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Re: Topband: Feedline Choke Placement in RX systems

To: Dennis W0JX <w0jx@yahoo.com>, "topband@contesting.com" <topband@contesting.com>, John Kaufmann <john.kaufmann@verizon.net>
Subject: Re: Topband: Feedline Choke Placement in RX systems
From: Adrian <vk4tux@gmail.com>
Date: Wed, 1 Dec 2021 04:11:50 +1000
List-post: <mailto:topband@contesting.com>
The feedline (if coax) outer braid responsible for imbalance RF radiation, is fed from the antenna end.

Choking it there eliminates a RF active length.


vk4tux

On 1/12/21 03:48, Dennis W0JX via Topband wrote:
K9YC made an interesting comment in his post, saying that the feedline chokes 
would be most effective if placed at the antenna end of the feedline.
W1FV's 9 circle YCCC array has them right at the controller.
The older K7TJR combiner utilized no feedline chokes. However, I believe that 
Lee's new design has built in common mode protection on the combiner circuit 
board.
So what is the best way? Is placement dependent upon the combiner design?
BTW, K3LR is using 2.4 in #31 toroids with at least 24 turns of RG-179 as 
feedline chokes in his 8 circle HiZ array and I believe that there are chokes 
on both ends of the antenna feedlines. Of course, K3LR operates in a high 
intensity, multi-transmitter environment and may need all that choking.
73 Dennis W0JX
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