>The radial height above ground clearly did not need to be 50 feet,. It did
>need to be high enough to easily be well above a tall truck, or more commonly,
>a horseback rider.
The advantage to this is that you can get away with wire composition
(copper clad steel, or even aluminum if handled properly) that would
not hold up on or under ground. And obviously, less wire is needed.
The fly in the ointment is that as you and K9YC mentioned they have to
be seriously elevated. The clearance for a vehicle may matter but the
real reason is antenna physics in terms of wavelength. Radials on
the ground act like a shield between the vertical element and earth.
When you go elevated, the radials become a counterpoise and the
antenna takes the form of a distorted vertical dipole but for that to
happen it has to be sufficiently removed from earth influence and
that's a matter of wavelength. That's why on 160 m. they have to be
high -- what I've heard is 1/10 wavelength but as mentioned, things
seem to go well starting at around 20 feet. Since it's more like a
distorted dipole, the length of the radials matters and they have
voltage on them. Their spacing should be equal. So, as usual with
antennas, there's no free lunch. I occasionally work someone with an
inverted L and "elevated" radials which turn out to be around 8 feet
high or less. Sorry, but no, not even close. But I've quit trying to
teach these guys because they believe what they want to believe.
73
Rob
K5UJ
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