A Klystron transmitter for use in weather radar systems has a transmitter module for operating with any of various Klystron tubes designed for different frequency ranges, such as a low S-Band range, a high S-Band range, and a C-Band range. Each of the Klystron tubes is designed to have similar operating characteristics, such as output power and operating voltages. In addition, the transmitter module has driver circuitry for driving the Klystron tube of the transmitter, and such driver circuitry is operable over a wide frequency range so that the same driver circuitry can be used for any of the contemplated bands. Accordingly, the same core transmitter circuitry can be used for any of the Klystron tubes allowing a manufacturer to control which of the contemplated bands is implemented by selecting the appropriate Klystron tube and stable local oscillator (STALO) for the desired band. By using the same core design of the transmitter circuitry for all of the Klystron tubes, the overall manufacturing and implementation costs of Klystron transmitters can be significantly reduced.