[TenTec] WIDER FILTER FOR WEAK CW DXING?

[Clark Savage Turner]

Hi Jeff -

I believe you.  All our ears are so very different.  I have experienced 
what you have, there are times that my own ears and brain do a better 
job of distinguishing the signal from the noise than the filters (in 
some rigs) will.  Have you ever profiled your hearing (the curves of 
where you hear/where you don't?)  I have, by a lot of trial and error, 
found that my ears can distinguish signals from noise better at a 
slightly lower frequency, so I've managed to get filters with lower 
center frequencies (like the roofing filter I use and the Ten Tec (NS) 
221 centered down at a 500 Hz note).  On many rigs, I prefer to hear 
wide open filters, on mine, with these filters and the PBT set just 
right, I can get a few more db to my brain with the filters.

I also suffer fatigue from hearing the same frequency all the time and 
often just tweak the CW note just a little and the difference perks me 
up to hear a bit better ... every few minutes.  I probably ought to use 
diversity - I bet that is the hot ticket.  Just haven't gotten around 
to dual receivers and dual antennas here at the QTH yet, too busy with 
my acoustic guitars and mandolins lately :-) .

Clark
WA3JPG

On Jun 16, 2007, at 6:19 AM, Jeff Frank wrote:

> I have an Omni 6 opt 1, which I like very much, but on weak cw 
> signals, my experience with the filters seems counter-intuitive. I 
> almost always have easier and clearer copy on weak cw signals when I 
> use the 1.8 khz filter vs. the .5 or .25 khz filters in my 6.3 mhz IF. 
> I've got nothing in the N1 position. Is this the way it's suppposed to 
> be? I always thought narrowing the filter bandwidth is supposed to cut 
> down on noise but it seems opposite. Has it got something to do with 
> receivers that are optimized for adjacent signal rejection vs. signal 
> to noise ratio? I think I read that somewhere. Can anyone explain this 
> to me? Thanks.
>

Clark Savage Turner, J.D., Ph.D.
Professor of Computer Science
Cal Poly State University
San Luis Obispo, CA. 93407