John S wrote:
Hi, Gentlemen -

What if we (just for fun and knowledge) design a short dipole antenna
together here in the group? How short should we go as a practical matter?

* What would be the worst input impedance we would would wish to deal
with? That will actually determine the shortness of the dipole, yes?

* There will be losses. How much are we willing to accept? This is
another determining factor to the shortness, yes?

* What might be the best feed arrangement for our short antenna? There
are lots of ways.

I don't know much about small loop antennas, but I can fade into the
shadows and try to learn from you.

Any other suggestions to this endeavor is also fine. Let's just discuss
what we enjoy doing. If you have other topics of small antennas, let's
put them on the table.

Gentlemanly arguments are welcome concerning the technical aspects of
our discussion. I have never had a problem with anyone who says "I
believe you are wrong in this assumption and here is why."

Thanks, Gentlemen.

Cheers,
John KD5YI

I would think a dipole would be a bad candidate for a "short" antenna
as you need to get the matching stuff close to the antenna to avoid
I^2R losses.

Some sort of ground mounted, or close to the ground, antenna might
make a better choice.

Also needed is some sort of definition of "short", e.g. total volume
of the antenna constrained to some fraction of a wavelength.

One interesting technique for shortning an antenna can be seen by
lookup up US Patent 6,642,902.

Essentially it is a coax in a coax with internal shorting stubs
inside the coaxes with capacitive end loading. Too complex to
explain in words, but the drawings in the patent are clear.


--
Jim Pennino