A C172 PLT HAS AN NMAC WITH ANOTHER C172 WHILE LNDG AT AN UNCTLED FIELD.

Narrative

I ENCOUNTERED A NEAR MISS SIT WITH ANOTHER AIRPLANE. I WAS DOWNWIND FOR RWY 31 AT ST CLOUD; WHICH I GAVE A RADIO CALL ANNOUNCING THAT I AM DOWNWIND FOR RWY 31. I THEN PREPARED MYSELF AND THE COCKPIT FOR THE LNDG. AS I APCHED ABEAM THE NUMBERS; I SCANNED THE AREA SE OF RWY 31 AND DID NOT SEE ANOTHER ACFT. I ALSO HAVE NOT HEARD ANYONE ELSE ANNOUNCE A POS IN THE TFC PATTERN DURING THE WHOLE TIME THAT I HAD BEEN IN THE TFC PATTERN. I GAVE A CALL THAT I WAS TURNING L BASE AND STARTED MY DSCNT. AS I AM ON BASE TO FINAL; I AGAIN SCANNED THE AREA SE OF RWY 31 AND DID NOT SEE ANOTHER AIRPLANE. I ANNOUNCED THAT I AM TURNING FINAL FOR RWY 31 AND PROCEEDED MY TURN ONTO FINAL WHEN I HEARD A PLT FROM THE GND CALL OUT 'DO YOU GUYS SEE EACH OTHER UP THERE?' I LOOKED OUT MY L WINDOW AND SPOTTED AN AIRPLANE ABOUT 300 FT BELOW ME HDG FOR RWY 31. I QUICKLY RESPONDED BY DOING A GAR AND AVOIDED THE HAZARDOUS SIT. I BELIEVE THE PROB WAS CREATED FROM NOT COMMUNICATING ENOUGH. I FEEL THE OTHER PLT SHOULD HAVE ANNOUNCED POS RPTS OR MORE OF THEM. I DID NOT HEAR A WORD FROM THE OTHER ACFT FROM WHEN I WAS MID DOWNWIND TO WHEN I WAS TURNING FINAL. SHORTLY AFTER THE PLT ON THE GND EXPRESSED HIS CONCERN; I DID HEAR THE ACFT THAT I ENCOUNTERED THE NEAR MISS WITH; ANNOUNCE THAT THEY WERE GOING MISSED APCH. MY CORRECTIVE ACTION TO PREVENT THIS OCCURRENCE FROM HAPPENING AGAIN IS TO EXTEND MY DOWNWIND A LITTLE MORE TO GIVE ME EXTRA TIME TO SCAN THE AREA AND ASK PLTS TO GIVE POS RPTS.