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KPA1500 Tuner Question for the Group

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Lyn WØLEN

KPA1500 Tuner Question for the Group

Since the tuner built in to the KPA1500 is not able to handle the full power
of the amp at a 10:1 SWR (like the KAT/KPA500 Combo), what tuner(s) are you
using if you need that kind of matching capability (i.e.: for balanced feed,
etc.)?

73

Lyn, W0LEN

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Clay Autery-2

Re: KPA1500 Tuner Question for the Group

To my knowledge the best (only?) auto-tuner capable of handling legal
limit is the HF Auto, which is rated at 18800 watts.... Don't remember
the duty cycle spec.
However, AFTER making my way through the learning curve on it and the
software available 3rd party, I have to say, it is simply awesome.

Of course, I don't think it will do 10:1 either.... Can't imagine the
monster tuner (likely manual) that you'd have to build to handle 10:1 at
1500Watss, 100% duty cycle...

73,

______________________
Clay Autery, KY5G
(318) 518-1389

On 04/21/20 09:59, Lyn Norstad wrote:

Rick Bates, NK7I

Re: KPA1500 Tuner Question for the Group

In reply to this post by Lyn WØLEN

I use resonant antennas now, but prior to this the KAT500 and before
that the Heathkit SA-2060 (which can use darn near anything).

Antenna Tuner SA-2060 Amateur-D Heathkit Brand, Heath Co.; B

It is safely stored away, one never knows if it will be needed again.

Rick NK7I

On 4/21/2020 7:59 AM, Lyn Norstad wrote:

> Since the tuner built in to the KPA1500 is not able to handle the full power
> of the amp at a 10:1 SWR (like the KAT/KPA500 Combo), what tuner(s) are you
> using if you need that kind of matching capability (i.e.: for balanced feed,
> etc.)?
>
>
>
> 73
>
> Lyn, W0LEN
>
>
>
> ______________________________________________________________
> Elecraft mailing list
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Lyn WØLEN

Re: KPA1500 Tuner Question for the Group

In reply to this post by Clay Autery-2

Thanks Clay.

The Palstar HF Auto, rated at 1800 watts PEP, "looks like" it has the same components as their 5K manual tuner, which is rated at 3500 watts PEP continuous and also rated at 2000 ohms max, which is 40:1.

What 3rd party software are you using?

73
Lyn, W0LEN

-----Original Message-----
From: [hidden email] [mailto:[hidden email]] On Behalf Of Clay Autery
Sent: Tuesday, April 21, 2020 10:23 AM
To: [hidden email]
Subject: Re: [Elecraft] KPA1500 Tuner Question for the Group

To my knowledge the best (only?) auto-tuner capable of handling legal
limit is the HF Auto, which is rated at 18800 watts.... Don't remember
the duty cycle spec.
However, AFTER making my way through the learning curve on it and the
software available 3rd party, I have to say, it is simply awesome.

Of course, I don't think it will do 10:1 either.... Can't imagine the
monster tuner (likely manual) that you'd have to build to handle 10:1 at
1500Watss, 100% duty cycle...

73,

______________________
Clay Autery, KY5G
(318) 518-1389

On 04/21/20 09:59, Lyn Norstad wrote:

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Jim Brown-10

Re: KPA1500 Tuner Question for the Group

In reply to this post by Rick Bates, NK7I

On 4/21/2020 8:33 AM, Rick Bates, NK7I wrote:
> Antenna Tuner SA-2060 Amateur-D Heathkit

I had one of these for a month or two from a neighbor who was moving and
wanted me to sell if for him. It was not nearly as good as my vintage
Ten Tec 238 with fixed caps replaced by higher voltage parts.
>
> It is safely stored away, one never knows if it will be needed again.

So is my 238.

73, Jim K9YC

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David Gilbert

Re: KPA1500 Tuner Question for the Group

In reply to this post by Lyn WØLEN

Well, not all 10:1 conditions are equal (low impedances tend to give
higher tuner voltages and power loss than higher impedances), and of
course 160m is generally the most problematic band because it takes so
much capacitance and inductance to get a decent result. But playing
around with TLW, the free transmission line software that comes with the
ARRL Antenna Book is very informative since it also includes a built in
tuner calculator. For a typical high pass T-Network tuner, the internal
voltages can approach 4,000 volts at 1.8 MHz with a 20 -j90 load
(roughly 10:1 SWR), depending upon the size of the output load
capacitor. That pretty much rules out relay switch tuning unless anyone
knows where they can steal a large quantity of vacuum relays, so we're
talking some pretty large motor driven components if it was to be an
auto tune unit.

I'm in the process of building my own high power manual tuner for use in
the shack, and it will be a high pass T-network with additional high
power ceramic doorknob capacitors that can be switch selected in
parallel with the main breadslicers. There are some incredibly high
power NOS doorknobs available on eBay from Russian and Ukrainian vendors
at remarkably low prices. I've bought from several suppliers and have
been pleased each time. Here's an example from an Austrian vendor from
whom I have recently purchased these exact units:

*https://tinyurl.com/ybofl2os

*In my case, in addition to switchable fixed parallel capacitors for
both the input and output variable capacitors, I will also have a switch
that shorts out one or the other in order to convert the tuner to an
L-Network in case the load prefers it.

Many years ago somebody whose callsign I have since forgotten came up
with the idea of making a remotely tuned high power L-Network tuner by
coupling the shafts of a rotary inductor and a variable capacitor
together and turning them at the same time with a single DC motor
through a gear reducer. It's not as precise as being able to tune each
individually, but it doesn't really need to be. The capacitor goes
through it's full range every turn of the inductor, and you simply
reverse the polarity of the DC voltage to tune back and forth until you
see a match at the shack. However, unless you have a REALLY large
variable capacitor, or some means of switching in parallel capacitors,
this technique probably doesn't work as well on the lower bands and
you'd want to know in advance whether your load was higher or lower than
50 ohms, which often determines whether you use the capacitor input or
inductor input configuration. It's a great way to make a wide range SWR
extender for a single band, though.

