A friend of mine told me recently that he has had the electrical utility
company out several times to fix noise problems and without ever leaving his
house tells them exactly which pole is the culprit. Further, that they were
always happy to help because he has not been wrong yet.
OK, so how did you do it, I asked.
First, his rotator is digital and as dead on accurately calibrated as can be
achieved. That is accomplished by using the roofline of the house on a
Satellite mapping program. He peaks the noise using his Yagi antenna. Then he
backs off the RF Gain so the noise is still audible to some level with AF Gain
all the way up. Then he moves the antenna off one direction and then the other
documenting the exact heading (to a tenth of a degree I guess) where the signal
audibly disappears, averages those two beam headings and plots a line from his
tower on one of the maps that shows everything in detail including power poles-
Google Maps, I suppose. The plotted line goes right through the pole causing
the problem. He said if Google didn't black out the numbers on the pole, like
they do on license plates, he could in most cases give them the pole number.
I know that QSB, the distance, duration of the interfering signal, and other
factors that I'm not even thinking about are in play but would think that if
you had multiple setups like that it would be possible in some cases to narrow
it down to a reasonably small area. SDR recordings with time and signal
strength linked to exact beam headings during a rotation of the antennas and
some good software sounds plausible to somewhat automate the process.
An interesting test would be for someone on the East Coast and someone in
Florida with an accurate calibration as described, try to zero in on someone in
the Midwest who is giving them about two minutes of key down. I think maybe
even a couple degrees error in the heading would not equate to but a few miles
(5-1/4 miles per degree?) at a distance of 600 miles, for example.
Regardless, I am much less excited about finding these guys as I am in some day
using this technique to pinpoint line noise. The time I told the supervisor at
the power company that I had spent the previous two hours going after his power
poles with a sledge hammer while talking to my wife on the phone with the radio
receiver going, he didn't even smile.:-)
73...Stan, K5GO
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