Thanks, Clark! I have a Timewave DSP-599zx. Occasionally, I've found
using it with a 100 or 75 Hz bandwidth can pull a weak CW signal out of
the noise when all else fails. Interestingly, it's best to do this in
conjunction with a 500 Hz or 250 Hz filter, so the noise doesn't overload
the filter and make matters worse (this is particularly true on 80/40/30m
at night). On the other hand, on satellite, where the noise is more
"white," I've often found it better to use SSB bandwidth and DSP noise
reduction.
I suspect that since I have the Timewave, dual 250 Hz filters would be
overkill. Since I have an Omni VI with Option 1, I've only got one "NAR"
position.
But I must say, I used to think that I'd never want a 250 Hz filter--I
thought it would be too narrow and too "ringy." The Ten-Tec filters have
completely changed my mind about that. Some other narrow filters I've
heard in other rigs actually seem to resonate noise, but the Ten-Tec
ladder filters don't. So I'm really glad I got the 250 Hz filter for the
6.3 IF.
73,
Peter - KD7MW
---
* My opinions do not necessarily represent those of Seattle University.
* Newsreaders may have an incorrect return address. Use pklein@seattleu.edu
Peter A. Klein (pklein@seattleu.edu) : -----==3== --- ---
Network Administrator, LAN/WAN/Novell : | | | | | | | |
Seattle University, 296-5569 : @| @| @| @| @| @| @| @|
On Wed, 25 Feb 1998, Clark Savage Turner WA3JPG wrote:
> The pair of 250's is probably a matter of taste and how much you
> like to dig for a signal. I own a pair in my OMNI VI and I like to
> have them when I am digging a weak one out of the noise, not just
> the QRM. The character of the one in the 9 MHz IF is different than
> the character of the one in the 6.3 IF, and I like to have both. If
> you own both 500's, I am sure you know what I mean. I like the pair
> of 500's for QRM, but the pair of 250's is super in digging in the
> noise (however, I occasionally use an outboard preamp even on 40
> meters to bring it all up enough to hear well, the pair of 250's
> gives me a great s/n ratio but is lossy.)
>
> My vote is to have both, but many good ops disagree.
>
> Clark
> WA3JPG
>
--
FAQ on WWW: http://www.contesting.com/tentecfaq.htm
Submissions: tentec@contesting.com
Administrative requests: tentec-REQUEST@contesting.com
Problems: owner-tentec@contesting.com
Search: http://www.contesting.com/km9p/search.htm
|