When I was living in San Diego about a decade ago, Z90 was pretty much an urban station, though they classified themselves as rhythmic. There was also the rhythmic oldies station Magic 92.5, which is still around. Later on, 98.9 was hip-hop station, but I was long gone when they came around. I realize San Diego is only about 7% black, but with a large Hispanic population that likes hip-hop, I'd think one could survive.
When I was. VP at Z90's HQ back when they were kicking' butt it was very much the music of the street for young blacks, Hispanics and the gringo wannabees - and one thing the station did not cowstore label itself: Clear Channel might have labeled it "Rhythmic" when they. Took over and started to screw it up, but under Califormula you literally had very young program and music directors who had a free rein to program the music they and their friends listened to in the hoods and barrios. CC brought in old white people to "professionalize" the place and the street cred went out the door.