Modem performance and modem selection.

These ground loop coax isolators are pretty smiple. Either a transformer or capacitor.

So long as the bandwidth is correct, they are bidirectional.

you are suggesting the OP get something that he might not even need.

True, but so many ground loop issues end up being related to the incoming coax. I’m unusually concerned because I’ve seen a number of charts suggesting that ground loops can occur with digital devices, causing jitter instead of hum, so it’s a tweak I like for myself and recommend.

something like this could also cause issues with the return path.

What??  If you mean power ground return path, there shouldn't be any through delicate signal wire. That's an invitation for a fire. 100% of a power fault's path to ground should be dealt with by ground wiring in the AC cables.

If you mean a cable modem, not sure there’s any difference other than speed and reliability but I have two suggestions:

Use a cable TV isolator in front of the modem. This will prevent ground loops between your gear and the cable tv entrance.


https://amzn.to/2ZxeXOz

Put all your networking/routing gear outside of your "clean power zone."


Use a separate power strip if necessary.

Do you mean a cable modem like from Motorola, or do you mean a streamer??