So just to clarify, physical proximity of the devices shouldn't matter, right? The PowerLinc is within two feet of the UPS and six devices (which are all plugged into the UPS). Circuit-wise, the PowerLinc and the UPS are plugged into the same outlet.
The nearest (and only other) outlet that the PowerLinc can reach with the 6-foot USB cable I'm using is a few feet above it, and is directly wired to that outlet. (I saw the wiring when my house was being built.) There was no noticeable improvement when I tried this outlet.
The outlet that does seem to work OK is the one across the room which is on a different circuit, but to reach it, I have a bright orange extension cord laying across the floor of my living room.
Aside from trying a new FilterLinc, what are your thoughts on these approaches (in case that doesn't work)?
1. Double up on FilterLincs, i.e. plug the UPS into one FilterLinc and then plug that FilterLinc into another FilterLinc
2. Using a USB extension cable like this one (http://www.amazon.com/dp/B004AGX4YO)