Tracking performance of the mercury quad-helix acquisition aid

Project Mercury uses a telemetry-frequency direction finder as an acquisition aid for assisting narrow-beam radars to acquire the spacecraft, but the broad beamwidth of the quad-helix antenna allows multipath reception to degrade tracking accuracy at low elevation angles. Analyses of aircraft and spacecraft tracking results prove that aircraft tests at close range are valid for evaluating orbital tracking performance. Aircraft acquisition tests show the ability of the equipment to place the AN/FPS-16 tracking radar on target.