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

Primary Source - Resolved!

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

History   Note: Even during these long appearances and disappearances 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.

Frequencies affected

Identification of source type

120Hz spikes from a typical recording of the rfi as seen on Audacity

Audacity 120hz

Audio/Video logsClick on to hear/see

Jan 11, 2021 Audio

Jan 12, 2021 Audio/Video

Triangulation & Final Identification

Either there is 2 sources or I mistakenly tracked to pole on West End Street. Was tracking for maximum noise and not noise pattern, see below.
The source on West End is still active although diminished to where it is not seriously affecting my station at this time.

Direction finding with my 6 meter beam at 40' proved to be misleading. Likely due to the close proximity of the source pole some 50' away.

            145Mhz HandiTalkie on AM and 3 element handheld yagi

  Update; Source reappeared in early April 2021 and was able to locate on this same pole with the ultrasonic dish.

The arcs are tiny but visible. They remind me of tiny welding arcs. One appeared to move an inch or so on the wire and would come
and go. The others were constant. My digital camera faintly picked up one of the arcs but little can be seen of the pole in the dark.
A night vision camera maybe something to add to my growing rfi toolbox.

Ultrasonic Location Diagram

Ultrasonic Pic

Pole Pic 1

Pole Pic 2

Pole Pic 3

Weather Log - To correlate weather conditions so those involved with finding the arc will have a better
chance of being present when the arc is active. Readings taken on 80 meter SSB for consistency.

Best Practices and notes for this hunt

indicative of a power arc.

on AM mode and a 2m yagi built with light weight metal tape measure elements. Retransmitted the noise from my HF receiver
to a HT on 440mhz FM thus being able to compare the noise pattern with the tracking HT/Yagi. Waiting until the
noise has a distinctive pattern is helpful.

but are expensive at this time. There are many youtube videos on how to remove the IR filter lens of a standard digital camera
to allow the CCD to be sensitive to IR light. Might be a worthwhile project


Wow, just Wow. Crews did the repairs requested some 3-4 days after requested. The local utility was nothing short of cooperative and willing
to work to resolve the issue best they could without outages. Its now about 3-4 days post repair as of this writing and the overwhelming majority
of the main source of 120hz noise is gone.

Even during times of lull's as noted in the logs above, I would occassionally hear a second or so of loud pop. Not even hearing
that anymore from the main source. One word of caution to myself though. Much of the hardware which built up the path to arc remains so this
could reoccur over time but its anyones guess as to how long it will take if ever since the wire is further away from the hardware where the path
likely built up.

Before After Pic


Crack in the fused disconnect likely the Ultimate cause of this issue