This is an authentic WWII-era BC-778-A Emergency Radio Transmitter, a component of the SCR-578-A Sea Rescue Radio Set. Later designated the T-74 of the AN/CRT-3 system. This was stored in any aircraft of the US Army Air Force or US Navy that may fly over water.
According to the US Army Air Force Airborne Radio Equipment Manual 1943:
Radio set SCR-57B-A is a hand powered, emergency transmitter designed for operation in a small - boat or life raft. It transmits a MCW Signal on a frequency of 500 kilocycles. This radio set is used by personnel in distress on water and provides for automatic transmission of predetermined signal upon which the radio compass of searching -parties can "home." This signal can also be keyed manually so as to communicate one's whereabouts to searching parties. No receiver is provided.
The above methods of manual and automatic keying are also used with a signal lamp which can be plugged into a socket on the transmitter case and used for visual Signaling. When the signal lamp is used in this manner no radio transmission takes place.
Operational adjustments and tuning of radio set SCR-57B-A have been kept to a minimum. Simplicity of operation thus permits inexperienced personnel having no knowledge of radio or radio transmission to operate this set by merely following the instructions printed on the equipment. All parts of radio set SCR-578-A are of a rugged construction to withstand rough usage, such as dropping with a parachute . To permit dropping the radio set in this manner, a parachute is permanently attached to the bags containing radio set SCR-578-A.
The antenna reel is in its place within the center compartment. The ground wire is in its place under the screw cap in the lower left corner. This offering includes the crank and the leg straps, which are in very good condition. The center selector knob rotates. The tune control knob does not turn, and the keying button does not spring back.
This item is offered for static display or parts, as its working condition is unknown. The service manual can be downloaded by clicking here