Spike wrote:

On 08/03/15 09:33, Jeff wrote:
Spike wrote

I think you are coming at this from the wrong view point.

Perhaps the question that you should be asking is what take-off angles
are required to produce maximum ground wave, and how do you maximize
that for a MF mobile installation.

I'm really after figures for the proportions of the RF power fed to that
antenna, that finish up in whatever 'they' are called (the use of the
well-known word 'waves' seem to upset people despite their having been
used for the specifics I mentioned, for about 100 years).

I'm aware that reconfiguring the set-up might affect these proportions,
but I did refer the original query to a typical /M (mobile) set-up of a
short rod antenna not connected to ground and operating over average
conductivity in the MF/low-HF bands.

For example, does 40% power the sky (redacted), another 40% power the
space (redacted), and the other 20% power the surface (redacted)?
Clearly, 100% of the RF power goes somewhere, and the various parts of
it must add up to 100% - so what are the proportions?

If the /M (mobile) set-up was changed to a /P (portable) one with a 5/8
lambda ground-mounted antenna, the sky (redacted) proportion would lower
and the surface/space (redacted) would increase - but from what to what?

I'm beginning to think that this topic is either so simple or so complex
that most Amateurs have either forgotten it or have never heard of it.

I suspect that the sort of precision with which one can measure signal
strength. plus very local variations of surface wave intensity due to
varying ground conditions, mean that it would be hard to know if the
signal level resulted from, say, one, five or fifty percent of the
transmitted power. So I suspect your question has never been answered.
An opportunity for some collaborative research between local amateurs?


--
Roger Hayter