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Old January 7th 05, 03:43 PM
Spam
 
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Default vertical dipole or 5/8 lamda?

What has higher gain?

A vertical dipole or a a 5/8 lamda vertical?

Is there any difference in gain between a center fed dipole or a 1/4
lamda matching stub feeding an end fed dipole such as the J-Pole?
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Old January 7th 05, 04:41 PM
Cecil Moore
 
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Spam wrote:
What has higher gain?
A vertical dipole or a a 5/8 lamda vertical?


A 5/8 WL vertical *with an excellent ground plane* has about
3 dB gain over a vertical 1/2WL dipole.

Is there any difference in gain between a center fed dipole or a 1/4
lamda matching stub feeding an end fed dipole such as the J-Pole?


Both radiating portions are 1/2WL so they have about the
same gain.
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73, Cecil http://www.qsl.net/w5dxp


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Old January 8th 05, 08:19 AM
 
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Cecil Moore wrote:
Spam wrote:
What has higher gain?
A vertical dipole or a a 5/8 lamda vertical?


A 5/8 WL vertical *with an excellent ground plane* has about
3 dB gain over a vertical 1/2WL dipole.



A little optimistic maybe....Normally, a dual 5/8 collinear
would give about 3 dbd. A single 5/8? As far as textbook
numbers,it's usually rated apprx 3.3 dbi vs the 2.1 dbi
for the 1/2 wave.
So only about a db or so...In modeling the 5/8 GP, using
sloping 5/8 wave radials gave the appx 3.1-3.3 dbi...
To get much more than that, you have to run two 5/8's elements.
The most I could get by using 5/8 radials sloped at a *real*
steep angle, was about 4.2 dbi. A normal dual 5/8 collinear
will do appx 5.1 dbi, but spacing can vary the gain.
MK

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