SCR-508 Jumbo Sherman Installation
Jacques Littlefield Collection

The SCR-508 radio set was the standard communication system for most US battle tanks. It was designed by Bell Labs and utilized the principle of Frequency Phase Modulation. In contrast to the much simpler German tank sets, the SCR 508 was significantly more complex, utilizing large numbers of varied internal components, several different types of vacuum tubes and each device was externally and internally dependent on the others. Power was shared between the radio devices through the FT-237 mount, and so was the antenna connection.




The SCR-508 installed in the Jumbo Sherman tank. The FT-237 mount is labeled with the 24 V designation. This means that 24 Volt dynamotors are installed on the transmitter and receivers to match the power supply system of the Sherman.



SCR-508 set mounted on the FT-237



Simplified diagram of a SCR-508 installation in a tank. Note the graphical description of how the antenna relay and radio/internal intercom relays are used.
Click on the components for detail page redirection.



The FT-237 mounting. It's currently set for 12 V battery operation.



FT-237 internal wiring connection block and 12 V fuse. Wiring connection chart.



The modification.



SCR-508 diagram
Click on the various component drawings to see restoration work for each device.


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