[Elecraft] [OT} Wireless chargers (or transmission of electrical energy by wireless methods.)

[Edward R Cole]

Probably unknown or forgotten was the NASA project to beam solar 
power from orbit to earth!  Yes, that was a real project (because I 
worked on it).  This was about 1972.  Experiments were made using the 
experimental station (DSS-13) at Goldstone Tracking Facility in the 
Mojave Desert.  I am not sure of the power transmitted but guess it 
was 20kW at 2115 MHz.  The receiving antenna was experimental made up 
of a huge array of "rectennas".  Half-wave dipoles made with silicon 
rectifier diodes with their leads cut to resonate as a dipole.  The 
distance power was successfully transmitted was something  like 
30-miles with 30% power transfer.

I was working on the orbiting transmitter portion of the project 
which consisted of solar arrays encompassing square miles of area 
above earth in a geostationary orbit.  Individual solar panels would 
power 2.5 GHz magnetrons for transmission of RF power down to earth 
to the receiving 'rectenna arrays".  We actually modified some 
microwave oven magnetrons to proof the concept.  So the concept had 
thousands of solar panels feeding thousands of magnetrons in some 
kind of phased array beaming this huge amount of RF to the surface of 
the earth.

It was not cancelled by technical difficulties.  I was cancelled due 
to environmental issues:  airline pilots concerned about flying thru 
one these "death rays" and of course the bird people concerned about 
killing birds flying thru the beam.  I wonder how well it would work 
with RFI to the 2.4G wifi services of today?

Sidenote:  Testla is the unsung hero/wizard responsible for our AC 
power transmission industry.  His inventions were literally stolen by 
peers of his time.  It is a fascinating read into history of electrical power.

73, Ed - KL7UW

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Subject: Re: [Elecraft] [OT} Wireless chargers (or transmission of
         electrical energy by wireless methods.)

Don't forget an ancient experimenter that wanted to transmit energy:
considerable amounts, by wireless!!!  He wasn't stupid and was deadly
serious about this quest.  Read his history!

His name was Nikola Tesla who spent untold amounts of money trying to do
just this!  He wasn't successful except over very short distances and the
efficiency wasn't good.

So don't get your hopes up.

Tesla revolutionized the AC electric generation and transmission system
with Westinghouse bankrolling him and made the polyphase AC system the
cornerstone for all the systems on the "grid" today except for the small
amount solar and wind power contribute at this time.  There really isn't a
technology that will outdo steam turbine power generation except perhaps for
nuclear plants which can become runaway hazards as demonstrated by 6 Mile
Island and Chernobyl Russia meltdowns plus the tsunami upset nuclear plants
in Japan!  Engineers and ecologists still haven't found a way to safely
store spent nuclear fuel rods without them having the possibility of
becoming toxic and extremely dangerous in the future.

Transmitting megawatts of power versus just a few watts wirelessly are
horses of two completely different colors in spite of what the "dreamers"
say.

73,
Sandy W5TVW


73, Ed - KL7UW
http://www.kl7uw.com
dubususa at gmail.com
"Kits made by KL7UW"