On Sep 10, 9:23*pm, Art Unwin wrote:
On Sep 10, 8:45*pm, wrote:

Art Unwin wrote:
What is the main factor that prevents HF radiation from focussing
for extra gain?

Money.

If you can afford to build a 20m parabola about 2,000 feet in diameter
and the place to mount it, you'll get lots of gain.

--
Jim Pennino

Remove .spam.sux to reply.

Then are you saying it is the antenna size that is the main factor?.
So my antenna which is physically small
can be focussed on a dish which would provide straight line radiation
or a radiation beam?
Working on a single element on the ground with a optimizer instead of
a half sphere I got a
straight vertical line at the sides which suggested a gun barrel
radiation with a perfect earth as the reflector.
Gain was around 8db vertical which is why the question regarding
focussing! If it was properly focussed the gain should be more.
2000 foot dish seems somewhat odd, probably based on a "straight"
wavelength and not a small volume in equilibriumas the directer
right?
Art

Let me ask the question another way. Whether it is believed or not,
if a 80 Metre antenna was compressed to the size of a couple of shoe
boxes
would the dish be reduced in size accordingly?
Regagards
Art