K2 - Strange, self-recovering problem

[stan levandowski]

My friend Tony W1ZMB just finished building his K2 this week and asked
me to visit him and try it out yesterday.  He did a great job and it
works great.  However, a strange thing happened two times during a CW
QSO I made at 5 watts using his perfectly matched OCF dipole on 20
Meters.  He has the KAF2, KAT2, and KNB2 options installed.

The problem:  during transmit the K2 powered itself off and then right
back on and operation continued.  The receiving station might not even
have noticed because it was that fast.  Tony did not have the K2
grounded.  He immediately ran a short braid directly to his copper
ground rod and has not since experienced this problem.

I'm not convinced it was the ground.   My K2 is grounded at home but I
frequently use it off-site without a ground and never had this 'dropout'
occur.

   Since Tony is not yet an member of our Reflector I'm posting this
query on his behalf.

Has anyone had a similar problem?

Thanks!

73, Stan WB2LQF
KX1 #2411    K1#2994    K2# 6980    K3#5244     K9 #1 (Cocoa the
Chihuahua)
Everything is QRP, even the dog.




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[Don Wilhelm-4]

  Stan,

That certainly sounds like RF was floating around in the shack and doing
strange things.  OCF dipoles are famous for creating common mode current
on the shield of the feedline (even with a balun at the feedpoint).

I would suggest adding an in-line choke at the point where the feedline
enters the shack building - and ground the shield of the coax on the
shack side of that choke.

73,
Don W3FPR

On 6/18/2011 8:42 AM, stan levandowski wrote:

> My friend Tony W1ZMB just finished building his K2 this week and asked
> me to visit him and try it out yesterday.  He did a great job and it
> works great.  However, a strange thing happened two times during a CW
> QSO I made at 5 watts using his perfectly matched OCF dipole on 20
> Meters.  He has the KAF2, KAT2, and KNB2 options installed.
>
> The problem:  during transmit the K2 powered itself off and then right
> back on and operation continued.  The receiving station might not even
> have noticed because it was that fast.  Tony did not have the K2
> grounded.  He immediately ran a short braid directly to his copper
> ground rod and has not since experienced this problem.
>
> I'm not convinced it was the ground.   My K2 is grounded at home but I
> frequently use it off-site without a ground and never had this 'dropout'
> occur.
>

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