[RFI] Difficult power line RFI find.

Tue Mar 16 11:51:13 EDT 2021

Hi Scott and gang,

Thought I would provide a status report on this case, and also provide a
warning to others regarding something I did which I certainly don't condone
(I'm certainly not proud of what I did and I can't stress safety enough).
I hate to even admit what I did in public, but thought I should mention it
as it's a good example of needing to be extra cautious around power poles
even if you think you are safe.

We were hoping the power pole (wooden pole) I found generating RFI last
week belonged to Johnson County REMC but I could not tell since the pole
tag number was covered up by a solar light that was likely installed by a
homeowner.  Johnson County REMC responded to our report and said the pole
actually belonged to AES, so we discussed the situation with our inside
contact person at AES and let them know we were going to get some
additional data before filing a formal complaint but we did send them a
link to a youtube video I created along with some pictures of the suspect
pole.  Here is a link to my video documenting the suspect pole:
https://youtu.be/uo5atDTo19w

I went back to the pole on Sunday to get more data and someone had
relocated the solar light so it was no longer covering the poles tag number
but one of two guy wires we previously reported were wrapped around the
pole was now partially covering part of the pole number.  I used a wooden
stick to push the guy wire slightly to the side (like a 1/4") to make sure
I could read the pole number and the RFI suddenly stopped on 135 MHz which
I had been monitoring by chance and the RFI started right back up as soon
as I stopped pushing on the guy wire.

I then did a closer inspection of the two guy wires that were wrapped
around the pole and one of them (not the one I was pushing on) did have a
connection to the neutral line high up on the pole and neither of the guys
were connected to ground as both of their bottom ends were just wrapped
around the pole about a foot up from earth (probably due to a car accident
or farm implement incident, etc), and both of these guys were in contact
with each other due to their wrapping around the pole on top of each other
near the bottom of the pole.  It appears that my pushing on the one guy
wire caused slight tension on a teardrop type clip that was on the top end
of the guy wire I was pushing and this teardrop clip (almost like a D ring)
rests (straddles) on a through bolt assembly high on the pole which acts as
the anchor point for the guy.  Note: At least the neutral line on this pole
is located below the hot (live) line so little chance for the guy lines to
come in contact with the hot (live) line even though they're not properly
secured.

I then did similar tests on 24.98 MHz, 1.8 MHz, and 1710 KHz, and the RFI
stopped each time slight pressure was applied to the guy line that was
covering the pole tag number.  I actually set up HF gear a good distance
from the pole, had my Iphone camera recording the HF gear while I ran back
to the pole to push slightly on the guy wire with my wooden stick.

I then contacted our inside person at AES and told them (admitted) what I
had done and that I was now concerned this pole was not just an RFI issue
but also a potential electrical safety issue since the guy wires were not
connected to earth at the bottom of the pole while one of them is also
connected to the neutral line up on the pole and the guys are also not
properly secured even though they are are wrapped around the pole (better
to remove them versus have them like they currently are).  Our AES contact
person then said they had actually already responded to the area on Friday
after our initial informal report to them and had identified a couple poles
generating RFI in the area which included the one I had identified, and
they had already issued a rush work order to fix the poles.

Note: one of the two guy wires might have actually been a steel strand for
supporting telephone wire in the past, I really have no idea.

I did take what I thought was reasonable precaution using my wooden stick,
but you can never be safe enough in my opinion and no reason to take the
risk.

Bottom line (no pun intended) is that you should not touch anything on a
power pole even if you think you are totally safe with what you are doing.
This is just my opinion, but I think it's sound advice which I know has
been mentioned previously (I know hitting a pole with a hammer has been
mentioned as a no no in the past, etc).  It took me a day to work up the
courage to post this story, and please don't chastise me.

73,
Don (wd8dsb)

On Wed, Mar 10, 2021 at 3:53 PM K9MA <k9ma at sdellington.us> wrote:

