[Lowfer] AC utility meter data signal

[Clint Turner]

Last I checked, the Turtle was made by Hunt Technologies.

Paul Hunt is a ham, btw - WB0DAA.

IIRC, the turtle works by modulating the power factor at a rate slightly 
different from the line frequency.  This modulation is extracted at the 
power company end (which could be many miles away) and serially-decoded 
using UNB techniques - that is, only a few bits per hour.  Every 
customer gets a unique frequency (w/relation to the powerline freq) and 
in the simplest message, it is the meter count that is transmitted.  It 
can take many hours to send a message - but if you only bill monthly, 
then who cares.

It is also used to observe power failures as a loss of carrier can be 
detected fairly quickly - and if properly configured and interfaced with 
the SCADA, the extent of the outage - and its likely source - can be 
determined.

My boss (who is WA7X - Google the call if you are interested) has one of 
these at his cabin and during the many times that we've operated from 
there we've not noticed any obvious hash on HF, or on what little LF 
I've listened to from that site - but then again, power is underground 
and the meter is hundreds of feet away from the cabin.  (It would be fun 
to put a grabber up there...)

We've tried to detect the modulation but with the detection point being 
upstream, it just doesn't work - at least not with anything we've tried 
yet...  (Yes, I tried a bunch of things although I didn't connect to the 
"utility side" of the power meter...)

Clint
KA7OEI



Scott Tilley wrote:
> Hi Dex
>
> Can you look at the meter and send me any information that would
> identify who made it ?  A picture would be nice :-)
>
> Does your utility offer any online information about their smart meter
> program?
>
> Thanks,
> Scott
> VE7TIL
>
>
>
> On 2/10/2011 7:01 PM, Howell, Laurence J wrote:
>    
>> Looks awful - managed to persuade utility to remove my Turtle which gave pulses across LF with an analogue which is read Manually - more houses coming up nearby so I'm sure it will get worse. I am going to see if I can shunt some of it by decoupling using some 660VAC 13uF's - may get some complaints!
>>
>> Laurence
>>
>> ----- Original Message -----
>> From: lowfer-bounces at mailman.qth.net<lowfer-bounces at mailman.qth.net>
>> To: Discussion of the Lowfer (US, European,&amp;	UK) and MedFer bands<lowfer at mailman.qth.net>
>> Sent: Thu Feb 10 20:45:21 2011
>> Subject: [Lowfer] AC utility meter data signal
>>
>> I just uploaded a spectrum display of my utility meter transmitting it's
>> data.  It appears most of the energy is around 4 kHz but the
>> transmission can be heard well up into the AM BC band.  Maybe higher.
>> I've been trying different antenna configurations trying to detect other
>> meter transmissions in the area.  This evening I was able to detect at
>> least a dozen.  Fortunately most are very weak.  Only the one on my
>> house and another on my property creates significant QRM.
>>
>> http://www.w4dex.com/misc/ac_utility_meter_data.jpg
>>
>> Dex
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