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This exhibit is an X band travelling wave tube. The valve acts as a high gain amplifier (40dB) at frequencies in the range 8-12 GHz. The output power is 15 Watts.

The connections are by flying leads. Green - cathode, White - heater cathode, Yellow - heater, Red - anode, Grey - collector, Brown - helix & base.

TWT amplifiers operate at lethal voltages, typically the helix needs a clean and very stable supply of 4000 - 5000 volts at up to 3 mA, the collector operates at 1450 volts at 15 mA, the anode at 2000 Volts at a few μA. The heater would be 6.3 V at about 0.7A. The RF signal is introduced at one coaxial socket and the output appears at the other.

Thanks to Derek Atter G3GRO for lending this exhibit and giving details.

The thin glass envelope is surrounded by magnets. The aluminium housing has a base plate 50 x 270 mm, the top radius is 19 mm.

Reference: G3GRO.