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[RFI] Re: rfi-digest V1 #92

To: <rfi@contesting.com>
Subject: [RFI] Re: rfi-digest V1 #92
From: Jim Keyes <jkeyes@mtnhome.com> (Jim Keyes)
Date: Tue, 15 Sep 1998 21:02:06 -0700
The "fuzzed up or fuzzed out" term refers to what the terminal looks
like. Lots of fuzzy hair growing around it! Usually aluminum oxide and
copper oxide mix. Both are semiconductors [because of contaminants, etc]
and pretty good rectifiers and re-radiators. Even becomes a form of
spark-gap xmtr in some cases! Your rf energy was being re-radiated
[probably on several new frequencies, too!]. Those problems give new
meaning to the term "spread spectrum". Glad you found it and told us
about it.
Jim Keyes, WA1TQG/5

rfi-digest wrote:
> 
> rfi-digest         Monday, September 14 1998         Volume 01 : Number 092
> 
> In this issue:
> 
>     [RFI] Follow-up static
>     RE: [RFI] Follow-up static
> 
> See the end of the digest for information about na-user-digest
> 
> ----------------------------------------------------------------------
> 
To: <rfi@contesting.com>
> Date: Mon, 14 Sep 1998 07:40:48 -0600
> From: kboswell@aetn.org (Kelly Boswell)
> Subject: [RFI] Follow-up static
> 
> >>Found the source of the static.  Utility pole 100 feet away.  The neutral 
> >>wire
> to a transformer primary was "fuzzing".  (The utility's term, not mine.)
> 
> >>Noise level dropped to S2.
> 
> >>Hooorrray!!
> 
> >>Thanks to all who responded.
> >>Kelly
> >>KA5MGL
> 
> It is certainly nice get rid of that static problem.  Another benefit is a
> reduction in RFI.  Previously, anything over 50 watts created such 
> interference
> my neighbor couldn't use the telephone, watch TV or listen to the radio.  Now,
> she says there is no interference at all--even at 500 watts.  Which brings up
> the question, why is that?  How could a bad neutral connection, (no, not
> ground) a hundred feet away increase the RFI to a neighbor less than twenty
> feet away?
> Any thoughts?
> 
> Kelly, KA5MGL
> 
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> ------------------------------
> 
To: <rfi@contesting.com>
> Date: Mon, 14 Sep 1998 10:19:13 -0500
> From: "EDWARDS, EDDIE J" <eedwards@oppd.com>
> Subject: RE: [RFI] Follow-up static
> 
> > >>Found the source of the static.  Utility pole 100 feet away.  The
> > neutral wire
> >  to a transformer primary was "fuzzing".  (The utility's term, not
> > mine.)
> >
> > How could a bad neutral connection, (no, not
> > ground) a hundred feet away increase the RFI to a neighbor less than
> > twenty
> > feet away? Any thoughts?  Kelly, KA5MGL
> >
>         [K0iL]  The neutral connection "IS" the ground connection both
> at the pole xfmr and at the the breaker panel or meter (or wherever they
> connect the ground at the entry to the house).  The distribution feed
> circuit to most homes is a bi-phase feed: i.e. two different 120V phases
> and a grounded neutral.  The voltage across the two phase is then 240VAC
> while the voltage across each phase to neutral (or ground) is 120VAC.
> The electrical safety ground (the third prong or the green wire) in your
> household wiring is connected to the neutral in the breaker panel.  This
> is also why you can have a power "outage" in half of your house while
> the other side stays hot.
> 
>         A bad ground or neutral connection at any of the grounded points
> can cause noise as well as other strange effects.  For example, it can
> also lead to shortening the life of light bulbs on one phase or the
> other.  If the air conditioning is on one phase, when it kicks on it can
> drag the voltage down (less than 120VAC) on the phase it's connected to.
> If the neutral connection is bad, this can result in an increase
> (greater than 120VAC) on the other phase leading to bulbs burning out
> prematurely or even other equipment failures if it's bad enough.
> 
>         Anything that can cause noise (EMI) can also pick-up noise (EMI)
> and conduct it to wherever it can do the most damage, and vice versa.
> You will normally induce some RF into nearby power lines since they are
> just wires (read "antennas").  This is a not a problem in well grounded
> electical circuits, and non-resonant transformers provide some isolation
> also.  But a loose connection or loose hardware anywhere in the
> electrical system can cause havoc in many ways!  You've found one very
> interesting way.  Congratulations!  Now if I can just convince my power
> company to quite using those pronged squirel guards that keep getting
> noisy!
> 
>         73,
>         de ed  -K0iL
>         Omaha, NE
> 
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> 
> ------------------------------
> 
> End of rfi-digest V1 #92
> ************************
> 
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