Hi,
Let's think of it this way: connect an insulated wire around each disk from
one side to the other, flat against the metal. The jumper is soldered to the
antenna element on each side of the disk. Now remove the solid disk. The
U-shaped wire is in effect is a section
of transmission line, less than a quarter wave long with one end shorted. It
therefore exhibits inductive reactance. If you wired another such section in
parallel, the total inductance would be half. How about 1000 such little
stubs all in parallel, forming a skeleton disk? So doesn't the solid disk
represent an infinite number of such stubs, and therefore has almost no
inductance? Is this why the padder under the chassis works? (I do this too).
The RF travels around the edges from top to bottom, plus through holes with
wires through them (like short sections of coax).
73, Roy K6XK
----- Original Message -----
From: "Larry Benko" <xxw0qe@comcast.net>
To: <dezrat1242@yahoo.com>
Cc: <amps@contesting.com>
Sent: Saturday, March 20, 2010 11:21 AM
Subject: Re: [Amps] placement of RF choke bypass cap. (Results of
experiment)
> Here are the results of the experiment:
>
> 1.) Dipole was made with #10 bare copper wire each side 12.0" long.
> 2.) Disks are 2.02" diameter x 0.01: thick copper with hole in center
> for #10 wire.
> 3.) 8ft. of RG-316 coax with 3 common mode chokes (Z>300 ohms at 200
> MHz
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