AN ACR B727 FLC RPT THAT THEY HAD DIFFICULTY TRACKING A VOR SIGNAL AND THEY SUSPECT THAT INTERFERENCE FROM A PAX'S COMPUTER MAY HAVE BEEN THE CAUSE. THE ARTCC CTLR GAVE THE FLC VECTORS ON COURSE.

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WE WERE ON THE JASEN 1 ARR TO DALLAS; DSNDING ON THE ARNEL 259 DEG RADIAL TO INTERCEPT THE LINDEN 206 DEG RADIAL. SHORTLY AFTER WE LEVELED AT 11000 FT AND WELL BEFORE MY VOR INDICATED ARR AT THE LDN RADIAL; THE CTLR ADVISED THAT WE WERE GOING TO MISS THE INTXN BY ABOUT 6 MI AND BEGAN TO VECTOR US. PRIOR TO THIS POINT; THE CAPT'S VOR HAD BEEN WAVERING BACK AND FORTH SLOWLY; THOUGH IT APPEARED HE WAS DOING A GOOD JOB OF FLYING THE AVERAGE INDICATION. AS SOON AS APCH ADVISED US OF THE PROB; HE RETUNED MY VOR TO AML; AND IT BECAME APPARENT THAT THE MAGNITUDE OF HIS VOR OSCILLATIONS WAS MUCH GREATER THAN MINE (ABOUT +/-3 DEGS VERSUS 1/2 DEGS). HOWEVER; AS WE GOT CLOSER TO DALLAS; BOTH RECEIVERS APPEARED TO SETTLE DOWN RATHER SUDDENLY; AND OPS ON THE ILS AND ON THE GND WITH LDN RETUNED APPEARED NORMAL. OUR NEXT LEG WAS WBOUND OVER ROUGHLY THE SAME RTE AS THE ARR. BOTH VORS AIR CHKED NORMALLY. POSSIBLE PROB COULD HAVE BEEN INTERFERENCE FROM A LAPTOP COMPUTER OR OTHER PAX ELECTRONICS. THE ARR GOT TOO BUSY TO HAVE FLT ATTENDANTS DO AN EXTRA CHK IN THE AIR; BUT DISCUSSION WITH THEM AFTER LNDG INDICATED A LAPTOP HAD BEEN IN USE; AND PAX WERE KNOWN TO SURREPTITIOUSLY USE OTHER DEVICES ON THIS LEG. UNFORTUNATELY; DUE TO DALLAS' UNIQUE PAX SYS; IT WAS NOT POSSIBLE TO DELAY THE PERSON WITH THE LAPTOP TO DO A GND CHK.