Elecraft

K2/100 Problem on 80 meters

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Pierre

K2/100 Problem on 80 meters

Hi to all

I have a problem on my K2/100 that manifests itself only on 80 meters:

If I operate QRP at 10 watts, I can match my antenna with a manual tuner, the SWR is very good near 1:1, and the rig operates smoothly.

But as soon as I switch (via power control) to QRO, without changing the settings on the tuner, the reflected power needle swings wildly as soon as I stop keying, even at only 11 watts.

For all other bands (40 up) the rig works fine QRP or QRO.

I would like to know where to look at.. ?

Thanks for your help!

Pierre VE2PID K2#5170

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Steve Ellington

Re: K2/100 Problem on 80 meters

Help me understand....You stop keying and the SWR meter swings wildly? Are you talking about the SWR meter on your tuner?

Steve Ellington
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----- Original Message -----

From: [hidden email]

To: [hidden email]

Sent: Tuesday, February 10, 2009 8:24 PM

Subject: [Elecraft] K2/100 Problem on 80 meters

Hi to all

I have a problem on my K2/100 that manifests itself only on 80 meters:

If I operate QRP at 10 watts, I can match my antenna with a manual tuner, the SWR is very good near 1:1, and the rig operates smoothly.

But as soon as I switch (via power control) to QRO, without changing the settings on the tuner, the reflected power needle swings wildly as soon as I stop keying, even at only 11 watts.

For all other bands (40 up) the rig works fine QRP or QRO.

I would like to know where to look at.. ?

Thanks for your help!

Pierre VE2PID K2#5170

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Steve Ellington

Re: K2/100 Problem on 80 meters

An SWR meter that goes up wildly after releasing the key is a sign of a possessed meter! It makes no sense. Do you have another tuner you can experiment with?

Steve Ellington
[hidden email]

----- Original Message -----

From: [hidden email]

To: [hidden email]

Sent: Tuesday, February 10, 2009 9:28 PM

Subject: Re: [Elecraft] K2/100 Problem on 80 meters

Well I spoke about the SWR meter on my MFJ-949E. If I send Cw, when I release the key, the reflected power needle goes up wildly.. sign of a high SWR...

----- Original Message -----

From: [hidden email]

To: [hidden email]

Cc: [hidden email]

Sent: Tuesday, February 10, 2009 9:23 PM

Subject: Re: [Elecraft] K2/100 Problem on 80 meters

Help me understand....You stop keying and the SWR meter swings wildly? Are you talking about the SWR meter on your tuner?

Steve Ellington
[hidden email]

----- Original Message -----

From: [hidden email]

To: [hidden email]

Sent: Tuesday, February 10, 2009 8:24 PM

Subject: [Elecraft] K2/100 Problem on 80 meters

Hi to all

I have a problem on my K2/100 that manifests itself only on 80 meters:

If I operate QRP at 10 watts, I can match my antenna with a manual tuner, the SWR is very good near 1:1, and the rig operates smoothly.

But as soon as I switch (via power control) to QRO, without changing the settings on the tuner, the reflected power needle swings wildly as soon as I stop keying, even at only 11 watts.

For all other bands (40 up) the rig works fine QRP or QRO.

I would like to know where to look at.. ?

Thanks for your help!

Pierre VE2PID K2#5170

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No virus found in this incoming message.
Checked by AVG - www.avg.com
Version: 8.0.233 / Virus Database: 270.10.20/1944 - Release Date: 02/10/09 07:20:00

No virus found in this incoming message.
Checked by AVG - www.avg.com
Version: 8.0.234 / Virus Database: 270.10.20/1943 - Release Date: 02/10/09 07:20:00

No virus found in this incoming message.
Checked by AVG - www.avg.com
Version: 8.0.233 / Virus Database: 270.10.20/1944 - Release Date: 02/10/09 07:20:00

daleputnam

Re: K2/100 Problem on 80 meters

If the meter isn't being fed something... (big if).. maybe it is static buildup on the meter face?
The plastic meters do that when it gets dry like it is here.
--... ...-- Dale - WC7S in Wy

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Ken Kopp-3

Re: K2/100 Problem on 80 meters

Yes, it -does- make ......

I'd say it's a certain sign that the PA is going into
oscillation when the drive is removed (key up) and
that the high SWR indicates that the oscillation is
on a frequency ... or several frequencies ... where
the antenna is not resonant. I'll venture that there
would be no SWR indication if the setup was fed
into a dummy load.

73! Ken Kopp - K0PP
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AC7AC

Re: K2/100 Problem on 80 meters

In reply to this post by daleputnam

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daleputnam

Re: K2/100 Problem on 80 meters

In reply to this post by Ken Kopp-3

It is very likely that the amp isn't a calm and quiet unit, without the effect of drive,
very good Ken.
The measurement of the amp with a scope might be revealing, or a dvm for drivelevels, during keyup.
A close look at the keying waveform through the amp would pretty much reveal where it would pay to dig deeper.
On the other hand, a real hard look at the grounding and bypass components would be time well spent. A single cold solder joint could be very disconcerting to an otherwise calm amp.

--... ...-- Dale - WC7S in Wy

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