In Southern California, there are a few key numbers that Angelenos need to know: when to take the 101 or the 405, the differences between people with 310 and 818 area codes, and why you should always, always turn on 89.9 FM when you’re in the car (and likely in traffic on the 101 or 405). That radio dial is the home of the world-famous KCRW, NPR’s flagship station in Southern California, broadcasting out of Santa Monica College, that has been a voice for the local community and beyond for nearly 50 years. From marquee programs like the weekday music soup served on “Morning Becomes Eclectic” to the latest offering, “Dance24,” a 24/7 electronic music channel (not to mention a rotating platter of news, political discourse, food programming, and film and art reviews), the nonprofit KCRW has been breaking the mold of what radio can be since 1977.…