I toured WCFL's transmitter site in 1971.
The engineer said their radial field was burried over 1' deep.
MK
-----Original Message-----
From: Topband [mailto:topband-bounces@contesting.com] On Behalf Of Donald
Chester
Sent: Friday, October 12, 2018 10:35 PM
To: topband@contesting.com
Subject: Topband: Historical note: Radial Depth
I was looking through my old ARRL Antenna Books. The text in the "Antennas
for 160m" chapter in the 1939, 1944 and 1949 issues in my collection state:
"The ideal form of ground is a series of conductors buried A FOOT OR TWO
beneath the surface, radiating like the spokes of a wheel from under the
vertical part of the antenna, as shown in (the drawing). Its construction
is beyond most amateurs, but it is mentioned here for the benefit of those
who may have the space and a plough to cut the furrows which contain the
ground conductors."
A drawing on the next page illustrates radials buried indeed a foot or two
below the surface. See pages 92-93 in the 1944 edition.
At first I thought this had to be a misprint, but upon further investigation
I see that this is repeated verbatim year after year for at least a decade.
The 1974 edition recommends a more realistic depth of two to four INCHES. I
couldn't imagine anyone digging all those trenches to bury radial wire 1 to
2 feet in the ground, and agreed this construction would be beyond most
amateurs, but neither can I imagine that someone writing for a respected
technical publication would have recommended such a thing in the first
place, and that it would have gone uncorrected for a decade or more. I
wonder how many hams of that era were discouraged from using a radial system
because of this misinformation.
Beside the arduous and unnecessary work to dig the trenches, the
effectiveness of the ground plane is compromised with that much lossy earth
between the vertical radiator and the radial ground plane.
Don k4kyv
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