Power Line Noise -- Power Line RFI

Hunting Power Line RFI by AF4O

Although my Power Company (small rural company) can call in TVA (large power distributor in this part of the U.S.), I decided to hunt down the remaining and new Power Line RFI sources myself. The reasons are:

• I want to make sure for myself beyond a reasonable doubt, that the RFI is indeed of power line origin.

• I followed TVA's RFI Engineers around for a few times they came here and learned their methods.

• It speeds up resolution of the RFI. TVA are busy folks and it may take them a while (sometimes weeks) to arrive.

• I have to take off work to be here with TVA . They need to go in the house to initially identify the RFI and it helps if I show them my findings.

• On my own I can hunt RFI as my time allows.

• I can hunt the RFI when the often intermittent RFI is present and at its worst (weekends, evenings, early mornings, etc).

• Often TVA would come and the RFI be quite and they would make a burnt run.

• I am learning and its fun!

General Methodology I use is as follows:

Remember typical bad hardware is most often lesser ominous things like wire wrap connections, loose hardware, insulators (slack spans are especially troublesome). NONE of mine were transformers.

• Step 1: Hunt first by beaming with the station beams. Note the noise patterns, they can be aggravating sometimes coming and going at random often agitated by wind, rain, etc.  If you really want to get deep, you might put a scope on your receiver and note the noise but I have not found this to be necessary. I have 6 meter and 2 meter horizontal beams. I have another set of vertical 2m beams. Since they are on different towers, this allows for some triangulation in some cases. Remember here that the power lines can act as an antenna to a certain extent and throw off your readings sometimes. Always find the strongest source first, get that fixed, and work your way down.

• Step 2: Hunt in the direction indicated in step 1with a portable receiver and portable beam. I use a FT-817 and 2m 4 element lightweight quad (bought off ebay, made from pvc pipe and wire). Again, triangulate and try to locate the pole. Remember as you get close to the pole the noise will be heard in ever increasing higher frequencies. A multi band HF/VHF/UHF AM capable receiver like the FT-817 helps for this.

• Step 3: Hunt on the pole (standing away from it of course, never ever touch their property!) found using the Ultrasonic Detector (Built from April 06 QST,   http://www.arrl.org/qst/2006/04/hanson.pdf    My detector shown below). Taking many readings around the pole carefully, often you can isolate down to less than a few pieces of hardware. I'm here to tell you, properly constructed and used, this thing works very well! (Thanks Again Jim W1TRC!) My first and successful hunt was an insulator and/or associated wiring (see next picture).

• Step 4: Email digital picture to Power Company Engineering and request repair. Circle suspected hardware with photo editor. Five days later my Power Company fixed this and the noise was gone!

• .

I guess I have been lucky in that all my sources were within about 75 yards of my house. Most within 150 feet. They were mainly on neighborhood feeder wires running by my house (lucky me!). If you have a distant source, then step one maybe your car, ft-817, and car mounted antenna to drive around and locate.

Here's to an all quiet RF location for you!

Be glad to give advice from my amateur finding.    af4o --at-- arrl --dot-- net

73,

Chuck

AF4O