Yuri

I sure disagree about being able to determine an antenna's efficiency by
either resistance measurements or by measuring received signa;l strength at
any one point in space. But, you are certainly a much smarter fuy than I
ever was. So, I am not equipped to get into a news group contest.
It is my contention that the antenna under test's complete radiation
pattern and field strength would have to be measured and integrated if
field strength is used to determine it's efficiency. That could get
coplicated.
It would have seemed to me that the loss in any "R" is dependent on the
current flowing in it. And, I'd be concerned that any resonances could have
higher circulating currents at the operating frequency.

If you can point out the errors in my convictions, I'd like to read about
where I'm wrong.

Jerry




"Yuri Blanarovich" wrote in message
...
But, if the "wonder antenna" is small enough to be enclosed (mostly) in
something transparent to the RF but not to the thermal thats generated by
any I^2* R losses, wouldnt the temperture rise inside the enclosure give
a
decent indication of efficiency?



No need for that really, too cumbersome. If you measure R you can
calculate
losses due to dissipation in heat.

Again, real comparison of efficiency of shortened antenna is to compare
against
the same pattern producing full (electrical) length antenna, everything is
included in what you would measure. Much simpler too. I can build quarter
wave
vertical faster than styrofoam igloo. :-)

Basic rules are, best inductive loading is about 2/3 up the radiator, coil
is
better than loading stub, top hat is the best. Anything else is jocker's
attempt at perpetuum mobile.

Yuri