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Re: [RFI] FW: Topband: Exciting noise sources (Tim Duffy K3LR)

To: rfi@contesting.com
Subject: Re: [RFI] FW: Topband: Exciting noise sources (Tim Duffy K3LR)
From: Jimk8mr@aol.com
Date: Tue, 29 Mar 2011 16:37:10 EDT
List-post: <rfi@contesting.com">mailto:rfi@contesting.com>
I have used this technique, with the cheaper Icom IC-R10 handheld scanner.  
I program into a memory bank ham frequencies for each bank, 160 though 1296 
 MHz, AM detection.  With one knob I can then QSY between bands to find the 
 highest frequency where the noise is present.
During warmer weather, after getting a beam heading from home, I head out  
on my bicycle where I have a 2 meter 5/8 wave antenna with a clip on mount 
to a  metal rack on the back of the bike. As noted, on 2 meters I can hear 
most noises  within half a dozen poles, and on 432 within one or two poles. 
The higher bands  (903/1296) have not been useful, at least with the antenna I 
I can also carry a 6L 432 yagi on the bike, that I can hook up (while  
stopped) to aim at suspect poles. It can sometimes provide useful information 
 the cross polarization null in the noise. This is most often true when 
there is  an angled wire running between sources. 
When I have a particular pole located, I will drive back with my ultrasonic 
 detector (W1TRC) to confirm the noise and try to get it down to a 
particular  location on the pole.
Though like many of us hams, I have lost interest in having talking on a  
VHF FM radio from the car, I do usually have one available, with just a 1/4 
wave  2M mag mount. I try to keep it tuned to an open frequency with the AM 
detector  enabled, while driving around close to my house. It can be a good 
way to keep  track of known noise sources that come and go.
Unfortunately I fall into the group of people that have an unresponsive  
power company.  The line noise guy is pleasant and I believe knowledgeable,  
but getting work done is rare.  This is First Energy, which is the same  
company that several years ago came within a quarter inch of stainless  steel 
having a nuke plant melt down in Port Clinton, Ohio. Not a  maintenance 
kind of culture there.
73   -  Jim  K8MR
In a message dated 3/29/2011 4:14:08 P.M. Eastern Daylight Time,  
robinsah@engr.orst.edu writes:

Hi  Frank,

Thank you for writing such a great email. You have been so  helpful that I 
hesitate to add anything, but here are a few comments for this  reflector (I 
am sure you know this info).

I use the Radar Engineers  equipment. I have an RE Model 240 RFI Locator, a 
Model 250 Ultrasonic, and a  Model 247-B Hotstick Line Sniffer. I think 
they are well worth the cost and  are invaluable for RFI locating.

I use the method developed by Marv  Loftness (KB7KK) as described in his 
book "AC Power Interference Handbook,  Third Edition", available from ARRL and 
HRO (and other places). This method is  the one Mike Martin (K3RFI) teaches 
in his excellent work  shops.

Basically the method involves searching with an AM receiver and  compact 
beam antenna tuned in the 2 meter band to locate the noise within a  few 
poles. Then I use a 6 element 440 MHz beam (Cushcraft Model A4496S) to  
"the pole". Then I use the ultrasonic the try to locate the offending  

(Side bar): I do use the RE 240's scope to get a  "fingerprint" of the 
interference. Then look for that "fingerprint" in the  field. For a description 
of this see Marv's book.

I do NOT climb poles.  I have used the 247 hotstick sniffer to train 
linemen in its use. (I have a  small portable noise generator for training). 
they use it with a bucket  truck to find the problem hardware and fix it.

Note: The lightening  arrestors that I have found had NO audio signature. 
However, one was so "hot"  I got a very strong signal with my 675 MHz 8 
element beam. I do usually find  an audio signature with the Ultrasonic. This 
helps the linemen to identify the  problem hardware.

I have also tried locating with the MFJ Model 852,  dipole only, power line 
noise detector. This has not worked well for me. I  would like to try their 
Model 856 with the built in 3 element beam. Perhaps  this would work well 
to get within a few poles of the source. But I believe  you really need to 
use 440 to 450 MHz to get "the pole".

Well that's  about it for now. Thank you again, Frank, I read all of your 
postings very  carefully.



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