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

[Marcin SQ2AF]

Don,

Thank you for patience and fast replays.

As my digital interface I'm using RigExpert and cable connection as on
the www.mixw.net/RigExpert/cable-elecraft-001.gif
After received your last reply I have been examined cable connections
and they are as on the diagram.
I have been checked RigExpert and K2 with my laptop computer also -
the problem also occurred. It means that my home computer is OK.
But there is interesting thing - when I setup  10W (KPA100 is still in
bypass mode) there is no problem, but when I setup 11W or more (KPA100
is on) problem occur.
So maybe the problem is somewhere in KPA100?

73,

Marcin SQ2AF

K2 #5408


2006/9/8, Don Wilhelm <w3fpr at earthlink.net>:
> Marcin,
>
> As a guess, your computer connections or even the computer itself may be
> picking up RF.
>
> Are you listening to the audio on the K2 speaker, or just observing it on
> the computer display (or listening to it on the computer speakers?  If you
> are seeing the drop in audio only on the computer, it may be the computer at
> fault and not the K2.
>
> If you do not have ground isolation between your computer and the K2, that
> may be necessary.  That means transformers in the audio lines to the
> soundcard and an optoisolator in the RTS to PTT line.  Be careful about how
> the optoisolator is powered so you do not negate the careful grounding
> isolation that you would do otherwise.
>
> There is a good schematic for proper isolation of the computer and
> transceiver grounds in Jan 2006 QST, page 60 (you need only consider the
> part in the shaded box).  Note carefully the grounding to the enclosure does
> not extend to the computer - if you have jacks for the soundcard connections
> mounted on a metallic box, that would destroy the ground isolation - you
> must either avoid audio jacks at the enclosure or if jacks are used, they
> must be mounted on an insulator.
>
> 73,
> Don W3FPR
>
>
> > -----Original Message-----
> >
> > Don,
> >
> > Today I have checked all connections in KPA100 T-R switch - they was OK.
> > After connection checking I assembled KPA100/KAT100 again and started
> > TX on 17 m again - the problem still occurred.
> > But .... as you know I'm digi modes fan so, all the TRX keying was
> > made by computer. Today, when I have been use VOX or foot switch the
> > problem disappeared!
> > In this moment I know, the problem occurs only when computer
> > control K2 keying.
> > So, it clears why TUNE coming back RX to normal sensitivity.
> > Do you know what can I do now?
> >
> > 73,
> > Marcin SQ2AF
> >
> > K2 #5408
> >
> >
>
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