Verticals properly are quire simple, this is
not a pure vertical and not very simple to
evaluate , Your making the assumption, that the system stops
radiating at the point of connection to the
loop ? .
The feed is at the corner making a Y
and not a T .. hence the question ,
At what point dose the transformation
take place , radiator to loading ?
16 US units of length ~ 4.9m, so that means it's a bit more than
half the height of mine. The top hat is near-enough infinite to all
intents and purposes, so its real height is 4.9m.
My antenna is only 7m high, with much smaller top hat. That amount of top
capacitance will drastically reduce the ground resistance, so all more than
likely all quite an efficient vertical radiator. If there is enough
buried metal in the ground it could be very good indeed.
so we're probably talking about a similar performance - perhaps an
efficiency of -40dB on 137kHz. That's what mines comes out as,
anyway.
Horizontal radiaitors don't when they are close to a reflector. And
the same good ground system that makes it radiate vertically stops the
horizontal bit doing anything. If the ground were very poor, sand for
instance with littel wire underneath, then perhaps the horizontal part may
generate some ExH, but then efficiency would no doubt be so poor that teh Hpol
contribution would be insignificant.
Not sure why you talk about wire separation, he said they are strapped so
its just a two wire, fat vertical. Which is exactly what I use - two
paralleled conductors of a twin feed.
Vertical antennas really are quite straightforward to analyse /
measure
Andy G4JNT
