[Lowfer] AC utility meter QRM on LF

[Stan, W1LE]

  Hello Dex,

1. Would be interesting to get a broadband current probe around one of 
the AC conductors,
then feed the probe output to the Rx.

2. Maybe the manufacturer has a out of band RF power trap to place at 
the source (meter).
Suppress the noise at the source.

3. Maybe the manufacturer or the electric coop RFI/EMI section can 
advise on where
the real energy is, freq wise. So all other energy can be suppressed.
I would lodge a formal RFI/EMI complaint with them first....
Interfering with FCC licensed emergency radio communications.... blah, 
blah, blah

4. The plastic (non-metallic) meter case may not provide adequate 
shielding,
supplement with a metal shield.

Stan, W1LE       Cape Cod     FN41sr


On 10/6/2010 1:05 PM, Dexter McIntyre W4DEX wrote:
> My local power utility recently replaced a 900 MHz remote reading meter
> with a new type.  The 900 MHz meter had a FCC ID and I was able to find
> all the test data on that meter when it was installed about 5 years
> ago.  The new meter has no FCC certification probably because it
> transmits it's data via PLC.  The 900 MHz meter required a drive by to
> read the power usage once a month where as this new meter transmits data
> multiple times per day.
>
> As soon as the new meter was installed I noticed several UPS units I
> have online would switch to battery.  Then I started havening problems
> with several X-10 devices which would either toggle on or off when the
> meter sent data.  The data regularly transmits every 12 hours with what
> appears to be random minute intervals.  I have also noticed it often
> transmits at either 4 or 8 hour intervals.  The data last for about 3
> seconds.  This data appears to be very wide band or at least generating
> a lot of wide band noise when it transmits.  I have been trying to
> determine at what frequency most of the power is on but so far haven't
> been able to.  At first I thought since the X-10 units were being
> scrambled the meter might be on 120 kHz.  But we know 120 kHz will not
> pass through power distribution transformers, at least not at X-10 power
> levels.
>
> Today with the SDR-IQ set to view 0 to 190 khz and connected to my LF
> xmit antenna I can detect what appears to be other meters also transmitting.
>
> Picture of the SDR display which shows the approximate 3 second
> transmission:
>
> http://w4dex.com/temp/ac_utility/utility_meter_data.jpg
>
> Picture of the meter:
>
> http://w4dex.com/temp/ac_utility/utility_meter_landisgry_focus.jpg
>
> I'm afraid this will be a real nuisance when I connect my LF receive
> antennas for the winter.
>
> Dex
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