Thanks for the info....my search came up dry, I thought maybe I fat-fingered it, but the ULS Advanced search comes back empty when searching by frequency in Maryland, but when I put in the call sign you posted (WPKV277), it comes back fine to the txmitter on Park Heights Avenue, which must be the one I'm hearing. And now I realize I must really have had too many beers that night, because now I find it here:
http://www.radioreference.com/modules.php?name=TRSDB&sid=3493
It's amazing how well it comes in now when I have the antenna pointed in the right direction...
I'm starting to wonder who's running the show at the Licensing Division, though....I came across 464.825 and did successfully look that up...according to the data, Johns Hopkins and the Aquarium should be walking all over each other, but all I hear is the JHU shuttle bus dispatches and campus cops/security....weird.