Apollo Comms Part 30: Double PLL Trouble!


We build a Phase Locked Loop (PLL) FM demodulator for extracting the Apollo downvoice from its subcarrier, using the classic 7046B IC. But in the meantime, as luck would have it, NASA’s own S-band receiver’s PLL seems to have gone bonkers, and we can’t lock to the spacecraft microwave downlink …

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From: Retro Roundup