Re: Erm, what about Microwave ovens???
"As I doubt if the ovens are linked to a frequency standard (mine aren't) or are crystal-controlled (I've got to whip one of mine apart 'cos of a funny sound - pictures at 11 - to discover this fascinating fact), they might stray into the WiFi band. Or just block the WiFi receiver."
As a point of information, they are in fact intimately linked. The 2.45GHz band is one of 11 internationally agreed Industrial, Scientific & Medical (ISM) bands. These bands are unlicensed because of the acknowledgement that various ISM devices such as microwaves, MRI scanners etc are likely to blast out noise in that band, making them impossible to regulate. Microwaves *have* to operate in the 2.45GHz band because that is the wavelength which produces the correct excitation in water molecules which is their whole principal of operation. 2.45GHz was deregulated *because* of microwaves - it's not a coincidence.
Microwaves aren't actually supposed to blast out noise, but they will if their shielding breaks - which is does occasionally. Licensing that part of the spectrum to a company would be a little unfair because every so often a broken microwave would take out their communications. Instead, OFCOM has allowed a free-for-all and we've developed noise-resistant devices such as Wi-Fi transceivers which can, in theory, operate in the presence of interference.
Hope that's useful.
Paul
http://en.wikipedia.org/wiki/ISM_band
http://www.ofcom.org.uk/radiocomms/isu/ukfat/
Biting the hand that feeds IT
