NMAC WHILE ON A STRAIGHT IN APCH TO UNCONTROLLED ARPT.

Narrative

AS PIC ON A SHORT PRACTICE FLT; I WAS RETURNING TO COE. WHEN I REACHED 1/2-3/4 MI SHORT FINAL APCH FOR RWY 19; A GREEN AND WHITE TWIN APPEARED 30-40' UNDER MY LEFT WING. HE WAS APPROX 30 DEGS OFF MY HDG (HE WAS HDG APPROX 220 DEGS) AND TURNING LEFT INTO HIS FINAL APCH LEG FOR RWY 19. I TOOK EVASIVE ACTION WITH A CLBING RIGHT TURN; MORE FROM REFLEX AS BY THAT TIME HE HAD PASSED ME. UPON LNDG I ASKED THE OTHER PLT WHY HE HAD NOT GRANTED ME RIGHT OF WAY AS I WAS ON FINAL APCH AND ALSO MY PORT SIDE WAS PRESENTED TO HIM AS HE HAD BEEN COMING OUT OF HIS BASE LEG. HE STATED THAT HE HAD NOT SEEN ME AND THAT THE 'SUN WAS IN MY EYES.' AT THAT TIME OF DAY THE SUN SAT APPROX 220-230 DEGS FROM OUR POS. PRIOR TO THE INCIDENT HIS BASE LEG WOULD HAVE HAD HIM HDG APPROX 280 DEGS; WHICH PUT THE SUN AT 10 O'CLOCK FROM HIS CABIN WHILE I WOULD HAVE BEEN TO HIS 1-2 O'CLOCK. HE ALSO STATED THAT HE HAD NOT HEARD MY RADIO XMISSIONS. I HAD JUST PREVIOUSLY DEPARTED FROM SILVERWOOD; IDAHO; WHICH IS 10 MI N OF COE. SILVERWOOD (PREVIOUSLY HENLEY AERODROME) RECENTLY SWITCHED TO OPERATING FREQ 122.7 AFTER YRS OF BEING ON UNICOM 122.8. I WAS ACCUSTOMED TO FLYING BTWN THE 2 FIELDS ON THE SAME FREQ. AS I BEGAN MY STRAIGHT IN APCH FOR RWY 19 AT COE I FAILED TO SWITCH BACK TO 122.8 FROM 122.7. AS A RESULT THE COE TFC DID NOT RECEIVE MY 2 ANNOUNCEMENTS: '5 MI LONG FINAL' AND '2 MI SHORT FINAL;' AND I DID NOT RECEIVE THEIR XMISSIONS.