If you have a ground loop you want to find out where it is.
Disconnect the sources one at a time. When the noise goes away that component has a ground loop. Make sure to turn or or mute the receiver when you pull cables.
If you still hear it when all the inputs are disconnected then the noise is coming from inside the HTS.
If the cable box is the culprit then disconnect the input to the box and listen again. If this works you can use a coax ground loop isolator on the that RG6 cable. You can try using a 3-2 ground lifter on AC cords. While not strictly speaking the best permanent solution is doesn't often cause any problems. There are isolators for analog audio and video but I don't not for digital. You have to work at the AC end for those.
http/web.mit.edu/~jhawk/tmp/p/EST016_Ground_Loops_handout.pdf
https
/www.amazon.com/Isolation-Transformer-Ground-Loop-Isolator/dp/B00B2HFE2O/ref=sr_1_fkmr0_4?s=electronics&ie=UTF8&qid=1534177777&sr=1-4-fkmr0&keywords=antenna+ground+isolator