KX3 SWR issues when running through powered-off KPA500

[chrisrut]

I drive my KPA500 with a KX3. The KPA 500 has the January release firmware
(sorry I don't have the number and I'm not at my QTH).

I generally have the tuner in the KX3 disabled because it should be when
running throught the KPA500, and isn't needed when operating directly into
my resonant fan dipoles.

In normal operation I see about the same SWR in both modes: say 1.3:1 on
the low end of 20.

However, if I've been using the KPA 500, then turn both it and the KX3 off,
then turn the KX3 on to use it without the amp, I'll see a very high SWR at
the KX3.

Power cyclking the KPA500 via the front panel switch does not clear the
issue (I don't think I've tried it by turning off the master power switch
onthe rear and I'm 3000 niles from the home QTH as I write this). To clear
it, I need to set the KPA500 to operate and briefly transmit - even a
single dit is enough. At that point the KX3 sees a normal SWR and I can
turn the KPA 500 off and continue to see a normal SWR.

This behavior is mildly annoying and doesn't seem right.

Can anyone shed some light on this?

73, Chris NW6V
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html

[mcduffie]

On Tue, 7 May 2013 09:24:00 -0700, Chris Rutkowski wrote:

> This behavior is mildly annoying and doesn't seem right.

Just for the record, I recently had a one-time occurrence of this sort
of thing.  It was on 6 meters and the reflected power into the TS-590
was quite high.  That was something I didn't expect, so didn't check
input SWR quite as quickly as I should have.  I simply noticed the
output power on the radio was less than half and wouldn't go up.  When I
did look at the SWR reading at the radio, it was high inline, as well as
in stby, and (I believe) power off (front panel).  I checked other
bands, all good.  Came back to 6M, and it was too.  ???

This brings up another thing.  With the pin-diode switching, the antenna
analyzer is not happy at all, especially on six.  It is useless for
looking at the antenna through the amp.  One could say "of course", but
it just needs to be noted that there are devices inline, even when
turned "off" or stby.

Gary
--
http://ag0n.net
3055: http://ag0n.net/irlp/3055
NodeOp Help Page: http://ag0n.net/irlp
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html