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Old August 20th 04, 11:26 PM
Richard
 
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Default radiation angles

Could someone tell me what the radiation angles of the following aerials
(roughly) a

Half wave dipole
Quarter wave verticle
Longwire

TIA,

Richard


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Old August 21st 04, 01:40 AM
Roy Lewallen
 
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All of these antennas radiate in all directions.

Roy Lewallen, W7EL

Richard wrote:

Could someone tell me what the radiation angles of the following aerials
(roughly) a

Half wave dipole
Quarter wave verticle
Longwire

TIA,

Richard


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Old August 21st 04, 02:14 AM
Cecil Moore
 
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Richard wrote:

Could someone tell me what the radiation angles of the following aerials
(roughly) a

Half wave dipole
Quarter wave verticle
Longwire


All can be known by downloading and running the free demo version of EZNEC from:

http://www.eznec.com

You will find the radiation angle of a longwire cannot be known with
the information that you furnished.
--
73, Cecil http://www.qsl.net/w5dxp



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Old August 21st 04, 05:58 AM
Reg Edwards
 
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Crudely, the lobes in the radiation patterns of the antennas you mention,
inevitably distorted by the local environment, are so broad they can be
considered largely omni-directional, except that purely vertical antennas
always have a vertical null and horizontal antennas don't radiate quite so
well in line with the wire as they do broadside to the wire.

The type of local ground also has a disturbing effect. As people seldom know
what type of soil they have it's somewhat statistically unpredictable.
Which all adds to the fun.

The term "radiation angle" doesn't really apply, its a misnomer, until you
have a high, multi-element, directional beam antenna which EZNEC (a computer
program) can get its teeth into.
---
Reg, G4FGQ

===================================

"Richard" wrote in message
...
Could someone tell me what the radiation angles of the following aerials
(roughly) a

Half wave dipole
Quarter wave verticle
Longwire

TIA,

Richard




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Old August 21st 04, 07:44 AM
Richard
 
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By radiation angles, I have read that a 5/8 has about 15 degree )so good for
DXing), and a quarter wave about 25 degress, but I am not sure if that is
correct.

What roughly is the angle that a dipole radiates?

Richard

"Richard" wrote in message
...
Could someone tell me what the radiation angles of the following aerials
(roughly) a

Half wave dipole
Quarter wave verticle
Longwire

TIA,

Richard






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Old August 21st 04, 08:32 AM
Richard Clark
 
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On Sat, 21 Aug 2004 07:44:31 +0200, "Richard"
wrote:
By radiation angles, I have read that a 5/8 has about 15 degree )so good for
DXing),


It also works nearly as well at 14 degrees or 16 degrees. And of
course only slightly worse at 13 degrees or 17 degrees (you couldn't
tell the difference at, say, 12 degrees or 18 degrees). And at 10
degrees or 20 degrees its not too shabby either, and probably as good
as 45 degrees (but maybe not, hard to tell).

and a quarter wave about 25 degress, but I am not sure if that is
correct.


About, or perhaps it is 28 degrees or 15 degrees.

What roughly is the angle that a dipole radiates?


Most of them. Actually it works best straight up into the clouds, but
that doesn't mean it is worse than a vertical at 20 degrees. Funny
about these things.... Which is better: ski boots or an ottoman?

Hi Richard,

It is all a continuum where eventually in comparison to the best
angle, some angles are obviously worse. If you are going to name one
angle (and it is done quite frequently here) you have to keep in mind
that this in no way defines an antenna rigorously. It is more a
shorthand.

73's
Richard Clark, KB7QHC
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Old August 21st 04, 10:07 AM
Paul Keinanen
 
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On Fri, 20 Aug 2004 23:26:14 +0200, "Richard"
wrote:

Could someone tell me what the radiation angles of the following aerials
(roughly) a

Half wave dipole
Quarter wave verticle
Longwire


These are quite irrelevant questions, unless you specify the height of
the antenna (in wavelengths) and the characteristics of the ground
(mainly conductivity) at the frequency of interest.

For instance a horizontal dipole more than 10 wavelengths above ground
would have quite omnidirectional pattern in the vertical pattern, but
nulls in the direction of the elements. Of course, this can be a bit
hard to implement on 135 kHz, but not a real problem on 1,3 GHz :-)

Paul OH3LWR

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Old August 21st 04, 03:31 PM
Cecil Moore
 
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Richard wrote:
What roughly is the angle that a dipole radiates?


By "angle that a dipole radiates" do you mean the
angle of maximum radiation? If so, it depends upon
the height and length of the dipole among other things.
Download the free version of EZNEC and see for yourself.
--
73, Cecil http://www.qsl.net/w5dxp



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Old August 21st 04, 06:39 PM
Richard Fry
 
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Earlier:
By "angle that a dipole radiates" do you mean the
angle of maximum radiation? If so, it depends upon
the height and length of the dipole among other things.

______________

To be more exact, a linear (1/2-wave) dipole produces maximum radiation at
all angles perpendicular to its center.

But as suggested by the quote above, radiation from the driven element along
with the distance, geometry, and electrical characteristics of nearby
conductors (including the earth) will determine the final pattern of the
radiated signal.

R. Fry


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