NAVAID PROB POLICY.

Narrative

FLT WAS A REGULARLY SCHEDULED FLT FROM LGA TO FLL. PROCEEDING OUT OVER THE ATLANTIC; NAVING ON THE NDB; I NOTICED WHAT APPEARED TO BE A DISCREPANCY IN THE PICTURE PRESENTED BY LOOKING OUT THE WINDOW AND WHAT THE TAIL OF THE ADF NEEDLE SHOWED. ATC GAVE A HDG TO RE-INTERCEPT AR- 1; AND WHEN WE WERE RPTED TO BE ON COURSE; THE TAIL OF THE ADF NEEDLE WAS FULLY 20 DEGS OFF; SHOWING US TO BE WELL TO THE W OF THE AIRWAY. I WROTE THE DISCREPANCY OF THE ADF UP IN THE ACFT LOGBOOK AS A MALFUNCTION. WE THEN NOTICED THAT ATC WAS GIVING ALL NON-FMC-EQUIPPED ACFT VECTORS TO STAY ON THE CTRLINE OF AR-1. WHEN I QUESTIONED ATC ABOUT THE SIT; THE CTLR SAID THAT THE LOW FREQ BEACONS WERE 'UNRELIABLE.' THE WIND WAS WESTERLY AT 100 KTS PLUS. I BELIEVE THAT; HAD WE HAD ONLY THE NDB'S TO NAV BY; IE; CTR RADAR FAILURE; WE PROBABLY WOULD HAVE PASSED E OF THE BAHAMAS. THIS WAS NOT A RTE I FLY REGULARLY AND I WONDER IF IT IS A COMMON PRACTICE BY ATC TO USE VECTORS TO KEEP NON-ROMEO EQUIPPED ACFT ON THE CTR OF THE ATLANTIC RTES.