Topband: AGC and Static

[w7dd]

I see several comments about AGC.  I have an AGC modification I do to my
TS-950SDX to help with noise crashes.  I operate the AGC with only about
half of its normal effect.  This gives the effect of operating with the AGC
OFF without the possible ear destruction that occurs when a strong station
comes on.  Also, if a strong station says hi to me at 40db over 9 I can
still understand their voice without distortion or excess level.  The
reduced AGC forces stronger IF signal levels into the product detector which
in turn acts like an RF Speech clipper on receive.  It isn't Hi Fi but it
sure improves readability on the weak ones on CW or SSB in the presence of
static.  I don't seem to find this an advantage above 40 meters.  I guess
there is not any static there to speak of.  I have a multi position switch
in a box mounted beside the TS-950SDX to activate it and give me several
choices of level.  The switch activates an rf voltage divider for the IF
signal to the AGC detector but not the product detector.  We often think in
terms of changing AGC time constant but not much about AGC voltage level.
The exact voltage level is determined by experimentation.  It is real
obvious when you have it correct.  I adjust the level for max effect without
excess distortion.  I can copy stations with this feature that can't make it
through the static without it.  I have installed this modification on a
TS-850 and a TS-830 in the past.  It never fails to amaze me.

73's, Don