[RFI] Noise Canceller vs DSP filter

Rob Atkinson, K5UJ k5uj@hotmail.com
Sat, 19 Oct 2002 01:28:33 +0000

This situation stinks; believe me I know, I've been there before.  (And I'll 
probably be there again so I'm knocking on wood a lot these days.)  First, 
if you have not done this already, be sure the noise isn't coming from your 
own place.   A fast way to do this is hook the 100D up to a car battery, 
turn it on with the antenna connected just like when you operate, then go to 
your breaker panel and kill all the ac to your house.  If the noise was 
there and now it's gone you are lucky--it's domestic.  If you still have it 
then you have to df it outside.  I realize you said you got it down to some 
poles but the bad news is that you can have more than one source.  Besides 
outside, I found my razor charger, dimmers and a touch lamp were 
contributing problems at my qth.
The lower you go in frequency the less the distance between your ant. and 
the lines has a preventive effect.  Also, at lower frequencies, you start 
rxing noise standing waves on the power lines.  This means the "sources" 
multiply and those cancelling boxes quit working.  Also, you might simply 
have more than one thing arcing.  The list archive has a bunch of past posts 
on finding noise and working with power companies.  I suggest you search it 
at www.contesting.com  The atmospheric noise you have might be due to the 
kind of antenna you have, a vertical for example.  Perhaps you can try some 
sort of horiz. antenna such as a loop.  That might cut the noise level down. 
  You could try using it as a rx antenna and tx with the vertical (if that's 
what ur using) to get a lower angle of radiation on tx.

I'm getting periodic bursts of line noise now--when it's on it consists of a 
burst of a few seconds with about 20 seconds of silence.  I'm thinking a 
neighbor has an electric blanket or fish tank heater turned on--something 
controlled by a thermostat.  Can't think of any other possibilities.  It 
hasn't been real bad so I'm living with it for now.



----Original Message Follows----
From: John Geiger <johngeig@yahoo.com>
To: rfi@contesting.com
Subject: [RFI] Noise Canceller vs DSP filter
Date: Fri, 18 Oct 2002 12:29:05 -0700 (PDT)

I am new to this reflector, so please forgive me if
this topic has been covered recently.  I have a decent
amount of power line noise at my QTH-S6 or so most of
the time.  Trying to work with the power company, and
have found a couple of suspect power poles, but have
not had success in fixing anything yet.

I began to solve the problem by getting a Yaesu
FT100D.  The NB is incredible, as QST stated in their
review, and it helps rid the noise on several bands,
mainly 20-10 meters.  Doesn't help much on 30 and
below, where I am still getting S5 noise.  So I bought
a used MFJ 1026 noise canceller and tried it out with
different antenna configurations.  Did not do any
good.   Luckily it had a return policy, so it is being

Has anyone had any luck using different DSP filters to
remove power line noise-like the TImewave 599+ or
anything like that.  What works, what doesn't?  ANd
should I just expect a S5 noise level on the low bands
due to atmospheric noise?  It seems to me I don't
remember it being that bad in the past.

73s John NE0P

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