"Jerry Martes" wrote in message
news:8RvWc.550$%11.374@trnddc02...

"Yuri Blanarovich" wrote in message
...

I was under the impression that radiation efficency was pretty much a"
no-brainer".If the antenna is built of quality materials with good
workmanship the antenna would be an efficent radiator with little ohmic
or
dielectric losses. The exception to this of course would be antennas
that
use an earth ground. I just found I was losing at least 3 db to heating
up
the ground.

Jimmie




Keep digging, you will find more lost dBs. Things get aggravated in
loaded
antennas when you start inserting coils, loading elements, folding them
back,
etc. Efficiency is roughly proportional to the area under the current
distribution curve along the radiator. That can be affected by any of
the
shortening "miraculous" gizmos, like Vincent DLM antenna. It is not just
heat
loses in resistances. You can't have "perfectly" conducting piece of 1
ft
copper tubing be as effcient as 130 ft full size radiator on 160m.
Getting smarter, Eh ? :-)

Yuri, K3BU

Yuri

I wonder where the power into a perfectly conducting 1 foot length of
copper tubing goes if it doesnt get either radiated or get converted to
heat. Can you tell me how the short (1 foot) copper tube looses the power
it receives from its power source?

Jerry


This isn't answering your question, but you forgot the effect of reflected
power. I wouldn't call that "lost power", but it sure isn't contributing to
the radiation.

Ed
wb6wsn