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Re: [RFI] Home networking birdies

To: "D. Kemp" <nn8b@yahoo.com>
Subject: Re: [RFI] Home networking birdies
From: W2RU - Bud Hippisley <W2RU@frontiernet.net>
Date: Sun, 17 Sep 2006 22:56:20 +0000
List-post: <mailto:rfi@contesting.com>
D. Kemp wrote:

>I have a home network with a cable modem connected to
>a D-Link router, then from there to 1 computer and to
>a wireless hub ( not on all the time) and to a Netgear
>hub in my shack that supplies 2 computers there.
>I am getting birdies from the Netgear hub. If I unplug
>the dc the RFI goes away. The hub is about 4 feet from
>the rigs. There is a ground wire on the hub. There is
>cat5 cable to and from the hub.
>Any ideas on how I can eliminate the RFI?

Yep.  Get the biggest, meanest type 31 or 43 ferrites you can find / 
afford and push as many turns of your cat5 cable through one at *each 
end* of *each cable*.    You may need to double or triple the length of 
any short cables you're using.  Also do the same thing for the leads 
from any and all wall-warts you're using in your network.  If you do it 
right, your wall-warts will have to be no more than a foot or two from 
the hubs and switches they're powering.... :-)    Forget about the 
ground wires.

All your networking cables are acting as antennas for the ethernet 
frequencies.  I have found with my various ethernet equipment that if I 
common-mode ferrite filter power cables and ethernet cables and even the 
DSL phone line just before it enters my DSL modem my MF/HF hamming at 
1500 watts and my high-speed internet and home network can coexist 
peacefully.  (Without the filters, I got garbage at discrete ethernet 
carrier frequencies on various ham bands and my 1500 watts on 160 used 
to reset the DSL modem.)

Bud, W2RU
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