Message-ID: <001a01c4ee6f$175d7d80$28540150@captbrian>
From: "captbrian" <captbrian@ukonline.co.uk>
To: rsgb_lf_group@blacksheep.org
References: <1d8.3390f377.2f04f91b@aol.com> <002001c4ee52$9e477a70$6501a8c0@eagles>
Date: Thu, 30 Dec 2004 12:57:15 -0000
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Subject: LF: Re: Power Line Carrier gear   de VY1JA
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The Part 15 rules restriction  of 15 metres seems to include the "feeder" ,
one would have thoght this precluded the use of  100 mile power lines as
"transmission lines" then....

One can only  applaud VY1JA's  suggestion of presenting "them" with results
of competently conducted tests.

Details of the Canadian's rotation of the transmission lines would be
interesting  to me.

Whether "they" in one country will take any notice of "Them" in another tho'
is anybody's guess.


Bryan


----- Original Message -----
From: J. Allen <vy1ja@northwestel.net>
To: <rsgb_lf_group@blacksheep.org>
Sent: Thursday, December 30, 2004 9:33 AM
Subject: LF: Power Line Carrier gear de VY1JA


> John,
>
> I would be quite surprised if Power Line Carrier equipment were disrupted
by
> amateur equipment.  The power lines are rotated physically to balance
fields
> for a number of reasons.  It just happens to help prevent line
transmission
> of PLC signals and pickup of our LF signals.
>
> Installation, and maintenance of PLCs  came under my supervision until I
> retired from Yukon Energy Corp three years ago.  If a small utility like
YEC
> installs and maintains things with this care, I suspect that the fears of
> power company problems in the populated world south of us are totally
> unfounded....
>
> I will find out some of this, because several of the men in my previous
crew
> are still with the power company and are all licensed amateurs.  My
> experiments will be done in such a way that they can monitor my early
> transmissions and signal levels (or as I suspect, absence of them) on the
> PLC subsystem.
>
> It is my belief and expectation that this kind of monitoring and testing
can
> demonstrate that amateur LF work can cohabit the same neighborhoods as PLC
> SCADA control systems.  The 138,000 Volt line which carries the PLC
signals
> is approximately 100 meters from the tower which will be the 137 kHz
> antenna.
>
> The way the PLC works is that the power transmission line also is used as
an
> RF transmission line.  The PLC transmitter runs approximately 75 -150
Watts
> directly into the line and the line carries that to a matched load of a
> transmitter/receiver pair on the opposite end of the line.  With the high
> signal levels that are forced into the line and received on the opposite
> end, I cannot see how the small amount of signal that is picked up by the
> antenna effects of the power line can compare or how it can cause any
> trouble.
>
> Has anyone in the UK heard of any LF transmitter causing problems with
> PLCs?.  If so, I would appreciate knowing the details.
>
> J.
>
> VY1JA
> CP20kw
>
>
>
>