Saturn V Instrument Unit directional CCS/PCM Antenna array, measuring 24 x 4.75 x 8.75, with the basic structure fabricated by Metal Research and the antenna cover, made of RF transparent epoxy impregnated fiberglass, was made by Calumet Fiberglass under subcontract to IBM. This antenna was a transmit-only high-gain directional antenna fixed on the Instrument Unit with the radiation pattern directed toward the earth by controlling the attitude of the spacecraft. The antenna contained 5 helical elements—four in quadrupole arrangement and one monopole element—and it assumed responsibility for the Omnidirectional antenna pair (once the launch vehicle exited range), provided the Command and Communications System (CCS) downlink and Pulse Code Modulation(PCM)/Frequency Modulated telemetry signals to ground stations, and acted as a backup tracking transponder. This example is likely a test article, given that it lacks the final white titanium dioxide paint coating, which would have been applied after installation on the launch vehicle. In fine condition.
Terms and abbreviations used in our descriptions.