NMAC BETWEEN AN AC-112B AND A BE35 AT 5500 FT; OPPOSITE DIRECTION TFC 3 SSE OF ALTAM INTXN; ACFT X ON FREQ WITH APCH CTL AT SCK.

Narrative

I WAS ON A SOLO FLT FROM SAN CARLOS (SQL) FOR PRACTICE MANEUVERING IN AN AREA E TO N OF BYRON (C83). I HAD LEVELED OFF TO CRUISE AT 5500 MSL AND HAD CONTACTED STOCKTON APCH WHILE CROSSING LIVERMORE ARPT (LVK) FOR VFR RADAR ADVISORIES. I WAS ADVISED TO CALL AGAIN IN TWO MINS; BUT WAS CALLED BACK SHORTLY BY THE SCK CTLR. I WAS GIVEN A SQUAWK CODE AND RADAR IDENTIFIED. LESS THAN A MINUTE LATER I MADE A TURN R FROM HEADING 030 DEGS TO HEADING 045 DEGS IN ORDER TO PASS S OF BYRON ARPT. JUST AS I LEVELED OUT; I FOUND MYSELF DIRECTLY HEAD ON TO ANOTHER ACFT CLOSING AT HIGH SPEED AT MY ALTITUDE. I FROZE FOR A SECOND OR TWO; THEN IMMEDIATELY PULLED UP; BUT STILL FELT LIKE WE WERE GOING TO COLLIDE UNTIL THE OTHER ACFT PITCHED DOWN AND PASSED JUST UNDER ME. I MADE A LEFT TURN TO TRY TO GET A LOOK AT AND IDENTIFY THE OTHER ACFT; AND CALLED STOCKTON APCH TO REPORT THE NMAC WITH A V-TAIL BONANZA. STOCKTON APCH RPTED THAT THEY HAD NO SECONDARY OR PRIMARY RADAR TARGETS IN MY AREA. SHOULDN'T IT CONCERN SOMEONE THAT ACFT CAN OPERATE IN THIS AREA SO CLOSE TO LIVERMORE LABS WITHOUT BEING PICKED UP ON PRIMARY RADAR? THE POINT OF NEAR COLLISION WAS 3 NM SSE OF ALTAM INTERSECTION OF V244 AND V334. THIS IS JUST OUTSIDE THE SFO MODE C VEIL. THE BONANZA WAS APPARENTLY OPERATING WITHOUT A TRANSPONDER WITHIN A FEW MINS OF ENTERING AN AREA REQUIRING A MODE C TRANSPONDER. THE BONANZA WAS ON A DIRECT HEADING (225 DEGS) PROBABLY FOR EITHER HAYWARD OR SAN CARLOS ARPTS AND WAS AT THE WRONG CRUISE ALTITUDE FOR VFR FLT.