[Elecraft] On ground - in ground radials

[Fred Jensen]

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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