[RFI] UPS interference/Recommendation Request

Alex extraham at earthlink.net
Fri Apr 28 09:19:56 EDT 2006

Hi there,

I purchased a Cyberpower BC1285C UPS yesterday and found immediately that it is generating TVI on the video carrier of broadcast channel 5, 77.25 MHz, when just plugged in and while it's still off. The interference propagates through the power cord and I can suppress it for the most part with about 10 ferrite VHF snap on cores. I will set up a web page to document this interference problem and inform the Cyberpower company. A quick test on the ham bands (MF-UHF) did not reveal any interference there yet. I have to do more tests to be certain.

Here's a link to the UPS:


I have very little experience with UPSes in an Amateur Radio setting, so I wonder how typical this is and if there's a known good RFI/TVI free alternative. I need about 1000VA. Perhaps it's wiser to keep this UPS if the channel 5 interference is the only interference it generates?

--Alex KR1ST

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