[RFI] Power inverter RFI

[Alan AB2OS]

I bought a "Vector" brand 350W power inverter (12V DC in, 120V "modified 
sine wave" out), intending to use it for Field Day to power devices that 
cannot run on 12v directly (such as the SteppIR controller and perhaps 
even a rotator), but it generates a lot of RFI at frequencies apparently 
varying as it warms up and as the load varies.

It's in a metal case, so I thought it might be reasonably quiet. It 
seems I was wrong.

Anybody used one of these things and managed to shut it up?

Alan AB2OS