I dont' think the original message on this subject came through to me, but
I'm interested since my next-door neighbor has an electric fence around a
flower bed to keep out the deer and bears. Much of the time it is (as much
as) 20db over S9 pulses from below the broadcase band to beyond 2 meters
somewhere. At its worst, I can hear it a mile away on 80 & 40m.
I called his fence charger manufacturer and actually got a knowledgeable guy
who was most helpful. In addition to the info given below, he suggested the
following...
1) Make sure the wire feeding the fence is insulated for 20K volts. Romex
or other wire, not intended for this use, can arc if it gets close to
anything else. (My neighbor used Romex. He actually used something that
looks like very light weight rotor cable with the conductors twisted
together for the last four feet of his ground connection.)
2) If there are "joints" in the wire, make sure the two sections are
connected with a compression clamp sold for that purpose, and try to avoid
mixing types of wire. (This one has multiple twisted and one soldered
connection, both of which the expert advised against.)
3) The insulators used in his self-installed fence are generally good, but
those he nailed to trees have very, very little insulation between the nail
and the wire. I bought some good nail-in insulators made for this use.
As so often happens... the day I bought about $40 worth of stuff to fix the
fence with, it quit radiating... for the first time in a couple of years,
according to a ham who has lived nearby for a long time. (We just moved
here in April.) So, the mere act of threatening the fence with repair
appears to have worked as at least a temporary fix. I can't hear it now
with an S1 noise level and no noise blankers turned on.
The fellow at the fence company had one last thought that might help
convince a fence owner to let you check his out... "If there is as much RF
being generated as you say, his 4,000-volt charger probably isn't delivering
200 volts to the fence. Interference always indicates something wrong that
will reduce the voltage, and the efficiency, of the fence."
Ed, W5EJ
----- Original Message -----
From: Brian Smithson <brian_smithson@vds.com>
To: <towertalk@contesting.com>
Sent: Tuesday, November 02, 1999 4:52 PM
Subject: RE: [TowerTalk] Fence Noise
>
> I have an electric fence at my house and there are three
> things that make it noisy -
>
> 1. Grounds somewhere. Most common is the nails holding
> the insulators to posts or trees. Walk around the fence
> at night listening for/and looking for sparks. I've fixed
> them by bending the wire out of the way and/or plastic
> spoons over the ends of the nails.
>
> 2. Poor ground at the charger, as Steve suggests. Often
> (as is the case with mine) there is just some wire
> wrapped around the terminal going to a ground rod. Make
> sure the connections are clean and solid. Ditto for the
> wire to the fence itself.
>
> > -----Original Message-----
> > From: owner-towertalk@contesting.com
> > [mailto:owner-towertalk@contesting.com]On Behalf Of K7LXC@aol.com
> > Sent: Sunday, October 31, 1999 9:59 AM
> > To: ATanner283@aol.com; towertalk@contesting.com
> > Subject: Re: [TowerTalk] Fence Noise
> >
> >
> >
> > In a message dated 99-10-31 08:16:57 EST, ATanner283@aol.com writes:
> >
> > > Anyone have any experiance with electric fence noise??? How can the
> > > "pulsing" be nullified at the source????
> >
> > Generally electric fence noise is worst when there is some
> > part of the
> > fence that is being accidentally grounded (i.e. weeds across the
> > bottom fence
> > wire or branches touching it) or in poor shape. You have to go to the
> > electric fence and clean up the weeds. Usually owners don't mind
> > you doing
> > that if you ask.
> >
> > I was having some problems with one and the owners said I
> > could look at
> > it. Turns out the ground wire had deteriorated and wasn't making
> > much of a
> > connection. Fixed it and the noise went away.
> >
> > Problem electric fence noise can be coming from miles away.
> > Remember
> > that fence acts like an antenna and the noise will propagate.
> >
> > Have you found the source yet?
> >
> > Cheers, Steve K7LXC
> > Tower Tech
> >
> > --
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> >
>
> --
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>
>
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