[TenTec] Purpose of 250 Hz 8 pole filters

[Ken Brown]

Hi Mark,


> If you ever work on a very noisy band looking for weak signals, you'll find 
> the 250's-even stacked-help quite a bit.
>   
This contradicts my experience, when by "a noisy band" you mean 
atmospheric noise. It may be true if by a "noisy band" you mean a 
crowded band.
> Also, on most cw contests, the narrow filter really makes a difference in 
> blocking out the "neighbors".
>
> Trying to work a station with 3 guys in the 500 Hz passband, is 
> futile....but SOMETIMES, the 250 solves the problem.
>   
I regularly work a station when there are three, or more stations inside 
the 500 Hz bandwidth, and not necessarily the strongest of the three or 
more stations. If one or more of them is 10 or 20 dB above the rest, 
then I cannot work the weak ones. As long as all three stations are of 
moderate strength (probably less than S 5) and spaced by at least 100 Hz 
from each other, I have no difficulty focusing on whichever one I 
choose, and working it.

If there is a lot of QRN, I find that my physiopsycoacoustic processing 
system works better with a 500 Hz last IF filter than with a 250 Hz one.
> Dont forget to touch up the PBT as it MAY be different than the 500Hz model.
>   
Yep, definitely important.

DE N6KB