A couple of thoughts:
1. You probably do not have an AC line noise problem since you
are using power supplies to power your radio.
2. I would start with the power supplies. Try one power supply at
a time to see if one of them is the problem. If you still hear
noise with either power supply running, then turn them all off
and power the radio with a car battery. If the battery cures the
noise problem, then you have to look at the power supplies.
If the power supplies are not the problem, then you need to
determine whether the noise source is close to your shack, or
somewhere beyond.
3. Disconnect your antenna from the back of the radio and replace
it with a short (6") wire. You should hear little or no noise
(of the type you have described) if the noise is coming from
someplace beyond your immediate vacinity. If the noise is still
very loud then you have to suspect something right in your shack,
or house. If the noise is very subdued, or gone, with the 6"
wire in place, then you need to refer to texts re tracking down
an external noise source.
-----Original Message-----
From: towertalk-bounces@contesting.com
[mailto:towertalk-bounces@contesting.com]On Behalf Of
Dinsterdog@aol.com
Sent: Wednesday, February 05, 2003 7:25 PM
To: towertalk@contesting.com
Subject: [TowerTalk] antennas and line filtering
I have a 756Pro that shows a nice steady pattern of noise moving
accross my
scope that my rig is picking up putting S9 noise out on 80M, S7
noise on 40M,
S6 noise on 20M, and less noise but the same pattern on higher
bands. This
is from a 5BTV antenna mounted in a suburban Denver neighborhood.
My
question to those with similar noise is this...is it simplier to
troubleshoot
the noise with an AC line filter or should one begin at the
antenna trying to
null things out with a 1026 or like device? I'm using 25 amp
radio shack
switching supplies that put out a nasty RF rash about every
100KHz..they
never had this problem at another QTH....makes me suspect my AC
in the house
has a contributing factor here----------------------any
suggestions on a
decent AC filter to try and/or other theory to attempt? MY noise
blanker
takes out about 2S units of noise- If anyone can refer me to a
webpage that
might have a proven method for troubleshooting noise like this,
pse let me
know-
73 Paul N0AH
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