Improve RFI

+11 @mapman Mu metal foil is designed to shield sensitive devices. & Etc. There is also a carbon based paper I believe. that you can use.

We use cases designed to cover transformers in our designs that help greatly.  As we manufacturer tube products, tubes almost always impart noise in the sound.  In some systems, you can hear the noise, in others no noise.  We use a horn system to hear if there is noise.  Using any RFI rejection always helps.

First off, I would like to thank everyone who has tried to help here.  My last post sounded snarky and ungrateful.

  Second, a new development.  I placed the the transmitter -relay device on the floor next to the rack.  Previously it had been on the top half of the rack, and then placed on top of a surround that is wall mounted at near the same height.  The RFI light is off now and the Universal Remote works again.

  There is a small window behind  and above the rack .  I am wondering if there has been an increase in RFI from the external environment (I live on a Flight Path for O’Hare Airport, for one thing).  However I don’t understand why the living room remote would not be effected, as the two systems are in parallel on different levels of the home.  Perhaps the weather updated windows in the living room are better for screening RFI?  I am just speculating.

  The floor location isn’t ideal-it might get kicked or placed back on the rack by my wife or someone else-but for now I will leave it there

@mahler123 said:

 I placed the transmitter -relay device on the floor next to the rack.  Previously it had been on the top half of the rack, and then placed on top of a surround that is wall mounted at near the same height.  The RFI light is off now and the Universal Remote works again.

Me thinks you found the source of the RFI. If you want to verify, I would suggest you place the transmitter -relay device back on the rack. Unplug all the associated A/V equipment from the 120Vac AC mains outlets. Then check for the presence of  RFI.

If you are using a surge protector plug strip, or a power conditioner with surge protection, unplug it as well from the AC mains wall outlet.

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Good move.

Proper shielding is always a good thing but may not be needed so much or at all  if the problem can be addressed by simply relocating affected components and/or the source of the EMI. 

As previously posted, a Trifield EMF meter is indispensable for finding sources of RFI. Routers with wifi the worst, hard drives and transformers can be pretty bad.