[RFI] utrasonic locator

[Alan Robinson]

I have been using a Radar Engineers Model 250 Ultrasonic Locator for about six
months. It works very well and has helped me find over twenty individual sources
on the power lines that run past my house (about 100 feet from my station). I
have both transmission and distribution lines running along my property. It's a
great RFI training area!

One of the sources was a pin insulator on the field phase of the distribution
lines on the pole in our yard. I had identified the source pole by using a Radar
Engineers Model 239 and a Cushcraft six element 440 MHz beam antenna. Then I
picked out the offending hardware, while standing on the sidewalk, using the
Model 250. The beam width of the 250 seems to be about a foot.

When the utility crew came out to fix it I monitored the repairs. The repairs
were made with the line hot. The foreman was standing next to me also listening
to the noise coming from the Model 250 as it listened to the problem insulator.
At the exact moment that the crew lifted the hot line off the offending
insulator the noise stopped. It was quite dramatic and convincing.

This cured the power line interference that I was getting from that source.
Unfortunately the lines and hardware are of an old design and another source has
appeared. 

In summary, I think the Model 250 is very effective in identifying sparking
hardware.

Now the disclaimer: I have absolutely no connection to Radar Engineers, I just
like their equipment. I am a retired engineering faculty member at Oregon State
University.

Sincerely, and 73s,

Alan, W4LKE