The PRA is a sophisticated radio receiver, attached to a pair of 10-m (33-ft) "rabbit ears." The PRA listens for radio signals produced by the Sun and planets, their magnetosphere, and lightnings. The Jovian, Saturnian, and Uranian systems all produced such signals.

The PRA works in one of two ways. First, the PRA switches among three single (programmable) frequencies, dwelling on each about six seconds. Second, the PRA scans its entire band of frequencies--starting from the highest and then sweeps down.

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PRA Science Objectives

• To locate and explain kilometric, hectometric, and decametric radio emission from the planets.
• To detect radio emissions indicative of planetary magnetic fields, and to determine the rotation rate of such fields.
• To describe planetary radio emissions and their relation to planetary satellites.
• To measure plasma resonance near the planets.
• To detect lightning in the planetary atmospheres.

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This is the block diagram for the PRA receiver: