Jim,
The problem is that, in that application, the cables must be 1/4 wave
long electrically. That already makes them shorter than desired and
"wound" chokes on each end would shorten them by another 5-7 feet
making the spacing of the 4 square much too small.
73,
... Joe, W4TV
On 9/25/2016 4:38 AM, Jim Brown wrote:
Tim,
I agree that they must be choked, but NOT with inductance, because those
short lines, by virtue of their length, are capacitive (in the common
mode circuit). So the choke MUST be resistive, which means turns wound
to make it parallel resonant at the operating frequency. Study my
RFI-Ham tutorial.
73, Jim
On Sat,9/24/2016 6:42 PM, Tim Duffy wrote:
Hello Jim,
We are talking about feedlines that are 20 feet (feedlines) above the
ground. They have to be choked (both ends). The raised radial application
(which is not as good as the ground mounted solution with 64 plus
radials).
The feedlines must not be radials - that is why they must be choked.
73,
Tim K3LR
-----Original Message-----
From: TowerTalk [mailto:towertalk-bounces@contesting.com] On Behalf Of
Jim
Brown
Sent: Saturday, September 24, 2016 3:36 PM
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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