[TowerTalk] K8UR wire 4-SQR characteristics vs 1/4 vertical array design from N0AH

[Tom Rauch]

> I assume he is talking of base-fed half waves, but wonder why center
> fed half waves would be immune from this requirement?
> 
> --
> Steve K8LX

Any time you stick a conductor carrying high RF current or voltage 
near dirt, it induces loss in the system.

The loss in a vertical dipole with the end near earth (in terms of the 
wavelength) will be nearly the same as an end-fed wire in the same 
position. The only additional loss would be because you'd have to 
"push" the end-fed antenna against ground, but even a modest 
ground would make that loss negligible.

This even applies to antennas like my low dipoles (horizontal). With 
no ground system, they are about 5-7 dB weaker than the same 
antennas with a large counterpoise below them.

It's been my experience that NEC tends, for some reason, to under-
estimate these losses. In actual dipole measurements made by 
Haagn-Barker over 30 mS/m soil, the error was about 4 dB or so at 
.05 wl height compared to a model on NEC-2. 

 
73, Tom W8JI
w8ji@contesting.com

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