On Wed, 2008-03-19 at 22:48 -0500, Bob McGraw - K4TAX wrote:
> The CW filter in the Collins 75S-3 on my desk has clearly and noticeably
> more ringing than either the 500 Hz or 300 Hz filters installed in my Omni
> VII.
>
> 73
> Bob, K4TAX
>
>
My 75S-3B has a 200 Hz CW filter. I was surprised it was useful compared
to the ringing of the SSB mechanical filter, but I've not used it much,
my ears are more accustomed to a wider noise spectrum.
The SSB filter rings so much on line noise that the envelope seen on a
scope on the IF is constant amplitude. With the AM "filters" switched in
the noise is distinct spikes every peak (360 times per second with 3
phase power lines in the neighborhood like they were when I made the
tests in 1965), but with the 2.1 filter the envelope was continuous from
filter ringing. I've been ranting about that ever since.
73, Jerry, K0CQ
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