On any given Oakland A’s home game — night or day, winning or losing — you’ll find charged-up, colorful and sometime cacophonous A’s fans sitting far out in the right field bleachers at the Oakland Coliseum. You can’t miss them. They bang drums, wave flags, chant, sing and make a lot of noise. But what they create is more than a big, enthusiastic sound. It’s a pounding beat and jangling rhythm with a point, a mission and a history. Metallic pops, stick snaps and rimshots let radio and TV audiences know immediately. This is Oakland. Welcome to Section 149. Video: Serginho Roosblad and Tena Rubio