[Lowfer] Progress comes to the boondocks

[Ed Phillips]

Lyle Koehler wrote:
> 
> This afternoon a guy from the local electric utility came and replaced my
> old electric meter with one of the new-fangled remote reading units.
> 
> Q: How does it work?
> 
> A: It sends pulsed signals via the power lines to the central office.
> 
> Q: All the time or just once a month?
> 
> A: All the time.
> 
> Q: Will it cause radio interference?
> 
> A: We have had no complaints. (Why didn't that make me feel any better?)
> 
> I now hear very strong pulsed noise across the entire LF (30-300 kHz)
> spectrum. The noise tapers off rapidly above 300 kHz, and is essentially
> gone by 500 kHz. Noise blankers in both of my receivers (IC-756PRO and
> IC-706) are fairly effective in suppressing the noise, to the point where I
> would be able to hear local LowFERs in aural CW mode. It is difficult to say
> how much effect this will have on weak-signal reception, but it certainly

	Southern Cal Edison installed such a meter here a while back and since
then I haven't noticed any noise such as you describe.  It's quite
possible different meters work on different principles, but a very
knowledgeable friend of mine consulted on the design of at least one
such system.  This operated on the principle of the RF ID gadgets; no
power supply and only transmit when someone in a car drives down the
street interrogating it with an RF signal (don't know what frequency). 
If you'll look up "RF ID" on Google (or elsewhere at your choice) you'll
get a lot of references.  Basically, these gadgets have some sort of
loop antenna which receives and rectifies an interrogate signal, 
storing enough energy to permit a coded reply transmission.  You can
find data sheets on more than one type on the web.  The ones with which
I'm personally familiar respond to a very near by transponder coil. 
Some of our parking lots at work use this principle.  You hold your
parking pass badge up to a "black box" and it reads the thing and raises
the gate.  Whatever circuits are involved, they fit into a credit-card
sized plastic gadget with no bumps.  I think I'll take a receiver to
work and try to see if I can hear the signal from the thing.

Ed

Ed