CAPT SUSPECTS ELECTRONIC INTERFERENCE CAUSED LOC RECEIVER ANOMALY THAT LED TO A MISSED APCH.

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IT WAS THE END OF AN 8 HR (FLT TIME) DAY IN WHICH WE HAD SHOT FULL IFR APCHS TO LOW CEILING; LOW VISIBILITY; ICING CONDITIONS AT DCA; ORD; AND NOW LGA. THE FO'S RADIO WAS ON THE 22 LOC AND MINE WAS LGA VOR AS 22 LOC HAS NO DME. THE CTLR TURNED US TIGHT ON THE LOC; ACTUALLY A LITTLE INSIDE THE MARKER; AND WE CORRECTED FOR THE MARKER. WE GOT 'LOC CAP' AND MARKER PASSAGE AT THE SAME TIME AND SWITCHED TO TWR. AFTER ITS INITIAL MOVEMENT; THE LOC SEEMED TO HANG UP ABOUT 1 1/2 DOTS L. WHEN WE CHKED IN WITH TWR; HE ASKED US IF WE WERE RECEIVING THE LOC. ABOUT THIS TIME THE FO'S LOC HAD GONE BACK FULL L. I TOLD TWR WE WANTED TO GAR AND TRY IT AGAIN. ON THE MISSED APCH; THE LOC CAME QUICKLY OFF THE L SIDE ON THE CASE TOWARD CTR; MUCH QUICKER THAN IT SHOULD HAVE FOR THE CORRECTION WE HAD IN. AFTER OUR MISSED APCH; WHILE ON DOWNWIND; I MADE A PA ASKING THAT IF ANY PAX HAD CELLULAR PHONES OR COMPUTERS TURNED ON THAT THEY TURN THEM OFF. OUR SECOND APCH WAS UNEVENTFUL WITH BOTH LOCS MONITORING NORMAL. AFTER DEPLANING; THE FLT ATTENDANTS SAID THEY HAD NOT OBSERVED ANY PHONES OR COMPUTERS IN USE. I SHOULD HAVE ASKED TWR IF THERE WERE ANY PLANES OR GND VEHICLES IN A POS TO INTERFERE WITH THE LOC; BUT I DID NOT. AT THE TIME; I WAS CONVINCED I WAS DEALING WITH ELECTRONIC INTERFERENCE; BUT NOW I DON'T THINK I CAN SAY FOR SURE; DUE TO OTHER POSSIBILITIES. HOWEVER; I FEEL THERE IS A STRONG LIKELIHOOD THAT THIS WAS THE CAUSE OF OUR PROB. THIS INSTANCE; ALONG WITH 3 INSTANCES OF CELLULAR PHONE INTERFERENCE I HAVE EXPERIENCED ON THE GND; MAKE ME BELIEVE THAT USE OF THESE DEVICES (E.G.; COMPUTERS; CELLULAR PHONES; ETC) ON ACFT SHOULD BE MORE TIGHTLY RESTR AND MORE THOROUGHLY INVESTIGATED.