[Antennas] Re: Elevated Ground Plane Question

[Charles Greene]

Hi Ron and All,

I am investigating vertical antennas with elevated radials, but haven't 
gotten too far.  However, I just finished reading an article in Spring 1998 
Communications Quarterly (now merged with QEX), by Jack, VE2CV on Elevated 
Radial Wire Systems for Vertically Polarized Ground-Plane Type 
Antennas.  Most of his work is by model, but he has some interesting 
ideas.  One is a half diamond loop which looks like an inverted V with the 
elevated radials at each drooping end, perpendicular to its plane.  The 
diamond loop is fed at one end, and each side of the diamond is 1/4 
wavelength.  Sort of the opposite of what you are envisioning.  He 
recommends it, if you have the space and sounds like you do, you might want 
to consider it.  He modelled a two element broadside array for 3.75 MHz.

I have EZNEC 3.0 and can model what you have in mind, if you give me the 
details of wire sizes and beginning and ending positions of each in the X, 
Y, and Z plane (or data that I can use to figure this out) and I will model 
it for you.  I don't believe EZNEC gives an absolutely correct result of 
gains and impedances; in fact I have some actual results which are 
different, but as Les Cebik said, it will give a relative picture of 
different configurations for comparison purposes.  So I would have to model 
what you have now and the proposed configuration for comparison purposes.


At 02:07 PM 10/7/2002 -0400, Ron W7MRR wrote:
>  Hi All:
>
>    I have a 160 meter, 1/4 wavelength wire vertical that is feed 
> approximately 30 feet off the ground.  The radials are horizonal from the 
> feed point and parallel to the ground.  I have the opportunity to raise 
> the radials to a height that is almost as high as the top of the vertical 
> radiator [approximately 160+ feet] and am wondering if this will enhance 
> the antenna effectiveness or not.  I am concerned about wave cancelling.
>
>    If anyone has a software program where this situation can be 
> simulated, I would be very interested in the results.  I will try it out 
> in any case, but am interested in what modeling or experience 
> suggests.  Please note the radials would now start at the feed point some 
> 30 feet off the ground with the other end being elevated to 160+ feet.
>
>    Thanks for taking the time to read this and to share your thoughts 
> with me.
>
>Ron W7MRR
>


73, Chas, W1CG
K2 #462