Narrative:

Passing sfo VOR; heading 140 degrees for vector to runway 28L. We both commented and discussed the consistent poor/tight vectors and late descent clrncs at sfo given by norcal. We configured early; and receiving the typical early/short base turn (relative to altitude) we put the gear down very early. Both navigation radios were tuned and idented to runway 28L. Receiving vector to final; I noticed that my localizer and glidepath were not steady; but rather were blinking on and off. I also got multiple A111 arming prompts on the hgs (normally only 2 prompts are given and canceled if not needed). This all occurred very close to course intercept. As we approached the localizer course (as noted on the navigation display) I noticed the autoplt did not capture the course; nor was my localizer showing it was active. I promptly turned off the autoplt and autothrottles and began a hard turn back to reintercept after having flown through the runway 28L localizer. I knew that there was traffic on runway 28R and ATC did say they had us in sight. We both looked at the frequencys and noted they were set correctly. I then noted that my approach reference (ILS frequency and course in the upper left of the pfd) was rapidly changing back and forth from the ILS frequency to the ILS identifier. The first officer's side was steady. By this time; the runway was in sight and we were lined up but too high; so we elected to go around. We notified sfo tower and norcal of the problem (in the event it was an airport problem and not our aircraft). Neither sfo tower; nor norcal made any mention of our incursion into runway 28R airspace. During the second approach; this time to runway 28R; I noted the same anomaly on my pfd. We quickly switched PF roles. When we advised norcal; they warned a flight; who also reported problems. We landed without incident. Upon arrival at the gate we notified maintenance and wrote up the discrepancy. The maintenance tech later said he noted a fault on the #1 receiver. When he swapped #1 for #2; the fault disappeared. The fault remained clear when he put #1 back in its original place. The aircraft was downgraded to CAT1; and we departed for ZZZ. The flight was completed with no additional problems. Norcal needs to stop vectoring aircraft to final when they are too high. Sfo reported 9 mi visibility; but it was not more than 5 mi due to smoke.

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Original NASA ASRS Text

Title: B737-700 INBOUND TO SFO RWY 28L EXPERIENCED EQUIP PROBLEM; EXECUTED GAR; REPORTER COMMENTING THAT NCT KEEPS SFO ARR'S TOO HIGH TOO LONG.

Narrative: PASSING SFO VOR; HDG 140 DEGS FOR VECTOR TO RWY 28L. WE BOTH COMMENTED AND DISCUSSED THE CONSISTENT POOR/TIGHT VECTORS AND LATE DSCNT CLRNCS AT SFO GIVEN BY NORCAL. WE CONFIGURED EARLY; AND RECEIVING THE TYPICAL EARLY/SHORT BASE TURN (RELATIVE TO ALT) WE PUT THE GEAR DOWN VERY EARLY. BOTH NAV RADIOS WERE TUNED AND IDENTED TO RWY 28L. RECEIVING VECTOR TO FINAL; I NOTICED THAT MY LOC AND GLIDEPATH WERE NOT STEADY; BUT RATHER WERE BLINKING ON AND OFF. I ALSO GOT MULTIPLE A111 ARMING PROMPTS ON THE HGS (NORMALLY ONLY 2 PROMPTS ARE GIVEN AND CANCELED IF NOT NEEDED). THIS ALL OCCURRED VERY CLOSE TO COURSE INTERCEPT. AS WE APCHED THE LOC COURSE (AS NOTED ON THE NAV DISPLAY) I NOTICED THE AUTOPLT DID NOT CAPTURE THE COURSE; NOR WAS MY LOC SHOWING IT WAS ACTIVE. I PROMPTLY TURNED OFF THE AUTOPLT AND AUTOTHROTTLES AND BEGAN A HARD TURN BACK TO REINTERCEPT AFTER HAVING FLOWN THROUGH THE RWY 28L LOC. I KNEW THAT THERE WAS TFC ON RWY 28R AND ATC DID SAY THEY HAD US IN SIGHT. WE BOTH LOOKED AT THE FREQS AND NOTED THEY WERE SET CORRECTLY. I THEN NOTED THAT MY APCH REF (ILS FREQ AND COURSE IN THE UPPER L OF THE PFD) WAS RAPIDLY CHANGING BACK AND FORTH FROM THE ILS FREQ TO THE ILS IDENTIFIER. THE FO'S SIDE WAS STEADY. BY THIS TIME; THE RWY WAS IN SIGHT AND WE WERE LINED UP BUT TOO HIGH; SO WE ELECTED TO GO AROUND. WE NOTIFIED SFO TWR AND NORCAL OF THE PROB (IN THE EVENT IT WAS AN ARPT PROB AND NOT OUR ACFT). NEITHER SFO TWR; NOR NORCAL MADE ANY MENTION OF OUR INCURSION INTO RWY 28R AIRSPACE. DURING THE SECOND APCH; THIS TIME TO RWY 28R; I NOTED THE SAME ANOMALY ON MY PFD. WE QUICKLY SWITCHED PF ROLES. WHEN WE ADVISED NORCAL; THEY WARNED A FLT; WHO ALSO RPTED PROBS. WE LANDED WITHOUT INCIDENT. UPON ARR AT THE GATE WE NOTIFIED MAINT AND WROTE UP THE DISCREPANCY. THE MAINT TECH LATER SAID HE NOTED A FAULT ON THE #1 RECEIVER. WHEN HE SWAPPED #1 FOR #2; THE FAULT DISAPPEARED. THE FAULT REMAINED CLR WHEN HE PUT #1 BACK IN ITS ORIGINAL PLACE. THE ACFT WAS DOWNGRADED TO CAT1; AND WE DEPARTED FOR ZZZ. THE FLT WAS COMPLETED WITH NO ADDITIONAL PROBS. NORCAL NEEDS TO STOP VECTORING ACFT TO FINAL WHEN THEY ARE TOO HIGH. SFO RPTED 9 MI VISIBILITY; BUT IT WAS NOT MORE THAN 5 MI DUE TO SMOKE.

Data retrieved from NASA's ASRS site as of May 2009 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.