[Elecraft] K2 filter attenuation

[Wallace, Andy]

> -----Original Message-----
> From: Ron D'Eau Claire [mailto:rondec@easystreet.com]
> Sent: Wednesday, October 16, 2002 5:34 PM
> To: elecraft@mailman.qth.net
> Subject: RE: [Elecraft] K2 filter attenuation

> In GENERAL, narrower bandwidths means a better signal-to-noise ratio.
> But when getting down into the signals that are in the noise, it is
> unlikely that anyone has built a filter that can compete with a
> well-trained human brain and ears. It is in that "twilight" zone that
> narrower is not always better. Often the brain can do better 
> with a less highly filtered signal, in my experience. 

This is what I find at times, Ron. It depends on the conditions.
But something to remember is that when you select a narrow filter, you
cut the passband down such that static crashes, electrical noise, etc.,
as WELL as the signal, are all within that passband and therefore
sound similar in frequency. Some filters also exhibit ringing, too.
This all combines to make things muddy under CERTAIN conditions.

With a wider filter setting, sometimes the brain can more easily pick 
a weak CW signal out of a combination of several signals, noise, and
static that ranges from 0 to say 700 Hz in frequency. It's like picking
out the solo violin from the orchestra. 

Believe me, I am SO happy to have the choice of THREE bandwidths in
my humble K1, in a time when other manufacturers only include the SSB
filter in their rigs. 

-Andy