[Elecraft] K3/KPA500/KAT500 SWR problem

[Igor Sokolov]

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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