PLT IN SMA ACFT APCHING SQL FROM THE S HAS AN NMAC WITH A DEP THAT WAS TURNING DOWNWIND (RPTR SAID UPWIND).

Narrative

I CALLED SQL TWR ON 119.00 WITH ATIS INFO OVER CRYSTAL SPRINGS; 7 MI W OF SQL AND WAS INSTRUCTED TO RPT OVERHEAD AT 1200 FT. RWY 30 WAS IN USE; R TFC. THUS; I WAS EXPECTED TO PASS OVERHEAD WITH AN APPROX HDG OF 060 DEGS; MID FIELD FOR DOWNWIND ENTRY. THIS IS COMMON PROC WITH WHICH I AM FAMILIAR. THERE WERE NUMEROUS ACFT IN THE PATTERN OR TALKING TO ATC. JUST BEFORE ARRIVING 'OVERHEAD;' THE TWR LAUNCHED A CESSNA CENTURION ON AN IFR DEP. I SAW THIS ACFT DEPART AND ON UPWIND BEFORE REACHING OVERHEAD. UPON DOING SO; THE AIR WAVES WERE FILLED WITH 'CHATTER' AND I COULD NOT RPT OVERHEAD. I CONTINUED AT 1200 FT MSL ON 060 DEG HDG UNTIL OVER DOWNWIND BEFORE GETTING CLR TIME ON RADIO TO RPT. AFTER A LONG PAUSE; THE CTLR DIRECTED ME TO TURN N FOR 3 MI AND HOLD FOR RE-ENTRY TO THE PATTERN. IMMEDIATELY UPON DOING SO; I SAW THE IFR CENTURION; NOW ON DOWNWIND; HDG STRAIGHT FOR ME. WE BOTH AVOIDED ONE ANOTHER AND I CONTINUED N UNTIL REACHING THE BAYSHORE LINE (APPROX 2.5 MI) AND TOLD THE CTLR HE HAD VECTORED ME TOWARD THE DEP IFR CESSNA. RATHER THAN ATTEND TO ALL THE TFC; HE APOLOGIZED TO ME AND TRIED TO 'CALM' ME DOWN. I GUESS MY CALL OF THE NEAR MISS SOUNDED 'EXCITED.'