LORAN NOT GIVING ACCURATE INFO; PLT REQUESTS DF STEER.

Narrative

PLANNED FLT FROM WESTMORELAND COUNTY (LBE) TO BRADFORD (BFD); PA. FLT PROCEEDED NORMALLY UNTIL PAST DUBOIS (DUJ). RECEIVED CONFLICTING INFO FROM LORAN AND VOR WHICH I ALLOWED TO CAUSE ME TO BECOME UNCERTAIN OF MY POS. LATER DETERMINED LORAN SIGNAL TO NOISE RATIOS (SNR) HAD DETERIORATED TO LESS THAN 35; 7; AND 9. I AM AWARE OF A PROB WITH LORAN SIGNALS AT DAWN AND TWILIGHT; BUT DID NOT EXPECT A PROB ABOUT XA00 PM ALTHOUGH THE SUN IS LOWER ON THE HORIZON THIS TIME OF YR. IN ADDITION; THE VOR FLAG DID NOT FULLY APPEAR CAUSING ME TO DOUBT ITS INFO. ALTHOUGH I WAS AWARE OF MY POS GENERALLY AND HAD OVER 2 HRS OF FUEL REMAINING; I DECIDED TO BE CONSERVATIVE AND ASK THE DUBOIS FSS FOR A DIRECTION-FINDING STEER TO THEIR ARPT. THE DF STEER AND MY LNDG WERE ACCOMPLISHED WITHOUT INCIDENT. I RETURNED TO LBE NAVING BY PILOTAGE; ALSO WITHOUT INCIDENT. NOTE THAT I USE A PORTABLE LORAN WITH A WINDSHIELD MOUNTED ANTENNA WHICH HAD BEEN VERY RELIABLE. I PLAN THE FOLLOWING CORRECTION ACTION: MONITOR LORAN SNR PERIODICALLY INFLT. HAVE THE VOR AND ITS INSTALLATION THOROUGHLY CHKED BY AN AUTHORIZED ELECTRONICS SHOP.