Characteristics of Reflex Klystron.

______ is a single cavity klystron tube that operates as on oscillator by using a reflector electrode after the cavity.
The klystron tube used in a klystron amplifier is a ______ type beam amplifier.
A major disadvantage of klystron amplifier is:
Reflex klystron is used in_____.
The main frequency determining element of a klystron is