"-=jd=-" wrote in message
...

[snip]

The one thing that I would like to do is try to figure out the actual
characteristic impedance of the antenna. I've found information that shows
me how to do this with a noise-bridge, but I don't have one of those.

I was wondering if anyone knows of a link or a formula for finding a
relatively close "ballpark" figure for characteristic impedance. I'm
thinking there isn't (without the inclusion of one or more physical
measurements) due to all of the variables involved.

[snip]

Reg Edwards has an interesting webpage:

http://www.btinternet.com/~g4fgq.regp/

He has many rather complicated formulas written into easy to use programs.
One of the RJELOOP programs might be helpful:

http://www.btinternet.com/~g4fgq.regp/page3.html#S301"

Be aware that the impedance will vary considerably with frequency, and will
have a large reactive component at most frequencies.

Aside from a noise bridge, MFJ sells some antenna analyzers, if you want to
spend the money:

http://www.mfjenterprises.com/products.php?catid=49

The ARRL Antenna book is a good reference. The Radio Amateur's Handbook has
less antenna info than their Antenna Book, but it may be available in your
public library.

LB Cebik has a tremendous amount of antenna info on his website. Loops(and
most everything else) are the

http://www.cebik.com/gup/groundup.html

http://www.cebik.com/radio.html

A grid dip meter is a cheap antenna toy. It is a metered oscillator which
can determine the resonant points of circuits. I got mine for about $15.
If you get one, be sure you get the coils!

I last used my grid dip meter to cut a perfectly resonant twin lead folded
dipole at 162 MHz. The perfectly resonant folded dipole worked about as
well as a meter test lead clipped to the antenna terminal. That's the way
it often goes with receiving antennas. The radios aren't usually very fussy
..

Sometimes the best approach for receiving antennas is to just string some
wire, play with transformers and experiment.

Frank Dresser