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KPA-1500 tuner questions

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Peter W2IRT

KPA-1500 tuner questions

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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Lovin' my K3S (S/N 10023)
73, Peter W2IRT

K9MA

Re: 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
>
>
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html

Paul Baldock

Re: KPA-1500 tuner questions

In reply to this post by Peter W2IRT

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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Paul Baldock

Re: KPA-1500 tuner questions

In reply to this post by Peter W2IRT

Peter W2IRT

Re: KPA-1500 tuner questions

In reply to this post by K9MA

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

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
>
>
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net Please help support this email
> list: http://www.qsl.net/donate.html

Lovin' my K3S (S/N 10023)
73, Peter W2IRT

Peter W2IRT

Re: KPA-1500 tuner questions

In reply to this post by Paul Baldock

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

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html

Lovin' my K3S (S/N 10023)
73, Peter W2IRT

Jim Brown-10

Re: KPA-1500 tuner questions

In reply to this post by Peter W2IRT

Hi Peter,

It's probably a bad idea to have to antenna tuners in series. Each tuner
adds loss, and the one in the KPA1500 is integrated with the amplifier.
No question, one should by bypassed, and I'd be inclined to remove the
Palstar from the signal path -- that is, connect switched antennas
directly to the KPA1500 and find a new home for the Palstar.

Why? Well, several years ago when I stopped by their booth in Dayton and
looked inside the box, I saw really bad engineering -- the circuitry
relied on chassis return for switching. I asked to talk to the engineer
for the product, and the guy in the booth said he was. When I pointed
out the problem, he didn't understand why it was a problem! This is
engineering 101!

BTW -- the otherwise very good Ten Tec tuners are built that way too.
Trying to make a TDR sweep through them is impossible, and trying to get
6M through it would be a train wreck, and the Palstar that I looked
would be as bad!

73, Jim K9YC

On 3/12/2019 9:24 PM, Peter Dougherty wrote:
> Palstar HF-Auto switches to AUTO mode rather than Manual to keep the match
> seen by the KPA below 1.2:1

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Dave wo2x

Re: KPA-1500 tuner questions

In reply to this post by Peter W2IRT

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
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html

Bob McGraw - K4TAX

Re: 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
>>
>> ______________________________________________________________
>> Elecraft mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:[hidden email]
>>
>> This list hosted by: http://www.qsl.net
>> Please help support this email list: http://www.qsl.net/donate.html
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>

Paul Baldock

Re: KPA-1500 tuner questions

In reply to this post by Dave wo2x

At 03:01 AM 3/13/2019, you 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.

I suggest you set KPA1500 "ATU HISWR RETUNE" to "OFF". The last thing
you want is for the ATU to start tuning when you don't expect it,
such as when you choose the wrong antenna by mistake.

- Paul

______________________________________________________________
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Post: mailto:[hidden email]

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K9MA

Re: KPA-1500 tuner questions

In reply to this post by Peter W2IRT

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
>>
>>
>>
>> ______________________________________________________________
>> Elecraft mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:[hidden email]
>>
>> This list hosted by: http://www.qsl.net Please help support this email
>> list: http://www.qsl.net/donate.html
>
>

Dave wo2x

Re: KPA-1500 tuner questions

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 <[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
>>>
>>>
>>>
>>> ______________________________________________________________
>>> Elecraft mailing list
>>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>>> Help: http://mailman.qth.net/mmfaq.htm
>>> Post: mailto:[hidden email]
>>>
>>> This list hosted by: http://www.qsl.net Please help support this email
>>> list: http://www.qsl.net/donate.html
>>
>>
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html

Peter W2IRT

Re: KPA-1500 tuner questions

In reply to this post by K9MA

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 <[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
>>
>>
>>
>> ______________________________________________________________
>> Elecraft mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:[hidden email]
>>
>> This list hosted by: http://www.qsl.net Please help support this
>> email
>> list: http://www.qsl.net/donate.html
>
>

Lovin' my K3S (S/N 10023)
73, Peter W2IRT

Peter W2IRT

Re: KPA-1500 tuner questions

In reply to this post by Bob McGraw - K4TAX

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:

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73, Peter W2IRT

Peter W2IRT

Re: KPA-1500 tuner questions

In reply to this post by Paul Baldock

Good point. Done!
What I have now is both tuners are ONLY in on the SSB portions of 40/80.
Everywhere else the Palstar is electrically bypassed...but I can't remove it
entirely for reasons stated in my previous posts.

- pjd

-----Original Message-----
From: [hidden email] <[hidden email]> On
Behalf Of Paul Baldock
Sent: Wednesday, March 13, 2019 10:46 AM
To: [hidden email]
Subject: Re: [Elecraft] KPA-1500 tuner questions

At 03:01 AM 3/13/2019, you 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.

I suggest you set KPA1500 "ATU HISWR RETUNE" to "OFF". The last thing you
want is for the ATU to start tuning when you don't expect it, such as when
you choose the wrong antenna by mistake.

- Paul

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Lovin' my K3S (S/N 10023)
73, Peter W2IRT

Jim Brown-10

Re: KPA-1500 tuner questions

In reply to this post by Peter W2IRT

On 3/13/2019 10:45 PM, Peter Dougherty wrote:
> Well that's just it, the SWR is very, very high in the phone portions of
> both 40 and 80.

Here's a VERY old solution that W6NL has taught to his EE classes. When
I asked him about it, he says it's not his original idea, far older than
him.

