The purpose of this letter is to inform all users of LaGuardia Airport of a radio transmission and reception problem at the east end terminals and the departure end of Runway 31.

 Pilots have had problems receiving radio transmissions when their aircraft are in position for takeoff on Runway 31. Controllers and pilots have problems with radio reception from the east end terminal ramp and other ramp areas on the airport on both Ground Control and Clearance Delivery frequencies.

 This problem does not occur when the aircraft’s upper antenna is used.  Flight crews are advised to use the upper antenna when calling for clearance or taxi instructions from the east end terminals.