Av To Rf Converters For Old Tvs

guys, probably no one's gonna believe this, but we actually bought a new sparkling WEGA just because CAS required AV inputs, which my old tv dint have.now to not let my good old ancient color tv waste, i'd like to buy a RF modulator for it. one that could convert the AV-out of the stb to RF.i did buy a locally made RF modulator to watch my vcds, but it was all crappy, sputtering, crackling sound, and pathetic picture quality.please suggest any place in delhi where i could buy this thing, but of good quality.also, the cables of all friggin' varieties that the touts sell in Nehru place are all of poor quality, so do suggest a good place to buy cables and accessories as well. :)
Nitin,I am sure you are mis leaded by someone.every CAS STB has one more loop port called RF out, this port used to transmit signal between 48 MHz to 760 MHz, you can directly connect the RF cable from this port to your TV.By the way, which CAS system u r usingmitesh