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Re: [TowerTalk] ferrite beads was...Re: [RFI] HIGH POWER and RFI...

To: "TOWERTALK@contesting.com" <TOWERTALK@contesting.com>
Subject: Re: [TowerTalk] ferrite beads was...Re: [RFI] HIGH POWER and RFI...
From: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Fri, 09 Mar 2007 08:03:22 -0800
List-post: <mailto:towertalk@contesting.com>
On Thu, 8 Mar 2007 23:40:40 -0800, Marlon K. Schafer wrote:

>Out of my 25ish tower sites I have a couple that are a LOT of trouble. 
>Can't find any other cause so I'm hoping that it's just a simple harmonic or 
>induction on the cat5 cables.

That's pretty vague. What sort of trouble? What sort of system? What is the 
ethernet doing?  

Ferrite chokes can effectively kill common-mode antenna behavior of ethernet 
lines at HF if you use the right materials and wind them appropriately. BUT: 
I've never seen an RFI problem with ethernet systems RECEIVING interference, 
only generating it, and I've run 1 kW in VERY close proximity to my ethernet 
wiring. Perhaps there's enough error correction to prevent data errors when 
RFI occurs. 

http://audiosystemsgroup.com/RFI-Ham.pdf

The tutorial at the link above may give you some troubleshooting ideas.

73,

Jim Brown K9YC


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