wrote:
Hi Art,

A few points below, but first just remember that the TOA of any
horizontally polarized antenna is primarily a function of ground
reflections which vary according to height above ground. Previously
you mentioned that your antenna was designed for a TOA of 10 degrees.
That cannot be true except for a specific height above ground. Whether
Yagi, Quad, Log, Rhombic or any non-vertically stacked antenna.
Something like a Sterba curtain is different because it has multiple
elements stacked vertically which CAN be steered by phasing.

That is entirely correct for known technology........... at this time !




art wrote:

yes it is twenty meters and I am
located in the couintryside that I understand is the highest between
Chicago and New Orleans and since this is the bread basket of the U.S
the ground loam is excellent.

1. Absolute height above sea level means nothing. What is important
to TOA is your relative height above the terrain within a mile or two
of your tower. I operated from Colorado for ~30 years and always got a
chuckle from the guys who said, "My antenna is over 1 mile high". In
fact what is important for determining TOA is not height above sea
level but height above surrounding terrain.

It is the highest point for the U.K. period



2. Ground conductivity has minimal effect on horizontally polarized
ground reflections. You may be thinking of vertically polarized
antennas like verticals where it has a huge effect. HFTA does have
conductivity as an input parameter but it has minimal effect, at least
in my case (average ground versus salt water).


Agreed, there was a Australian article that showd that very well



I use 7/8 andrews plus a long length
underground and the tower is hinged in two places
as well as another one for array tilting.

Phsical tilting has minimal effect on the ground reflections for the
angles of interest (4-10 degrees) because the vertical lobe is not very
narrow (typically a Yagi has ~50 degree 3 dB vertical beamwidth). In
other words tilting has a far secondary effect on TOA versus changing
the antenna height.

Lawson W2PV wrote about that while he was working in Schenectady G.E.
on the computor that replaced zillions of vacuum valves but with
respect to planar arrays
Mine is not a planar array




You can prove this to yourself by modeling with a
program like EZNEC (HFTA does not allow tilting because it is
physically impractical and has little effect).

As I said above mine is not a planar array. The computor program I use
is AO-PRO
by Beasley


Pretty simple question for
those who know the answer after all you start off with 3 db gain in two
different directions thereffore it would seem to me that a yagi was
only 50% efficient

I believe you're referring to a dipole which has 2+ dB gain over
isotropic in the two directions broadside to the element.
Yes, I rounded it off to 3


If we add ~6
dB from ground reflection gain, we get 8 dB gain over isotropic, but
this is ONLY for a specific TOA which is determined by the antenna's
height above ground.

Fully undertstood when referring to planar arrays

Of course a good Yagi will typically have 25-30
dB Front to Rear, so its backward lobe has very little of the total
energy (far less than 50%). F/B for planar arrays is for a single angle , front to rear is more appealing but at the same time it ignores pattern lobes in all directions including upwards. I have found that TOA on its own is pretty wothless as one can get the gain of a larger antenna with a wider but narrower lobe that follows the bottom half of a higher gain lobe. Lets face it for planar arrays gain is obtained at the axpense of half power area.


Bottom line to all of this is that your antenna's height above ground
has the primary influence on TOA. The only other way to "steer" the
vertical lobe is to mount your antenna on a motorized tower (unless you
go to vertically stacked elements and phasing).

Obviously height is important and totally constrictive of all planar
arrays where the TOA is captive. As soon as you add another vector such
that the array is three dimensional as with a stack things change

Put your single antenna at 120' and the vertical pattern will be
centered on about 9 degrees (assuming flat terrain).

I assume you mean vertical elevation and yes mine cannot be much over
100 feet
and I will have various lobes available at various TOA's and most
important variable beam depth to accommodate propagation changes as
arrival angles change
Thanks for the contact The most interesting thing that I am looking
forward to is operation at the bottom of the cycle to see if there is
still propagation but only for low angles. As you gat older you look
for any excuse to stay indoors
Art


73 & GL!

Bill W4ZV

P.S. Here are some results using HFTA for my 10 meter 3-stack:

Yup there was an extensive article on that for the NE area where it
shows the impact
of a ground projection on a collective angle.

http://users.vnet.net/btippett/terrain_&_toas.htm

On 24 Sep 2006 16:11:33 -0700, "art" wrote:

You can squeese the main lobe as much as you want for extra gain but it
will not change the vbolume of the main lobe one iota

Art,

You know that your arguments sound like you are trying to crucify
yourself and expect applause?

