Indeed! and I've seen Tom Shiller's presentation of his "Illuminator."
My HOA antenna at home is a 41 m end-fed wire on the top of a 2 m high
wooden fence. It "works" surprisingly well considering what we all know
about antennas. It also "works" for the HOA. Tom even came up with a
3-lamp "phased V-array" that also "worked" although I doubt that it
"worked" much better than the single-lamp model that gave him WAC.
Ufer grounds were developed by Herbert Ufer [you thought it was an
acronym? [:=)] during WW2 for lightning protection for ammunition and
bomb storage vaults in S. AZ. He found that encasing the earth
electrode in concrete provided better conductivity in the bone dry soil
than just a rod driven in. They are safety grounds. I'm pretty sure
they aren't very effective for antennas and RF however.
Radials follow the diminishing returns rule: None will "work" although
getting RF current into the antenna may be hard with none. Going to 1
will make a BIG difference, and 2 a not-as-big difference ... the
contribution of the 2nd isn't as big as the 1st. Likewise for 3, 4, and
beyond. Most AM broadcast stations with bottom-fed ungrounded monopoles
use a radial field with as many as 1 per degree. Or, you can follow the
plan of KFBK [1530 kHz] in Sacramento CA and erect a Franklin antenna in
a rice field. No radials required and it's sometimes referred to as
"The Flame Thrower of the S. Sacramento Valley."
73,
Fred ["Skip"] K6DGW
Sparks NV DM09dn
Washoe County
Jim Brown wrote on 1/16/2022 10:41 AM:
On 1/16/2022 10:21 AM, jerry wrote:
Have you actually tried one? Mine seems to work.
Define "work." N6BT famously said many years ago that everything
"works" by quickly working all continents on a light bulb.
I was ready to put
out radials
also, but doesn't seem to be necessary.
The earth is a big resistor. A connection to it does NOT make a
transmit antenna work better -- indeed, using earth as a return adds a
resistor in series with the antenna that burns TX power, making our
signal weaker! Radials serve as both a counterpoise -- a low
resistance return for antenna current -- AND to shield the antenna's
field from the lossy earth beneath it, also minimizing the loss of TX
power.
There's a conceptual discussion of this in slides for a talk I've done
at Pacificon, Visalia, and to several large clubs.
http://k9yc.com/160MPacificon.pdf
73, Jim K9YC
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