Hi Trevor, I would do like Chadan said and try to do some troubleshooting. Could be the BNC connector at the radio, connector at the antenna, coax cable, or broken antenna element, or a combo of all?
Try listening to the weather stations as they are always broadcasting and wiggle the coax and connector. Try a weak station and see if you hear an increase in white noise while you move that connector. Here are the weather stations you can receive in the SF Bay Area: 162.450 (weak), 162.550 (moderate), 162.400 (strong Full Quieting)
Now, if you heard Katy Perry on the airband then I would lean toward a strong broadcast station bleeding into your radio which would affect your radio's airband performance.
http://www.scannermaster.com/HPN_30118_Combined_Notch_Filter_p/24-531024.htmKen