🚀 go-pugleaf

In article <17660140@hpfcdj.HP.COM>, myers@hpfcdj.HP.COM (Bob Myers) writes:
> A quarter-wave vertical antenna works just fine against
> an *infinite* ground plane, if said plane is flat and orthogonal to the
> radiating element.  So any length in excess of 1/4 wavelength should work,
> and we see that ground-mounted verticals require no radials whatsoever, 
> assuming that the local ground (in the sense of the earth itself) is good
> enough.

  [ as the radial "droop" angle goes from 90 deg to 0 deg...]

> Obviously, it damn well better be 1/4-wave when you get to zero and the 
> thing becomes a vertical dipole!

Wait! The 0-degree case (horizontal radials) does indeed require 1/4-wave
radials.  The object is for the radials to present a zero impedance at
the center, thus simulating a good artificial ground.  The 1/4-wave case
uses the impedance transformation property to convert the open-circuit
at the end of the radial to a short-circuit at the center.  Making the
radials arbitrarily longer than 1/4 wave just doesn't cut it.

The reason that untuned radials can be used for ground-mounted verticals
is that they are used to couple into the true ground (so to speak).

-Paul wb6cxc

-- 
      Paul M. Elliott      Optilink Corporation     (707) 795-9444
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 "If I had known it was harmless I would have killed it myself." - P.K. Dick