Topband: Coping with Noise

Charles Bibb zedkay at telepak.net
Mon Dec 8 12:45:07 EST 2008


Hello, fellow topbanders

I have the same problem that many of you have.

We all know this situation:  Trying to hear a weak DX signal that's 
not quite copyable due to man-made noise (usually, but not limited to 
power line noise).

A good noise blanker works wonders on this pulsed type noise, making 
the weak signal readable - that is until a strong US station or 
stations (pileup) starts up nearby. Then the noise blanker might as 
well be off. And, the strong station(s) doesn't have to be 
particularly close - 10khz or more at my QTH. Frequently, while 
listening in the early morning for weak JA's with the NB on, I can 
hear multiple CQDX's of keyed wideband noise - my noise floor being 
pumped by STRONG US stations.

Short of eliminating the source(s) of the noise (have had limited 
success at this), is there any way to mitigate this problem?

I've heard some say that W8JI's noise blanker fix might help.  Others 
say an INRAD roofing filter helps.  Are both needed?
I wonder if the noise blanker fix is applicable in my case.  As I 
understand it, the fix is to cure a problem that occurs when the NB 
is NOT turned on, and I must always use it here on 160M

I'd like to hear from anyone with first-hand experience using the 
roofing filter if it helped with this problem.

Thanks,
Charles - K5ZK



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