Use of K3 Antenna Tuner to match amplifier input

[W7GJ, Lance]

I need some guidance, please.  My K3 built in antenna tuner seems to do a very nice
job on the HF bands, and it now permits me to use a single 160m inverted V antenna to
get coverage on all the HF bands.  I do not currently have an amplifier anymore for
the HF bands, since I rarely operate on them.  The antenna tuner seems to work FB
direct from the K3 to the antenna - but only when I am in the receive mode.

HOWEVER, when I operate on 6m, I use an amplifier with external preamp, coax relays,
sequencer, etc.  The K3 is put into XMIT by the sequencer through the front panel PTT
line, which is triggered either by a footswitch or the computer.  Which means, the
amplifier is only connected to the antenna when I am in XMIT mode.  Of course, you
say!  BUT, to get the K3 antenna tuner to work into the amplifier, I need to be in
XMIT mode, and the K3's antenna tuner does not seem to work when I am in XMIT mode!
Is there some special setting or something somewhere that I need to change to enable
the antenna tuner to work when the K3 and the rest of the station is switched into
XMIT mode?

I can't imagine I am the only person running an amplifier with my K3, so SOMEBODY
must have an idea how to conveniently do this ;-)  Right now, the only solution I
have found is to put the station into XMIT, but disconnect the PTT line going to the
K3, so it is still in RECV.  Then with everything EXCEPT the K3 in XMIT mode, I can
press the ATU TUNE button and have it match up to the input of the amplifier.  Then I
can reconnect the PTT line to the K3 for normal operation.  This can't be the best
way to do this :-(  Thanks for your help!  VY 73, Lance
--
Lance Collister, W7GJ (ex: WN3GPL, WA3GPL, WA1JXN, WA1JXN/C6A, ZF2OC/ZF8, E51SIX)
P.O. Box 73
Frenchtown, MT  59834  USA
QTH: DN27UB
TEL: [phone]
URL: http://www.bigskyspaces.com/w7gj
2m DXCC #11/6m DXCC #815

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[Doug Joyce]

Lance:  Is it really necessary to use the tuner to match the input of the
Amp?  My K3 works just fine into the Alpha 86  on all the HF bands without
the use of the K3 tuner.  Why is your 6 meter amp different?

73,  Doug   VE3MV

----- Original Message -----
From: "Lance Collister, W7GJ" <[hidden email]>
To: "Elecraft Mailing List" <[hidden email]>
Sent: Thursday, September 17, 2009 2:46 PM
Subject: [Elecraft] Use of K3 Antenna Tuner to match amplifier input


> I need some guidance, please.  My K3 built in antenna tuner seems to do a
very nice
> job on the HF bands, and it now permits me to use a single 160m inverted V
antenna to
> get coverage on all the HF bands.  I do not currently have an amplifier
anymore for
> the HF bands, since I rarely operate on them.  The antenna tuner seems to
work FB
> direct from the K3 to the antenna - but only when I am in the receive
mode.
>
> HOWEVER, when I operate on 6m, I use an amplifier with external preamp,
coax relays,
> sequencer, etc.  The K3 is put into XMIT by the sequencer through the
front panel PTT
> line, which is triggered either by a footswitch or the computer.  Which
means, the
> amplifier is only connected to the antenna when I am in XMIT mode.  Of
course, you
> say!  BUT, to get the K3 antenna tuner to work into the amplifier, I need
to be in
> XMIT mode, and the K3's antenna tuner does not seem to work when I am in
XMIT mode!
> Is there some special setting or something somewhere that I need to change
to enable
> the antenna tuner to work when the K3 and the rest of the station is
switched into
> XMIT mode?
>
> I can't imagine I am the only person running an amplifier with my K3, so
SOMEBODY
> must have an idea how to conveniently do this ;-)  Right now, the only
solution I
> have found is to put the station into XMIT, but disconnect the PTT line
going to the
> K3, so it is still in RECV.  Then with everything EXCEPT the K3 in XMIT
mode, I can
> press the ATU TUNE button and have it match up to the input of the
amplifier.  Then I
> can reconnect the PTT line to the K3 for normal operation.  This can't be
the best
> way to do this :-(  Thanks for your help!  VY 73, Lance
> --
> Lance Collister, W7GJ (ex: WN3GPL, WA3GPL, WA1JXN, WA1JXN/C6A, ZF2OC/ZF8,
E51SIX)
> P.O. Box 73
> Frenchtown, MT  59834  USA
> QTH: DN27UB
> TEL: [phone]
> URL: http://www.bigskyspaces.com/w7gj
> 2m DXCC #11/6m DXCC #815
>
> Interested in 6m EME?  Ask me about subscribing to the MAGIC BAND EME
email reflector!

> ______________________________________________________________
> 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
>
>

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[W7GJ, Lance]

Doug Joyce wrote:
> Lance:  Is it really necessary to use the tuner to match the input of the
> Amp?  My K3 works just fine into the Alpha 86  on all the HF bands without
> the use of the K3 tuner.  Why is your 6 meter amp different?
>
> 73,  Doug   VE3MV
Hi Doug,

Well, I don't know why my TE SYSTEMS amp is different than your Alpha 86.  I know
that without the tuner being activated in the K3, the SWR is 3:1 and I have to run
about 50% more power just to get the same amount of output from the amp.  I just
thought it would be nice to have things better matched than that.  73, Lance


--
Lance Collister, W7GJ (ex: WN3GPL, WA3GPL, WA1JXN, WA1JXN/C6A, ZF2OC/ZF8, E51SIX)
P.O. Box 73
Frenchtown, MT  59834  USA
QTH: DN27UB
TEL: [phone]
URL: http://www.bigskyspaces.com/w7gj
2m DXCC #11/6m DXCC #815

Interested in 6m EME?  Ask me about subscribing to the MAGIC BAND EME email reflector!
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[Guy, K2AV]

Your amplifier should be close enough to a 50 ohm drive impedance that the
bypass mode in the K3 is easily usable when driving the amp. If you need an
ATU to drive the amp, it is a problem of some sort with the amp tube, its
input circuitry or connecting circuitry.  I have seen a bad 3 foot piece of
coax between a transceiver and amp make the amp appear undrivable.

