ORIGINAL MESSAGE: (may be snipped)
On Sun, 25 Aug 2013 17:38:32 -0700, Tom wrote:
>I guess it might boil down to what exact width is my Inrad 250 cycle filter?
>It might be more - it might be less than 250. But, I do know that for RTTY
>and also CW, the 250 cycle filter works much better to reduce QRM than the
>500 cycle filter in my other radio.
REPLY:
As I said before and will say again, don't take the "250 Hz" label on your
filter as absolute truth. Whether it works or not depends on the steepness
of the skirts. My IC-756Pro3 had a "250 Hz" filter that printed perfectly.
My IC-7600 also has a "250 Hz" filter that does not print worth a darn. What
is the difference? The steepness of the skirts. The 'Pro3 had relatively
wide skirts, the '7600 skirts are steeper. When I widened the '7600 out to
300 Hz, the print was fine again.
The correct bandwidth for your receiver is one, that if you widen it out,
you see no improvement.
73, Bill W6WRT
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