P210 PLT DOWNWIND TO LNDG HAD TO TAKE EVASIVE ACTION TO AVOID ANOTHER ACFT.

Narrative

I WAS APCHING ARPT FROM THE ENE; AND TALKING TO APCH. I WAS CLRED FROM APCH FREQ AND RADAR SVCS TERMINATED TO COMMUNICATED ON CTAF. I ADVISED THAT I WOULD BE LNDG RWY 17 FROM THE E. I WAS TOLD BY SOMEONE IN THE PATTERN ON UNICOM THAT THE ACTIVE RWY WAS RWY 22. ATC ALSO ADVISED OF TFC ON APCH TO RWY 22 AND A PRACTICE INST APCH. I WAS AT APPROX 2000 FT MSL AND ELECTED TO STAY ABOVE THE FINAL APCH COURSE AND PASS TO THE WNW OF THE ARPT AND DSND TO THE PATTERN AND A L TURN TO THE SW THEN ANOTHER L TURN TO ENTER PATTERN ON DOWNWIND TO RWY 22. KEEP IN MIND RWY 22 HAS R-HAND TFC. SHORTLY AFTER MY TURN TO THE SW APPROX 2 MI WNW OF THE ARPT; I ENCOUNTERED OTHER ACFT ON A WIDE R DOWNWIND FOR RWY 22 -- A 2 PLACE TRAINER; I BELIEVE. WE BOTH SAW EACH OTHER AND BOTH ACFT TOOK EVASIVE ACTION AND TURNED R. HOWEVER; IT WAS VERY CLOSE. I BELIEVE NEITHER ACFT SAW THE OTHER COMING. THIS COULD HAVE BEEN PREVENTED IF I WOULD HAVE GONE FURTHER TO THE W OF THE ARPT AND RETURNED FOR LNDG. HOWEVER THIS ARPT IS UNCTLED AND VERY BUSY WITH TRAINING AND OTHER OPS. IT SEEMED THAT NOT ALL ACFT WERE COMMUNICATING AS I WAS UNAWARE OF THE OTHER ACFT IN THE PATTERN.