The AR6A Single-Sideband Microwave Radio System: Microwave carrier supply

In the AR6A repeater bay, microwave carrier power for both the receiver and the transmitter is derived from a single voltage-controlled crystal oscillator. For long-term stability, this oscillator is phase locked to an external-reference frequency, available at each radio station. From the output signal of this oscillator, an active frequency-multiplier chain generates about +21 dBm power in the 6-GHz band. Part of this power serves as the local oscillator signal for the transmitter directly. The other part is shifted in frequency, to produce the local oscillator signal for the receiver.