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KPA100 Power Output Problem

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John Grimm

KPA100 Power Output Problem

K2 #4842 has been fb for over a year, and I've been working between
baby diaper changes to complete my KPA100. Everything has proceeded
smoothly through the bias current adjust, but having problems with the
transmit tests. All proceeds okay to about 20 watts. With K2 power
control set to 50W output, I hit TUNE and power output reads 20-25
watts on both K2 and external meter. While TUNING, I increase the
power control pot clockwise, and power quickly jumps up to the higher
(50W) output level. Toggle TUNE off then back on again, and power
again drops to 20-25 watts until I tweak/increase the power control
pot and power out then jumps to a level >50W. Toggle again, output is
back to 20-25 watts out until I tweak/increase the power control pot,
and power then again jumps up to an even higher level. Toggle
TUNE off again and back on, and power out is back to 20-25 watts until
I move the power control pot, etc. etc.. With the power control
pot full clockwise the unit is putting out a full ~110W. I re-did R26
alignment and all seems okay. Checked the common reflector section
and didn't see anything similar to this, so I'm hoping to get some
investigation suggestions from any willing higher powers.

Thank you in advance.

John / K0YQ
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Dan Barker

RE: KPA100 Power Output Problem

RTFM.

The TUNE button puts out 20W.
The Key (or PTT) puts out the requested power.
Moving requested power with key down just confuses the issue.

Dan / WG4S / K2 #2456

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Don Wilhelm-3

RE: KPA100 Power Output Problem

In reply to this post by John Grimm

John,

Your KPA100 is working as it should!
TUNE will transmit at 20 watts - it was designed that way.
If you want to use TUNE at the setting of the Power knob, press TUNE and
DISPLAY together, or press TUNE and rotate the POWER control to the setting
you want (you are already doing that).

You should see full power output by pressing the key.

73,
Don W3FPR

> -----Original Message-----
>
>
> K2 #4842 has been fb for over a year, and I've been working between
> baby diaper changes to complete my KPA100. Everything has proceeded
> smoothly through the bias current adjust, but having problems with the
> transmit tests. All proceeds okay to about 20 watts. With K2 power
> control set to 50W output, I hit TUNE and power output reads 20-25
> watts on both K2 and external meter. While TUNING, I increase the
> power control pot clockwise, and power quickly jumps up to the higher
> (50W) output level. Toggle TUNE off then back on again, and power
> again drops to 20-25 watts until I tweak/increase the power control
> pot and power out then jumps to a level >50W. Toggle again, output is
> back to 20-25 watts out until I tweak/increase the power control pot,
> and power then again jumps up to an even higher level. Toggle
> TUNE off again and back on, and power out is back to 20-25 watts until
> I move the power control pot, etc. etc.. With the power control
> pot full clockwise the unit is putting out a full ~110W. I re-did R26
> alignment and all seems okay. Checked the common reflector section
> and didn't see anything similar to this, so I'm hoping to get some
> investigation suggestions from any willing higher powers.
>
> Thank you in advance.
>
> John / K0YQ
>

Ron D'Eau Claire-2

RE: KPA100 Power Output Problem

Be aware too that the automatic power control circuit is not enabled in TUNE
mode. That is so the K2 won't try to adjust the output power automatically
while an Antenna Tuner is being adjusted, either automatically or manually.

Ron AC7AC

-----Original Message-----
From: [hidden email]
[mailto:[hidden email]] On Behalf Of Don Wilhelm
Sent: Monday, February 20, 2006 11:01 AM
To: John Grimm; [hidden email]
Subject: RE: [Elecraft] KPA100 Power Output Problem

John,

Your KPA100 is working as it should!
TUNE will transmit at 20 watts - it was designed that way.
If you want to use TUNE at the setting of the Power knob, press TUNE and
DISPLAY together, or press TUNE and rotate the POWER control to the setting
you want (you are already doing that).

You should see full power output by pressing the key.

73,
Don W3FPR

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