"Ian Jackson" wrote in message
...
In message ,
writes
Like I said, there is no difference in free space between a V and an
inverted V.
There are slight differences when close to ground.
Assuming it's a halfwave dipole, I would have thought it was better to
concentrate on getting the centre (where the current is) as high as
possible, rather than the ends. [Obviously this depends on whether you
have a suitable sky-hook available for and at the centre.] However, I
believe that there is at least one commercial loaded dipole (essentially
for portable use, I think) that has a short mast, and the ends of the V
are up in the air.
In free space I would not think there would be much of any differance.
Near the ground where most of us are is what we have to live with. In my
back yard I have enough room to string wire dipoles for 80 meters and
shorter. I don't have a way to support the antennas in the middle. I can
go up about 60 feet or so at the ends.
One of my antennas is sort of flat as it is a windom and the long leg runs
by my tower and was drooping to about 40 feet, so I put a piece of PVC pipe
at the 50 foot level to help support it.
The OCF antenna is suported so the ends are on some pulleys and a cinder
block on the ground with a rope so that as trees swing the block will
sometimes raise off the ground with high wind. I have put a spectrum
analizer/tracking generator and return loss bridge on it a few times and
watched the SWR/RL go up and down as the wind blew. Really interisting as
the RL did not change much in amplitude, but the frequency shifted.
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