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

Right on Jeff
Obviously I would like to rob Peter of everything he
stole and give it to Paul because he is doing something constructive
with his energy where as Peter is robbing energy and just throwing it
away
If Paul had posession of that energy then his half power beam width
would
increase as opposed to decreasing in the pursuit of gain using the
small amount
of radiation available to him
Art



Jeff wrote:
When one looks at a.radiating array pattern one can see that the yagi
is very inefficient. Does anybody know of the relative volume
contained in the main radiation lobe versus the total volume of the
entire pattern? I know there are a lot of different type antenna gains
and
arrangement but I am trying to determine in an informal way the
efficiency ratio and compare it to what would appear to be a very
efficient
antenna such as a dish.

I think the parameter that you are searching for is GAIN !!!!

An antenna only has gain by compressing power more into one direction more
than another. It is a case of robbing Peter to pay Paul, the more power you
have in the main lobe the less you have in other directions.

73
Jeff

It is unintelligible and displays no practical understanding of antenna theory.

The Man in the Maze
QRV at Baboquivari Peak, AZ

On 21 Sep 2006 17:05:44 -0700, "art" wrote:

Hi Art,

To close this out, we have discovered through the various
correspondents that:

When one looks at a.radiating array pattern one can see that the yagi
is very inefficient.

Is false. That much is clear through evidence, no theory necessary.

Does anybody know of the relative volume
contained in the main radiation lobe versus the total volume of the
entire pattern?

Yes, someone does. It was pointed out quite clearly that ALL the gain
from sidelobe or back lobe could not be assembled into very much
constructive gain. Economists call this the law of diminishing
return.

A casual look at a yagi radiation pattern would suggest
that it is less than 50% efficient at best

Is false. One can certainly contrive for abysmal efficiency (you use
mylar and bamboo in place of tubing don't you?); but that does not
make the range of yagis fall into disrepute through aberrations of one
designer.

especially when considering

Is false - there are no externalities, except local ground loss, to an
antenna (and that exception is because ground is part of the radiating
system).

DX work
where even the main lobe is less than 50% efficient when looking at
available
signal paths beyond 4000 miles which are somewhat below 12 degrees and
where the main lobe itself is centered between 13 and 14 degrees with
an
average amateur antennah

You don't have any choice in the matter. No element pair is ever
going to offer better. No single yagi is going to draw the peak
launch angle down to the elevations I've already identified. A stack
of yagis is hardly likely either.

The long and short of it is that you are facing 0.001% "efficiency"
without any probable method to even budge it up to 0.0015%.

Creationist scienze might help tho'.

73's
Richard Clark, KB7QHC

Richard Clark wrote:
On 21 Sep 2006 17:05:44 -0700, "art" wrote:

Hi Art,

To close this out, we have discovered through the various
correspondents that:

When one looks at a.radiating array pattern one can see that the yagi
is very inefficient.

Is false. That much is clear through evidence, no theory necessary.

Does anybody know of the relative volume
contained in the main radiation lobe versus the total volume of the
entire pattern?

Yes, someone does. It was pointed out quite clearly that ALL the gain
from sidelobe or back lobe could not be assembled into very much
constructive gain. Economists call this the law of diminishing
return.

A casual look at a yagi radiation pattern would suggest
that it is less than 50% efficient at best

Is false. One can certainly contrive for abysmal efficiency (you use
mylar and bamboo in place of tubing don't you?); but that does not
make the range of yagis fall into disrepute through aberrations of one
designer.

especially when considering

Is false - there are no externalities, except local ground loss, to an
antenna (and that exception is because ground is part of the radiating
system).

DX work
snip

That was funny
You don't have any choice in the matter. No element pair is ever
going to offer better.
No element pair etc pretty specific statement which offers safety

No single yagi is going to draw the peak ............................
But you are sticking with the inefficient Yagi, that should make it a
safe statement
I would listen more intently if you stated that the angle cannot be
drawn down regardless of the array used


launch angle down to the elevations I've already identified. A stack
of yagis is hardly likely either.

Again you cover yourself my involving the inefficient Yagi

The long and short of it is that you are facing 0.001% "efficiency"
without any probable method to even budge it up to 0.0015%.

Creationist scienze might help tho'.

73's
Richard Clark, KB7QHC


Well it still gave me a laugh seeing you seeking safety in the Yagi
shadow

Do you also agree with what Roy said in a senior moment about wasted
yagi energy?

Art

On 22 Sep 2006 16:15:41 -0700, "art" wrote:

You don't have any choice in the matter. No element pair is ever
going to offer better.
No element pair etc pretty specific statement which offers safety

Hi Art,

Safety? The world recognizes a dry comment that is factual and does
not attach notions of sensation to it. [Fair warning to the
alliteration intolerant.] Fantasy fear (from prophecies) is called
the Pathetic Fallacy.

I would listen more intently if you stated that the angle cannot be
drawn down regardless of the array used

Another fallacy. Art, no one believes you would.... aw let's just
test the hypothesis to expose another fallacy:

The angle cannot be drawn down to those needed regardless of the array
used. You haven't got a chance at all. You are fated to cower
forever as being "inefficient" without any brighter prospects ever.

Do you also agree with what Roy said in a senior moment about wasted
yagi energy?

He wasted a lot of energy on you, Old Man, didn't he?

Still frightened? They say if you talk about your nightmares, they
will go away. I heard that last night in a movie "This Gun For Hire"
as told by Raven (Alan Ladd) to Veronica Lake. [This thread needs a
modicum of real entertainment value now that all technical content has
been drained.]

73's
Richard Clark, KB7QHC

art wrote:

When one looks at a.radiating array pattern one can see that the yagi
is very inefficient. Does anybody know of the relative volume
contained in the main radiation lobe versus the total volume of the
entire
pattern? I know there are a lot of different type antenna gains and
arrangement but I am trying to determine in an informal way the
efficiency
ratio and compare it to what would appear to be a very efficient
antenna
such as a dish. A casual look at a yagi radiation pattern would suggest

that it is less than 50% efficient at best especially when considering
DX work
where even the main lobe is less than 50% efficient when looking at
available
signal paths beyond 4000 miles which are somewhat below 12 degrees and
where the main lobe itself is centered between 13 and 14 degrees with
an
average amateur antennah
Art


Ok, I reread the original post, and it is right here.

The problem is that you need to understand that the angular center of
the main lobe is dependant on the height of the beam above the ground,
so this part -

where the main lobe itself is centered between 13 and 14 degrees with
an
average amateur antennah

is actually a variable.

Here lies your problem.

tom
K0TAR

As my girlfriend likes to say "WORDS MEAN THINGS!"

Having a weird definition of efficiency doesn't help anyone out.

Needing an antenna with super-high-gain at one particular elevation and
azimuth angle is a weird, but... sort of valid question... but has
nothing to do with the efficiency of said antenna.

Dan