[Top] [All Lists]

[CQ-Contest] Nagging problem

Subject: [CQ-Contest] Nagging problem
From: cascjs@snet.net (Chet and Carol Slabinski)
Date: Wed Feb 20 18:54:18 2002
Similar problems here in the past- on a specific band with a certain antenna 
located near
the house, my LPT keying interface would latch on, and stay on, until I would 
kill the
transmitter power. Miniature axial leaded chokes (100uH) cured the problem.  I 
put one in
series with the collector of each transistor in the interface (the CW key line 
and PTT
lines). Without the chokes, the key line would go negative by a few volts DC  
from the
rectified RF, and stay there, keying the transceiver, until I turned its 
transmit power

Shielded cables would not work. (Currents flowing on the shield will still 
induce an RF
voltage in the conductors inside it.)
Capacitors did not work too well for me either. But the chokes made a rock 
solid cure.

Maybe CT only toggles one of the pins to the transistor's base and emitter, and 
software does it differently, don't know, but that might explain the other 

Chet, N8RA

CQ-Contest on WWW: http://lists.contesting.com/_cq-contest/
Administrative requests: cq-contest-REQUEST@contesting.com

<Prev in Thread] Current Thread [Next in Thread>