The AN/PRC-77 Portable Transceiver, also known as AN/PRC 77 Radio Set, is a man-pack, portable VHF FM combat-net radio transceiver manufactured by Associated Industries and used to provide short-range
AN/PRC 77 radio and handset
American soldier using the KY-38 "man-pack", part of the NESTOR voice encryption system that was used during the Vietnam War. The upper unit is an AN/PRC-77 radio transceiver. The combined weight of the units, 54 pounds (24.5 kg), proved an obstacle to their use in combat.
U.S. Marine carrying a PRC-77 during a training exercise in 1989
NESTOR (encryption)
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NESTOR was a family of compatible, tactical, wideband secure voice systems developed by the U.S. National Security Agency and widely deployed during the Vietnam War through the late Cold War period. N
AN/PRC-77 Portable Transceiver
…the PRC-25 could not support voice encryption devices, but PRC-77 transmitter audio bandwidth was widened to give it the ability to use the TSEC/KY-38 NESTOR voice encryption system used in Vietnam, and the later KY-57 VINSON family. The transmitter's spurious emissions were cleaned up to create less…
KY-8, vehicular or fixed
KY-28, airborne or shipborne, with KYK-28 key loader
KY-38, man-pack, with key loader