[RFI] rfi from Refrigerator

Jim Brown jim at audiosystemsgroup.com
Mon Jun 23 11:31:58 EDT 2008

Hello Kostas,

Several thoughts. First, if you have owned the refrigerator for years or 
months and the noise just began, it may be the result of some failure within 
the refrigerator. If that is true, it should be repaired. 

Yes, a serious ferrite choke on the power cord to the refrigerator has a 
good chance of fixing it. To be effective, it would need to be at least 6-8 
turns around a 2.4 inch outside diameter toroid of #43 or #31 material or 
some part like that. It should be placed very close to the refrigerator 
cabinet. Clamp-on ferrites will NOT help -- they provide FAR too little 
choking impedance on the HF ham bands. These parts are designed for the VHF, 
so you MUST use multiple turns to move them down to the HF spectrum. 

A commercial line filter would also work. It should be bonded to the metal 
of the refrigerator and inserted into the power cord close to where it 
enters the refrigerator. 


Jim Brown K9YC

On Mon, 23 Jun 2008 15:56:19 +0300, Kostas SV1DPI wrote:

>I am new in this reflector.
>I found that i have a noise (mainly on 20,17m and 30m bands). This noise 
>exists the last week, it is over 9 s units and is periodically. It comes 
>goes every 1-2 minutes, keeps for a while and after that is totally clear 
>and agn. Finally i made a research and found that my refrigerator is 
>the problem. Any ideas what can i do? Do you think that some ferrites in 
>power cable of the refrigerator will solve the problem?

>Kostas SV1DPI 

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