FLC OF B737 ON APCH; 7 MI IN-TRAIL OF A COMPANY B737 ENCOUNTERS WAKE TURB. THE AIR WAS UNUSUALLY STILL AND THEY WERE THE FIRST ARRS OF THE MORNING.

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FLT X; WHILE ON THE BSR1 ARR INTO SFO AT APPROX 8000 FT ENCOUNTERED WAKE TURB. FLT X WAS 7 MI IN-TRAIL OF FLT Y ALSO ON THE BSR1; THEN TIP TOE VISUAL APCH INTO SFO RWY 28L. 45 DEGS L YOKE DEFLECTION WAS USED TO CORRECT A R ROLL WHICH REACHED APPROX 20-25 DEG ANGLE OF BANK. THE WINDS AT 8000 FT AND ON THE GND WERE UNUSUALLY CALM. SFO WINDS WERE RPTED CALM. WHILE WE WERE ON LONG FINAL; WINGTIP VORTICES WERE OBSERVED MOVING ACROSS THE WATER UNDER THE FLT PATH (SHORT FINAL) OF FLT Y. AT THIS TIME WE WERE 4 MI IN-TRAIL; AND WE CHOSE TO STAY A MINIMUM OF 1 DOT HIGH ON THE ILS/VISUAL RWY 28L. A NIBBLE OF WAKE TURB WAS FELT ON SHORT FINAL. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR STATES THAT THE AIR WAS UNUSUALLY STILL IN THE SFO AREA THAT MORNING AND THEY WERE THE FIRST ARRS TO THE ARPT. THEY HAD VISUAL SIGHTING OF THE ACFT AHEAD; ALSO A B737; AND KNEW IT WAS ON THE SAME STAR AS THEY WERE. HAD THEY ANY IDEA AT ALL THAT THE B737 WOULD CREATE A WAKE TURB CONDITION THEY WOULD HAVE BEEN MORE PREPARED. THEY JUST DID NOT THINK THIS WOULD HAPPEN FROM A B737. NOW HE KEEPS HIS THUMB CLOSE TO THE AUTOPLT DISENGAGE SWITCH AND FLIES 1 DOT ABOVE GS WHENEVER HE IS IN-TRAIL OF ANOTHER ACFT JUST AS PRECAUTIONARY PROCS.