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 <[email protected]>
To: <[email protected]>
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
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