Abstract: In the present invention, a tuning circuit which includes a controllable switch based on a diode (D1), for example, and which is connected in parallel with a resonator, is located between the low impedance end of a center conductor (11) of a quarter wavelength resonator and ground, whereupon resonant frequency tuning is based mainly on a change in the inductance of the resonator. Voltages and power affecting a tuning circuit realized according to this invention are essentially smaller than in a circuit in which the capacitive load of a resonator is tuned by means of a similar tuning circuit located at the high impedance end of the resonator.

Abstract: A VHF television tuner circuit for selection of a television signal through mechanical selection of inductance coils comprises a first terminal for receiving a VHF television signal comprising a high and low VHF channel signals; a second terminal for receiving a UHF/VHF converted television signal; a mechanical channel selection switch arrangement for selection of a plurality of channel positions by rotation of a channel selection shaft said mechanical channel selection switch arrangement comprising a radio frequency coil switching stage and an oscillation coil switching stage; a radio frequency coil means coupled to the radio frequency coil switching stage; an oscillation coil coupled to the oscillation coil switching stage; a radio frequency amplifier coupled to the radio frequency coil switching stage for selectively amplifying a desired radio frequency signal; a local oscillator coupled to the oscillation coil switching stage for providing a local oscillation frequency, the frequency of which is different