Octave tuning and the effect of second-harmonic loading on avalanche-diode oscillators

The letter describes a simple coaxial-line 2-bead tuner which allows continuous tuning of an avalanche-diode oscillator over an octave bandwidth. Experiments with such a tuner provide direct evidence that the control of second-harmonic impedance is important if maximum output power is to be achieved; also that large power variations can be obtained with relatively small second-harmonic components in the voltage waveform.