Abstract: There is disclosed a miniature hand-held radio-frequency transmitter. An operating frequency is determined by a lumped-circuit oscillator which feeds an antenna etched on the periphery of the circuit board. The antenna is tuned to a frequency which is slightly above the second harmonic of the operating frequency, it being the second harmonic which is radiated. By slightly mis-tuning the antenna, the effects of an enveloping hand are minimized. The clasping of the transmitter by a human hand results in the absorption of some of the radiated power, but hand-capacitance effects also shift the center frequency of the antenna characteristic toward the second harmonic of the operating frequency, thus increasing the radiated power. In this way the signaling range under free-space conditions is the same as that under operating conditions. The oscillator circuit can thus be adjusted for maximum power output under free-space conditions within the guidelines of F.C.C.

Abstract: A circuit for providing TV channel selection and tuning voltages utilizes a plurality of fixed resistors and a plurality of Q variable inductances. A channel selection switch connects particular resistors and Q variable inductances for channel selection and fine tuning. The Q variable inductances are used for fine tuning and are connected in circuit with an oscillator and a detector. The Q variable inductances each have an adjustable steel core with the position of the core determining the amplitude of the detected oscillator voltage and thus the fine tuning control voltage.

Abstract: A television tuner includes a rotatable turret and a plurality of coil forms positioned in the turret. There is a pair of tuning coils mounted on each coil form and an adjustable tuning screw extending outwardly from each end of each coil form. The housing mounting the rotatable turret includes means for adjusting the tuning screws at opposite ends of each coil form. The turret is detented within its housing such that there are twice as many detented positions of the turret as there are coil forms and such that at each detented position only one tuning screw can be adjusted.