[TenTec] Crystal vs. DSP Filtering

[John Pfeifer]

Hello all,

I've been playing around with my Omni V.9 in some QRP contests lately where I am trying to pick out one weak signal from a bunch of  weak signals.  Everybody's running QRP and nobody is above S5.  When I crank in any filtering below 1.8 kHz, however, all of the signals are attenuated to the point that I can't hear anything.  I've noticed the same phenomena with my Elecraft K1 as well.  It seems like narrow filtering only works for signals that are S6 and above.

Is this simply a function of crystal filtering?  Is there always some attenuation occuring inside the passband? 

If so, do rigs with DSP filtering like the Argo V and Pegasus/Jupiter do better with weak signals when narrow filters are used?

BTW, I also notice that when I'm not using filters, it seems easier to pick out weak CW signals when you are tuned further off frequency and the resulting tone is higher.

Thanks,

John Pfeifer - KL0WN
Kodiak, Alaska