Re: KPA-1500 tuner questions

Posted by Peter W2IRT on Mar 14, 2019; 5:50am
URL: http://elecraft.85.s1.nabble.com/KPA-1500-tuner-questions-tp7649648p7649719.html

Hi Bob,
Please see my earlier message. It's not possible to use the internal ATU in the KPA-1500 for the SSB portions of 40 and 80 meters.

I use both SSB and CW on both bands. My 80m antenna is a vee that I can fold back the ends for SSB contests, and that works to a degree, but I can't work both CW and SSB in the same band. As a DXer that's not an acceptable solution.

40 is far worse. It's a shorty-40 that only has 175 kHz below 2:1, and about 200 kHz below 3:1, where power will start folding back.

I vehemently dislike the Palstar. I think it's a huge waste of money, but frankly I can't see any other way to accomplish what I need to do. I can't put up a full-size 40m Yagi--my tower's very close to being overloaded now--so I have to try and make a silk purse out of the proverbial sow's ear.

Yes, two tuners is a horrible solution, but the only other way is to ditch the Palstar and give up SSB operation entirely on 40m--and that's absolutely not an option.

I have one feedline going from the shack to the tower and an automatic antenna switch outside.

 - pjd

-----Original Message-----
From: [hidden email] <[hidden email]> On Behalf Of Bob McGraw K4TAX
Sent: Wednesday, March 13, 2019 8:58 AM
To: [hidden email]
Subject: Re: [Elecraft] KPA-1500 tuner questions

Personally I'd try to correct the antenna issue so the tuner in the
KPA1500 performs  as designed.  The antenna should be able, with the
KPA1500 tuner, to cover then entire 75/80M band. Although I use the KAT500, same equivalent circuit, I have no issue with full band coverage on 75/80M.

As to the Palstar, I'd take Jim's advice, and find it a new home.  Two automatic tuners in line is a formula for disaster as I view it.   If you wish to use the Palstar all of the time, then set the one in the
KPA1500 to bypass all of the time.

73

Bob, K4TAX



On 3/13/2019 5:01 AM, Dave wrote:

> The problem you will run into is if the antenna SWR changes above the threshold for both the KPA1500 tuner and HF Auto bothtuners will initiate a retune and the two will be fighting each other.
>
>   Example - ice, branches against antenna, etc.
>
> For the bands where you need to use the HF Auto, you are better off leaving the KPA1500 in bypass.
>
> Dave wo2x
>
> Sent from my iPad
>
>> On Mar 13, 2019, at 12:25 AM, Peter Dougherty <[hidden email]> wrote:
>>
>> I think instead I'll go the route of always leaving it in line, but that
>> method would certainly work too! Thanks, Paul!
>>
>>
>>
>> - pjd
>>
>>
>>
>> From: Paul Baldock <[hidden email]>
>> Sent: Tuesday, March 12, 2019 3:36 PM
>> To: Peter Dougherty <[hidden email]>; 'Reflector Elecraft'
>> <[hidden email]>
>> Subject: Re: [Elecraft] KPA-1500 tuner questions
>>
>>
>>
>> At 07:49 PM 3/11/2019, Peter Dougherty wrote:
>>
>>
>>
>>
>>
>> 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,
>>
>>
>> One method (there are others) is to connect a dummy load to the KPA1500, and
>> do a TUNE for each bin in those ranges. The tuner will then learn to go into
>> BYPASS for those BINS.
>>
>> - Paul
>>
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