Ian White, G3SEK wrote:

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.

Yep, the IEEE Dictionary says the "ground wave" possesses a
space wave component. "From a source in the vicinity of the
surface of the Earth, a wave that would exist in the vicinity
of the surface in the absence of an ionosphere. The ground wave
can be decomposed into the Norton surface wave and a space wave
consisting of the vector sum of a direct wave and a ground-
reflected wave."
--
73, Cecil http://www.qsl.net/w5dxp


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Cecil Moore wrote:
Ian White, G3SEK wrote:

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.

Yep, the IEEE Dictionary says the "ground wave" possesses a
space wave component. "From a source in the vicinity of the
surface of the Earth, a wave that would exist in the vicinity
of the surface in the absence of an ionosphere. The ground wave
can be decomposed into the Norton surface wave and a space wave
consisting of the vector sum of a direct wave and a ground-
reflected wave."

Thank you - that's a new one to me.

So what does the IEEE define a "Norton surface wave" to be?


--
73 from Ian G3SEK 'In Practice' columnist for RadCom (RSGB)
http://www.ifwtech.co.uk/g3sek

Ian White, G3SEK wrote:
So what does the IEEE define a "Norton surface wave" to be?

"Norton surface wave - a guided EM wave produced by a source
over or on the ground. It is the non-geometrical optics
component of the ground wave."

"geometric optics - the treatment of propagation of light as
rays. Note: Rays are bent at the interface between two dissimilar
media or may be curved in a medium in which refractive index is a
function of position."

Presumably, there are no geometric optics involved in RF emissions
from an antenna. Therefore, for an RF antenna, the Norton wave
equals the surface wave. The surface wave and ground wave are
NOT the same thing. Besides the surface wave, the ground wave
contains part of the space wave which itself consists of two
parts, direct and ground-reflected.

So according to the IEEE, it is not ground wave Vs sky wave.
It is surface wave Vs sky wave. Ground wave = part surface
wave and part sky wave.
--
73, Cecil http://www.qsl.net/w5dxp


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