Well I know I talked about this subject before here someplace- damned if I can find it.
Short answer is if you call it a "tester" and expect it to work like a Wiggy there ain't no such thing.
What you need is a signal level meter. It does take some interpretation as well as knowledge of CATV to be able to use it. They don't come cheap and unless you are willing to learn a new trade and have someone to teach you I recommend that you not waste your money.
In my opinion you would be beter served just to install the cables and leave everything else for the cable guy.
-Hal
