[Lf] LF: Aerials and grounds ..Les N1LF]

[Andre' Kesteloot]

Alan Melia wrote:

> Hi Les thanks for your input, all experimental data is of immense interest.
>
> The subtle difference is that I suspect we are not talking about quite the
> same type of antenna. As I understand it 'Lowfer' beacons are restricted to
> 50feet total from the terminal of the TX. This means most of the antenna has
> to be vertical, with a small amount in capacity hat top-loading. I believe
> these aerials do perform as you say.
>
> We seem to have a slightly different effect when we are considering an
> inverted L configuration, which differs depending upon the ground
> conductivity of the site. It would seem from some experimental data as
> though the configuration of the top-load wires can significantly reduce the
> ground loss, without apparently increasing the top-load capacity. In these
> aerials the height of the vertical is about 10 to 15m  (33 to 50ft) and the
> horizontal top-load wires totalling 90 to 150m. Mike raises the point of the
> 'phasing' of various grounded components, but I think we may be stumbling on
> a simpler explanation. This seems to be related to the 'footprint' of the
> top-load wire. I am trying to beat the data into some sense at the moment
> but not succeeding as I either don't have enough, or its not detailed
> enough. (I am not sure which).
>
> The 'punch line' from the idea seems to be that whilst it is not worth
> spreading multiple top-load wires further apart than about 0.8m because you
> dont get any further increase in capacity, a wide separation might lead to
> lower measured ground loss (BUT ONLY ON SITES WITH A LOW GROUND
> CONDUCTIVITY, where putting extra copper in does not make any improvement)
> It also might go some way towards explaining why very long low resonated
> antennas work so well, when the 'theory' says they should not.
>
> It may all be rubbish, but its an interesting pass-time for the static
> season!!
>
> Cheers de Alan G3NYK
> Alan.Melia at btinternet.com