[AMRadio] Carrier Current Transmission (was Westinghouse Test

D. Chester k4kyv at charter.net
Sat Apr 12 15:59:46 EDT 2008

> From: "Chuck Kembring" <kembring at epix.net>

> Hello Bruce...
> I believe the panel you describe is from an Electric Utility Company's
> transmission sub-station carrier current test panel.
> They frequently transmit carrier current acrossed the high tension lines 
> to
> control devices at a remote location and transmit voice and telemetry 
> data.
> This is just a simple vom and RF milliamp meter you describe.
> It slips into a bracket usually near the top of a 19" rack. You generally
> have a couple of these at the site and you can move them from rack to rack
> as you test and calibrate the carrier units associated with each power 
> line.
> I hope this answers your question. Sorry it's not about some neat piece of
> rare radio gear but it is still RF...
> 73,
> Chuck WB3LGG

That carrier current transmission takes place at LF and VLF, down below the 
AM broadcast band.  It is unlicensed, operating under Part 15 of the FCC 
rules.  This is the unlicensed serviced that pre-empted the proposed 
low-frequency amateur radio allocation.  The FCC said they were afraid that 
licensed amateur operation in this part of the spectrum would interfere with 
the unlicensed carrier current communication used by electric power 

Yet, they make a completely about-face claim regarding BPL, maintaining that 
digital rubbish transmitted over unshielded elevated power lines at HF will 
not cause harmful interference to amateur radio and other licensed services 
in the 1.8 - 80 mHz part of the spectrum.

Go figure.

Don k4kyv

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