A collection of information to assist those in locating powerline arc rfi involving amateur radio licensee W4NBO (formerly AF4O)

Updated as information is available

FCC License Data: https://wireless2.fcc.gov/UlsApp/UlsSearch/license.jsp?licKey=4439683

Fall 2021 #2 Source

---#1 source tentatively resolved 10/7/21

---Pole location behind 637 Clifft Street

Radio Frequency Interference in the area of West End Street and Clifft Street in Bolivar, Tennessee

History

Note: Source is fairly constant but can become intermittent. Such that the source may not be active when a RFI location crew is able to come by. I am in a rural area and it takes time for them to come out.

My power company graciously offered to request a TVA rfi location crew to come out but my concern was that they would come out and the source not be active due to its highly intermittent nature, thus the location efforts here.

• Active since ~ late August 2021. Very Strong affecting all HF frequencies. About s7-s9

• Typically is absent only with a heavy, long term rain. But can become intermittent or inactive after a long rain. Humidity on clear days seem to affect it very little when it is often constant.

• When absent, no other significant 120hz RFI heard at this time.

• Pulling breaker at house made no difference.

Frequencies affected

• All HF frequencies

• Up to at least 450mhz near the source.

Identification of source type

• 120hz spikes can be seen on Audacity audio processing program (see photo below) Audio fed into Audacity from recording of HF reception when active.

Video Here; https://youtu.be/MY3hZeUJa9U

Recorded after a moderate rain at a point it was intermittent. Most of the time its almost constant.

Triangulation & Final Identification

• Peaking signal with 6m & 2m beam points very near the pole behind 637 Clifft Street. Listening to 6m / 2m / 28mhz etc on separate receivers, all 3 are in harmony when source is intermittent.

• Also triangulated with 2m portable and yagi matching the retransmitted HF audio.

• Unable to hear with Ultrasonic but part of one side of the pole is inaccessible due to private property (backyard) and also dense jungle like foliage. House was a rental that was mistreated and recently put up for sale and possibly already sold.

• Good news is pole has fairly minimal hardware compared to Source #1 (3 phase).

• Request submitted to Utility 10/2/21

UPDATE

Purchased a 450Mhz 5 element yagi. This helped significantly to pinpoint the source vs the 145mhz yagi. Results below. Still centering on the pole behind 637 Clifft Street.

Resolution 10/26/21

The weekend before the Utility crew arrived, the source became intermittent and then almost completely inactive on its own. The Utility crew reported they found a loose wire on a wire nut on the stapled ground and went over the entire pole and found nothing else. So I am not sure if the source became inactive on its own, the Utility fixed it, or a combination of both. I heard some bursts the night after the Utility visit with similar characteristics of the source but far to intermittent to identify. Now I think this was not related as later I heard this type noise and it was about 40 degrees off the beam heading of the target source. For 4 days now I have kept the volume up near full on my IC-7100 on 2m pointing at the target source to where I can here it all over the house if it breaks the squelch. I have not heard it at all. So now I am in the clear as far as 120hz is concerned. Hope it lasts!