[OKDXA] Power Line Noise

[Kimberly Elmore]

Recently, I've noticed some pretty severe, intermittent power line noise at my QTH. It had previously been a marvelously quiet place for radio, but over the past moth or two, that has changed. I had it again this morning and so decided to do some sleuthing.

I live E of Norman in the center of a section bordered by Robinson on the S side, 48th St on the W side, Rock Creek Rd on the N side and 60th St on the E side. Both OG&E and OEC lines run down all roads. The OG&E lines run 35 kV -- I don't know what the OEC lines run. My neighborhood is served by OG&E and all wiring is under ground; step down transformers are above ground on concrete pads.

Here are the details: 

I cannot detect the noise on any band above 40 m, but it's clearly apparent on 40, 80 and 160 m. My Orion II noise balnkre is ineffective on 40 m (either the software or hardware noise blanker) but is very effective on 80 and 160 m. Because I cannot hear it above 7 MHz, I'm pretty sure that the source is not emanating from a neighbor's house or from a nearby step-down transformer.

Using my K9AY loops, I can detect the noise when the loops favor either NE or SE, but not when they favor NW or SW. Thus, the source is either to my N or my E.

Using my 2 el 40 m beam, I found sharp nulls with the beam pointed either N or S (probably nulls off of the sides), and less noise when the beam is pointed W than when it is pointed E (~S9+25 dB pointed E, ~S9+15 dB pointed W). So, F/B ratio favors a source to my E.

I then got in my car, tuned my mobile rig to the aviation band and to a quiet frequency (Westheimer tower) so that I could use the AM detector at VHF and started driving E along Robinson to 60th street. I heard nothing of substance along Robinson. I turned N and drove along 60th and found a strong noise source. I double checked my traverse and found the same spot three different times. It was considerably weaker from across the road than it is next to the pole. There is a private going E from 60th street and away from the offending pole and driving down it 100 feet diminishes the signal strength significantly. The ground wire for the pole appears intact at the base.  I am absolutely positive that I have identified the pole holding the faulty hardware. I could see nothing obviously loose, but the culprit is most certainly there.

The noise is intermittent: it starts and stops abruptly as the wind blows, though I can detect no obvious correlation to wind changes and the starting and stopping of the noise.

What now? Whom do I contact with my information? And now for the cynical question: what are my chances that they will care?

Kim Elmore, N5OP