I just came across a 26 min. training film on the AN/GRC-46, made in 1963. You can view it at http://www.spokenword.org/program/1174008 We have a working unit at the AWA Museum. Have fun, Duncan Brown, K2OEQ USASA 31J Chief TTY operator & repairman AWA Electronic Communication Museum http://www.antiquewireless.org/