On Fri, 20 Jan 2006 06:56:42 GMT, Owen Duffy wrote:

One of the things that intrigues me is the common "expert" advice to
cut radials for 7MHz to 33' long and bury them. It seems to me that
when buried and considering the wire as a transmission line, the
velocity factor will be somewhere between 0.3 and 0.8 depending on the
soil type, so that 33' is likely to be closer to a half wave
electrically, and present a relatively high and reactive impedance at
the antenna base if it were not for the attenuation of the wave on the
radial.

Hi Owen,

Calling them "tuned" radials is an artifact of their length being
described in free space wavelength. The proximity of earth negates
such illusions. The association with the necessity of being a quarter
wave long comes by the field data obtained by Brown, Lewis, and
Epstein. This was simply an arbitrary selection born more of the
available wire being portioned out in binary increasing counts
(2,4,8,16....) such that 119 radials depleted their stock (short of
that magic 128). Their work has been offered on the web through the
interests of our discussions here, and by one or several
correspondent's scanning and posting their report. Google this
newsgroup for that link using the authors as a keyword search. This
was offered last summer.

73's
Richard Clark, KB7QHC