[Elecraft] [KX3] Unstable SWR reading

[Bill Frantz]

I had an experimental antenna which exhibited this kind of 
behavior. I could not send out my QTH data on PSK31 without 
having the SWR go through the roof. My conclusion was that the 
common mode choke, wound with parallel wires on a small type 41 
core, was heating up enough to pass the curie point and lose 
inductance and choking ability. I changed the feed arrangement 
and the problem went away. Getting the old feed technique to 
work is on the future projects list.

Cheers - Bill, AE6JV

On 3/31/14 at 10:02 AM, gary at hawkins-zhu.com (Gary Hawkins) wrote:

>On my last two portable outings I've noticed that after a few 
>QSOs I start to get unstable SWR readings, with the radio 
>reporting fluctuating SWR ranging into the 2 and 3's.  I'm 
>using a tuned antenna, plus pressing the ATU button results in 
>1:1 matching. Everything is fine for a while and then the SWR 
>reading go unstable midway through the QSO.  Pressing the ATU 
>button seems to resolve the problem for a while but it starts 
>up again.  I realize it could be a problem with the cabling or 
>antenna but visual inspection seems to indicate everything is 
>fine and so far I've not been able to replicate the problem on 
>the bench.  Has anyone seen this type of problem with the KX3?

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