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UPDATE KPA1500 on 160M

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Ronnie Hull

UPDATE KPA1500 on 160M

The original thread has gone off on some tangents. I truly appreciate all the suggestions.

I seem to have cured the problem!

ORIGINAL ISSUE was using a new W7FG 160m doublet with 600 ohm true ladder line. The ladder line was hooked to a Balun Design 4:1 ( as recommended by the seller of the antenna). The antenna would be matched great in 160M by the internal ATU in the K3 but with the KPA1500 inline it all went north really fast, resulting in the 1500 faulting out

Earlier today I swapped in a DX Engineering maxi core 4:1 and it worked a hell of a lot better but the KPA1500 still could not match it better than 9:1

Mind you this antenna matches superb on other bands with the KPA1500

Also the KPA1500 works great into a dummy load so I knew the issue was the antenna or part of it

Last I put in line a DX Engineering maxi core 6:1 and BAM... it worked!
The KPA1500 matches to 2.5:1 which is good enough for now.

Next I will experiment with the 600 ohm ladder line length. Right now I’m using 57’. I will add 10’ tomorrow and see what shakes out and will let you fellas know

Thanks for all the help and suggestions!

Ronnie W5SUM

Sent from my iPhone
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Adrian-3

Re: UPDATE KPA1500 on 160M

Ronnie, well done. Moving to a different ratio balun is a smart obvious
move towards obtaining a better match,

especially at higher power maintaining insulation specs required.

From curiosity what was the model number of the BD 4:1 balun you had
initially please ?

On 3/9/20 10:03 am, Ronnie Hull wrote:

> The original thread has gone off on some tangents. I truly appreciate all the suggestions.
>
> I seem to have cured the problem!
>
> ORIGINAL ISSUE was using a new W7FG 160m doublet with 600 ohm true ladder line. The ladder line was hooked to a Balun Design 4:1 ( as recommended by the seller of the antenna). The antenna would be matched great in 160M by the internal ATU in the K3 but with the KPA1500 inline it all went north really fast, resulting in the 1500 faulting out
>
> Earlier today I swapped in a DX Engineering maxi core 4:1 and it worked a hell of a lot better but the KPA1500 still could not match it better than 9:1
>
> Mind you this antenna matches superb on other bands with the KPA1500
>
> Also the KPA1500 works great into a dummy load so I knew the issue was the antenna or part of it
>
> Last I put in line a DX Engineering maxi core 6:1 and BAM... it worked!
> The KPA1500 matches to 2.5:1 which is good enough for now.
>
> Next I will experiment with the 600 ohm ladder line length. Right now I’m using 57’. I will add 10’ tomorrow and see what shakes out and will let you fellas know
>
> Thanks for all the help and suggestions!
>
> Ronnie W5SUM
>

Jim Miller

Re: UPDATE KPA1500 on 160M

Have you measured the impedance presented to the amplifier with an antenna analyzer?

Jim ab3cv

On Sep 2, 2020, at 9:03 PM, Adrian <[hidden email]> wrote:

Ronnie, well done. Moving to a different ratio balun is a smart obvious move towards obtaining a better match,

especially at higher power maintaining insulation specs required.

From curiosity what was the model number of the BD 4:1 balun you had initially please ?

> On 3/9/20 10:03 am, Ronnie Hull wrote:
> The original thread has gone off on some tangents. I truly appreciate all the suggestions.
>
> I seem to have cured the problem!
>
> ORIGINAL ISSUE was using a new W7FG 160m doublet with 600 ohm true ladder line. The ladder line was hooked to a Balun Design 4:1 ( as recommended by the seller of the antenna). The antenna would be matched great in 160M by the internal ATU in the K3 but with the KPA1500 inline it all went north really fast, resulting in the 1500 faulting out
>
> Earlier today I swapped in a DX Engineering maxi core 4:1 and it worked a hell of a lot better but the KPA1500 still could not match it better than 9:1
>
> Mind you this antenna matches superb on other bands with the KPA1500
>
> Also the KPA1500 works great into a dummy load so I knew the issue was the antenna or part of it
>
> Last I put in line a DX Engineering maxi core 6:1 and BAM... it worked!
> The KPA1500 matches to 2.5:1 which is good enough for now.
>
> Next I will experiment with the 600 ohm ladder line length. Right now I’m using 57’. I will add 10’ tomorrow and see what shakes out and will let you fellas know
>
> Thanks for all the help and suggestions!
>
> Ronnie W5SUM
>

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Ronnie Hull

Re: UPDATE KPA1500 on 160M

In reply to this post by Adrian-3

4114T was the BD Balun model #. I'm not putting down there product at all.
When strictly using the ATU in the K3 it matched wonderfully. The fly in
the buttermilk was when the KPA1500 was thrown into the mix.

