[RFI] apc ups

Donald Chester k4kyv at hotmail.com
Mon Apr 11 18:37:48 EDT 2005

>What you describe Leonard is similar to what my UPS
>does. Presumeably what you are seeing when the
>interference changes frequency is the operating
>frequency of the switchmode power supply inside the
>UPS drifting around in response to temperature and
>load variations. The fixed I described in my earlier email
>with the toroids on the line cords should be helpful to you
>as well.

Mine generates a lot of rubbish up around 2400 kHz, above 160 and just below 
WWV.  Sounds like a buzzsaw.  Doesn't seem to  get into any of the ham 


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