ZTL CTLR WARNED BY ENRTE ACFT OF NON TRACKED; CONFLICTING ACFT NOT RADAR TAGGED OR TRACKED.

Narrative

ACFT X WAS ENRTE FROM PTK TO LZU OVER VXV (DUE SBOUND). HE WAS LEVEL AT 11000 FT. HE ASKED IF I HAD ANY TFC IN THE AREA. I REPLIED NEGATIVE; JUST THE D328 (ACFT Y) THAT HAD CLBED THROUGH HIM VISUALLY ABOUT 2 MINS PREVIOUSLY. ACFT X REPLIED HE HAD JUST PASSED AN ACFT; OPPOSITE DIRECTION; AT 11000 FT. NO IFR TFC. NO TARGET. I INFORMED ANOTHER ACFT (ACFT W) INBOUND TO TYS FROM THE N OF POSSIBLE TFC (ACFT Z) AT 11000 FT. HE ASKED FOR LOWER. THE PRIMARY RADAR COVERAGE FOR THIS LOCATION IS QRI (LYNCH) (30 MI NW TRI CITIES). VXV IS ABOUT 60-80 MI AWAY. THE SECONDARY COVERAGE IS QRV (CROSSVILLE). QRV IS SECONDARY ONLY; NO SEARCH (PRIMARY RADAR) RADAR. ABOUT 5 MINS LATER; I OBSERVED A PRIMARY TARGET NBOUND MERGING WITH THE TYS INBOUND. EVIDENTLY; WE DON'T HAVE PRIMARY RADAR COVERAGE OVER VXV AT 11000 FT. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR WAS ADVISED THAT LYNCH (QRI) RADAR SITE HAD PRIMARY RADAR CAPABILITY; BUT MAINT KNEW ABOUT PRIMARY RADAR PROBS; AND SINCE THERE WAS OVERLAPPING RADAR COVERAGE FROM CROSSVILLE (QRV); SUFFICIENT OVERLAPPING SECONDARY RADAR COVERAGE PROVIDED A NECESSARY LEVEL OF SAFETY. THE RPTR WAS ADVISED THAT THE FAA WAS IN A MAJOR; NATIONAL; ARTCC LONG RANGE RADAR SITE REPLACEMENT PROGRAM. ONE OF THE NEW SYS REPLACEMENTS WAS CONVERSION OF RADAR SITES TO MODE S. THE RPTR ADVISED THAT THE CTLR'S UNION HAD GONE ON RECORD WITH THE NTSB NOT TO DELETE EXISTING; PRIMARY RADAR SITES. FAA IS RPTED NOT TO CONCUR WITH THIS OPINION. CTLR WAS CONCERNED THAT THE FACILITY WAS NOT SENDING NOTAMS INFORMING THE FLYING PUBLIC OF THESE CHANGES AND PRIMARY RADAR OUTAGES. RPTR WAS IN FURTHER COM WITH HIS FACILITY MGMNT ON THE ISSUE.