Abstract: In the UHF tuning portion of a television receiver, a varactor tuned circuit is coupled to the gate electrode of a field effect transistor (FET) through an impedance transformation network comprising a series connected capacitor and shunt connected inductor. In order to increase the signal power transferred between the tuned circuit and the FET at the lower end of the UHF range, the values of the capacitor and inductor are selected so that the relatively low value of equivalent parallel impedance exhibited by the tuned circuit at the lower end of the UHF range is impedance transformed to a value approximately equal to the value of the impedance exhibited at the gate of the FET. A second impedance transformation network, similar to the first, is coupled between the drain of the FET and a second varactor tuned circuit to further increase the signal power transferred between the FET and the second tuned circuit at the lower end of the UHF band.

Abstract: A tuner for a television receiver comprises a circuit board formed by a slab of dielectric material having conductors located on one side and discrete components mounted on the other so that it may be readily assembled and soldered. Some of the conductors are arranged to form capacitors and distributed parameter inductors. In the UHF portion of the tuner a strip-like conductor and a wider ground conductor are spaced apart in parallel relationship. The length of the gap between the strip-like conductor and the ground conductor is selected to provide inductive reactance in the UHF band. A slot is cut, punched or otherwise formed through the dielectric material in the gap between the strip-like conductor and the ground conductor to increase the Q (the figure of merit inversely related to loss) of the inductor at the upper end of the UHF range. In addition, the slot significantly improves thermal stability of the inductor.