[RFI] Hyperlan interference

Jim Brown jim at audiosystemsgroup.com
Fri Feb 9 11:55:00 EST 2007

On Fri, 09 Feb 2007 12:49:03 +0100, Marco Spalluzzi wrote:

>Probably it's an overload coming from some FM radio stations tx between 
>88 and 108 MHz, or maybe a repeater-studio link of one or more of these 

If you're right, what you need are common mode ferrite chokes on the LAN 
cables that are connecting the RF link to your Ethernet system (and maybe the 
power supply). 

Don't be too sure that you are right about the source of the RFI though -- 
take a spectrum analyzer (or broadband receiver) to the site and poke a bit. 
You may find other sources, including AM broadcast, variable speed motors, 
and power quality. 

I've written a tutorial that, among other things, includes advice on the use 
of ferrite chokes to suppress RFI.  


It's a free download. Pay careful attention to the discussion of Threshold 


Jim Brown K9YC

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