N6LF's work is well worth studying. It emphasizes the importance of
current on radials be as nearly equal as possible when there are only a
few radials. He emphasizes that loss in radial systems is lower if
currents in the radials are more nearly equal. Also, radials are NOT
"ground;" rather, they SHIELD the fields of the antenna from the lossy
earth, and in doing so, provide a low loss path for return current (that
is, they act as a counterpoise as well as a shield). And this is NOT a
solid metal ground plane, it is wires of certain electrical lengths
insulated at the end.
Remember the analysis showing that the loss in radials is the sum of all
the I squared R factors from each radial. When we have MANY radials, the
current in each is so small that variation doesn't matter. But when
there are only a few, the variation can makes a difference. And I think
"a few" radials per vertical is what most 4-squares have.
73, Jim K9YC
On Sat,9/24/2016 1:18 PM, David Robbins wrote:
But it doesn't matter if the ends of the radials are connected or not... in
the extreme case of a solid metal ground plane all the 'grounds' are
connected together with an infinite number of paths and that is considered
the 'best' possible 'ground'. Why would having the shield of the feedlines
act as a radial be different than having a radial run from the feedpoint of
each vertical back to the center with the feedline taped to it??
David Robbins K1TTT
e-mail: mailto:k1ttt@arrl.net
web: http://wiki.k1ttt.net
AR-Cluster node: 145.69MHz or telnet://k1ttt.net:7373
-----Original Message-----
From: TowerTalk [mailto:towertalk-bounces@contesting.com] On Behalf Of Jim
Brown
Sent: Saturday, September 24, 2016 19:36
To: towertalk@contesting.com
Subject: Re: [TowerTalk] 4 square for 80
On Sat,9/24/2016 10:07 AM, David Robbins wrote:
I fail to
see why the shield of the feedlines is different from the radials it is
connect to at the base of the vertical.
The radials are not connected to anything at the far end. The feedline is.
I've seen several recommendations from people I view as "authorities"
say that the feedlines of vertical antennas should be choked. Sorry, I don't
recall who.
73, Jim K9YC
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