Ronnie

-----Original Message-----
From: Adrian
Sent: Wednesday, September 02, 2020 7:59 PM
To: Ronnie Hull ; Elecraft
Subject: Re: [Elecraft] UPDATE KPA1500 on 160M

Ronnie, well done. Moving to a different ratio balun is a smart obvious
move towards obtaining a better match,

especially at higher power maintaining insulation specs required.

From curiosity what was the model number of the BD 4:1 balun you had
initially please ?

On 3/9/20 10:03 am, Ronnie Hull wrote:

> The original thread has gone off on some tangents. I truly appreciate all
> the suggestions.
>
> I seem to have cured the problem!
>
> ORIGINAL ISSUE was using a new W7FG 160m doublet with 600 ohm true ladder
> line. The ladder line was hooked to a Balun Design 4:1 ( as recommended by
> the seller of the antenna). The antenna would be matched great in 160M by
> the internal ATU in the K3 but with the KPA1500 inline it all went north
> really fast, resulting in the 1500 faulting out
>
> Earlier today I swapped in a DX Engineering maxi core 4:1 and it worked a
> hell of a lot better but the KPA1500 still could not match it better than
> 9:1
>
> Mind you this antenna matches superb on other bands with the KPA1500
>
> Also the KPA1500 works great into a dummy load so I knew the issue was the
> antenna or part of it
>
> Last I put in line a DX Engineering maxi core 6:1 and BAM... it worked!
> The KPA1500 matches to 2.5:1 which is good enough for now.
>
> Next I will experiment with the 600 ohm ladder line length. Right now I’m
> using 57’. I will add 10’ tomorrow and see what shakes out and will let
> you fellas know
>
> Thanks for all the help and suggestions!
>
> Ronnie W5SUM
>

Elecraft mailing list

Re: UPDATE KPA1500 on 160M

In reply to this post by Jim Miller

Ronnie,

I’m kinda late to this dance, but did want to toss in my thoughts. I assume you are running a length of beefy coax from the back of the KPA1500 to the balun. I do the same with my KPA500/KAT500. About 10 feet of 9913 coax to the Balun Designs box, then 110 feet of 600 ohm line to the antenna feed point. I initially had a very ugly SWR on 20 meters that the KAT500 balked at; the other bands were fine. Changing the length of the coax between the tuner and the balun cured the problem - I went from 20 feet (a convenient piece of coax I had lying around) to 10 feet. If you’ve got some other lengths of coax available, you might want to try switching them in / out - might be easier than chopping the ladder line.

73, Jim / W6JHB

> On Sep 2, 2020, at 6:06 PM, Jim Miller <[hidden email]> wrote:
>
> Have you measured the impedance presented to the amplifier with an antenna analyzer?
>
> Jim ab3cv
>
> On Sep 2, 2020, at 9:03 PM, Adrian <[hidden email] <mailto:[hidden email]>> wrote:
>
> Ronnie, well done. Moving to a different ratio balun is a smart obvious move towards obtaining a better match,
>
> especially at higher power maintaining insulation specs required.
>
> From curiosity what was the model number of the BD 4:1 balun you had initially please ?
>
>
>> On 3/9/20 10:03 am, Ronnie Hull wrote:
>> The original thread has gone off on some tangents. I truly appreciate all the suggestions.
>>
>> I seem to have cured the problem!
>>
>> ORIGINAL ISSUE was using a new W7FG 160m doublet with 600 ohm true ladder line. The ladder line was hooked to a Balun Design 4:1 ( as recommended by the seller of the antenna). The antenna would be matched great in 160M by the internal ATU in the K3 but with the KPA1500 inline it all went north really fast, resulting in the 1500 faulting out
>>
>> Earlier today I swapped in a DX Engineering maxi core 4:1 and it worked a hell of a lot better but the KPA1500 still could not match it better than 9:1
>>
>> Mind you this antenna matches superb on other bands with the KPA1500
>>
>> Also the KPA1500 works great into a dummy load so I knew the issue was the antenna or part of it
>>
>> Last I put in line a DX Engineering maxi core 6:1 and BAM... it worked!
>> The KPA1500 matches to 2.5:1 which is good enough for now.
>>
>> Next I will experiment with the 600 ohm ladder line length. Right now I’m using 57’. I will add 10’ tomorrow and see what shakes out and will let you fellas know
>>
>> Thanks for all the help and suggestions!
>>
>> Ronnie W5SUM
>>
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Adrian-3

Re: UPDATE KPA1500 on 160M

In reply to this post by Ronnie Hull

Ok on that. I have good success with true OCF (not windom) antennas and
Balun Designs 4:1 current baluns in the past.

