[Lowfer] Re: New ham band

[James Moritz]

Dear Perry, Lowfers,

At 07:56 21/01/2003 -0500, you wrote:
>Other than that, PLC usage by utilities is at it's lowest point ever,
>with all "intelligent" or data type modes being conveyed on Microwave
>or Fiberoptic links.   The remaining usage consists mainly of "trip blocking"
>signals that are sent to "prevent" unnecessary tripping of substation breakers
>when a fault occurs somewhere on a HV path.


At my QTH north of London, UK., there is a steady S5 carrier at about 
136.65kHz, in the middle of the CW band segment here, so quite irritating. 
A while ago, I D/F'd it to some power lines about 10 miles away near the 
town of Watford, so I assume it is one of these "trip blocking" signals. 
But in spite of what a power company might perceive as my protracted 
efforts to jam this signal by transmitting to other amateurs using various 
types of modulation at full legal limit power levels (which are a couple of 
dB higher than proposed in the US), nothing seems to be happening. Of 
course, at this distance my signal is tiny compared to the government and 
utility transmitters that fill the LF spectrum here.

I can't quite believe that power companies would be foolish enough to risk 
their multi-billion dollar operations by using a signalling system so crude 
that it fell over whenever anyone keyed a transmitter (or some other piece 
of power electronics for that matter) nearby. The European experience is 
that it does not happen anyway. So I would suspect that the US power 
companies either have not really thought it through, or are more worried 
about radio users complaining about interference from PLC signals, rather 
than interference to these signals.

Hope you get 136k soon,

Cheers, Jim Moritz
73 de M0BMU