Smart meters.

I was chatting to Kerrie's mum the other day and she was worrying about Smart meters. These are utility (usually electric) meters that can communicate their readings via radio waves & the internet to the utility companies to allow them better control of their generation plant. She'd been surfing the internet and had found sites warning about cancer and other health problems caused by the radiation from Smart meters. These sites are creating fear, uncertainty and doubt in order to sell solutions to problems that don't exist. Oh, dear.

Warning! Radio Frequency (RF) engineering stuff:-

See the graph below?

The horizontal axis is incorrectly labelled. Distance (d) is in metres (m), not kilometres (km).

Trust me. I know what I'm talking about. I was an RF design engineer for 29 years. See my CV.

The vertical axis is path attenuation (loss) in decibels (dB).

Decibels 101: Power loss in dB = 10 x LOG10 of the loss as a fraction.

A power loss of down to One tenth = 10dB. One hundredth = 20dB. One thousandth = 30dB. One millionth = 60dB. One million millionth = 120dB. One half = 3dB. One quarter = 6dB. One eighth = 9dB. Got it?

Smart meters transmit at frequencies from 900MHz (Vodafone & O2) to 1.9GHz (Orange & T-mobile etc). I mentioned mobile phone networks, as people don't seem to mind having mobile phones glued to their ears for long periods of time.

If you stand 4 metres away (at the end of someone's garden path, say) from a Smart meter fitted to their house & operating at 900MHz, there's a path loss of 29dB. The RF energy reaching you is 1/800th of that emitted by the meter. Also, the meter doesn't produce RF energy all of the time. The duty cycle is 1% to 5% i.e. RF energy is only produced for 1/100th to 1/20th of the time.

In conclusion, even if you stand with your nose touching the glass window of a Smart meter, you get less RF radiation (RF radiation is Transverse Electromagnetic Radiation a.k.a. radio waves and not ionising radiation as from radioactive materials) than from your mobile phone.

Are you feeling reassured, now? My work here is done!