LTT ON DSCNT HAS NMAC WITH SMT.

Narrative

THIS WAS A REVENUE PAX FLT FROM JAX TO MCO. WE WERE ON THE BITHO 6 ARR INTO MCO AND HAD RECENTLY RECEIVED A CLRNC TO DSND TO 6000 FT. THE WX AT AND ABOVE OUR ALT WAS CLR; THERE WERE BROKEN CUMULUS CLOUDS BELOW US. AS WE PASSED THROUGH 8700 FT I WAS STARTLED BY A TWIN SMT FLASHING BENEATH US. THE ACFT HAD BEEN AT OUR 11 O'CLOCK POS; AT OR BELOW THE HORIZ. IT WAS A NEAR MISS (200 FT VERT AND ABOUT 300 FT HORIZON). IT WAS A NEAR MISS (200 FT VERT AND ABOUTU 300 FT HORIZ). I QUESTIONED ATC ABOUT THIS TFC AND WAS INFORMED THAT THE TFC HAD JUST 'POPPED UP' ON RADAR. THE TWIN SMT WAS APPARENTLY ON VFR FLT FOLLOWING; AS I HEARD THE PLT CHK IN WITH DAYTONA APCH SHORTLY FOLLOWING THE NEAR MISS. APCH ASKED THE SMT PLT IF HE HAD SEEN US; TO WHICH THE REPLY WAS NO. THE CTLR APOLOGIZED TO ME AND TOLD ME THAT HE HAD A LATE HDOF; AND THAT THERE EXISTED A 'RADAR CONE OF SILENCE.' DIRECTLY OVER THE ANTENNA. SCAPEGOATS IN THIS SIT: 1) SMT TWIN PLT SHOULD KEEP EYES OPEN WHEN FLYING OPPOSITE DIRECTION NEAR A BUSY ARR CORRIDOR! 2) SECOND CTLR SHOULD HAVE HANDED OFF THE POTENTIALLY CONFLICTING TFC SOONER. 3) I SHOULD BE MORE ALERT IN THE ARR PHASE; ESPECIALLY AT VFR CRUISING ALTS ON THE EAST COAST OF FLORIDA! 4) THERE SHOULD BE A WAY TO COVER 'BLIND SPOTS' IN RADAR IN SUCH BUSY AREAS.