Posted by Marc Martin on
URL: https://www.es-forum.com/leakage-in-a-shielded-room-and-using-Zoom-tp4036803p4036823.html

A ground loop occurs when you've got two different paths to ground connected together (usually indirectly), which can cause interference on audio/video equipment.  It also seems to amplify the fields surrounding everything, which makes EMF symptoms worse.

A ground loop isolator for coax cable eliminates the grounding from the incoming coax cable from interfering (causing a ground loop) with electronics that are already grounded to your electrical system (e.g. router, amplifier, TV, etc. with a 3-prong grounded AC cord)

They look like this:
https://www.amazon.com/dp/B08FRGH4X2/

I have one of these on my incoming coax cable, before it reaches the splitter to my cable TV DVR and my cable internet modem. As I've got a couple of electronics that have 3-prong AC cords (audio amplifier, and internet router).  So having those electronics grounded and the cable coax grounded causes a ground loop, which can be heard on my loudspeakers as an audible 60hz hum.  That hum goes away with the coax ground loop isolator.  Also my tolerance for my cable internet improves with that in place.

Marc