[Elecraft] Problem with 17m band in K2 + KAT100/KPA100 in EC2

[Marcin SQ2AF]

Don,

Yes, yes, you are right! - it is caused by stray RF.

I attached counterpoise wire cut for a quarterwave on 17 meters and it
resolve the problem.
Now, with your help, I'm sure that my K2 and KAT100/KPA100 are OK and
my problem is antenna. So, I must go to the roof, recheck antenna
connections and realign it.
Thank you again for your help!

73,

Marcin SQ2AF

K2 #5408



2006/9/8, Don Wilhelm <w3fpr at earthlink.net>:
> Marcin,
>
> I checked the RigExpert specifications, and while they claim isolation on
> the soundcard connections, they do not make any such claims for the digital
> connections (to the PTT, CW Key, or AUX I/O).
>
> So you still may have a problem with RF getting onto the RigExpert or the
> computer chassis ground that is being then transmitted into the K2.
>
> This is not a problem with your connections, but it may be a problem with
> the RigExpert on your K2 in combination with your antenna situation.  I am
> not yet convinced that it is a KPA100 problem.
>
> If you can test it with the KPA100 working into a dummy load, that would be
> of interest, but it may be hard to detect if your receive is desensitized
> with the dummy load connected.
>
> If you do not have the K2 mic jack shell grounded, you could try doing that
> as a first measure of defense.
>
> The other thing you can try is attaching a counterpoise wire cut for a
> quarterwave on 17 meters to the KAT100 ground.  The far end may carry a high
> RF voltage, so keep it clear of human and pet contact (the far end connects
> to nothing - just an insulator).  If a counterpoise wire corrects the
> problem then you can be certain it is caused by stray RF - unfortunately, if
> it does not cure it, stray RF could still be the problem, but it is worth a
> try - a piece of wire an electrical quarterwavelength on 17 meters is
> approximately 3.9 meters long.
>
> 73,
> Don W3FPR
>