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| Re: Cell Phone not invented 106 years ago (320238) | |||
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Re: Cell Phone not invented 106 years ago |
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Posted by SelkirkTMO on Wed May 21 21:14:38 2008, in response to Re: Cell Phone not invented 106 years ago, posted by RonInBayside on Wed May 21 20:37:57 2008. Nope ... it was the first "inductive loop" telephone ... didn't work at radio frequencies at all, it used DC (battery) and inductive coupling at speech frequencies.If you take #30 copper wire (used for winding coils) and put up 8 turns or so around the perimeter of any sized room on the ceiling, and hook it up to the speaker terminals of an amplifier and then wind about 600 turns of it on a pencil and hook it up to a small battery-powered amplifier and a headset, you've reproduced exactly how the above works. And ... many museums have done just this over the years for "self-guided tours" and as you move from room to room, you're listening to the "ceiling loop" for that room ... |
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