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is an informative, cynical and sometimes humorous look at what is happening in the world of amateur radio.

Friday, 24 July 2009

Wireless charges coming soon?

The BBC has news of a wireless power system which sounds a bit too like like snake oil hocus pocus for me to believe it has any real world use. Its proponent Eric Giler, chief executive of US firm Witricity, showed mobile phones and televisions charging wirelessly at the TED Global conference in Oxford. The system is based on work by physicist Marin Soljacic at the Massachusetts Institute of Technology (MIT) and uses a magnetically resonant antenna to ‘transmit’ power to a similarly equipped device.

It is able to do this by exploiting an effect that occurs in a region known as the “far field”, the region seen at a distance of more than one wavelength from the device. In this field, a transmitter would emit mixture of magnetic and potentially dangerous electric fields, but, crucially, at a distance of less than one wavelength – the “near field” – it is almost entirely magnetic. The technology uses low frequency electromagnetic waves, whose waves are about 30m (100ft) long. Shorter wavelengths would not work.

30 metres! That would be the 30 metre band gone then and imagine the massive interference that would be generated if everyone in the country had a couple of these things in their homes.

So they are saying that you would be safely away from the potentially dangerous electric fields which would occur where? Surely the accumulative effects of living 24/7 bathed in RF from multiple sources can not be ‘harmless’.

Magnetism itself has been shown to have an effect on living cells. Plants grow bigger in a magnetic field for example. How about tumours? Maybe all our children will grow to seven feet tall. How can they be so certain it will be harmless?

If I remember rightly Nikola Tesla was doing this ages ago. He even went so far as to build a 29m-high aerial known as Wardenclyffe Tower in New York to prove power could be transmitted , but he ran out of money. If this turns out to be more than just a snake oil salesman’s pitch for a cure all then the technology has been a long time coming and it makes me wonder what else that was derided by science at the time should we be looking at again?

Now where was that stuff I read on zero point energy?

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