[Elecraft] OT: Elevated vs. Buried Radials

[David Cutter]

Further to that, if you desire, as I might, to have more radiation in one 
direction, eg from here to North America, I would have one elevated radial 
pointing that way and the radiation pattern tilts that way a little.

One further point not brought out so far: the antenna itself does not have 
to be resonant; as long as the impedance is transformed to match the tx, it 
will accept power and radiate, minus the transformation and system losses.

Since ocf has been mentioned a few times: I've seen VNA sweeps of ocf 
aerials in which the vswr dips nicely in band but the resonance as shown by 
X passing thro zero is often nowhere near.

David
G3UNA
>
> IMPT POINT:  If you want your antenna actually to have a vertical 
> radiation pattern (low angle, omni-directional) then the elevated radials 
> must be symmetric.  If there are two, they must be of exactly equal length 
> and point in exactly opposite directions.  If there are four, they must be 
> equal and point in directions 90 degrees from one another. This symmetry 
> guarantees that the "radials" do not radiate.  The do carry currents, they 
> do help resonate the antenna, but if they are symmetric radiation from 
> them cancels and they therefore do not radiate appreciably.
>
> 73,
>
> Oliver
> W6ODJ
>