What is the indicated SWR on the K3 display when driving the amp? If it's
not 1.5 or less, got work to do on the amp.

73, Guy.
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[W7GJ, Lance]

Guy Olinger K2AV wrote:

> Your amplifier should be close enough to a 50 ohm drive impedance that the
> bypass mode in the K3 is easily usable when driving the amp. If you need an
> ATU to drive the amp, it is a problem of some sort with the amp tube, its
> input circuitry or connecting circuitry.  I have seen a bad 3 foot piece of
> coax between a transceiver and amp make the amp appear undrivable.
>
> What is the indicated SWR on the K3 display when driving the amp? If it's
> not 1.5 or less, got work to do on the amp.
>
> 73, Guy.
> ______________________________________________________________
> Elecraft mailing list
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> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>
>

The SWR is 3:1 according to the SWR meter on the K3.  The amp is a solid state TE
SYSTEMS amp with an untuned input, which is why I want to try to use the K3 antenna
tuner to match into it.  TNX for your suggestions.  VY 73, Lance

--
Lance Collister, W7GJ (ex: WN3GPL, WA3GPL, WA1JXN, WA1JXN/C6A, ZF2OC/ZF8, E51SIX)
P.O. Box 73
Frenchtown, MT  59834  USA
QTH: DN27UB
TEL: [phone]
URL: http://www.bigskyspaces.com/w7gj
2m DXCC #11/6m DXCC #815

Interested in 6m EME?  Ask me about subscribing to the MAGIC BAND EME email reflector!
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[N5GE]

On Thu, 17 Sep 2009 20:20:42 +0000, "Lance Collister, W7GJ"
<[hidden email]> wrote:

>The SWR is 3:1 according to the SWR meter on the K3.  The amp is a solid state TE
>SYSTEMS amp with an untuned input, which is why I want to try to use the K3 antenna
>tuner to match into it.  TNX for your suggestions.  VY 73, Lance

Lance,

I have one of the TE Systems 0532G amps.  In the manual on page 6-2
are instructions for tuning the amp's input SWR.

One more thing!  

Important! Do not drive this amplifier at more than 16w input un less
you know foe certain that your transmit power does not have a short
peak output greater that 25 watts at the beginning of TX when driving
the amp with 20 to 25 watts.  If the TX does have this anomaly the
finals will be damaged.

I had been driving mine with k3 #806 at 20 watts and found this out
the hard way.  They ain't cheap to fix....  I now drive it with 16
watts as recommended in the pink sheet that comes with new TE Systems
0532G amps.

Tom, N5GE

[hidden email]
K3 #806, K3 #1055, PR6,
XV144, XV432, KRC2,
W1 and other small kits.
http://www.n5ge.com
http://www.swotrc.net

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[Eric Swartz - WA6HHQ]

Hi Lance,

Once you have manually tuned the K3 into your TE amp usnig the K3's ATU
TUNE button, any other time you transmit into it using the PTT the ATU
will be always be in-line and tuned to the load. It will always reset to
the last tuned ATU value when you are on 6M. So I'd recommend
pre-setting the ATU tuning by running the TE amp into a dummy load, and
then use the K3's ATU TUNE button to tune it manually without using the
external keying sequencers. Then re-hook up your sequencers and run
normally.

73, Eric
----

Lance Collister, W7GJ wrote:
> The SWR is 3:1 according to the SWR meter on the K3.  The amp is a solid state TE
> SYSTEMS amp with an untuned input, which is why I want to try to use the K3 antenna
> tuner to match into it.  TNX for your suggestions.  VY 73, Lance
>
>  
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[N5GE]

On Thu, 17 Sep 2009 18:25:10 -0500, Radio Amateur N5GE <[hidden email]>
wrote:

>On Thu, 17 Sep 2009 20:20:42 +0000, "Lance Collister, W7GJ"
><[hidden email]> wrote:
>
>>The SWR is 3:1 according to the SWR meter on the K3.  The amp is a solid state TE
>>SYSTEMS amp with an untuned input, which is why I want to try to use the K3 antenna
>>tuner to match into it.  TNX for your suggestions.  VY 73, Lance
>
>Lance,
>

Just to correct an error in the original; It is the 0552G I was
referring to...

>I have one of the TE Systems 0532G amps.  In the manual on page 6-2
>are instructions for tuning the amp's input SWR.
>
>One more thing!  
>
>Important! Do not drive this amplifier at more than 16w input un less
>you know foe certain that your transmit power does not have a short
>peak output greater that 25 watts at the beginning of TX when driving
>the amp with 20 to 25 watts.  If the TX does have this anomaly the
>finals will be damaged.
>
>I had been driving mine with k3 #806 at 20 watts and found this out
>the hard way.  They ain't cheap to fix....  I now drive it with 16
>watts as recommended in the pink sheet that comes with new TE Systems
>0532G amps.
>
>Tom, N5GE
>
>[hidden email]
>K3 #806, K3 #1055, PR6,
>XV144, XV432, KRC2,
>W1 and other small kits.
>http://www.n5ge.com
>http://www.swotrc.net
>
>______________________________________________________________
>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

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