Smart Meter

Smart Meters send data about your electricity use to your electricity company over a radio link.  Some Smart Meters communicate over the cellphone network, while others use a purpose-built network.

Smart Meters that use the cellphone network are usually made by EDMI.  Usually they only send data back once per day. Apart from that they only transmit very briefly every hour or two to keep in touch with the cellphone network.  

The graph below shows exposure measurements recorded inside a house, just behind an EDMI Smart Meter that sends data over the cellphone network mounted on the outside wall.  The measurements were recorded over two days.  

The red trace shows the times when the meter is transmitting. (When you see the red trace the meter is active.  If you don't see it, the meter is not transmitting.)  Most of the time it is only active about every hour and a half.  During most of these active periods, the total time during which there is some transmitter activity is about four seconds.  

A couple of the red lines look slightly thicker than the others (for example, just after midnight on the second day).  This is when the metering data is being sent.  The total time over which data is transmitted is about 40 seconds.  Altogether, the transmitter was active for just over two minutes per day.  

The blue diamonds show how strong the radio signal is at the point where the measurements were made . The peak exposure was recorded twice per second while the transmitter was active.  The maximum exposure varied between 0.1 and 0.01% of (ie between one to ten thousand times lower than) the limit allowed for the public in the New Zealand exposure Standard.  

The transmitter does not transmit continuously while the communication is active, so the average exposure over these periods is even lower.  The exposure would be much weaker away from the point right behind the meter.  

One of the consequences of the way this type of meter operates is that measurements can be very time consuming.  


Last updated: 12 May 2018