The CV5437 (commercially the Z237/1KW) is an external cavity reflex klystron oscillator. It operates from 3.505 to 3.535 GHz and has an output power of 0.25 Watt.
The cathode current is given as 50 mA. The reflector voltage is -400 referenced to the earthed resonator. The cathode would likewise be referenced to the earthed resonator cavity at -300 Volts.
The valve is marked as GPO Serial number 485. The UK General Post Office (later British Telecom) was a government monopoly provider of telephone services in the landline era as well as postal services and the controller of all access to the RF spectrum in the country. Microwave links handled bulk traffic between centres.
Manufactured under licence from Sperry-Rand corporation of USA.
The reflector connected to the top cap to send the electron stream back into the resonator.
The cathode end of one resonator connector.
Under the microscope the edge ridges have a clear structure.
The structure can be seen as a few vertical strips across the gap.
The wide glass tube envelope is 20 mm in diameter, and excluding the B9A base pins is 71 mm tall.
