I have an Analog Cable TV signal which needs to be transmitted to a HD Monitor. So far I have been using the following setup:

Analog Cable RF Input --> LCD TV Tuner --> Output [VGA] to LCD HD Monitor

But the signal is worse & hence I wanted to use a DVB STB [CISCO Z255DVB-NM] available here in India as per my friend's advice. I tried giving the Analog RF input to the DVB STB box & the Cable Output to the TV tuner [and then to the monitor via VGA] but I do not get a TV signal. Is there a problem with the setup? I tried to use the RCA output to RF Input to the TV tuner card but no luck. Any ideas would help me a lot.