EF-111A ALQ-99 transmitter installation (above, below). These images show a typical mix of transmitter modules, with unique steerable antenna installations for four different bands. The emitter boresight depression angle is a compromise intended to accommodate both standoff and escort jamming. The aircraft, 66-0041 of the 429th ECS at Cannon AFB, NM, was photographed at Malmstrom AFB, Montana (© 2012, Phil Peterson).