cant find radio for artillery support

help.......mission 5, tiger at bridge..........i ve shot all the nazis trying to blow up the bridge,and now im supposed to use a radio to call in artillery support.....both binoculars and radio are shown in upper right screen ......b ut what key do i press to acess radio...............do i have to hunt around until i find an actual radio or what....many thanks...........i dont want to get stuck here.........strom