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basics | Generating Power through Induction with a HAM radio Antenna

There are 3 messages in this thread.

You are currently looking at messages 0 to 3.

Generating Power through Induction with a HAM radio Antenna - Aaron S - 2007-03-06 07:00:00

Is it possble to use an inductor with a stepdown transformer to generate 
power by using the power ouput of a ham radio through it's antenna?  My 
friend states his antenna is a 40Watt'er.  If I can, about how much power 
can i expect to gather using a n inductor. 





Re: Generating Power through Induction with a HAM radio Antenna - chuck - 2007-03-06 08:57:00

Aaron S wrote:
> Is it possble to use an inductor with a stepdown transformer to generate 
> power by using the power ouput of a ham radio through it's antenna?  My 
> friend states his antenna is a 40Watt'er.  If I can, about how much power 
> can i expect to gather using a n inductor. 
> 
> 

Well, the transmitter may be 40 watts, but the antenna is usually not 
rated that way.

All of the radiated energy can theoretically be recovered from a 
transmitting antenna. The problem is how to capture it all. At a 
distance, the instrument used to capture radiated energy is another 
antenna, and tiny fractions of the radiated power can often be captured 
halfway around the globe.

A stepdown transformer will lower the voltage produced at the antenna, 
but that really has nothing to do with the amount of radiated energy you 
capture.

If you use a simple inductor as an antenna to capture radiated energy, 
you will find that it will probably not be possible to situate the 
inductor so as to capture very much, since the antenna may be radiating 
in many or even all directions! If the inductor gets too close to the 
antenna, it will affect the antenna's properties, and that further 
complicates the exercise.

Does any of that help?

Chuck

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Re: Generating Power through Induction with a HAM radio Antenna - Charles Schuler - 2007-03-06 17:22:00

"Aaron S" <t...@hot.rr.com> wrote in message 
news:45ed57d2$0$5255$4...@roadrunner.com...
> Is it possble to use an inductor with a stepdown transformer to generate 
> power by using the power ouput of a ham radio through it's antenna?  My 
> friend states his antenna is a 40Watt'er.  If I can, about how much power 
> can i expect to gather using a n inductor.

Any large antenna can gather enough energy to run low-power circuits, if it 
is near powerful transmitters.  Free-power radios used to be all the rage 
among hobbyists.  A big wire antenna fed a rectifier circuit that produced 
enough snot to power a receiver and amplifier to drive a loudspeaker for 
modest audio levels.  I built one and used it many years ago in Pittsburgh, 
PA.  My home was close to several AM stations and my antenna was a wire 
about 60 feet long (along with a good ground).

Tesla had dreams about this scheme, by the way, and did produce some 
intriguing demonstrations.