Thank you Michael. Your advice is greatly appreciated. Following
this same procedure which you explained to me several months ago I
successfully located numerous sources which have since been fixed.
The method works great and has been very helpful!
Evidently this last small area exceeds my ability. Constantly
changing strength of the noise has me at wits end. As soon as I
eliminate the weaker signal they both disappear. In the time it
takes to move from one set of poles to the next the strength of the
source is guaranteed to have changed. It is virtually guaranteed to
change in the second it takes to swing the yagi from one pole to the
other. I can't get a consistent or repeatable reading anywhere. If
peaks occurred with some regularity it might help, but they don't. A
given peak level observed at one instant may not be seen again for
hours. I have made dozens of attempts and still do not know for
certain which pole is the source.
It looks as though I will have to live with this one unless I get
better equipment or the noise changes in some way that makes it
easier to locate.
There is just one house with a live electrical feed in that stretch
(plus two vacant and disconnected).
There is one final bit of purely circumstantial evidence. I realize
this doesn't prove a thing. Even if it did, I would still be left
with 7 poles and no way to be certain which of them is responsible.
There has been only one fair weather day in the past 8 months when
these two noise signatures were not present. The 5 hour absence
coincided to the second with opening and closing of cutouts on a
section of the 46 kV line. The 13 kV line remained live during this
time.
Paul, N1BUG
On 12/27/2012 05:15 AM, RFI Services' Michael Martin wrote:
If you receive the signal across 7 poles, you know the signal will be
stronger at the source pole. Reduce your gain to eliminate the weaker
signals. Stand at least 20 feet away from the lines at equal distances from
two poles. Pointing your yagi back and forth as you reduce your gain to
eliminate the weaker signal. Once you determine which of those two poles has
the stronger signal move in that direction and perform the same test between
the next two poles. Then repeat.
The fact that you don't receive the signal at UHF is not a good sign for
arcing. However it is a good indication of either further away or inside one
of the houses connected to one of those 7 poles. That would also explain one
of several reasons for no success using ultra sound. The first reason for a
lack of Ultra sound success is lack of sensitivity. This one is for sure.
Remember, ultra sound is your last step and it can only be as successful as
the proceeding step. Do Not use ultra sound unless you are 100% positive
about the structure containing the source. Don't put your foot before the
crutch! Also, Ultra sound on a windy day is a mess and very un reliable.
That's like using it while someone is shaking the pole. See what I mean?
Use my "how to locate the residence" instructions. It works!
(http://www.rfiservices.com/residence.htm )
Look out for the next edition of the ARRL's RFI Handbook.
Merry Christmas,
Michael C. Martin
RFI Services
6469 Old Solomons Island Rd
Tracys Landing, MD 20779
www.rfiservices.com
240-508-3760
-----Original Message-----
From: RFI [mailto:rfi-bounces@contesting.com] On Behalf Of N1BUG
Sent: Wednesday, December 26, 2012 5:19 PM
To: eddieedwards@tconl.com
Cc: RFI@contesting.com
Subject: Re: [RFI] Power line noise question for the experts
Ed,
It is one of the DIY "kit" units. However it is the recently released RX3,
not the older RX2 or RX1. Under controlled test conditions, this unit picks
up a spark at 100+ feet vs. 35 feet for the previous model. What that
equates to in terms of sensitivity specifications I leave to brighter minds.
(Disclaimer: while I do not profit in any way from sales of this unit, I did
play a minor role in the R&D process)
The power company has checked that pole twice with a Radar Engineers model
250 without hearing anything.
I'm now questioning whether in fact I have the right pole. It is hard to
have faith in my findings on those windy days when I could barely hold onto
the dish.
73,
Paul N1BUG
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