When we discard the errant nonsense, almost every posting you make
here is weighed with material of self-defeating goals. The quote
above is a remarkable admission that you reject the solution you seek.
When you paint yourself into a corner, what color is the floor?

73's
Richard Clark, KB7QHC

Hi Art,

art wrote:

It is the highest point for the U.K. period

I don't understand. I thought you were in Indiana and wanting to
optimize your path to England.

As I said above mine is not a planar array. The computor program I use
is AO-PRO
by Beasley

That's the best there is in my opinion. You are fortunate to have a
copy since he no longer sells to hams.

Thanks for the contact The most interesting thing that I am looking
forward to is operation at the bottom of the cycle to see if there is
still propagation but only for low angles. As you gat older you look
for any excuse to stay indoors

You're welcome. Here is a long but interesting story related to low
angle TOAs. W3CRA was a legend and I can vividly remember him working
one Asian after another that I could not detect the slightest trace of
using a 3 element Yagi at 60' from my home in NC at that time:

http://users.vnet.net/btippett/w3cra.htm

Good luck with your new system!

73, Bill W4ZV

Just read your page... very interestin. We don't have large hills in
Illinois but a helicoptor pilot stated that this town is visible for
miles around and another ham told me that the DX bureu staed that this
town got more cards than all of Chicago I remember once when I gave a
local talk where I spoke about Lawson and his work and I repeated some
of his statements. Well I was challenged on some things but since I am
not a DXer they and the suurounding counties waited until a rare
station was comming on and taking only three stations from each
district. Boy I got a shock with the noise and pandemonium and couldnt
see how any station could be picked out but I was fortunate plus two in
the Chicago area. I know I was very lucky and have no idea why people
collect those things or enter contests... the noise is horrible I think
I had 13 elements on a 60 foot boom at that time plus a couple of
reflectors to experiment with. From that moment on I gave up on
aluminum elements and now use exclusively telescopic fishing poles with
an aluminum shell as it is cheaper in the long run and not susceptable
to ice build up
Art
Artl
wrote:
Hi Art,

art wrote:

It is the highest point for the U.K. period

I don't understand. I thought you were in Indiana and wanting to
optimize your path to England.

As I said above mine is not a planar array. The computor program I use
is AO-PRO
by Beasley

That's the best there is in my opinion. You are fortunate to have a
copy since he no longer sells to hams.

Thanks for the contact The most interesting thing that I am looking
forward to is operation at the bottom of the cycle to see if there is
still propagation but only for low angles. As you gat older you look
for any excuse to stay indoors

You're welcome. Here is a long but interesting story related to low
angle TOAs. W3CRA was a legend and I can vividly remember him working
one Asian after another that I could not detect the slightest trace of
using a 3 element Yagi at 60' from my home in NC at that time:

http://users.vnet.net/btippett/w3cra.htm

Good luck with your new system!

73, Bill W4ZV

Richard
why don't you get with it instead of the constant adverserial role
Go to the library and get a good book on antennas and maybe study up on
curls?
Oh shucks I forgot you were bald... Never mind keep talking to yourself
and maybe there will be an echo for you to talk to and belittle.
Frankly to me you are just a bore
that struts around in shakesperian tights and write in the language of
my forefathers
and glory only in your perceived triumps in the repair shop. Why not go
back and try to repair some shoes of some people which you cannot fill
See you finally got a response but don't bank on a lot more until you
become less adverserial with respect to all work other than your own
and provide the same respect that you one time would like to receive
Put me in your plonk file and I will respond also
Art



Richard Clark wrote:
On 24 Sep 2006 16:11:33 -0700, "art" wrote:

You can squeese the main lobe as much as you want for extra gain but it
will not change the vbolume of the main lobe one iota

Art,

You know that your arguments sound like you are trying to crucify
yourself and expect applause?

When we discard the errant nonsense, almost every posting you make
here is weighed with material of self-defeating goals. The quote
above is a remarkable admission that you reject the solution you seek.
When you paint yourself into a corner, what color is the floor?

