CONFLICT AT CRUISE ALT.

Narrative

I WAS CRUISING AT 11500' MSL FROM PORTERVILLE TO CHINO; CA (SE); FLYING AS STRAIGHT A LINE AS POSSIBLE; REMAINING OFF THE CENTER FREQS. I FLY THIS ROUTE AT LEAST ONCE A WK AND AM VERY FAMILIAR WITH THE FREQ CHANGE OVER POINTS. XING TEHACHAPI; I WAS MONITORING EDW ON 126.1; LISTENING FOR HIGH SPD TFC IN THE MOA. ALTIMETER WAS 29.95 AND I WAS INDICATING 11450' MSL. JUST AFTER XING THE EDGE OF THE MOUNTAINS S OF TEHACHAPI; I WAS COMPARING MY VISUAL REF POINTS TO THE D/G FOR WIND CORRECTION ANGLE. I WAS LOOKING STRAIGHT AHEAD WHEN AN SMA APPEARED APPROX 1000' IN FRONT OF ME IN A LEFT TURN AWAY FROM ME. I STARTED TO TURN LEFT; BUT BY THAT TIME THE SMA WAS DSNDING IN A LEFT TURN OFF MY RIGHT. I AM NOT AWARE IF THE SMA WAS CLBING OR LEVEL FLT WHEN I SAW IT. I RULED OUT A DSCNT BY THE ATTITUDE OF THE PLANE AS IT TURNED AWAY FROM ME. I'D LIKE TO RULE OUT LEVEL FLT BECAUSE I DO HAVE A GOOD TFC SCAN THAT I'M CONTINUALLY TEACHING TO MY STUDENTS. THE SMT HAS A LONG NOSE AND IF THE SMA WAS CLBING I WOULD NOT HAVE SEEN IT; DEPENDING ON ITS CLB ANGLE. I FLY WITH STROBES AND BEACONS ON. THIS IS MY FIRST NEAR MISS IN 11 YRS OF FLYING IN AND AROUND THE LA BASIN. THE ONLY WAY IT COULD HAVE POSSIBLY BEEN PREVENTED IS IF I HAD BEEN USING FLT FOLLOWING. I HAVE BEEN DENIED FLT FOLLOWING PROBABLY 75% OF THE TIME AND ONLY TRY OCCASIONALLY NOW. SVC DENIAL IS USUALLY DUE TO 'UNABLE' OR 'TOO BUSY FOR VFR'S.' THE ACFT IS EQUIPPED WITH TRANSPONDER AND ENCODER WHICH WAS ON.