Tapping the pole with anything isn't a good idea and really
unnecessary. I just ended a 6 month issue here with TONS of help from
ARRL HQ and there is a real long story here but bottom line it comes
down to simple DF'ing the noise with a 2 meter AM receiver and hand
held yagi. Get a sense where the noise is coming from as there will be
a predominant direction. When you believe you are getting close to it,
swith to a 400 Mhz receiver and hand held yagi and you'll be able to
nearly pin point the area on the pole (or whatever) where the problem
is coming from. It would help to first characterize the noise however
- get a PC based sound card spectrum analyzer program (I use Zelscope -
it was 10.00 after a 30 day free trial) and see if it's the classic 120
hz pulsed wave indicative of gap noise - tyical of insulators breaking
down. It may also be corona - much harder to fix, but again, try to
see what it is.
ALSO, very key, see if it goes away with rain. IN my case the 20 over
S9 noise goes completely out with rain. Last year the noise would go
out whenever the outside humidity went above 60% but this year it has
to rain. That indicates the source is definitely outside. (again a
long very frustrating story here with power company who has now
received an FCC leter thanks to ARRL).
If it's gap noise and from the power line (it could be a nearby
switched PS or charger) get the two hand held Yagis and a radio capable
of AM on both bands. I use an FT817 and my HT. ARRL actually came here
to help (since they are so close and IEEE wanted to look at this case
for documentating characterization methods, etc. )and they brought a
sonic device which actually pinpointed the exactly insulator on two
towers with banks of 16 insulators each. It's a parabolic microphone
with a hand held trigger like device and requires great skill to aim at
the source and find the noise - but it does that. SO we actually did
power co. job - something they horsed around with for months of totally
lame and dumb excuses and sadly, the guy running that program a ham.
The problem here is they reconductored 69Kv lines 2 years ago and did a
very sloppy job replacing insulators - another long story - but I have
many examples of very poor work. I noticed the noise level increase as
they passed through the area but power co. denied it. I believe they
KNOW - it will now cost $$ to go back and fix these and we only spotted
2 out of likely many more.
Get ARRL RFI Handbook too. It's almost fun (if it weren't so painful -
this kept me off 160 last year and still isn't fixed) but I beleive it
will be most helpful if you go out and pin point the crud yourself not
counting on your power company. If you are hearing it that loud it's
close.
Pete W2PM
-----Original Message-----
From: Mike Waters W0BTU <mrscience65704@yahoo.com>
To: Brad Anbro <n9en@charter.net>; topband@contesting.com
Sent: Thu, Nov 26, 2009 3:48 pm
Subject: Re: Topband: Power Line Noise (long)
> From: Brad Anbro <n9en@charter.net>
> Subject: Topband: Power Line Noise (long)
> To: "TOPBAND" <topband@contesting.com>
> Date: Thursday, November 26, 2009, 5:27 AM
[snip]
> If anyone has any ideas on how I can pin-point the
> exact source of the noise, I would sure appreciate
> the information. Thank you in advance.
Hello Brad,
What I used to do to find noisy poles was tap them with a 7 pound hand
sledge at
about 5 or 6 feet up from the ground. If there was loose hardware, a
portable AM
radio tuned to a quiet spot would go nuts. Or, in other cases, the
noise would
stop.
You don't usually have to hit the pole hard. I did once, and the
vibration
travelled down the wires and made a pole several hundred feet away
start (or
stop) making noise.
73 Mike
_______________________________________________
160 meters is a serious band, it should be treated with respect. - TF4M
_______________________________________________
160 meters is a serious band, it should be treated with respect. - TF4M
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