[TowerTalk] Gap Vertical, Verticals in general

[force12@interserv.com]

Good morning.

I have always been fascinated by various verticals appearing to "work" 
better when they are elevated. If it is really an HF vertical-vertical, then 
the highest one would want the feedpoint is about 1/4 wavelength high, such 
as a vertical dipole. As it moves higher, there is a high angle lobe that 
appears and overtakes the energy on the lower lobe. The lower lobe is 
eventually recovered, but not until the antenna is substantially higher.

Does anyone else model these things?? All of our software indicates this to 
be the case. Our ZR verticals are vertical dipoles and really do not want to 
be mounted very high. Since they are for 20-15-10, elevating it too much 
will create the high angle lobe on 10 mtrs, although 20 might be all right. 
As a 1/4 wave vertical is elevated to where the feedpoint matches the 
vertical dipole, the pattern looks like the vertical dipole! This means the 
main lobe is compressed from the typical 1/4 wave vertical pattern at a 
lower height.

If a vertical indeed works better at a high height, there might well be 
something else going on.

What does anyone else's models/experience show?

Many are tower mounted, so it might be interesting.



Have a good day and 73,
			Tom, N6BT
			Force 12 Antennas and Systems
			(Home Page   http://www.QTH.com/force12 )



--
FAQ on WWW:               http://www.contesting.com/towertalkfaq.html
Submissions:              towertalk@contesting.com
Administrative requests:  towertalk-REQUEST@contesting.com
Problems:                 owner-towertalk@contesting.com
Search:                   http://www.contesting.com/km9p/search