Posted by
Don Wilhelm-4 on
Jun 12, 2010; 6:23pm
URL: http://elecraft.85.s1.nabble.com/K2-KPA100-Antenna-Help-tp5170458p5172292.html
David,
I just thought of something else - the KPA100 may be oscillating on
you. That fact will not show up on a dummy load, but because an antenna
is frequency selective, it will indicate Hi-refl. The KPA100 *should*
detect that condition and reduce the power, but for some reason yours is
not. and I strongly suspect the T/R switch area.
Check the T/R switch components carefully - particularly the orientation
of Q6 and Q7 and the diodes. Also check the soldering for C31. Make
certain the value of C31 is .22 uF.
Since you likely do not want to test on-the-air with that condition, if
you have a tuner (preferrably a link coupled tuner), connect the output
to a dummy load and then adjust the tuner for a 1:1 SWR at the frequency
you will be testing. If the KPA100 is oscillating at some parasitic
frequency, Hi-Refl will be indicated because of the tuned circuit
between the KPA100 and the dummy load.
73,
Don W3FPR
David Douglass wrote:
> OK, to add to my last,
>
> I've just tried with a different antenna on 40m. Again, once I engage the KPA100, I get high SWR, power overshoot and a blown fuse. So it doesn't seem to be antenna related but seems to be band related. 30m-10m is Ok. I don't have an antenna for 80/160 so can't check.
>
> All bands are fine with a dummy load...
>
> David
> ----- Original Message -----
> From: David Douglass
> To:
[hidden email]
> Sent: Saturday, June 12, 2010 12:04 PM
> Subject: [K2] KPA100 - Antenna Help
>
>
> Hi All,
>
> A bit of a strange one here..
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