On Fri, 31 Oct 1997, Paul Plasters wrote:
> Well gosh Peter, now I almost feel bad! I went for the whole ball of wax.
> Was it worth it? I do not know yet. They said they would start it on the
The extra 9 mHz filter may be worth it to some. I think a serious
contester would want dual 1.8 filters for SSB, and either a 500 Hz or 250
Hz for CW. Or, if you're into RTTY contesting, the special 9 mHz RTTY
filter.
Dual 250 Hz filters would be the ultimate in CW bulletproofing, but how
much better it would really be than my 500 Hz filter in the first IF and
choice of 500 and 250 Hz in the second? Some swear by the narrowest
combination possible. Others don't like the hair trigger tuning and the
way the remaining noise becomes less distinguishable from signal the
narrower you get.
Since I already have an external Timewave DSP box, I decided to go with
all the optional filters for the Omni VI (including the 500 Hz NAR
filter), and the Option 1 upgrade. Most of the time, the radio is fine
without the external box. Every so often I will use the Timewave to give
me the equivalent of a second 1.8 or 250 filter. Yes, it's after the AGC,
but since I'm using the Timewave to supplement an existing filter rather
than substitute for one I don't have, it seems good enough.
And I gotta tell you, folks, I've found a real nice trick for very weak
CW. You use your narrowest filters in the rig, and set your external DSP
to between 50 or 100 Hz. You can copy signals that way that you can
barely hear with normal filtering. The catch is they have to be
slow-speed--10-18wpm works best.
I first learned this trick on satellite, but it helps on nighttime 40m,
too. The Omni's 250 Hz filter cuts out most of the noise, which leads to
less overloading of the DSP box than with a 500 Hz filter.
--Peter
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