[Lf] Utility PLC Interference]

[Andre' Kesteloot]

Richard Brunner wrote:

> " K0TO's deliberate comments on lowfers operations and proposed low-band
>  amateur licensing are well taken. However his contention that the
>  utilities "are not protected from interference" in the low-band raised
>  some concerns by this reader"
>
> The last time that amateur operation was proposed for 160-190 kc, there was
> a very emotional response from the utility people, fearing disasters.  It
> was a case of the blind leading the blind, or people in charge knowing
> nothing about it, but fearing the worst.  Hopefully this time discussion
> will be rational.  In theory, unlicensed operation, (PLC's) has no standing
> and cannot complain about interference.
>
> Utility PLC's are inherently self-protected against interference-caused
> maloperation.  Unless my memory has failed, when they operate something,
> they shift frequency about 500 cycles, and increase output 10 dB to assure
> working through a faulted line.  What we hear, (that dead carrier) is merely
> a keep-alive indicator showing that it is active.  QRM will have no effect
> because at least two things must happen to have any effect; the keep-alive
> carrier disappear and the new one appear.
>
> Note also that power lines are a very rf-noisy environment, which anyone who
> has driven under power lines can attest.  Thus, PLC receiver sensitivity
> ranges from millivolts to volts.  They will never hear a transmitted signal,
> and indeed, the only places they have had trouble was in the vicinity of
> high-power military transmitters.  At best, under ideal conditions, they may
> weakly hear Loran-C.
>
> I will write this up, in detail, with documentation, and submit to the FCC.
>
> Richard Brunner, AA1P, rbrunner at gis.net
>
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