[Elecraft] K3/KPA500/KAT500 SWR problem

[Bill OMara]

I saw the problem when operating a  Multi-op contesting and the 80M OP was
running 1.5kw and the RF is induced into the 160M Phased inverted L array
and the combination of induced energy and the SWR reflected power on the
array kick the KAT500 back into a retune mode. So, either local energy on
Broadcast energy will both make this happen.

I now have built coaxial Stubs and look forward to seeing if this solves my
Local energy problem.


73 Bill   W4RM

-----Original Message-----
From: elecraft-bounces at mailman.qth.net
[mailto:elecraft-bounces at mailman.qth.net] On Behalf Of Igor Sokolov
Sent: Monday, December 30, 2013 1:28 PM
To: Jeffrey Otterson; elecraft at mailman.qth.net
Subject: Re: [Elecraft] K3/KPA500/KAT500 SWR problem

It may be not relevant to this particular case but another reason for weird
KAT500 behavior can be strong interfering signal of a neighbor or nearby
broadcasting station. I did run into situations where such signals induced
up to 5 volts into low band antenna. Then KAT500 counts that signal as
reflected and thinks that SWR is very high. One may try to connect broadband
spectrum analyzer to the antenna and see what is going on. If it is
broadcasting signal well below ham bands then high pass filter between the
tuner and antenna can help.

73, Igor UA9CDC

----- Original Message -----
From: "Jeffrey Otterson" <otterson_nospam at nhrc.net>
To: <elecraft at mailman.qth.net>
Sent: Monday, December 30, 2013 8:58 PM
Subject: Re: [Elecraft] K3/KPA500/KAT500 SWR problem


> I, too, have seen this spurious KAT500 retune problem.
>
> I'm running a similar setup:
> K3->KPA500->LP-100A->KAT500->coax->balun->ladder line->hf doublet
>
> I'lll be happily working 75M and all of a sudden the KAT500 starts
> re-tuning, and with the LP-100 alarm going off and the relays chattering 
> in
> the KAT500, it sounds a bit like all hell breaking loose.
>
> I reverted the KAT500 to firmware version 1.32 and the problem *seems* to
> happen less often...  That could be my imagination, though.  Also I think
> that this has happened in MANUAL mode, as well as automatic.
>
> Perhaps it would be useful to have an option to only re-tune during the
> first few seconds of transmit?
>
> Jeff
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