AN/PRC-77 Portable Transceiver

[2] In the Joint Electronics Type Designation System (JETDS), AN/PRC translates to "Army/Navy, Portable, Radio, Communication."

It differs from its predecessor mainly in that the PRC-77's final power amplifier stage is made with a transistor, eliminating the only vacuum tube in the PRC-25, as well as the DC-DC voltage converter used to create the high plate voltage for the tube from the 15 V battery.

The receiver's performance was also hardened in the PRC-77 to enable it to better reject interference suffered from nearby transmitters, a common operating set up that reduced the effectiveness of the PRC-25.

The equipment tag glued to the edge of the front panel was the main (external) way to tell the difference.

With the more efficient all-transistorized circuitry, and without the DC-DC step-up voltage converter for the tube, the common battery lasted longer in the PRC-77 under the same conditions.