Sorry ... this post turned into more of a ramble than I planned.

73,
Dave AB7E

On 4/21/2020 7:59 AM, Lyn Norstad wrote:

K8TE

Re: KPA1500 Tuner Question for the Group

In reply to this post by Lyn WØLEN

The Palstar-HF Auto has 100% duty cycle and a maximum 8:1 "matching range",
according to its manual.

I have a pair of the Nye Viking MB-V-A tuners which handle 1,500 Watts with
no noticeable signs of distress although I haven't used them much on RTTY,
and definitely not in a contest. They're useful in a few cases where the
KPA1500 internal tuner can't handle the VSWR.

I too would be interested in the 3rd party software you are using Len.

73, Bill, K8TE

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Ed Pflueger

Re: KPA1500 Tuner Question for the Group

In reply to this post by Lyn WØLEN

I use the Palstar HF-Auto for 80 and 160. The Tuner in the KPA1500 works
great on my Hy-gain 6 meter, TH11, and Hy-Tower and it only has to teak just
a hair but normally I just leave the tuner in By-Pass mode and the HF-Auto
turns into an antenna switch. Probably the best I've ever had are the Ten
Tec 238 series of tuners. I should have kept the last one but I didn't. It
also had the Balun for twin lead built in as well. In my Man Cave in the
garage I have the KPA500/KAT500 combo and they work the same antennas just
fine.

Ed.. AB4IQ

-----Original Message-----
From: [hidden email]
[mailto:[hidden email]] On Behalf Of Lyn Norstad
Sent: Tuesday, April 21, 2020 10:00 AM
To: [hidden email]
Subject: [Elecraft] KPA1500 Tuner Question for the Group

Since the tuner built in to the KPA1500 is not able to handle the full power
of the amp at a 10:1 SWR (like the KAT/KPA500 Combo), what tuner(s) are you
using if you need that kind of matching capability (i.e.: for balanced feed,
etc.)?

73

Lyn, W0LEN

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Mark Goldberg

Re: KPA1500 Tuner Question for the Group

In reply to this post by David Gilbert

On Tue, Apr 21, 2020 at 12:29 PM David Gilbert <[hidden email]>
wrote:

>
> Well, not all 10:1 conditions are equal (low impedances tend to give
> higher tuner voltages and power loss than higher impedances),

Dave's comment is very significant. Matching capability, loss and the power
level a tuner can handle will vary with the specific impedance of the
antenna and the construction of the tuner in question. You can't generalize
by SWR alone. So the answer, really is "it depends".

I have a switchable 4:1 or 1:1 balun and that helps get the impedance the
tuner sees into a better range for a specific frequency. I've got a
horizontal loop, not resonant on any band and the switchable balun is one
more tool in the toolbox. Unfortunately, tuner manufacturers don't publish
the capacitance and inductance ranges or voltage and current capability of
the parts they use. You can open it up and read the values off the parts
and then software like TLW or Elsie will allow you to know if it can tune a
specific impedance. If not, you can add components. My loop is a little
short for 160, so I have an external shunt inductor to help the tuner. It
will tune, but everything gets hot, so it is pretty lossy.

73,

Mark
W7MLG
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Ignacy

Re: KPA1500 Tuner Question for the Group

MFJ-998 seems to tune anything. I am always trembling that it will smoke, but
for 5 years, no smoke. Even matching 80m dipole (fed by ladderline) on 40m.

It has 2 outputs and keeps matches in memory. Getting it to tune at
frequency previously tuned takes a fraction of a second. If both antennas
were used at same frequency, tuning for one antenna automatically brings
tune in the second. Very convenient for A/B comparisons.

The tuner displays L, C and SWR.

Ignacy, NO9E

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Rick Bates, NK7I

Re: KPA1500 Tuner Question for the Group

The KAT500 utility will show the LC values in play after tuning (and
caps on/not on the antenna side) . I expect that the KPA1500 utility
will do the same thing; I'll know more next week when I put the KPA1500
online (the new station and shack are almost completed).

I keep the entire station, including the KPA500 and KAT500 utilities
running 24/7/365; this allows simpler remote station operations. Plus
it's nice to compare the SWR on both devices (though neither has ever
been different from the other); belt and suspenders. I don't keep the
amp(s) on all the time, just when I'm actively using the station.

Rick NK7I

On 4/23/2020 12:18 AM, Ignacy wrote:

> MFJ-998 seems to tune anything. I am always trembling that it will smoke, but
> for 5 years, no smoke. Even matching 80m dipole (fed by ladderline) on 40m.
>
> It has 2 outputs and keeps matches in memory. Getting it to tune at
> frequency previously tuned takes a fraction of a second. If both antennas
> were used at same frequency, tuning for one antenna automatically brings
> tune in the second. Very convenient for A/B comparisons.
>
> The tuner displays L, C and SWR.
>
> Ignacy, NO9E
>
>
>
>
> --
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Paul Baldock

Maximum RF power through KP1500 in Standby ?

What is the maximum power allowed though the KPA1500 when in Standby ?

What is the maximum power allowed though the KPA1500 when in Power Off ?

Thanks

- Paul KW7Y

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Roy Koeppe

Re: Maximum RF power through KP1500 in Standby ?

200 watts both counts.

73, Roy K6XK

> What is the maximum power allowed though the KPA1500 when in Standby ?
>
> What is the maximum power allowed though the KPA1500 when in Power Off ?
>
>

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