Dave, G3YXM wrote:

So even if the calculated erp of two stations is the same we have to

consider the surrounding terrain?<

yes, Dave, it looks like this might make a difference. My first thought was
that only obstacles that are in the magnitude of the wavelength play a
role. But it may well be, that a city or a large forest (with all the
moisture trapped in the trees) or a lake or something like this makes a
difference in how your signal is transferred to the receiving station.

I will further investigate, but at least my observations show that your
signal is 2 dB stronger here in the East compared to Graham's (I would wish
my signal would be a couple of dB stronger, still my ODX is 402 km, which
is ON7YD ...).

73

Geri, DK8KW (W1KW)