73's
Richard Clark, KB7QHC

"art" wrote in message

I know I was very lucky and have no idea why people
collect those things or enter contests... the noise is horrible I think
I had 13 elements on a 60 foot boom at that time plus a couple of
reflectors to experiment with.

Art,

Why do people run Marathons, race cars, boats, airplanes or turtles? Some
like to walk, some roll in the mud, some like to compete in the stadium.

Contesters like to prove that they can design better antennas, assemble
better stations and prove that they are better operators. It is also real
test for antenna designs and propagation knowledge and how to exploit both
for better results that can quantify the performance and weed out junk and
junk science. It takes years of devotion to show up in the top ten listings.
If you have revolutionary design, we contesters will be first, dying to use
it and cream the competition - that's the real test and not mumbo-jumbo
claims.

BTW I have a "secret weapon" too, it is a ferrite stick in the dish. Very
efficient, no side lobes, one sharp beam, no side or back lobes. It is right
up there with EH, Freaktals and perpetual motion machines.

If you assume that propagation between you and UK is as you describe, you
are way off. We are also ducting, use skewed path and changing angles
depending on the point in the sunspot cycle, sun' activity, etc. etc. So for
optimum propagation one needs either antenna that has wider beamwidth or
sharp and stearable one in H and V planes.

Can you enlighten us about your new revolutionary invention? Is it better
than your patented reflector that is shorter than the driven element?

73

Wow Yuri has arrived

I remember that long discusting arguement he had with Tom Rauch
that brought words to the fore that brought shame to amateur radio
I'm gone, I want no part of what is now on the near horizon
Have a great year fellars I enjoyed the short visit while it lasted
Art



Yuri Blanarovich wrote:
"art" wrote in message

I know I was very lucky and have no idea why people
collect those things or enter contests... the noise is horrible I think
I had 13 elements on a 60 foot boom at that time plus a couple of
reflectors to experiment with.

Art,

Why do people run Marathons, race cars, boats, airplanes or turtles? Some
like to walk, some roll in the mud, some like to compete in the stadium.

Contesters like to prove that they can design better antennas, assemble
better stations and prove that they are better operators. It is also real
test for antenna designs and propagation knowledge and how to exploit both
for better results that can quantify the performance and weed out junk and
junk science. It takes years of devotion to show up in the top ten listings.
If you have revolutionary design, we contesters will be first, dying to use
it and cream the competition - that's the real test and not mumbo-jumbo
claims.

BTW I have a "secret weapon" too, it is a ferrite stick in the dish. Very
efficient, no side lobes, one sharp beam, no side or back lobes. It is right
up there with EH, Freaktals and perpetual motion machines.

If you assume that propagation between you and UK is as you describe, you
are way off. We are also ducting, use skewed path and changing angles
depending on the point in the sunspot cycle, sun' activity, etc. etc. So for
optimum propagation one needs either antenna that has wider beamwidth or
sharp and stearable one in H and V planes.

Can you enlighten us about your new revolutionary invention? Is it better
than your patented reflector that is shorter than the driven element?

73

On 24 Sep 2006 19:34:22 -0700, "art" wrote:

Put me in your plonk file

Shirley, you jest!

And miss all the weeping and your lush interpretation of Camille at
the Hammerlund? It took you 30 posts to get around to one significant
factor in propagation: the frequency you were working!

73's and XOXOXOXOX
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


Does anyone know why the efficiency of the Stanford Big Dish (150 feet)
is only 35% on 1420MHz, compared to 55% on 150 and 400MHz?

http://www-star.stanford.edu/rsg/bigdish.php

--Zack Lau W1VT

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

On 26 Sep 2006 10:31:14 -0700, "Zack" wrote:

Does anyone know why the efficiency of the Stanford Big Dish (150 feet)
is only 35% on 1420MHz, compared to 55% on 150 and 400MHz?

http://www-star.stanford.edu/rsg/bigdish.php

Hi Zack,

You may be confusing (or have been confused with the content of this
thread) antenna effeciency with system efficiency. The page makes the
point of there being a feed "appropriateness." I would suspect the
method of feed makes the difference (and those issues that lie beyond
that include method of detection, noise, and so on).

As for putting it to the antenna's merit, the roughness is far more
significant to shorter wavelengths (roughness is on order of eight
wave). This in itself produces problems of phase control, and phase
control is the name of the game in directivity.

73's
Richard Clark, KB7QHC