"Sal M. O'Nella" wrote in message
...

I share your skepticism, Ian, and I'd like to take it a step further.

There is real math (imagine that!) to address the notion of "stealing
power from a nearby transmitter." Free-space attenuation is given by the
formula
20 log Rf + 37dB, where R is the range in Nautical Miles and f is the
frequency in MHz.

True, a close-in VLF transmitter gives good coupling and actually will
light an unconnected fluorescent tube. However, these stations are quite
rare and nobody moves near them to "steal power," since they are built in
large open areas with fences and guards. Need backup plan.

Next best bet: Get within 500 feet of a 50KW AM station, say KFI, AM-640
or KBOI, AM-670. Per the formula, the coupling loss will be about 13 dB,
making 2500 watts of power available to you at that location. However, to
realize that power, you need an antenna with near unity gain at that
frequency. Any guesses as to how much they cost? Try $Millions. (It's
called a 600-foot tower.) Much better to call your local utility and tell
them how much you appreciate their service. Resolve to be more realistic
about power-robbing schemes.

COMING NEXT ON THE POWER ROBBER CHANNEL: Tap into your neighbor's garden
lights -- it's easy!

73,
"Sal"

Hello Sal. Thank you very much for the maths and the workings. Stories of
"getting useable power from a transmitter" are always hard to track to an
accurate source. The nearst I've gotten is a friend who knew of a cottage
with a 33kV power line passing overhead. Seems that some turns of wire were
fitted under the cottage's eaves and some useful power was obtained.
Transfoemer action, I assume.
I've read science fiction stories form the 1930s where "broadcast power" was
in general use. One story had all users switch off their powere receivers so
that the authorities could D/F a wanted person by measuring the strength of
the power field. Ah - unfettered imagination though induction does work when
the power source and appliance are close together.

73, Ian.