Rep. John Dingell (D-Mich.) has sent a letter to the Federal Communications Commission (PDF) requesting clarification on several points of upcoming spectrum auctions. A few of the specifics he’d like to know: How many stations will share a channel or go off the air? How many stations will need to move to a new channel or be repacked? How many viewers will lose or gain service? Dingell is requesting answers by June 27.