[TowerTalk] 4 square for 80

Jim Brown jim at audiosystemsgroup.com
Sat Sep 24 17:06:50 EDT 2016


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 at arrl.net
> web: http://wiki.k1ttt.net
> AR-Cluster node: 145.69MHz or telnet://k1ttt.net:7373
>
>
>
> -----Original Message-----
> From: TowerTalk [mailto:towertalk-bounces at contesting.com] On Behalf Of Jim
> Brown
> Sent: Saturday, September 24, 2016 19:36
> To: towertalk at 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
>
> _______________________________________________
>
>
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk at contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
>
> _______________________________________________
>
>
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk at contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
>



More information about the TowerTalk mailing list