These days I just use apex high delta loops with direct feed via a
lmr240 multi-wound toroid choke at feedpoint for great results.

Bottom corner fed (vertically polarised), so feed-line length and losses
are kept minimal . I find this type of antenna very quiet,

and neighbour friendly in all respects.

It would have been interesting to see how a 4116 performed on yours.

On 3/9/20 11:37 am, [hidden email] wrote:
> 4114T was the BD Balun model #. I'm not putting down there product at
> all. When strictly using the ATU in the K3 it matched wonderfully.
> The fly in the buttermilk was when the KPA1500 was thrown into the mix.
>
> Ronnie
>
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Adrian-3

Re: UPDATE KPA1500 on 160M

In reply to this post by Elecraft mailing list

Yes I have seen that, very good point, and I was also thinking about the
lmr400 length earlier in the thread.

I felt that Ronnie may not warm to that idea, so did not mention it.

It is a bit of hit and miss sometimes with that solution, but once
there, your done.

On 3/9/20 11:41 am, James Bennett via Elecraft wrote:
> Ronnie,
>
> I’m kinda late to this dance, but did want to toss in my thoughts. I assume you are running a length of beefy coax from the back of the KPA1500 to the balun. I do the same with my KPA500/KAT500. About 10 feet of 9913 coax to the Balun Designs box, then 110 feet of 600 ohm line to the antenna feed point. I initially had a very ugly SWR on 20 meters that the KAT500 balked at; the other bands were fine. Changing the length of the coax between the tuner and the balun cured the problem - I went from 20 feet (a convenient piece of coax I had lying around) to 10 feet. If you’ve got some other lengths of coax available, you might want to try switching them in / out - might be easier than chopping the ladder line.
>
> 73, Jim / W6JHB
>
>
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K8TE

Re: UPDATE KPA1500 on 160M

In reply to this post by Ronnie Hull

Nowhere has there been a mention of what VSWR the tuner sees, only the result
of its match which is 2.5:1.
That means the VSWR it sees is beyond its capability to tune properly and
run full power. This information is available on the KPA1500 panel display.
It will also state the maximum allowable power output. What are those
values?

I suspect the VSWR is quite high and the allowable power well below 1,500
Watts. It's likely you're expecting more power-handling capability than the
BALUN, either one, can handle.

When one writes "quickly" that is interpreted differently by all those who
read it. Obviously, 20 to 30 seconds is not "quickly", at least to me, but
a very good indications of something overheating, but not instantly. The
latter could lead toward a very different conclusion.

My current (pun intended) conclusion is don't run over 800 Watts on 160m!
That is about the same level you run with your other amplifier without a
failure, maybe, if you don't run it too long at that level. I'm glad you
concluded it's an antenna system problem.

BTW, W8JI has written about this antenna and recommends an 80-20% ratio,
rather than the typical 67-33% ratio. He has modeled it for various bands
on his web site. I don't know why the common 67-33% values are used when
someone has shown there is a better choice. Old habits, good and bad, die
hard.

73, Bill, K8TE

--
Sent from: http://elecraft.365791.n2.nabble.com/
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Adrian-3

Re: UPDATE KPA1500 on 160M

Bill, ok on that, yes more electronic amplifiers especially use a swr
limit to protect against the high voltages

generated at high swr. Sometimes you are better off using a robust
manual tuner made for the job external to the amp.

High swr between a remote balun and atu at amp, will emphasis balun
heating loss as the signal passes the feedline length many times before

totally dissipating in the coax loss & balun core,some as heat loss, and
some as desired induced balun current to antenna radiated RF.

Ladder line back to a close-by matchbox, which can handle KV, close to
amp, would give best power efficiency, as ladder line has minimal
feedline loss.

I would be using a manual ext tuner with this type of antenna, also
taking away risk of damaging the amp.

On 3/9/20 2:19 pm, K8TE wrote:

