Topband: DSP and Digital Filter Effectiveness for Summer Static?

[John Kaufmann]

On Fri, 10 May 2002, "Tom Cathey" wrote
> Now that the summer static is upon us, and the new
DSP rigs have been out
> for awhile, I wonder if anyone can offer opinions as
to the effectiveness of
> DSP and digital filters for receiving weak signals in
summertime static?
> (lightning generated static)

I never found the DSP filtering inside the FT1000MP to
be of any use in dealing with static crashes.  Part of
the problem is that the DSP is not inside the AGC loop,
so that signals and noise outside the DSP passband
cause receiver gain pumping.  The new MP Mark V
apparently has some different DSP implementation, which
I haven't tried, so I can't comment on it.

Part of the trick in dealing with static crashes is
setting the AGC time constant correctly.  I have the
IC-781 which has a continuously adjustable AGC.
Depending on the noise and interference situation, I'm
always fine-tuning the time constant to optimize
reception.   It's the best radio I've found for dealing
with this, and I use the narrowest IF filters (250 Hz)
all the time with no problems.

73, John W1FV