I just got back from a project in Manhattan.
Condo on the 43rd floor.
MSC 400 with an RFX.
There is a ton of interference bombing in at this height and location. The RFX light was lit no matter what we did. Even with the emitters disconnected. After reading this thread, I went down to one of the 53 Radio Shacks in Manhattan! Found a couple of snap on ferrite cores. I tried the cores with the emitters and other wires without success. Finally Nick the other tech on the job slid the ferrite core directly on the antenna of the RFX. Dead quiet!! Remote now works consistently after a couple of days of testing.
I suspect that we are just attenuating the signal,but success is success.
I tried it on mine at home and things seem a little snappier as well.
It is interesting to note that a Niles Intellicontrol in the next room(in the same condo) running at the 418mhz does not have any problems at all? I recall Niles upgrading their RF stage a few years ago. Adding about $100 to the cost. I would speculate we will see an upgrade for the RFX from URC in the near future. It needs some help I would say.