Topband: K1N DQRM Tracking Project

[Stan Stockton]

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