NAVAID PROB LAX VOR UNRELIABLE DIRECTLY OVER VOR USING VOR-DME RECEIVER FOR NAV.

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BACKGND DATA: THE LAX VOR SCALLOPS AND LOSES SIGNAL INCREASINGLY WITH ALT. AT FL370; DEPENDING ON THE RECEIVER CONFIGN; THE SIGNAL WILL BE LOST 15 DME FROM THE STATION IN ANY DIRECTION. SOMETIMES THE DME WILL CONTINUE WITH NO AZIMUTH AND SOMETIMES THE DME SIGNAL WILL BE LOST. THIS CONDITION IS WELL DOCUMENTED BY PREVIOUS RPTS. TO MY KNOWLEDGE NO CORRECTIVE ACTION HAS EVER BEEN TAKEN. ON THIS DAY WE WERE DSNDING FROM FL370 INTO SAN DIEGO ON THE CARDI 2 ARR OVER THE LAX VOR. WE LOST THE SIGNAL SHORTLY AFTER THE VOR BEGAN TO SCALLOP. AZIMUTH INCORRECTLY GOING FROM SIDE TO SIDE WITH SUBSEQUENT LOSS OF SIGNAL. ZLA ADVISED US WE WERE 5 MI E OF THE LAX VOR AND ASKED US WHAT OUR HDG WAS. WE SAID OUR HDG WAS 120 DEGS. WE LOOKED VISUALLY DOWN ON THE LAX ARPT AND APPEARED TO BE JUST SLIGHTLY E OF THE ARPT. OUR DME CONTINUED TO FUNCTION WITH NO DME LOSS. THE DME COUNTED DOWN TO 7.8 MI AND BEGAN TO INCREASE WHICH WOULD HAVE HAD US NO FURTHER THAN 2 MI E OF THE VOR. I ASKED THE CTR IF THERE WAS A PROB; MEANING CONFLICTING TFC. CTR REPLIED; 'I DON'T KNOW; IS THERE A PROB?' I STATED BASICALLY WHAT I HAVE TOLD YOU IN THE BACKGND DATA. THIS HAPPENS ALL THE TIME. WHY SHOULD CTR BE SO SURPRISED WHEN IT HAPPENS? THIS WILL HAPPEN EVEN MORE AS WINTER TIME APCHS WITH THE RESULTING HIGH VELOCITY HIGH ALT WINDS. WE HAVE RECEIVED CORRESPONDENCE FROM THE CTR STATING ALMOST NO ONE ELSE SEEMS TO HAVE THIS PROB BUT THIS PARTICULAR CARRIER. MOST OTHER CARRIERS ARE OPERATING WITH INS OR RNAV. SINCE WE DON'T USE ANYTHING BUT VOR RECEIVERS AND PROBABLY COMPOSE THE VAST MAJORITY OF TFC OVERFLYING THE LAX VOR; I THINK THIS IS PROBABLY CORRECT AS IT SHOULD BE CONSIDERING THE DIFFERENCE IN OPERATING NAV COMPONENTS. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: ZLA PROCS SPECIALIST STATED THEY HAVE NO RPTS OF A PROB WITH RELIABILITY OF THE LAX VOR.