Wide-Range Tuned Circuits and Oscillators for High Frequencies

Tuned circuits for frequencies from 100 to 1000 megacycles are described, which combine the mechanical simplicity and compactness of low-frequency coil-capacitor circuits with electrical performance suitable for very-high-frequency and ultra-high-frequency applications. Tuning ranges of 4 to 1 are readily obtained, both with and without sliding contacts. Application of the circuits in negative-grid-triode oscillators is discussed.