[Lowfer] Smart Meter Noise

[Dexter McIntyre W4DEX]

I have a underground multi pair cable running several hundred feet to 
two buildings that I laid while installing water and power to the 
buildings.  I initially had no particular plans for the cable but I had 
it so I took advantage of the opportunity to bury it while the trench 
was open. Since it was installed about 23 years ago I have used the 
cable for phone, intercom, feeding packet audio and various control 
functions.  The intercom has some AC hum on the audio but is very tolerable.

When the present smart meter was installed on my house last summer I 
initially heard the brief transmission very strong on the intercom.  
This noise was in sync with my UPS switching so I immediately suspected 
the smart meter as the source.  The meter transmission are about 4 
seconds duration and occur about every 4 to 6 hours.  The noise is very 
noticeable from VLF up through MF. 

Today I noticed, very faintly, more frequent transmissions on the 
intercom, obviously not from my meter but perhaps from the polling 
station.  This gave me the opportunity to investigate the signal more 
throughly.

What I found, which may be the prime signal, is a burst occurring 
between the seventh and ninth harmonic of 60 Hertz centered at 480 
Hertz.  Below is a SpectraVue capture of the signal.

http://www.w4dex.com/qrm/smart_meter/smart_meter_signal.jpg

I suspect someone who lives near the polling station or closer to a main 
power line would have much more problem with this signal if they listen 
to AM radio or by chance they are a VLF/LF enthusiasts.  I may take a 
portable out the the substation just to find out.

Welcome to the Smart Grid world.

Dex