[TenTec] Re: Roofing filters

[Bill Tippett <btippett@alum.mit.edu>]

Hi Grant,

NQ5T wrote:
>I was thinking "6Khz slot" when I made the comment above (brain on 
vacation), but
generally my statement really was to say that it doesn't make sense to use a
narrower roofing filter than DSP bandwidth.

        In general I agree...especially on SSB.  However there is one case 
where
you might want to use a narrower roofing filter than the DSP BW.  For very
narrow DSP CW BW's, DSP filters can have multiple passband sidelobes which
do strange things to CW signals at the noise floor.  Occasionally I use my
250 Hz roofing filter and set DSP higher to get rid of these sidelobe effects.

>I still sense confusion among some (you not included) about roofing vs. 
IF filtering in
the flow of the discussion,  however.   And think we're getting bamfoozled 
to some
extent by the option count :-)

        I agree.  Outside of contests, I doubt most of us would ever need 
any of
the optional filters.  Orion, with just the 2.4 and 1.0 kHz roofing filters is
already far better than any other unmodified rigs on the market in terms of
strong signal handling, both on SSB and CW.

                                                        73,  Bill  W4ZV



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