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Re: Antenna



Subject: Re: Antenna
  Date: Sat, 3 May 1997 22:44:47 -0500
  From: "Robert W. Stephens" <rwstephens-at-headwaters-dot-com>
    To: Tesla List <tesla-at-pupman-dot-com>


> Date:          Tue, 29 Apr 1997 02:18:57 -0500
> To:            tesla-at-poodle.pupman-dot-com
> Subject:       Antenna
> From:          Tesla List <tesla-at-pupman-dot-com>

> Subject:  Antenna
>   Date:   Mon, 28 Apr 1997 14:38:10 -0400 (EDT)
>   From:   JMJinx-at-aol-dot-com
>     To:   tesla-at-pupman-dot-com
> 
> 
> I don't know a thing about Tesla Coils. I at least want to buy one. 
> 
> But does anyone know how to use the Tesla Coil as a powerful antenna. 
> How can I use it to transmit radio signals that are in a FCC no-licensce
> band.
> 
> 
> Thanks
> 
> 

Mr. Jinx,

A Tesla coil represents a very low frequency RF resonator in a 
compact package where its own physical size represents such a tiny 
fraction of the freespace wavelength at the frequency of operation 
that it just does not occupy a big enough space with the surrounding 
medium to be an efficient radiator, OR receiving antenna!  The law of 
reciprocity applies to all such devices.

The fact that Tesla coils do not radiate well in the E.M. band at 
their operating frequency is a saving grace for all of us coilers.

Using a Tesla coil as a high-Q receiving antenna works, but the 
efficiency is not high.  It is in fact making a very high-Q receiver 
tuning front end coil, and then attaching virtually no antenna.  At 
these frequencies, one should string longwire antennas hundreds to 
thousands of feet long, the *big* toroid on top your 50 kHz Tesla 
coil just doesn't occupy enough of a 50 KHz freespace wave to collect 
any usefull energy (relative term).

rwstephens