Line noise that goes away in the rain is usually the sign of either bad
insulators or a loose ground connection. On the insulators they will arc
when it is dry, but when the water fills the voids they conduct easily and
don't have to arc which makes the noise. Loose ground connections just fill
up with water and don't arc when its wet, but do when the water dries out.
If it's a slow effect, that is the noise fades out slowly when it rains and
comes back slowly its more likely insulator(s)... a noise that stops quickly
when its hit by rain could be either. A thermal imager would likely help
find either problem, leaking insulators and bad connections both get hot.
An ultrasonic detector will find the high pitched noise of the arc, but
unless the inspector is in a bucket truck close to the pole may not tell you
if its hardware or insulators.
Sometimes pointing out that a noise is getting worse and you are worried
that something may fail helps... dropped or shorted lines are an emergency
that most utilities will try to avoid if they get some warning that things
are failing.
And sometimes pointing out that all that rf noise means there is lots of
power being lost through bad insulators or connections will help.
The way for you NOT to do it is to go tug on pole guys or hit them with a
mallet to see if you can find a sensitive pole... on rare occasions the
poles or hardware is rotting on the inside and can break from what seems
like a small bump to you.
David Robbins K1TTT
e-mail: mailto:k1ttt@arrl.net
web: http://www.k1ttt.net
AR-Cluster node: 145.69MHz or telnet://dxc.k1ttt.net
> -----Original Message-----
> From: doug [mailto:cxe@shaw.ca]
> Sent: Wednesday, October 08, 2008 19:39
> To: rfi@contesting.com
> Subject: Re: [RFI] DTV and Power line RFI
>
> To all.
>
> Read this.
>
> I moved to Pender Island in October 1993. Had lots and lots of
> noise, (buzzing) on all bands.
> Wrote letter to Radio Inspector in Victoria and sent an Audio
> tape of the noise.
> One year later, still no reply. Wrote another letter, and after
> a couple more months delay had a visit from an Inspector
> who also brought a BC Hydro crew with him. Arrived 9.30am.
> (By then had a Beam up and noise heaviest towards Europe,
> which was my main interest in those days. Nulls to the West.
> Power lines about 200 feet East of house run N/S.)
>
> BC Hydro crew INSISTED the noise was coming from my
> house, as did the Inspector.
>
> Main breaker was shut off in the house, Inspector took my little
> SW Portable outside and noise was there.
>
> BC Hydro crew then did the following.
> 1...Disconnected the Power to the Service inlet at my house. Still
> heavy noise on Portable (outside the house).
> 2...Disconnected Power line from the Secondary of the Xfmr on
> the Pole across the street. Still noise but a bit lighter.
> 3...Opened the Switch feeding the PoleTransformer from the
> overhead power line and the noise dropped considerably.
>
> All of the noise was heard on my little portable. The Inspector
> had one of those units which only indicates where HEAT is,
> I think it is called Ultra-sound.
> He had no VHF rcvr nor any DF antennas.
>
> He spent 10 minutes with my small Portable in his car going up and
> down the street. His comment was ...."it is all over the place"
> I had already told them that one year before and also that same year.
> I had WALKED 15 miles of our 30 mile tarred roads on the Island
> and found noise everywhere. At noon same day, he told me that
> I would have to find the noise myself and then they MAY come and
> see what they can do. He spent a total of 2 1/2 hours at my place.!!
>
> A local HF guy told me he had noises many years ago and traced
> it to a Transformer. BC Hydro advised, but nothing done until the
> day came and the Transformer BLEW. Apparently a short to the
> outer case had done the trick. But by this time the local HF guy
> had QUIT Ham radio because of the noise and the lack of
> understanding or help from the BC Hydro.
>
> 12 years later with the same noise, I again wrote to the BC Hydro
> and was given some other fellows name. I got in touch with him
> and he arranged to come over to see what could be done.
>
> Eventually he came and brought an RFI locator receiver with him.
> He hooked up my Beam coax to this and looked on the Screen
> to see what the noise was like. He then went out in his car
> and eventually came back saying it was quite widespread and
> he would have to come back and spend more time looking for
> the source. That was nearly two years ago and that was the last
> I heard from him.
