Thought that I should pass this bit of experience along concerning a grounding problem that I encountered. The situation was clear to me, i.e. that I was getting a hum in my audio system from the connection made from my cable tv company. To resolve this issue, you can purchase an isolation transformer from most electronic companies that will isolate the difference in ground potential from the cable company to your power ground at your home. The transformer works great, and is very easy to install. Hope that this info helps the next person as much as it helped me.  Greg

the unit that I am viewing on ebay is 5-300mhz, with an insertion loss of less than 1 db. it is a barrel design approximately 3 inches long, and 3/4 inch in diameter. Seems like the prce was only $15 postpaid. And as a unique feature, one end is male and the other female. That way yu wont put it in backwards. Also the design negates the need for a short piece of coax between the unit and the cable tv box.