Mike Coslo wrote:
Perhaps there is confusion by some people with the idea that the
takeoff angle. I suspect that a lot of people think of their RF leaving
the antenna as a "blob" that leaps out at some desired or undesired angle.

Instead, the RF is heading off in all directions, with some angles
having more relative power.

So even if an antenna has a lower TOA, it might be less gain than an
antenna that has a higher TOA has at that angle.

An inefficient antenna with a low TOA can be less efficient at that
low TOA than a more efficient antenna with a higher TOA is at that same
low TOA.

Maybe a picture is worth a thousand words. Here's a comparison
radiation pattern for my 130 ft dipole Vs my 40m vertical with
elevated radials. In the dipole's favored direction, it's TOA
is greater than the vertical's yet the dipole radiates more
power than the vertical even at the vertical's TOA. Here's the
pictu http://www.qsl.net/w5dxp/dipvsver.htm
--
73, Cecil, W5DXP


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Thanks, Cecil.

Roy Lewallen, W7EL

Cecil Moore wrote:

Maybe a picture is worth a thousand words. Here's a comparison
radiation pattern for my 130 ft dipole Vs my 40m vertical with
elevated radials. In the dipole's favored direction, it's TOA
is greater than the vertical's yet the dipole radiates more
power than the vertical even at the vertical's TOA. Here's the
pictu http://www.qsl.net/w5dxp/dipvsver.htm
--
73, Cecil, W5DXP

On Sat, 29 Jan 2005 07:54:16 -0600, Cecil Moore
wrote:

Maybe a picture is worth a thousand words. Here's a comparison
radiation pattern for my 130 ft dipole Vs my 40m vertical with
elevated radials. In the dipole's favored direction, it's TOA
is greater than the vertical's yet the dipole radiates more
power than the vertical even at the vertical's TOA. Here's the
pictu http://www.qsl.net/w5dxp/dipvsver.htm

Exactly!

Thing is....So did my model when using "medium" ground quality.
But I know in the real world, my vertical smoked the dipole on long
haul/low angles. I'm almost positive that the verticals are
"underpowered" when
modeling, unless you bump up the ground quality. Or at least when used
on the low bands at night. To make the model of my dipole vs vertical
actually pan out as in real life, I had to bump up the ground quality
to
"excellent". Even then, it might have been a bit lower than real life.
I'm not sure what to make if this....
I'm not the only one to notice this also.... Talk to W8JI about his
nearly
300 ft dipole vs his verticals on 160m...He always thought the dipole
would be
better. After all, modeling says it should be. But it didn't quite pan
out...
I basically ignore Cecils bad experience, because #1, his vertical
needed more radials,
and he never used it for long haul paths. So of course, the vertical
should
have lost in his case. Heck, even with my vertical, that was a bit
better than his,
I had to get over 1000 miles to start seeing the vertical overtake the
dipole.
Those dipole vs vertical modeling plots are *very* misleading. Or to me
anyway...
Myself, I think the ground qualities applied are in error for some
reason..
They overly stunt the vertical when modeling...Either that, or my
ground here is
really good...My ground quality is pretty good, but it's not *great*,
being I'm
in the city cement jungle of Houston. MK

On 30 Jan 2005 15:00:33 -0800, wrote:

Either that, or my ground here is
really good...My ground quality is pretty good, but it's not *great*,
being I'm in the city cement jungle of Houston. MK

Hi Mark,

Actually, according to the FCC ground conductivity map, you are very
well situated sitting on very good to exceptionally good soil (as you
look towards the Gulf) which is 4 to 16 times better than my own here
in Rain City.

73's
Richard Clark, KB7QHC

Well...Depends on what part of town...On the coast, it's great. A 30...
But in town, they rate it as about a 15. But that would vary greatly
I'm
sure...I'm in a suburban area, so I might be maybe a "20" ???
I know that I had very mediocre results using ground mounted verticals.
I had one with 32 full length radials, and it was poor compared to my
ground plane at 36 ft, with 4 radials. It was probably about as good as
Cecils vertical he ran....LOL...:/ MK

On 30 Jan 2005 16:51:17 -0800, wrote:

Well...Depends on what part of town...On the coast, it's great. A 30...
But in town, they rate it as about a 15. But that would vary greatly
I'm
sure...I'm in a suburban area, so I might be maybe a "20" ???
I know that I had very mediocre results using ground mounted verticals.
I had one with 32 full length radials, and it was poor compared to my
ground plane at 36 ft, with 4 radials. It was probably about as good as
Cecils vertical he ran....LOL...:/ MK

Hi Mark,

You have to think deeper into the ground than the thickness of
concrete or asphalt. Unless the project developer scraped off the top
6 feet and dumped it into Galveston Bay for fill, and then backfilled
your neighborhood with industrial waste.... RF and your antenna is
looking at a BIG foot print below it from your antenna's elevation
(probably a greater boon than ground mounted - your experience seems
to support this).

This means that when your RF first strikes earth at a DX angle of 5 to
10 degrees, it is a vastly bigger surface than that seen with a ground
mount because that ray strikes further away. (About half a mile away,
if I did my Trig right.) Instead of illuminating your driveway and
street, the elevated vertical is lighting up 100s of acres that
averages the ground conductivity over lawns, streets, gardens, homes,
lots....

Off hand, I would say the modeler with higher ground settings is
validated by your experience and conforms to your environment.

73's
Richard Clark, KB7QHC

Hummm. Maybe that explains the large difference I saw between it and
the ground
mount. I know the antenna seemed to really come alive once it's up
about a 1/4
wave. I never was too crazy about ground mount verticals. To me, it's
like
ground mounting a dipole...Makes about the same sense....Of course, the
GP may
not be for everyone...Not really hard to put up, but it's a 68 ft tall
antenna,
the way I had it installed. I took it down a couple of summers ago,
because the
lightning had been so bad. Was paranoid I'd take a hit eventually...It
was
boom-boom every day at that time...It's now resting on the side of the
house..
MK