Narrative:

Initial contact with bay approach was made 35 NM east of san mateo bridge. Approach couldn't pick up the first squawk, and after asking my position, then over the sunol golf course, the controller said to maintain VFR and hold over the sunol golf course. I was in the process of descending VFR from 6500 to 4500'. I set up a right-hand pattern, west of the sunol golf course, approximately 1 min legs. In the meantime, I had asked approach for another squawk to try and they still couldn't pick up the second squawk. (It is well to note this problem has happened once before in this same area; however, no other radar facility throughout the entire west coast area has had any problem identing the squawk on this aircraft.) on 1 outbnd holding turn at 4800', using a 20 degree angle of bank, just starting to roll out of the right turn to 260 degrees and descending through at 4800', an air carrier medium large transport passed overhead from behind to appear in the top of my windscreen, in a descent, apparently to oak. I had previously heard him talking to approach but couldn't concentrate on that conversation due to trying to get approach to pick up my squawk. I did understand approach identing a target at 4800' to him. They were still maintaining no pickup of my squawk. The rest of the flight was uneventful; approach picked up my third squawk and I was vectored in sequence on into sfo.

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Original NASA ASRS Text

Title: SMA HAS NMAC WITH AR MLG WHILE IN A VFR HOLDING PATTERN.

Narrative: INITIAL CONTACT WITH BAY APCH WAS MADE 35 NM E OF SAN MATEO BRIDGE. APCH COULDN'T PICK UP THE FIRST SQUAWK, AND AFTER ASKING MY POS, THEN OVER THE SUNOL GOLF COURSE, THE CTLR SAID TO MAINTAIN VFR AND HOLD OVER THE SUNOL GOLF COURSE. I WAS IN THE PROCESS OF DSNDING VFR FROM 6500 TO 4500'. I SET UP A RIGHT-HAND PATTERN, W OF THE SUNOL GOLF COURSE, APPROX 1 MIN LEGS. IN THE MEANTIME, I HAD ASKED APCH FOR ANOTHER SQUAWK TO TRY AND THEY STILL COULDN'T PICK UP THE SECOND SQUAWK. (IT IS WELL TO NOTE THIS PROB HAS HAPPENED ONCE BEFORE IN THIS SAME AREA; HOWEVER, NO OTHER RADAR FAC THROUGHOUT THE ENTIRE W COAST AREA HAS HAD ANY PROB IDENTING THE SQUAWK ON THIS ACFT.) ON 1 OUTBND HOLDING TURN AT 4800', USING A 20 DEG ANGLE OF BANK, JUST STARTING TO ROLL OUT OF THE RIGHT TURN TO 260 DEGS AND DSNDING THROUGH AT 4800', AN ACR MLG PASSED OVERHEAD FROM BEHIND TO APPEAR IN THE TOP OF MY WINDSCREEN, IN A DSNT, APPARENTLY TO OAK. I HAD PREVIOUSLY HEARD HIM TALKING TO APCH BUT COULDN'T CONCENTRATE ON THAT CONVERSATION DUE TO TRYING TO GET APCH TO PICK UP MY SQUAWK. I DID UNDERSTAND APCH IDENTING A TARGET AT 4800' TO HIM. THEY WERE STILL MAINTAINING NO PICKUP OF MY SQUAWK. THE REST OF THE FLT WAS UNEVENTFUL; APCH PICKED UP MY THIRD SQUAWK AND I WAS VECTORED IN SEQUENCE ON INTO SFO.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.