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 #1 Source (currently 1 of 2)   

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

History

Note: Source is 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.

• Noticed when the primary source was absent and since its been resolved. Although this source is on the same pole, ultrasonic indicates on the opposite side of the pole. Signal strength and other aspects of the repaired Spring 2021 source do not match either.

• Typically about s6 at 28mhz

• Its long term nature unknown since it was obscured by the the source since resolved Spring 2021

• Typically is absent with a light rain or rain and/or high humidities.

• Has become very reliable to be active below about 60% humidity

• Pulling breaker at house made no difference.

Frequencies affected

• All HF frequencies

• Up to at least 150mhz near the source.

• Peaks a bit around 19.5mhz on the IC-7100

Identification of source type

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

Triangulation & Final Identification

• Peaking signal with 6m & 2m beam points right at the same pole Spring 2021 pole was on. Listening to 6m / 2m / 28mhz on separate receivers, all 3 are in harmony when source is intermittent

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

• Better pin pointed with Ultrasonic.

• 4/22. Might have seen a tiny spark at the ground lug that wire goes to the fused disconnect.

• Built a Ultrasonic test source to more precisely site the Ultrasonic Dish.

Resolution

Utility arrived early October ~10 days after emailing the PE Engineeer. I spoke to the linemen onsite. The lineman found a significant issue that was likely the cause of this issue as well as the ultimate cause of the Spring 2021 #1 issue also. They replaced the Fused Disconnect and showed me the hairline crack it had. Long term monitoring will tell for sure but at this time the pole has been inactive and very quiet. This is very hopeful.