UPS causes RFI interference

[Anonymous user]

I have a APC UPS 1000W unit. I uses it to protect and back up my A.C. power for
Amateur Radio Equipment. Between 1.8-7MHz there is a terrible buzz sound
showing up on my Amateur Radio's receiver. I tracked it down to the UPS.

I did a little snooping on the Web and found this to be a common problem with UPS
units that are used by Amateur Radio Operators.

The only way I could eliminator the terrible radiated emission sounding like a buzz
was to first remove the UPS power cord then hit the power button.
It is not the equipment plugged into the UPS. I had nothing connected to
the back of the UPS other than its own line cord.

Would be interested in know if there is a fix for this.

Thank you,
Ken

[EZ_Button_apc]

Just curious how close is the UPS to the equipment. It should be at least 3 feet away from it.

[Anonymous user]

You could try putting the UPS inside a "Faraday Cage", but that might be troublesome and a little awkward ! I would just try getting the UPS as far from your ham equipment as possible ...like in another room close by ... run a 25 ft extension cord from it.

Dave

Message was edited by: Battman

[Anonymous user · Accepted solution]

Running a long extension cord would make things worst because it was radiating from the line cord.

I did wrap the line cord with several turns through a clamp on piece of ferite material very close to where

the line cord exits the UPS.   The APC units where old and the batteries started to fail.  The cost of

the replacement batteries where more than buying another 1000W UPS from another company that offered sinewave output.

The replacement unit does not cause the RFI problem

K