[Lf] [Fwd: LF: Counterpoise comment]

[Andre Kesteloot]

Vernall wrote:

> Hi all,
>
> The tests done by Jim, and comments made are all very interesting.  The
> following is a further matter to consider:
>
> For any counterpoise system that is elevated and insulated from ground,
> there will be an "interface" situation at the outer ends of the counterpoise
> and that could influence the strength of a ground wave lauched from the
> antenna (assuming the antenna as such can be considered as a separate part
> of the wider environment).  There must be some degree of "mutual coupling"
> between the elevated radials and the ground.  However, despite whatever
> occurs with ground coupling, amateur LF DX is mostly a result of sky wave
> propagation.
>
> The lower that losses can be made within the antenna, the higher the current
> for a given applied power, so the better the DX result by sky wave mode.
> Carrying out field strength readings a few km away would be more of an
> investigation of the ground wave mode rather than the manner in which the
> antenna actually launches "rays" that can then reflect off the ionosphere.
> So it is not easy to investigate the impact of elevated radials with respect
> to radiating energy that goes into sky wave mode.
>
> Most text books are concerned with efficiently launching ground waves and
> having reliable coverage.  The matter of how the antenna launches energy
> that supports sky wave mode of communication is not so easy to find.  Any
> comments on that?
>
> 73, Bob ZL2CA