harsh output note?

[Chris Kantarjiev K6DBG]

I just had occasion to listen to my K2 with another receiver (my KX1) for
the first time in a long time. The received note is much ... harsher
than I'd expect. There seems to be a harmonic an octave or so down from
the main carrier, so there's a fairly complex tone coming across
rather than pure sine.

I don't often listen to my output, probably poor practice on my part.
The last time I did, it sounded better than this. With the radios reversed,
that is sending on the KX1 and listening on the K2, the KX1 sounds much
better/purer.

The main thing I've done recently is add the key shaping mod...
which led to some power out problems that I haven't dug into yet
(the power bounces more than I'd expect, and it's hard to get exactly
5w out on the RF meter).

Should I be concerned about this? How do I go about diagnosing?

Thanks!

73 de chris K6DBG
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[k7svv]

I find it VERY difficult to judge the quality of my signal on another local
receiver.  Rely on what others say rather than on what your ears hear.

John   [K7SVV]
----- Original Message -----
From: "Chris Kantarjiev" <[hidden email]>
To: <[hidden email]>
Sent: Tuesday, May 29, 2007 3:29 PM
Subject: [Elecraft] harsh output note?

>I just had occasion to listen to my K2 with another receiver (my KX1) for
> the first time in a long time. The received note is much ... harsher
> than I'd expect. There seems to be a harmonic an octave or so down from
> the main carrier, so there's a fairly complex tone coming across
> rather than pure sine.
>
> I don't often listen to my output, probably poor practice on my part.
> The last time I did, it sounded better than this. With the radios
> reversed,
> that is sending on the KX1 and listening on the K2, the KX1 sounds much
> better/purer.
>
> The main thing I've done recently is add the key shaping mod...
> which led to some power out problems that I haven't dug into yet
> (the power bounces more than I'd expect, and it's hard to get exactly
> 5w out on the RF meter).
>
> Should I be concerned about this? How do I go about diagnosing?
>
> Thanks!
>
> 73 de chris K6DBG
> _______________________________________________
> Elecraft mailing list
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> You must be a subscriber to post to the list.
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>
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> 1:01 PM
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>

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[Chris Kantarjiev K6DBG]

Rick Tavan N6XI wrote:
> Have you rearranged your station or added any equipment lately? Your
> problem sounds somewhat like the magnetic flux interference that some
> K2s experience in proximity with large power transformers. It can be
> quite dramatic if you transmit while moving the radio in and out of the
> magnetic field. Just transposing the positions of the K2 and an
> amplifier can introduce it. There is a shielding fix available from
> Elecraft if in fact this is your problem.
>

This was exactly it! Removing the amp completely restored the note to the purity
I have come to expect. Rearranging my desk so that I can place the amp on the
right side of the K2 instead of the left kept it that way.

This is the HFpacker/HFprojects 35W amp; it's got a voltage doubling switching
supply inside it, and that seems to be the source of the interference.

73 de chris K6DBG

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