y'all remember my problem. I modified the AGC to give a fast recovery for
fluttery CW stuff. I unhooked the QSK fast/slow switch and wired that to
the AGC mod to allow me to switch between fast and slow AGC. But when I
select fast, I the receiver gets desensitized after transmit.
The problem is RF getting into the AGC circuit. When I crank the RF power
back, the problem goes away. At 5 - 10 watts there's no problem. As I
raise the power, the problem gets progressively worse. By 25 - 30 watts
it's noticeable. At 50 watts is terrible. It's also worse if I kick in
the crystal filter. The audio filters aren't bothered nearly as much. I'm
not sure why the crystal filter is bothered, but it is.
I'm assuming the problem is having this cap connected to a long ungrounded
wire (can we say antenna!!). So I'll have to figure out how to work around
this one. Maybe moving the mod to the cap that controls the hang time
constant rather than the AGC time constant would be a better approach.
I'll have to go review the schematic.
Keith Darwin
KD1E
Ferrisburg, VT
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