin cans.
> On Mar 13, 2019, at 11:02 AM, K9MA <
[hidden email]> 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 <
[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
>>>
>>>
>>>
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