Cable ground loop / Mondial Magic help


I have a hum in my system. I cured the hum today by installing a $15.00 ground loop break purchased at my local dealer, however it had the added ‘benefit’ of killing all of my High Definition cable channels. I couldn't get a picture on any HDTV channels until I removed the unit. UGH!

I am considering buying a Mondial Magic unit but I am concerned that I might spend $100 and still not be able to receive my HDTV channels. Can anyone provide some insight on this unit?
The Mondial MAGIC I purchased over 10 years ago, and still use, will pass HDTV (and high speed internet) just fine. Also, if you have to use a splitter anywhere, get a high quality one as well. If you still have problems, you incoming cable signal may not be strong enough. If your entire house is wired for cable, as mine is, consider splitting the signal to only the rooms you need, or at least use a high quality multi-splitter. Should your cable TV also have high speed inernet service, a splitter cannot be used to drive two computers. You must use a router. I can provide complete details if needed.
I just solved the same problem with a Jensen-Transformers' ground isolator. It cost $60 shipped to my house and works fine w/ digital cable and HDTV. I think the specific product number is Model VRD-1FF.