> If your local utility is cooperative, they may share with you maps of
> their distribution lines.
>
> 73,
> Scott K9MA
>
>
> On 3/10/2021 11:18 AM, Don Kirk wrote:
> > Hi Eddie,
> >
> > Thanks for sharing your very similar story, and very interesting based on
> > the configuration of lines I was dealing with.  As a matter of fact I was
> > using Google Earth this morning to look at the lines I was dealing with
> > yesterday and wish I knew more about power distribution to better
> > understand all the hardware.  Nevertheless I too was dealing with
> parallel
> > running lines  in the area where I found the suspect pole.  One set of
> > lines which appear to be 3 phase run the full length of the road on the
> > North side of the street, and the suspect pole I located was also on the
> > North side of the street but it was fed by parallel running lines on the
> > South side of the street and I don't believe the South side of the street
> > lines are 3 phase.  The suspect pole then fed some additional poles
> running
> > up a very long driveway to a house set way back off the road.  The lines
> > that my antennas always pointed perpendicular to were the 3 phase lines
> on
> > the North side of the street which were not physically connected to the
> > lines with the suspect pole as far as I can tell, and if my theory is
> > correct that would say the RFI I was getting induced into the 3 phase
> lines
> > by the lines running on the South side of the street that were connected
> to
> > my suspect pole.
> >
> > We shall see, but boy my story sounds very familiar with yours as far as
> > parallel running lines with a cross over to my suspect pole right under
> > what I'm calling the 3 phase lines that run the full length of the street
> > East/West.
> >
> > Thanks,
> > Don (wd8dsb)
> >
> > On Wed, Mar 10, 2021 at 10:49 AM EDWARDS, EDDIE J <eedwards at oppd.com>
> wrote:
> >
> >> Don,
> >>
> >> Great story!  Thanks for sharing.
> >>
> >> We had a very similar experience near my QTH several years ago affecting
> >> my home location and also another ham on about a mile north of me.  Only
> >> difference was it was strong on low bands, and it was strongest on 80
> >> meters at S9+, and probably on 160meters too but neither of us had
> antennas
> >> for 160 meter back then.  The other ham is a mile north of me and we are
> >> both in nearly a north-south line perpendicular to a 161 KV transmission
> >> line.
> >>
> >> Also, I should mention that I work in the utility department that is
> >> responsible for tracking power-line noise although it's our technicians
> >> that do these RFI cases regularly.  I only get involve in problem case,
> or
> >> in this case when I am affected at my home shack.
> >>
> >> It appeared to be coming from the direction of the161KV line that runs
> >> East-West; however, when the tech was using our new HF loops we had the
> >> same perpendicular indications no matter which direction we traveled.
> It
> >> was staying strong for 1 to 2 miles in each direction before beginning
> to
> >> fade.  Our mistake was to stay too focused on using HF freqs for
> tracking
> >> that day, but we were also initially confused by the southwest
> direction we
> >> got at the ham's QTH 1.5 miles north of the 161KV line.  We only
> switched
> >> to VHF/UHF in the area to the southwest finding nothing there.
> >>
> >> We unknowingly drove past the actual source directly south of both ham's
> >> QTHes a few times not realizing this before ending our search at the
> end of
> >> the work day (techs are union, no OT on RFI cases).
> >>
> >> The actual source turned out to be a distribution pole on a 13.8KV line
> >> that ran parallel with the 161KV line for a short distance as it crossed
> >> over the main street perpendicular to both lines to reach a couple
> houses
> >> on that street.  The RFI source was apparently causing induction into
> the
> >> 161KV line from the shorter 13.8KV line.
> >>
> >> We never had to track the source down to fix it.  On my way home from
> the
> >> office that same day, as I drove toward the 161KV line while listening
> to a
> >> blank spot on my AM radio, it appeared the noise was already gone!  As I
> >> approached the 161KV line I see a couple of our utility trucks working
> to
> >> install a new pole replacing one of the old poles on the line that ran
> >> parallel under the 161KV line.  Since the noise never returned, I assume
> >> the old pole that was replaced was our source pole.
> >>
> >> Some days you just get lucky!
> >>
> >> 73, de ed -K0iL
> >>
> >> -----Original Message-----
> >> From: RFI <rfi-bounces+eedwards=oppd.com at contesting.com> On Behalf Of
> Don
> >> Kirk
> >> Sent: Tuesday, March 9, 2021 6:27 PM
> >> To: RFI <rfi at contesting.com>
> >> Subject: [RFI] Difficult power line RFI find.
> >>
> >> Just thought I should share something that was a first for me when
> >> tracking down power line RFI and man it was frustrating, and I have
> tracked
> >> down a lot of powerline RFI.
> >>
> >> I noticed some weak RFI at Dans (KB9AX) on 160 meters earlier this year
> >> but did not have time to track it down.  Dan also complained about the
> RFI
> >> and he mentioned this week that it was not strong but had become very
> >> consistent.  It definitely looked and sounded like powerline noise (120
> Hz
> >> spikes observed on audio scope and SDR receiver, etc.)  ---snip---
> >>
> >>
> > _______________________________________________
> > RFI mailing list
> > RFI at contesting.com
> > http://lists.contesting.com/mailman/listinfo/rfi
>
>
> --
> Scott  K9MA
>
> k9ma at sdellington.us
>
> _______________________________________________
> RFI mailing list
> RFI at contesting.com
> http://lists.contesting.com/mailman/listinfo/rfi
>