"Frank" wrote in message
news:_c3Hh.16918$lY6.10683@edtnps90...

"Owen Duffy" wrote in message
...
"Frank" wrote in news:f71Hh.16901$lY6.7593
.......
As an example consider a horizontal 75 m dipole, constructed of
#14 AWG copper, at various heights above an average ground.
The radiation efficiency, according to NEC, is shown below:

height 10 ft, efficiency 14%;
height 30 ft, efficiency 54%,
height 90 ft efficiency 82%

The above results do not include the ground wave, which
can be considered lost power. Ground absorption also increases
with proximity to the ground.

Frank,

What is the figure for free space? I suspect closer to 99%. If that is
the case, don't your figures include loss (or absorbption) in rays
reflected by the ground?

Owen

Correct Owen. NEC shows 97.3% for free space, and 100 %,
as expected, with perfect conductors. Certainly the loss does
include absorption of the reflected rays. As mentioned before, in
previous threads, it is very tedious to determine what percentage
of the "Loss" is due to ground wave radiation. One of these
days I will write the code necessary to compute the actual
TRP including ground wave.

Frank


Interesting. Thanks Frank.