>
> He had been told that even while listening to the AM Bdcst band
> on 600kHz there was one place over 1 mile away from my QTH
> that the noise was quite heavy on this QRG. He said he had
> also taken that into consideration.
>
> Normally the noise was the heaviest, and I mean heaviest,
> during the HOT summer months. When it rained the noise either
> diminished or reduced intensity, depending on how heavy the
> rain was. But soon after the rain stopped and the Sun came
> out the noises began, gradually building up to strong.
>
> I made an Audio tape many years ago of the noise, if anybody is
> interested in listening to it. It takes a few minutes to download,
> that is the problem. I sent this tape to AC5K (who used to be
> a Power Utility Noise finder) many years ago and he confirmed
> the noise was Power Line noise. It's not a very good Video but
> gives an idea what it is like at my QTH.
>
> There have been times during some contest or other I have had
> to operate with 16dB of Attenuation on the Rcvr and with the
> RF gain way below half way. The noise blanker is of course
> useless.
>
> My routine now is dry WX in the morning and go out and play
> a round of golf, come back and pray for heavy rain to give me
> a noiseless background. Never happens that way.
>
> By the way, I have no VHF (Aircraft QRG) RX with which to
> go around the Poles, and have to rely on my Portable handheld
> SW receiver.
>
> 73
> Doug/VE7NH
>
>
>
> ----- Original Message -----
> From: "EP Swynar" <gswynar@durham.net>
> To: "G. White" <radiotrade@rogers.com>; <rfi@contesting.com>
> Sent: Wednesday, October 08, 2008 10:50 AM
> Subject: Re: [RFI] DTV and Power line RFI
>
>
> > On 8th October, it was written:
> >
> > "... In Ontario, you must NEVER tell Ontario Hydro (Power) that you are
> a
> > HAM or they will ignore you. Tell them you are a disgruntled television
> > owner and chances are they will give you more attention..."
> >
> >
> > ***********************************
> >
> > I have to disagree with that statement, based upon my own first-hand
> > experience in that regard...
> >
> > A couple of years ago I started getting an S-9 PLUS buzzing noise on
> > 40-meters. The ONLY time it would "cease & desist" was on wet, rainy
> > days...
> >
> > Cruising the area in my car, with the AM radio tuned to a dead spot on
> the
> > band, I traced the source of the racket to be a hydro pole at the end of
> > my
> > neighbour's driveway.
> >
> > I phoned Ontario Hydro on a weekday morning, and was assured that
> someone
> > would be at my place that very same day! Sure enough, a few hours later,
> > there's a white & orange "cheery picker" parked out front, with two
> > servicemen visually scanning the poles along the street. I brought one
> > fellow into the shack, & showed him first-hand what the noise sounded
> > like.
> > While he listened, he was in communication with his partner outside via
> a
> > walkie-talkie radio, as the latter hammered each pole, one by one, with
> a
> > huge hammer.
> >
> > No change in noise.
> >
> > Finally, I directed them to where I thought the noise was coming from,
> and
> > one of the crew went "topside" in the cherry-picker to see. Sure enough,
> > when he opened the knife switch that connected the main line to my
> > neighbour's drop line, the noise stopped.
> >
> > Examination of the switch revealed corrosion, which was the result of
> > prolonged arcing. They installed a new switch, & I confirmed that the
> > noise
> > had completely disappeared --- with my deepest of thanks.
> >
> > I later wrote a letter of appreciation to the local head office of
> Ontario
> > Hydro, expressing my gratitude...
> >
> > On the other hand, LOCAL utility companies here fall into the "...Hams
> are
> > on the back-burner" category of PR. That's why, when we lived in the
> city
> > and street lamp ballasts would go awry, causing all sorts of mayhem on
> the
> > low bands, I would call & complain that the intermittent operation of
> the
> > pole lamp was of concern to the citizenry walking their dogs after dark.
> >
> > It worked every time.
> >
> > ~73~ Eddy VE3CUI - VE3XZ
> >
> > _______________________________________________
> > RFI mailing list
> > RFI@contesting.com
> > http://lists.contesting.com/mailman/listinfo/rfi
>
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