21.   Inaccurate radar signals could prompt pilots to fly at an improper altitudes, which could conceivably lead to crashes.

22.   One problem Adams confronted was how materials reacted differently to radar signals as their temperature changed.

23.   The arrangement allows radar signals bounced off the Earth by Endeavour to be received by antennas positioned within the cargo bay and at the tip of the mast.

24.   The finding was based on radar signals from Clementine, a Defense Department spacecraft.

25.   The Science authors conclude that the unusual radar signals indicate very rocky surfaces rather than ice.

26.   The receivers detect radar signals from enemy installations and warn pilots when a plane is being tracked by enemy radar.

27.   The strength of the radar signal beamed at people is so small, Hall said, that there is no possible hazard.

28.   The transponder identifies a plane in response to a radar signal.

29.   Certain air-to-ground missiles, called high-speed antiradiation missiles, or HARMs, can follow an incoming radar signal back to its source.

30.   From now on flights from the north will follow a radar signal in a straight line over some residential areas, said Federal Aviation Administration spokesman Fraser Jones.