Introduction: We are all told to depart the pattern at a single-runway, non-towered airport either straight-out or via a 45 degrees left turn, above TPA (AIM 4-3-3). At my home airport (06C - Schaumburg), when departing runway 11, you cannot leave the pattern via a straight-out nor with a left-45 because we are 3.5 miles west of Chicago O'Hare's Class-B surface sector. The local procedure is to exit the pattern via left crosswind if heading north, and left downwind for west and south directions. (East-bound travel requires the north or south departure and circumnavigation of the Bravo space). Question: what is the best-practice for radio calls announcing this kind of departure (ie, leaving the pattern via crosswind or downwind leg)? Observation: most pilots flying out of 06C when 11 is in use, announce departure before taking the runway, and that's it. A few, myself included, make the following announcements. For example: At hold short: Schaumburg traffic, Archer 12345, departing runway 11, to the north, via left crosswind, Schaumburg. At the end of the departure leg: Schaumburg traffic, Archer 12345, turning left crosswind runway 11 will be leaving pattern from here, Schaumburg. As always, thanks in advance for your helpful comments.