On 08/03/15 14:22, Ralph Mowery wrote:

I think that Jeff may be on to something. What you need to do is download
one of the antenna modeling programs. Set it up for the antenna type you
want. Then you can look at the patten and see the take off angle. The take
off angle is what determins the ammount of power you have the differant
types of propogation.

That's an interesting thought, and one that had crossed my mind.
However, modelling is only as good as the modeller, and if things are
set up to model only the sky-wave component, I might not get the sort of
information I'm looking for. BICBW, as I've no experience of this.

However, I've just recalled that while researching the topic some time
ago, I came across some polar diagrams for cross-field antenna trials in
Egypt, which showed the ground/surface wave components as well as the
sky wave, the idea being for the MF broadcast band to maximise the
former and minimise that latter. Sadly, I didn't keep the url, but it
looks like it might be possible to determine some measure of the
relative power/field strengths. I'll see if I can find those diagrams,
the model used might have been mentioned.


--
Spike

"Hard cases, it has frequently been observed, are apt to introduce bad
law". Judge Rolfe