I've been in the vicinity before - the secret service used analog, but REALLY low power, so you couldn't hear it very far away.
They (secret service) are using a repeater on 165.375 in P25 encrypted tonight.
Looks like they are staying in Sheraton downtown (sidewalks barricaded). I heard a rumor there was a block of 50 rooms bought out...looks like windows covered on top floor.