I think this is a wording issue. We all understand the difference between
VF in the transmission line and VF in free space.
What caused difficulty was the term "arriving at". I took this to mean "at
the antenna" not free space, as there's no need to mention the antenna if
the desired meaning was "free space".
Chuck
Frank said:
"Signals arriving at the BOGs are not travelling in the ground, therefore
their velocity of propagation (Vp) is unaffected by the ground. "
That seems OK to me. I can't think of a better way to say it, but maybe
someone else can.
The Beverage antenna itself, just like any antenna, is also a transmission
line. The only significant change in velocity factor by laying the antenna
on ground is in transmission line mode characteristics of the BOG. The
signal arriving at the antenna and in space all around the antenna is not
any more affected by the ground than it would be with any other antenna.
The same effect could be simulated by a series inductance distributed along
the antenna, or a dielectric. It isn't the signal around the antenna or
arriving at the antenna that is changing, it is the transmission line mode
of the antenna as the signal passes along through the wire.
73 Tom
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