Source of RFI Pinpointed!

In an earlier post, I had mentioned that two strong bands of radio frequency interference noted on the waterfall display in my radio was due to my computer UPS. It was a surprise finding today that it is not so. I had noted that the RFI disappeared when the UPS was switched off, only to reappear when it is switched on. This led to my earlier presumption. Actually the culprit was a small SMPS adaptor which I use to power an amplispeaker for my computer. The small SMPS was connected to an extension board from the output of the computer UPS. So, switching off the UPS naturally switches off this SMPS as well. That was how I initially thought that the UPS was the culprit!