RFI
[Top] [All Lists]

Re: [RFI] RFI From Wireless Internet Radio

To: "rfi@contesting.com" <rfi@contesting.com>
Subject: Re: [RFI] RFI From Wireless Internet Radio
From: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Wed, 06 Jul 2005 12:24:16 -0500
List-post: <mailto:rfi@contesting.com>
On Wed, 6 Jul 2005 07:27:47 -0700, Dana Roode wrote:

>Does anyone have any experience with RFI from a device like this one
>and have suggestions as to how I might eliminate it?

I suspect that at least some of the trash may be common mode radiation 
from the Ethernet cables that connect it to the rest of your system, or 
to the DSL or cable modem, or both. There is an applications note on my 
website that gives specific recommendations on the use of ferrites to 
choke this common mode current. There may also be common mode radiation 
from the low voltage power cable (to the wall wart). The chokes would 
also apply there. 

I suspect that at least some of the trash is also being radiated by the 
box itself due inadequate shielding. That, of course, would require more 
serious measures. But I would try the chokes first, and see what's left. 

To find the applications note, click the link on the main page for 
"Publications," then select the two downloads about ferrites. The first 
one has a lot of explanatory text that is aimed at RFI to audio and 
video systems, but it tells a lot about how the chokes work. The second 
is a Power Point of a presentation I gave to my local ham club, and it 
addresses RFI from computer wiring in general, and Ethernet in 
particular.

I seriously doubt that the trash that is bothering you has anything to 
do with the 2.4 GHz transmitter itself, but rather from the other stuff 
in the box, and is being radiated by the two mechanisms above.  

Jim Brown K9YC
http://audiosystemsgroup.com



_______________________________________________
RFI mailing list
RFI@contesting.com
http://lists.contesting.com/mailman/listinfo/rfi

<Prev in Thread] Current Thread [Next in Thread>