[Milsurplus] A New Concept: Virtual Spectrum

[w8au@sssnet.com]

At 09:02 AM 10/14/2003, RJ Mattson wrote:
>Do you think hackers had anything to do with these blackouts?

I don't think so.  I checked with the system dispatchers at First Energy
and they mentioned that one of their monitors (CRT) was down.  This
is normally not an emergency and is reported the next morning so that
the techs can repair it.
A major inter-tie with American Electric Power (Canton, OH) automatically
tripped and caused a major reversal of power flow through Canada and Mich.
This could have been avoided, perhaps.   However, this one instance was
not the only cause.

>You mentioned " Utilities use of  PLC is very
>minimal these days, with only "trip blocking" and "trip enabling" modes
>used
>between substations and power plants.

This is true, and it's major point is that the FCC rejection of the LF 
amateur band
due to "power grid integrity" was just a smoke-screen.  Interaction between
Radiated RF and conducted RF on HV lines is highly unlikely due to many
factors.  However, even if this could happen, the likelihood of any damaging
effects is nil.  A zero beat signal on a "trip blocking" circuit would only 
reinforce
the trip-blocking and no breakers would open.   The trip-enabling scheme calls
for two signals to shift in opposite relation to each other.....  one 
signal shifts
1 kHz low and the other shifts 1 kHz high, simultaneously.   No amateur 
communication would
imitate this, (two separate xmtrs)  and especially on the specific 
frequencies involved.
Another safety factor is that Carrier Current receiver sensitivities are 
measured
in volts, not microvolts.  This is to eliminate noise problems that are 
inherent
on AC lines.

The former uses of AM and FM voice, SSB telephone channels, telemetering
and remote control on PLC are long gone.....shifted to Microwave and Fiber.

I sometimes wonder why the FCC has a "chief engineer."  Lately they either
have not used his services, or he has been over-ridden by other agendas....?

73,

Perry