Gentlemen,
I want to thank everyone for their insights and contribution to this list.
I have been getting power line noise for a few years here. It is pronounced
when sunny and dry then wind picks up. The Flex 6600m wide noise blanket can
drop the pan adapter noise floor 20 dB or better but issue is with the wind the
noise rapidly comes and goes.
I am now disabled and cannot walk far but I am going to try and track it down
using some of the techniques outlined here. I have used my Yagi on 15 meters to
get a W-NW heading, so someplace to start. I have the ability to watch the HF
pan adapter on my iPhone while searching. I also have two portable SW receivers
and a VHF/UHF scanner capable of AM mode.
Again, thanks for sharing your stories. I have learned a lot and looking
forward to hopefully isolating the source to help the utility company fix it. I
know the person in charge of the group that fields RFI complaints so that
should help.
73 and keep up the good work!
Dave wo2x
Sent from my waxed string and tin cans.
> On Mar 10, 2021, at 10:49 AM, EDWARDS, EDDIE J via RFI <rfi@contesting.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@contesting.com> On Behalf Of Don Kirk
> Sent: Tuesday, March 9, 2021 6:27 PM
> To: RFI <rfi@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---
>
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