Dale Parfitt wrote:
The ARRL Antenna Handbook describes ground wave as:"...any wave that
stays close to the earth, reaching the receiving point without leaving
the earth's lower atmosphere."
That definition is very misleading at VHF, since normal tropospheric
refraction takes place entirely in "the earth's lower atmosphere" but
generally doesn't involve ground at all. It's a gradual bending of the
space wave.
Kraus doesn't address VHF ground wave that I can see.
Perhaps scatter mode might be a better description- in this case tropo
scatter.
That isn't quite it, either, because "scatter" has a specific meaning
which doesn't fully apply to this complex (and varying) mixture of
propagation modes. In fact, no attempt to label VHF/UHF propagation as
one single mode can ever be correct.
--
73 from Ian G3SEK 'In Practice' columnist for RadCom (RSGB)
http://www.ifwtech.co.uk/g3sek