Course and Speed Calculator Mk II Ref 6B/119 RAF 1939 F-14 it was used as a

it was used as a high power jamming transmitter of sufficient power to screen a large bomber within two miles of enemy radar systems operating within its frequency band of 350-800 mc

and also contains an anchoring hole for an HF wire antenna support

in its original packaging

published in 1940 by the British Royal Air Force Air Ministry

system installation in a B-29 began early in June

Course and Speed Calculator Mk II Ref 6B/119 RAF 1939 F-14 it was used as aThis is an original WWII era Course and Speed Calculator Mk II as used by aviators of the British RAF in its wooden case. The case is marked as having been made for a different serial number, but the correct serial number has been painted on the outer end. The case measures ~ 11 in x 6 in x 2 in. It is in good condition given its age as the center rotates and slides along the base when the locking clamp is released.