h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

Does anyone know if it is safe to put up a mobile phone mast inside a church steeple? I am worried about the health risk to children who use the building all week for community activities such as playgroup, not just Sunday school.

If you ask any authorities then they will tell you (in other words) that 'the darkest place is always right under the lamp'. However, there are some quite complicated factors in the equation: * Base stations are designed to cover the /area/ (not a volume) surrounding them, hence their antennas are designed to radiate in a wide horizontal beam which is quite narrow in elevation, and has close to /no/ radiation up/downwards. There's still some spurious radiation from so-called sidelobes of the antenna patterns. * On the other hand: A base station transmits total power of some 1..10 Watts, which is spread into 360� azimuth. Power levels decrease with an inverse square law over distance, that is, if you double the distance then you receive a quarter of the initial power, thrice the distance yields 1/9 power etc. Given the geometry of a church (as in the posting above), the total dissipated power in some building across the road is by far more than right under the steeple. * The mobile phone in your hand transmits between 0.5 and 1.0 Watts with close to omnidirectional distribution, and if held close to the ear then your head is exposed to roundabout half that power at nearly zero distance! * But: Base stations can be assumed to be operating 24 hours a day, whereas your mobile phone logs into the nearest station (and updates this contact every 1/2 of an hour, requiring some split seconds) and then remains quiet, as long as you aren't having a conversation. * Most of the studies covering the issue only elaborate on the thermal effects of microwave radiation, ie, they are talking in terms of SAR, specific absorption rate. The underlying model is that of human tissue representing some ohmic lossy media which more or less effectively converts microwave energy into heat. What SAR does not cover is any interaction between electromagnetic waves and nerves as the human 'signal processing equipment'. So the bottom line is that... there is no bottom line . An awful lot of studies has been produced, and their results clearly depend on who payed for them :-( You might also want to follow this conversation: http://www.bbc.co.uk/h2g2/guide/F19585?thread=99068