Tune your 80M dipole to 3675 kHz, feed it with a half-wave of 50 ohm
coax starting at the antenna, then a quarter wave of 75 ohm line. Line
lengths are at 3675 kHz. Add 50 ohm coax as needed to reach the shack,
or coil up the excess if those two lengths are too long. The result will
be SWR below 2:1 from 3500 kHz to 3900 kHz. With good RG213 and RG11,
Line loss is about 0.5 dB at the resonant point and about 0.7 dB at the
limits.

If you want to do some engineering, you can probably tame that 40M
antenna too. Here's a tutorial applications note.
http://k9yc.com/PacificonSmithChart.pdf

73, Jim K9YC

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Larry (K8UT)

Re: KPA-1500 tuner questions

In reply to this post by Peter W2IRT

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" <[hidden email]>
To: "'K9MA'" <[hidden email]>
Cc: "'Reflector Elecraft'" <[hidden email]>
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 <[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
>>>
>>>
>>>
>>> ______________________________________________________________
>>> Elecraft mailing list
>>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>>> Help: http://mailman.qth.net/mmfaq.htm
>>> Post: mailto:[hidden email]
>>>
>>> This list hosted by: http://www.qsl.net Please help support this
>>> email
>>> list: http://www.qsl.net/donate.html
>>
>>
>
>
>______________________________________________________________
>Elecraft mailing list
>Home: http://mailman.qth.net/mailman/listinfo/elecraft
>Help: http://mailman.qth.net/mmfaq.htm
>Post: mailto:[hidden email]
>
>This list hosted by: http://www.qsl.net
>Please help support this email list: http://www.qsl.net/donate.html

Don Wilhelm

Re: KPA-1500 tuner questions

In reply to this post by Jim Brown-10

That is the antenna I use on 80 meters. It has a double-humped SWR
response and stays below 2:1 between 3500 and 3900kHz. Up at 4000kHz it
is a little higher than 3:1. The 1/4 wave 75 ohm section is a
transmission line transformer. The 1/2 wave 50 ohm line repeats the
impedance at the antenna feedpoint.

Mine is an inverted Vee with a 120 degree angle at the apex.

Since the 75 ohm section is 1/2 wavelength on 40 meters, the same
feedline can be used on 40. So I also have two radiator wires for at
right angles to the 80 meter radiator. Being at right angles, there is
no interaction.

73,
Don W3FPR

On 3/14/2019 2:51 AM, Jim Brown wrote:

>
> Here's a VERY old solution that W6NL has taught to his EE classes. When
> I asked him about it, he says it's not his original idea, far older than
> him.
>
> Tune your 80M dipole to 3675 kHz, feed it with a half-wave of 50 ohm
> coax starting at the antenna, then a quarter wave of 75 ohm line. Line
> lengths are at 3675 kHz. Add 50 ohm coax as needed to reach the shack,
> or coil up the excess if those two lengths are too long. The result will
> be SWR below 2:1 from 3500 kHz to 3900 kHz. With good RG213 and RG11,
> Line loss is about 0.5 dB at the resonant point and about 0.7 dB at the
> limits.
>
> If you want to do some engineering, you can probably tame that 40M
> antenna too. Here's a tutorial applications note.
> http://k9yc.com/PacificonSmithChart.pdf
>
> 73, Jim K9YC

Peter W2IRT

Re: KPA-1500 tuner questions

I love this idea, but there's one problem, though. I only have one coax line
leading out of the shack. It runs from the Palstar (or it could run from the
KPA-1500) to the input of my antenna switch. I have 5 antennas connected off
that--three Yagis, and the 80m vee off the tower, and a 160 inverted-L in
the back-40.

Antenna-2 on the K3s is my 6m antenna, and if I take the Palstar out of
line, how do I feed the vee separately? My 80m vee is also at about a 120
degree angle, about 65' at the apex, and it plays REALLY well to Europe, the
Pacific and North America. It doesn't do squat to Asia, unfortunately.

- pjd

-----Original Message-----
From: [hidden email] <[hidden email]> On
Behalf Of Don Wilhelm
Sent: Thursday, March 14, 2019 10:59 AM
To: [hidden email]
Subject: Re: [Elecraft] KPA-1500 tuner questions

That is the antenna I use on 80 meters. It has a double-humped SWR response
and stays below 2:1 between 3500 and 3900kHz. Up at 4000kHz it is a little
higher than 3:1. The 1/4 wave 75 ohm section is a transmission line
transformer. The 1/2 wave 50 ohm line repeats the impedance at the antenna
feedpoint.

Mine is an inverted Vee with a 120 degree angle at the apex.

Since the 75 ohm section is 1/2 wavelength on 40 meters, the same feedline
can be used on 40. So I also have two radiator wires for at right angles to
the 80 meter radiator. Being at right angles, there is no interaction.

73,
Don W3FPR

On 3/14/2019 2:51 AM, Jim Brown wrote:

>
> Here's a VERY old solution that W6NL has taught to his EE classes.
> When I asked him about it, he says it's not his original idea, far
> older than him.
>
> Tune your 80M dipole to 3675 kHz, feed it with a half-wave of 50 ohm
> coax starting at the antenna, then a quarter wave of 75 ohm line. Line
> lengths are at 3675 kHz. Add 50 ohm coax as needed to reach the shack,
> or coil up the excess if those two lengths are too long. The result
> will be SWR below 2:1 from 3500 kHz to 3900 kHz. With good RG213 and
> RG11, Line loss is about 0.5 dB at the resonant point and about 0.7 dB
> at the limits.
>
> If you want to do some engineering, you can probably tame that 40M
> antenna too. Here's a tutorial applications note.
> http://k9yc.com/PacificonSmithChart.pdf
>
> 73, Jim K9YC

Lovin' my K3S (S/N 10023)
73, Peter W2IRT