[RFI] My power line noise problems, revisited (Warning, thisislong!)

[Jim Miller]

Sounds like you need some kids I remember from 45 years ago that used to
walk down the gravel road with 22s and use the insulators for target
practice.  Not sure who they were, hi.  That would get them replaced.

73, de Jim KG0KP

----- Original Message ----- 
From: "David Robbins K1TTT" <k1ttt at arrl.net>
To: "'John Pelham'" <john at radiophile.com>; "Rfi" <rfi at contesting.com>
Sent: Thursday, February 05, 2004 7:13 PM
Subject: RE: [RFI] My power line noise problems, revisited (Warning,
thisislong!)


> If they had old porcelain insulators and wire and just changed the line
> voltage without replacing them both they that is most likely the biggest
> cause of your problem.  Some engineer planning the upgrade determined
> that the existing insulators and wire were 'good enough' and decided to
> save money by not replacing them.  Most likely there are multiple
> insulators that have hairline cracks which arc when they are dry but
> conduct nicely when they are wet.  If all the rfi guy is doing is
> tightening down clamps and taking care of stray wire ends he is missing
> the likely bad insulators, and while he may get some improvement will
> likely miss the worst sources.  Also if there are old lightning
> arresters called expulsion tubes on the line those should probably be
> checked and likely replaced with newer mov ones, they were mostly
> designed for lower voltages and may cause problems just like old
> insulators.  If you are in a high contamination area, downwind from coal
> burning power plants, downwind from major interstate where they salt
> heavily, etc, the insulators could benefit from a good washing also.
> One important thing that is often overlooked, you are actually doing the
> company a service... every arc they stop is power they are saving, and
> while one insulator arcing may only dissipate a few watts, hundreds of
> them add up... and they are going 24/7 wasting power that adds on to
> your bill in the end.
>
>
> David Robbins K1TTT
> e-mail: mailto:k1ttt at arrl.net
> web: http://www.k1ttt.net
> AR-Cluster node: 145.69MHz or telnet://dxc.k1ttt.net
>
>
> > -----Original Message-----
> > From: rfi-bounces at contesting.com [mailto:rfi-bounces at contesting.com]
> On
> > Behalf Of John Pelham
> > Sent: Friday, February 06, 2004 00:35
> > To: rfi at contesting.com
> > Subject: [RFI] My power line noise problems, revisited (Warning, this
> > islong!)
> >
> > In 2001 I posted here about a line noise problem I was having.  Well,
> I'm
> > still having it and I seek the group's advice as to how best to
> proceed.
> >
> > First, a description of the problem.  I truly believe it to be line
> noise,
> > as it sounds like a 60- or 120-Hz buzz, sometimes containing hissy-
> > sounding
> > audio frequencies and sometimes just a hummy buzz.  Depending on
> > conditions,
> > it is present continuously or intermittently (kind of a sputtering
> sound).
> > It tends strongly to be present in the daytime and not at night, and
> on
> > crisp dry days, and not on rainy, humid, or even just cloudy, days.
> It is
> > most strongly audible on 15, 10 and 6 meters.  Occasionally I can hear
> it
> > on
> > 20M and even on 2M.  When it's going good (which is lots of the time)
> it's
> > S9 on 6M.  It's never audible on, say, the AM broadcast band.
> >
> > In one of my original 2001 postings I lamented how, when I contacted
> my
> > power company, they sent someone out who didn't seem to know or care
> much.
> > He said that if he couldn't hear the noise on his truck's AM radio he
> > couldn't find it, but if I found suspected poles he'd be happy to
> examine
> > the poles and fix any found problems.
> >
> > To make a very long story a bit shorter, I build a DFing apparatus
> > consisting of a 3-element 2M yagi and a 2M HT with an AM detector and
> an S
> > meter.  Right away I found one source: the pole right across the
> street
> > from
> > my house was easily DF'ed as a strong source.  The power company found
> > nothing when they checked the pole, but "tightened the hardware
> anyway."
> > It
> > made a big improvement, which lasted a few weeks as I recall.
> >
> > I kept on complaining, and eventually found that my power company
> really
> > does have an RFI troubleshooting specialist.  Why I wasn't put in
> touch
> > with
> > him the first time, I don't know.  I stayed home from work one crisp
> > morning
> > in January 2003 and met this friendly and cooperative person, and we
> went
> > around the neighborhood a bit together checking poles.  He used three
> > pieces
> > of equipment:  He had an HT-like radio with a rubber duckie antenna
> that
> > he
> > said was tuned to 50 MHz.  He said he used this to check on
> > interference-to-TV-channel-2 type problems.  He also had two
> _ultrasonic_
> > (high frequency audio) receivers; one with a clear plastic parabolic
> > reflector that he used from street level to identify bad poles, and
> one
> > that
> > he used right up at the wires and insulators to search out the actual
> > problem spot.  He said that it was easiest to find arcing by listening
> > ultrasonically rather than listening to radio frequencies.  And
