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

[Jim Brown]

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