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Old September 24th 13, 07:40 AM posted to rec.radio.amateur.antenna
David Platt David Platt is offline
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First recorded activity by RadioBanter: Jul 2013
Posts: 46
Default Powerline TX antenna? Am I crazy?

In article ,
Anya T. wrote:

Should I expect appliances and electronics in the house to blow up (or
otherwise be damaged) by upward of 100W coming down the power lines?
Would it be effective only as a TX antenna? i.e. would RX noise be too
great even with the filter network?


Some folks used to try to use house wiring as an "incredibly powerful
TV antenna" (via a simple capacitive coupling). Fancy-looking gadgets
were sold through catalogs, often for high prices, to do
this... actual parts cost was probably a dime. By all accounts they
worked poorly - far too much RF "hash" on the mains, even in the days
before switching power supplies became common - static-filled,
multipath-ridden ghosty TV images were about the best you could
expect. For weak signals such as ham transmissions I doubt you'd find
it worth the trouble.

As to transmitting? I'd expect that you'd probably succeed in
completely disrupting the reception on any TV or radio in the house,
or on the same mains circuit. Might even fry something in the front
end, crash computers, etc. - the RF filters built into power supplies
are designed to block low-level RF noise, not a shrieking holocaust!
You'd certainly trip every GFI in the house the instant you keyed
up... they'll sometimes trip just from having near-field coupling between
the house wiring and a dipole.

These days, "pole pigs" sometimes have capacitive bypass built in, to
allow over-the-powerline signals from the power company to reach the
power meter. Even for those that don't, you could probably figure
that you'd be coupling a significant amount of power through the
transformer via inter-winding capacitance. So, the 'pig probably
won't block your signal very effectively.

So, I suspect that the interference complaints from your neighbors
would probably start churning in very quickly. The power company
would probably be miffed when they found out. If your tuning placed a
high RF voltage on the pole pig windings and started some arcing
within the pig... well, that could be both embarrassing and
expensive. Since there's no way any such transmitting attachment to
the mains would be UL certified, you could easily be found at fault
for any Badness which occurred.

Sounds like a Bad Idea to me, unless you like interesting fireworks.