C172 PLT ENTERING THE PATTERN AT CCB HAS AN NMAC WITH A DEPARTING LOW WING SEL NOT UTILIZING CTAF COM PROCEDURES.

Narrative

I WAS ON THE VOR RWY 6 APCH INTO CABLE ARPT (CCB). UPON TERMINATION OF IFR I SWITCHED TO THE CABLE CTAF TO MAKE A 5 MI POS RPT. I HAD THE ARPT IN SIGHT AND PROCEEDED TO DSND TO A TFC PATTERN ALT OF 2300 FT MSL. WHEN REACHING 2 MI FROM THE ARPT; I MADE A POS RPT STATING THAT I WAS SETTING UP FOR A L DOWNWIND FOR RWY 24. ANOTHER ACFT (C152) MADE HIS XWIND RPT AND I QUICKLY IDENTED THE TFC AND TURNED L TO ALLOW THE TFC TO CROSS SAFELY WHILE TELLING HIM MY INTENTION OF LETTING HIM GO AHEAD OF ME IN THE TFC PATTERN ON THE RADIO. AT THIS TIME I NOTICED ANOTHER AIRPLANE (UNIDENTED LOW WING SINGLE ENG) WHICH TOOK OFF SHORTLY AFTER THE C152 THAT WAS MAKING A CLBING L TURN RIGHT INTO MY FLT PATH. AT THIS TIME; I PULLED PWR AND MADE AN IMMEDIATE DSCNT TO ALLOW MORE ROOM BTWN MYSELF AND THE UNIDENTED TFC. AFTER THE INCIDENT; I MADE ANOTHER POS RPT AND HEARD NO RESPONSE FROM THE TARGET ACFT; WHICH DEPARTED THE PATTERN. THE UNIDENTED ACFT MUST HAVE MISSED MY ACFT IN HIS/HER SCAN PRIOR TO TURNING; AS I HAD MADE NUMEROUS POS RPTS AS A FORCE OF HABIT. I ALSO CERTAINLY WASN'T EXPECTING ANOTHER ACFT TO TAKE OFF SO SHORTLY AFTER THE C152. I AM NOT AWARE OF ANY EVASIVE ACTION TAKEN BY THE UNIDENTED ACFT; SINCE I HEARD NO RADIO CALL. THIS ISSUE MAY HAVE BEEN EXACERBATED BY THE FACT THAT CABLE ARPT IS LOCATED IN A SMALL HOLE ON THE EDGE OF THE ONTARIO INTL ARPT (ONT) CLASS C AIRSPACE; WHICH MEANS THAT ALL DEPARTING VFR ACFT MUST TURN L TO USE THE TFC PATTERN FOR A N DEP FREE OF TWRED AIRSPACE AFTER TKOF; AS WELL AS WITH THE BRACKETT ARPT (POC) CLASS D AIRSPACE TO THE W.