[BC] Part 15 radio station

[RichardBJohnson at comcast.net]

Actually double digits. And I am sure that a 3 meter loop will
be more efficient than a 3 meter whip at broadcast frequencies.
Furthermore, you get to adjust your input impedance, getting
it out of the lossy mud of a tiny vertical, where most of your
power goes into heating up the mud.

I have made 60 kHz loops for receiving NIST and They were quite
efficient, having an aperture about 40 times their size. The NIST
transmitter is in 50kW in Colorado. There is no skywave so what
you get follows the earth's curvature and is very weak on the East
coast. 

Something like these would work just fine.

http://www.frontiernet.net/~jadale/My%20Loop%20Antennas.htm

Basically, you wind enough wire around your frame until you can
resonate it with a small trimmer capacitor, the smaller the better.
Ideally, self-resonance. Then you add a turn, not connected to
anything but a coax connector, or in your case a transmitter. If
the impedance is too low, you add another turn, etc.

These things can give crap radios uV/M sensitivity. A 60 kHz
one made out of 50-pair cable, resonated to 60 kHz provides
enough signal to feed a CMOS logic gate directly for the frequency
standard I designed.  

--
Cheers,
Richard B. Johnson
Read about my book
http://www.LymanSchool.org


 -------------- Original message ----------------------
From: Cowboy <curt at spam-o-matic.net>
> On Friday 16 May 2008 05:29 pm, Dana Puopolo wrote:
> >  They'd probably use the total length if the loop.
> 
> >  From: RichardBJohnson at comcast.net
> >  
> >  May I suggest a loop antenna? Something that is the allowed height,
> >  but square, should produce a reasonable field on-edge, with
> >  practically nothing at 90 degrees.
> 
>  You'd find that the efficiency of a small loop for transmitting
>  is on the order of percent in single digits.
> 
> -- 
> Cowboy
>