It occurs to me that by art's definition, all antennas are
"inefficient". When you're talking with someone, only a teeny, tiny
fraction of the radiated power is going precisely in the right direction
to be collected by his antenna, so the remainder is wasted. Shucks, I'd
be amazed if the "efficiency" of the best HF antenna is better than
0.001% by this criterion.

Roy Lewallen, W7EL

The other point I note is that he wants enhanced HF radiation between
10 and 4 degrees elevation and apparently beamed to a specific point
on the globe... The cubic size and the towers and the arrays that it
will take to accomplish this are not efficient in time, money, and
effort... He is chasing a unicorn...
As has been pointed out already, the percentage of time that the major
portion of the arriving HF EM wave is below 10 degrees can be
enumerated on the fingers of one hand... Besides, who is going to have
the array on the other end with comparable response?

denny / k8do

Dear Neighbor Denny:

1. One may have reasonably smooth HF radiation between 4 and 10 degrees
with a yagi that is a little over two WL (2.2) above ground (with a maximum
of about 7 degrees). The second null will be in the neighborhood of 14
degrees.

2. Many "DXers" exist who have antennas that even at 14 MHz are two WL
high. Money-efficiency is very much an individual thing.

3. Many years of dealing with arrival angles of HF signals from over 7 Mm
away suggests that such angles are mostly smaller than ten degrees. Larger
than 12 or 13 and smaller than about 2 degrees is unusual. With truly
serious antennas on both ends, as you have suggested, one might see 1 to 4
degrees.

4. Great to know that we are both still alive. It has been a long time
since we have talked.

73, Mac N8TT


--
J. Mc Laughlin; Michigan U.S.A.
Home:

"Denny" wrote in message
ups.com...
The other point I note is that he wants enhanced HF radiation between
10 and 4 degrees elevation and apparently beamed to a specific point
on the globe... The cubic size and the towers and the arrays that it
will take to accomplish this are not efficient in time, money, and
effort... He is chasing a unicorn...
As has been pointed out already, the percentage of time that the major
portion of the arriving HF EM wave is below 10 degrees can be
enumerated on the fingers of one hand... Besides, who is going to have
the array on the other end with comparable response?

denny / k8do

On Fri, 22 Sep 2006 03:32:13 -0700, Roy Lewallen
wrote:

"efficiency" of the best HF antenna is better than
0.001% by this criterion.

Hi Roy,

Not far off.

If absolutely EVERYONE (presuming 6 billion of us) on the planet got
art's signal at S9 from a 100W transmission, that would only be 300 mW
captured (0.3% efficient).

I suppose the 99.7W lost would contribute to Intergalactic Warming
(which would be 99.7% efficient). However, HF temperature is for all
practicable purposes indistinguishable from absolute Zero.

73's
Richard Clark, KB7QHC

Neat
Art
Richard Clark wrote:
On Fri, 22 Sep 2006 03:32:13 -0700, Roy Lewallen
wrote:

"efficiency" of the best HF antenna is better than
0.001% by this criterion.

Hi Roy,

Not far off.

If absolutely EVERYONE (presuming 6 billion of us) on the planet got
art's signal at S9 from a 100W transmission, that would only be 300 mW
captured (0.3% efficient).

I suppose the 99.7W lost would contribute to Intergalactic Warming
(which would be 99.7% efficient). However, HF temperature is for all
practicable purposes indistinguishable from absolute Zero.

73's
Richard Clark, KB7QHC