ACR X GPWS EXECUTED CLB.

Narrative

ACR X WAS CLRED TO 3000 FT WHILE BEING VECTORED FOR THE OAK ILS TO RWY 11. I WAS ROUNDING THE ACFT OFF AT 3100 FT AND 800 FPM. WE GOT 'TERRAIN; TERRAIN; TERRAIN; WHOOP PULL UP; WHOOP WHOOP PULL UP; TERRAIN.' EXECUTED GPWS ESCAPE MANEUVER -- PULLED UP AND WENT TO FIREWALL PWR FOR APPROX 10 SECONDS AND CLBED TO APPROX 4000 FT THEN WAS RECLRED BACK TO 3000 FT. WE CALLED IN THE INCIDENT TO BAY APCH AND THE CTLR SAID THERE WAS AN ANTENNA OUT THERE IN OUR AREA. JUST PRIOR TO THIS THERE WAS A DISCUSSION FROM BAY TO ANOTHER ACFT ABOUT A DISCREPANCY BTWN HIS ALT AND HIS MODE C READOUT. COULD ATC HAVE THE WRONG ALTIMETER SETTING? SUPPLEMENTAL INFO FROM ACN 294895: OUR ACFT WAS IN CONTACT WITH BAY APCH IN IMC CONDITIONS. WE HAD BEEN CLRED TO DSND TO 3000 FT MSL. WHILE DSNDING AT APPROX 800 FPM; WE GOT A 'HARD' GPWS WARNING AT ABOUT 3100 FT MSL. ALTIMETERS WERE SET AT THE 30.16 OAK LCL. OUR POS WAS APPROX 9 DME OAK 320 DEG RADIAL. CAPT IMMEDIATELY EXECUTED 'ESCAPE' MANEUVER PER COMPANY PROCS. BAY APCH RECLRED FLT TO DSND TO 3000 FT COMMENTING THAT THE ANTENNAS IN THE VICINITY PROBABLY CAUSED THE WARNING. SFO AREA CHART SHOWS 3100 FT TERRAIN CLRNC IN THAT AREA SUGGEST RAISING MVA IN THAT AREA TO 3500 FT MSL.