[Towertalk] Grounding an Elevated vertical

[K3BU@aol.com]

>  ES5TV:
>  > Thus how can you deny that installing a nearly perfect ground screen 
under 
>  > elevated vertical with a few radials frees you from 3-4-5-6 or whatever 
>  > DBs of ground loss in the system?
>  > 

>  K4IA:
>  I just don't understand how a ground screen, unconnected to the antenna 
does 
>  anything to remove ground loss.  Where does the power go?  Cebik's article 
>  suggests you have created a parasitic reflector that shoots your signal 
>  straight up.
>  

Ground screen prevents RF from penetrating and "reflecting" from poor ground, 
it shields it from the RF generated by the radiator and elevated radial(s) = 
better efficiency.

This is analogous to having salt water "ground" which helps to pull the 
pattern down close to horizon. If one radial is used then the horizontal 
component is not canceled, but contributes to fat vertical lobe, which is 
desired in the transmit antenna.

Single or more elevated radials (with screen under) provide more efficient 
"the other half" of antenna than radials on the ground or buried. ON4UN, 
ES5TV and others can attest the practical results and benefits of this 
arrangement.

Cebik gets too involved with mathematical modeling and sometimes loses sight 
of practical world. With properly positioned vertical radiator and balanced 
radials, there is almost nothing to shoot up when using ground screen. 

Yuri, K3BU