military: T-17 microphone

The T-17 is an anti-noise carbon-button hand microphone used with standard radio and telephone equipment of the US Army Signal Corps.  As a carbon microphone, it needs a source of low-voltage DC in series, powered by the circuit to which it is connected.  Like most US military electronics, especially in the 1940s, there were multiple manufacturers for the same or similar devices.  Frequency response is 400 - 2600 Hz.  Impedance is designed to match a 35 to 90 ohm circuit.  Output is 34 to 50 db depending upon frequency. The push-button and the microphone face are typically made of Bakelite.  Some of the T-17 had a hook on top.  Other variations did not.  I have uploaded a copy of the relevant page of specifications from the Signal Corps.

See also the RadioMuseum separately listed Microphone T-17 6490-CHI-42 made by Shure. 

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