[RFI] URGENT: Washing Machine RFI

Jim Brown jim at audiosystemsgroup.com
Mon Feb 25 02:19:57 EST 2013

On 2/24/2013 7:16 PM, Michael Sciascia wrote:
> All of the washers that I have listened to in the store (on a portable shortwave radio with a whip) make RFI.   Many are not heard 10 or 15 feet away.

You should be aware that noise can be radiated directly by wiring 
internal to the source, and it can also be conducted to external wiring 
(like the power line) and radiated from that.  In both cases, the trash 
is picked up on our antennas just like any other RF source, and it can 
also couple into our equipment when external wiring for our equipment is 
not bonded to the chassis.

And for a variety of reasons, including the form of suppression that 
might be provided (or not) an electronic source that is relatively quiet 
in one frequency range can be noisy in another. Switching power supplies 
that SteppIR sold for their motor controllers were MUCH MUCH noisier on 
the higher HF bands, especially 12M.  I've worked more than 175 
countries on 12M since moving here six years ago, but I could not have 
worked ANY of them with that power supply in service.

73, Jim K9YC

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