Abstract: A portable radio frequency/channel display control system for use in a portable radio device or the like which is powered by a battery and of the type which includes a display for indicating the frequency/channel to which the radio is tuned. The system senses when a radio control is operated (such as the on/off switch, channel selector, etc.) and develops a control signal having a predetermined duration. The control signal causes the display to be energized for the predetermined duration and then the display is automatically de-energized.

Abstract: A system is provided for developing a gating signal when a radio-frequency signal receiver is tuned to the center-frequency of a selected radio-frequency signal. The system comprises circuit means for tuning the receiver to a plurality of frequencies within a range of frequencies which includes the selected signal and for producing an intermediate frequency signal corresponding to the frequency to which the receiver is tuned. A frequency discriminator is coupled to the circuit means and is tuned to a predetermined frequency, with the frequency discriminator being responsive to the intermediate frequency signal for developing an output signal having a DC component which varies systematically in accordance with the deviation of the intermediate frequency signal from said predetermined frequency.

Abstract: In a radio of the type having a selectively operable transmitter portion and an associated receiver portion for two-way communication, such as a CB radio, plus an auxilliary receiver for reproducing auxilliary audio signals, such as an AM/FM radio, a system is provided for automatically interrupting the audio signal output of the auxilliary receiver whenever the transmitter portion is operated. When the transmit/receive switch is in the transmit position, an auxilliary electronic switch interrupts the audio output of the auxilliary receiver by by-passing to ground the audio signal input to the audio amplifier section of the auxilliary receiver.

Abstract: Manually rotatable control or selector knob member adapted to be connected to an operating shaft for an electrical or electronic device, such as a rotary switch, a volume control, etc., said operating shaft having a forward end portion fluted in the longitudinal direction thereof, which has a locking hole formed centrally therein and an annular lining of resilient material provided inside the wall of the locking hole. With this construction, the knob member can be fastly coupled to the operating shaft, while being locked in place at any desired angular position with respect to the forward end portion of the shaft.

Abstract: A preferably vertically oriented dipole antenna structure comprises a downwardly extending coaxial cable-like connector at the bottom of the structure attached to and insulated from a dipole element-forming sleeve whose upper end is rigidly connected to an insulating housing. The upper end of the housing supports a dipole element-forming rod extending vertically upwardly therefrom. The coaxial cable-type connector includes an outer rotatable conductive sleeve extending coaxially of the dipole element-forming sleeve and a central downwardly extending plug-in pin, the sleeve and the plug-in pin being coupled and connected to a cable extending through the dipole element-forming sleeve to a point within the insulating housing where a pair of cable conductors make connection to inductive coupling means for coupling signals between said conductors and the inner ends of the dipole element-forming sleeve and rod.

Abstract: A variable impedance circuit is included between the antenna and the RF amplifier stage of a radio receiver portion of a transceiver and is responsive to a phase-inverted and amplified AGC signal to automatically protect the receiver from breaking down or otherwise malfunctioning when it receives an over-input or excessive input signal level. When the input signal level to the receiver is at the typical operating level, the circuit provides a substantially infinite impedance to ground so as not to interfere with signal transmission from the antenna to the input stage and the successive stages.

Abstract: A system is disclosed for generating a plurality of preselected frequencies in a radio frequency device such as a receiver, transmitter or transceiver. It comprises means for generating a first reference signal having a predetermined frequency and means, including at least two voltage controlled oscillators (VCO), a mixer, a programmable frequency divider, and a switch, for generating a second reference signal, with the mixer being coupled to the first reference signal generating means and being selectively coupled on one of the VCO's by the switch to generate an output signal having a frequency corresponding to the difference between the frequency of said first reference signal and the frequency of the selected variable-frequency oscillator.

Abstract: A system is disclosed for generating a plurality of preselected frequencies in a radio frequency device such as a receiver, transmitter or transceiver. It comprises two crystal-controlled reference signal oscillators. First and second controllable variable-frequency oscillators (VCO's), first and second mixers, and a programmable frequency divider, together generate first and second output signals, with the first mixer being coupled to the first crystal oscillator and to the first VCO to generate the first output signal having a frequency corresponding to the difference between the frequency of the first reference signal and that of the first VCO. The second mixer is coupled to the second crystal oscillator and to the second VCO to generate the second output signal which has a frequency corresponding to the difference between the frequency of the second reference signal and the frequency of the second VCO.

Abstract: A combination microphone, loudspeaker, and control unit is disclosed which is adapted to be coupled by a multiconductor cable to a radio transceiver which is capable of transmitting and receiving a plurality of radio signals at preselected frequencies. A multi-conductor cable is secured to a housing for the unit and is adapted to electrically connect the unit to a radio transceiver. A multi-position switch is mounted in the housing and connected to the cable, with the switch being operable to select individually the preselected frequencies. An electromechanical transducer is mounted in the housing and connected to the cable and operable to convert audible sound wave signals into corresponding audio frequency electrical signals and audio frequency electrical signals into corresponding audible sound wave signals.