> Nowhere has there been a mention of what VSWR the tuner sees, only the result
> of its match which is 2.5:1.
> That means the VSWR it sees is beyond its capability to tune properly and
> run full power. This information is available on the KPA1500 panel display.
> It will also state the maximum allowable power output. What are those
> values?
>
> I suspect the VSWR is quite high and the allowable power well below 1,500
> Watts. It's likely you're expecting more power-handling capability than the
> BALUN, either one, can handle.
>
> When one writes "quickly" that is interpreted differently by all those who
> read it. Obviously, 20 to 30 seconds is not "quickly", at least to me, but
> a very good indications of something overheating, but not instantly. The
> latter could lead toward a very different conclusion.
>
> My current (pun intended) conclusion is don't run over 800 Watts on 160m!
> That is about the same level you run with your other amplifier without a
> failure, maybe, if you don't run it too long at that level. I'm glad you
> concluded it's an antenna system problem.
>
> BTW, W8JI has written about this antenna and recommends an 80-20% ratio,
> rather than the typical 67-33% ratio. He has modeled it for various bands
> on his web site. I don't know why the common 67-33% values are used when
> someone has shown there is a better choice. Old habits, good and bad, die
> hard.
>
> 73, Bill, K8TE
>
>
>
> --
> Sent from: http://elecraft.365791.n2.nabble.com/
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
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> Post: mailto:[hidden email]
>
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> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to [hidden email]
>

Lyn WØLEN

Re: UPDATE KPA1500 on 160M

In reply to this post by Adrian-3

Adrian -

Comment on the BD #4116 "hybrid" balun:

It's a combination 4:1 impedance transformer and 1:1 current balun all in one unit.

I am using that on my 360' center fed EDZ (with 160' true ladder line and 15' coax) and it combines to give my KPA/KAT500 a match of 1.2:1 or less (mostly less) SWR across all bands 160-6m.

73
Lyn, W0LEN

-----Original Message-----
From: [hidden email] [mailto:[hidden email]] On Behalf Of Adrian
Sent: Wednesday, September 02, 2020 9:37 PM
To: [hidden email]; Elecraft
Subject: Re: [Elecraft] UPDATE KPA1500 on 160M

Ok on that. I have good success with true OCF (not windom) antennas and
Balun Designs 4:1 current baluns in the past.

These days I just use apex high delta loops with direct feed via a
lmr240 multi-wound toroid choke at feedpoint for great results.

Bottom corner fed (vertically polarised), so feed-line length and losses
are kept minimal . I find this type of antenna very quiet,

and neighbour friendly in all respects.

It would have been interesting to see how a 4116 performed on yours.

On 3/9/20 11:37 am, [hidden email] wrote:
> 4114T was the BD Balun model #. I'm not putting down there product at
> all. When strictly using the ATU in the K3 it matched wonderfully.
> The fly in the buttermilk was when the KPA1500 was thrown into the mix.
>
> Ronnie
>
______________________________________________________________
\

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Elecraft mailing list

Re: UPDATE KPA1500 on 160M

I am using the same unit as Lyn (BD4116) on a center fed 250’ doublet Inverted Vee with about 50 feet of 600 ohm open ladder line and about 15 feet of 50 ohm coax.

The KAT500 matches all bands except 6 to 1:1. 6 is matched to 1.3:1. I have been told by some that the hybrid unit is worthless, but I am happy with its performance.

(However truth be known although licensed since 1965 I am a casual ham, just a fun side hobby for me. Not a serious contest’er or DX’er.

I have a SteppIR DB-18E on a MA-770 so I use the doublet mainly on 160 & 80/75.

Cheers,
Kim - K7IM

Sent from my iPad

> On Sep 3, 2020, at 13:26, Lyn Norstad <[hidden email]> wrote:
>
> Adrian -
>
> Comment on the BD #4116 "hybrid" balun:
>
> It's a combination 4:1 impedance transformer and 1:1 current balun all in one unit.
>
> I am using that on my 360' center fed EDZ (with 160' true ladder line and 15' coax) and it combines to give my KPA/KAT500 a match of 1.2:1 or less (mostly less) SWR across all bands 160-6m.
>
> 73
> Lyn, W0LEN
>
>
> -----Original Message-----
> From: [hidden email] [mailto:[hidden email]] On Behalf Of Adrian
> Sent: Wednesday, September 02, 2020 9:37 PM
> To: [hidden email]; Elecraft
> Subject: Re: [Elecraft] UPDATE KPA1500 on 160M
>
> Ok on that. I have good success with true OCF (not windom) antennas and
> Balun Designs 4:1 current baluns in the past.
>
> These days I just use apex high delta loops with direct feed via a
> lmr240 multi-wound toroid choke at feedpoint for great results.
>
> Bottom corner fed (vertically polarised), so feed-line length and losses
> are kept minimal . I find this type of antenna very quiet,
>
> and neighbour friendly in all respects.
>
>
> It would have been interesting to see how a 4116 performed on yours.
>
>
>>> On 3/9/20 11:37 am, [hidden email] wrote:
>> 4114T was the BD Balun model #. I'm not putting down there product at
>> all. When strictly using the ATU in the K3 it matched wonderfully.
>> The fly in the buttermilk was when the KPA1500 was thrown into the mix.
>> Ronnie
> ______________________________________________________________
> \
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
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