[LAD] Wireless Electricity vs audio quality

[Bob Sanders]

Dan Mills, mused, then expounded:
> 
> Wireless power transmission by low frequency resonant coupling **IS** a
> useful trick in some circumstances (I have seen it used to charge hand
> lamps for use in explosive atmospheres for example (Well over ten years
> back)), and in intels case could be used to for example power a wireless
> mouse or charge a phone, but you can bet there would be a handshake
> between the device and the charging pad prior to RF being applied. 

About 10 yrs ago, I worked for a company that made a transponder that
mounted on the bottom of a locomotive and communicated with an RFID
r/w tag that was mounted on the sleeper between the rails.

The transponder had a low freq - 125 KHz, loop that sent power to the
tag, which woke up and converted the power to DC, approx. 15mw to power 
the tag.  Data communications took place at 2.4GHz.  I forget if they 
went to England or France, but they may still be in use today.

Bob
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