Radio stations that cannot communicate directly due to distance, terrain or other difficulties sometimes use an intermediate radio relay station to relay the signals. Examples include airborne radio relay, microwave radio relay, and communications satellite. The American Radio Relay League was founded for this purpose but did not change its name when this became a less important part of its work. Radio stations that cannot communicate directly due to distance, terrain or other difficulties sometimes use an intermediate radio relay station to relay the signals. Examples include airborne radio relay, microwave radio relay, and communications satellite. The American Radio Relay League was founded for this purpose but did not change its name when this became a less important part of its work.