[Antennas] RE: J POLE QUESTION
Dave Shrader
[email protected]
2002年7月11日 17:06:02 -0400
The gain of a properly fed J Pole over a properly fed 1/2 wave dipole
under the same conditions is 0 dBd. The gain of a 1/2 wave = the gain of
a 1/2 wave.
The 5/8 wave has gain IF the 5/8 is mounted over a conducting surface.
The image antenna creates an effective two 1/2 waves in phase separated
by 1/4 wavelength. However mount your J pole over the same conducting
plane and you have two 1/2 waves at 1/2 wave spacing. This is higher
gain than the 5/8 wavelength.
The advantage is that you don't need a matching section as you do for
the 5/8! The J section is the matching section.
Deacon Dave, W1MCE
Manager, Textron Antenna Range, retired.
--------------------
[email protected] wrote:
>> So, what is the gain of a J-Pole over a vertically polarized dipole?
> Over a 5/8 wave? I've been thinking about building a J-Pole, but won't
> waste my time if a 5/8 wave is simpler and has more gain? What are the
> advantages of a J-Pole?
>> Sean
> WD8OKN
> Midland, MI
> www.qsl.net/wd8okn
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