> indeed, we
> > really couldn't hear anything on his 50-MHz radio with the rubber
> duckie,
> > but we identified a couple of arcings with the ultrasonics.
> >
> > It was a very educational morning for me.  But, at this point I need
> to
> > give
> > a bit more background on my problem.  I've lived at this location
> since
> > 1983, and until 1995 or 1996 (I can't remember exactly) there was no
> noise
> > of any kind, ever.  In 1995 or 96 my line noise problems started, and
> they
> > started virtually overnight like someone turned on a switch.  I didn't
> > complain about the problem at that time because my ham radio activity
> > level
> > was very low -- I had other family and job concerns that prevented me
> from
> > doing much hamming.  I had, however, developed the habit of leaving my
> 6M
> > radio on all the time on the SSB calling frequency, so I'd not miss
> any
> > openings.  So it was obvious to me, even though I wasn't active, that
> my
> > quiescent 6M noise level had gone from S0 to S9 overnight.  I just
> didn't
> > have any time to investigate it for several years.  I did notice a big
> > clue
> > right at that time, though.  The power company had just rebuilt the
> entire
> > power grid in my area.  All the lines, insulators, transformers, even
> some
> > of the poles and pole locations, were brand new.  The line noise
> started
> > exactly when they did this.
> >
> > When I told my power company line noise guy this story that morning,
> he
> > nodded knowingly.  He said they had increased the distribution voltage
> at
> > that time.  I don't recall what the old distribution voltage was (I
> think
> > he
> > said either 7200 or 9600 volts), but he said the new voltage was
> 14400.
> > He
> > said that they usually get RFI complaints when they increase the
> voltage,
> > and wasn't surprised that that was when my problems started.
> >
> > What I learned that morning, in a nutshell, was that it's amazing that
> any
> > power can be distributed at 14400 without problems.  Arcing, as
> indicated
> > by
> > our ultrasonic testing, came and went for the most capricious of
> reasons.
> > For example, if a piece of debris were to strike one of those thick
> > stranded
> > cables that jump power from one insulator on one side of a pole to the
> > other, it might get unraveled or "unstranded" slightly.  I'm talking
> about
> > just a tiny fraction of an inch of strand separation, and just for a
> short
> > length, say two inches, of cable.  Just these separated strands would
> arc
> > merrily, despite being fully connected just one inch away.  The
> tiniest
> > hairline or speck of debris on an insulator would cause arcing.  This
> > stuff
> > just loves to arc.
> >
> > Anyway, despite fixing the apparent problems at a couple of poles that
> > morning (and even having my wife listen to the 6M radio in my shack
> while
> > we
> > wiggled stuff and hearing the noise level vary), I noticed no
> appreciable
> > reduction in line noise in my ham shack later.  It was apparent (it
> > actually
> > had been clear to me already) that there were _many_ different sources
> of
> > noise affecting my radio reception.  As he parted, the power company
> RFI
> > guy
> > said that if I would DF the noise with my tower-mounted beam and tell
> him
> > the direction, he would come out and try to find the source and fix
> it.  I
> > did this many, many times over the ensuing months, and he came out
> many,
> > many times in response.  He would usually tell me that he found this
> or
> > that
> > problem and fixed it.  Unfortunately all this activity produced at
> most
> > only
> > a transitory reduction in noise level.  Sometimes there was no
> difference
> > at
> > all.  Often I found the noise very hard to DF since there were several
> > sources emitting at once from different directions.
> >
> > And that's where I find myself today.  My line noise problem, which
> has
> > been
> > going on since 1996, is as bad as ever.  Usually there are several
> sources
> > all acting together to make 15 through 6M unusable no matter which
> > direction
> > I beam in.  As always, the noise is strongest on crisp, dry, winter
> days,
> > and sometimes entirely absent on humid and cloudy days.  My last
> contact
> > with the power company guy was in December 2003.  I bet he's tired of
> > coming
> > out here only to have me report "no improvement" over and over again.
> >
> > So I solicit advice.  Even though the power company guy seems
> > knowledgeable
> > and has noise-finding tools, he hasn't gotten any results in a year of
> > work.
> > I don't exactly know what to do at this point; at least I feel that he
> is
> > "on my side" regarding his willingness to work toward a solution.  I
> don't
> > want to alienate him by suggesting he get help.
> >
> > Also, does anyone know if is really suitable to distribute power in a
> > residential area at 14,400 volts?  From my experience, this stuff will
> > never
> > stop arcing.
> >
> > I hope you enjoyed reading this as much as I did writing it!  Thanks.
> >
> >
> >
> > John, W1JA
> > E-mail    john at radiophile.com
> > Antique Radio Web Site    http://www.radiophile.com
> >
> >
> >
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