Abstract: A vehicle-mounted device that enables adjustment by wireless communication from an external portion, of a threshold value employed for detecting strength of a radio wave emitted from a roadside device. A vehicle-mounted device is disposed within an electromagnetic-shield box, and radio waves for activating use are sent from an antenna within the electromagnetic-shield box to the vehicle-mounted device. The vehicle-mounted device, when activated by this radio wave for activating use, sends an activation acknowledgement signal. A computer determines whether the vehicle-mounted device has been activated according to the presence or absence of the activation acknowledgement signal. The computer sends a radio wave from the antenna to the vehicle-mounted device to set a threshold value in correspondence to the presence or absence of this activation, and sets the threshold value of the vehicle-mounted device.

Abstract: After a vehicle-mounted unit determines that a vehicle has entered a toll chargeable area, if communication is determined to be allowable through a flag, communication operations are performed and after finishing communication operations, the flag is set and communication operations thereafter are prohibited. Next, the unit determines if a travel distance has exceeded a toll chargeable distance. The travel distance is measured by counting the number of vehicular speed pulses received after the end of the communication operations, and the toll chargeable distance is set to be equal or greater than the travel distance needed by the vehicle to enter the communication area and leave it. If it is determined that travel distance has exceeded toll chargeable distance, the flag is reset, communication prohibition is released and communication thereafter is allowed.

Abstract: A high frequency filter for an electric instrument including a casing of metallic conductive material, an internal electric circuit element arranged within the casing, and a connector mounted on a peripheral wall of the casing for connecting the internal electric circuit element to an external electric circuit. The high frequency filter comprises an insulation substance layer arranged between the connector and a connection terminal of the circuit element, the insulation substance layer being made of a dielectric material whose dielectric constant decreases or increases in accordance with increase or decrease of wireless frequency applied thereto, and a pair of conductive layers formed on opposite surfaces of the insulation substance layer, one of the conductive layers being connected at one end thereof to the connector and at the other end thereof to the connection terminal of the circuit element, and the other conductive layer being connected to a portion of the casing.

Abstract: A portable receiving antenna system for providing communication with a transmitting station carried by a geostationary satellite. The system includes a portable case, a flat plate antenna arranged to cover an opening of the portable case, and an adjustable support arranged within the portable case to support the flat plate antenna at an incident angle capable of receiving electromagnetic waves from the transmitting station. The flat plate antenna is in the form of a micro strip line slot array antenna including a dielectric layer, a metallic earth film formed with a plurality of spaced slots and secured to the surface of the dielectric layer in such a manner that the slots are arranged to receive the electromagnetic waves from the transmitting station, and a feeder line circuit secured to the rear surface of the dielectric layer. Preferably, an azimuth compass and a converter are mounted within the portable case, the converter being connected to an output terminal of the feeder line circuit.

Abstract: An antenna system for use in an automotive vehicle comprises a housing mounted on a body of the automotive vehicle and having at least a portion of an upper surface thereof made of a dielectric material which transmits radio waves, at least one planar antenna disposed rotatably within the housing to receive radio waves transmitted through the portion of the upper surface of the housing made of the dielectric material, and driving means for driving the planar antenna to effect scanning of a radio wave receiving direction to search for the radio wave receiving direction of higher sensitivity. The housing protects the antenna system and maintains the fine appearance of the automotive vehicle. Further, the housing has a shape like that of an air spoiler, which makes it possible to maintain the satisfactory aerodynamic characteristic of the automotive vehicle.

Abstract: A high frequency filter for an electric instrument including a conductive casing insulated on a stationary structure, an internal electric circuit arranged within the casing, and a connector mounted on the casing for connecting the internal electric circuit to an external electric circuit. The filter comprises an insulation thin plate arranged between the connector and the internal electric circuit and being folded at its intermediate portion, a pair of conductive thin plates secured to opposite surfaces of the insulation thin plate and extending along the folded portion of the insulation thin plate, one of the conductive thin plates being connected at its one end to the connector and at its other end to the internal electric circuit, and the other conductive thin plate being connected to a portion of the casing to provide a short circuit. In such arrangement, the conductive thin plates are opposed to each other through the insulation thin plate to provide a distributed constant circuit.

Abstract: A nozzle for gas shielded arc welding having a support ring to be mounted on a welding torch, a cylindrical nozzle member to be mounted on the support ring and a holddown ring for securing the nozzle member to the support ring. The nozzle member is formed of a heat-resistant non-conductive material so that spatters seldom adhere to the nozzle member. The nozzle member is fixed by being pressed against the support ring, which structure facilitates the manufacture of the nozzle member. This is useful especially as a nozzle for CO.sub.2 arc welding.

Abstract: A microwave oven for a camping or other vehicle includes a heating room in which an object is heating by applying microwaves thereto, a microwave guide to propagate the microwaves into the heating room, a magnetron to produce the microwave for the microwave guide, and a voltage supply device to supply the magnetron with an appropriate voltage. The voltage supply device includes a transformer to boost the three-phase AC voltage from an alternator mounted on the vehicle, and a rectifying circuit to rectify the three-phase AC voltage boosted by the transformer. The magnetron receives the voltage rectified. The heater terminal and other main terminal of the magnetron are connected to terminals of the battery mounted on the vehicle.

Abstract: An apparatus for measuring the ratio of alcohol contained in mixed fuel which flows through a fuel pipe to the engine. The fuel pipe is made of a high frequency signal permeable material such as rubber, teflon or nylon, for example. A microwave chamber is provided outside the fuel pipe, enclosing a part of the fuel pipe. The microwave chamber comprises a pair of wave guides opposed to each other with the fuel pipe interposed between them. One of the wave guides is provided with an antenna section for transmitting microwaves received from a microwave generator. The other wave guide is provided with a receiving antenna section for receiving the microwaves permeating through the fuel pipe through which the mixed fuel is flowing. The microwaves passing through the fuel pipe are attenuated according to the amount of alcohol in the fuel.

Abstract: In an unauthorized entry detection system for automotive vehicles, an oscillator is installed within the passenger compartment of the vehicle to generate an electromagnetic wave with a predetermined frequency defined by the interior size of the compartment, a first antenna connected to the oscillator to propagate the electromagnetic wave in the whole interior of the compartment in such a manner that the compartment resonates as a cavity resonator when all the doors and windows are closed, a second antenna arranged within the compartment to generate an induced voltage in response to the magnetic field component of the propagated electromagnetic wave, and a detecting circuit connected to the second antenna to detect a change of the induced voltage level caused by entry of a human body into the compartment and/or opening of the doors or windows, thereby to generate a detection signal therefrom.

Abstract: A diesel smoke meter which uses micro-waves to detect the density of black smoke contained in the exhaust gas discharged from the diesel engine through an exhaust pipe. A micro-wave transmitting device is coupled to the exhaust pipe and transmits micro-waves into the exhaust pipe. Micro-waves transiting the exhaust pipe are attenuated by the black smoke in the exhaust gas. A micro-wave receiving device receives the attenuated micro-waves and provides a received signal which varies in accordance with the signal level of the attenuated micro-waves. A measuring device receives the received signal and provides an output indicative of the density of black smoke in the exhaust gas.

Abstract: A vehicle radio receiver apparatus constitutes an antenna device including an antenna element and also a radio receiver integral with the antenna device so as to receive a signal from the antenna element. The radio receiver includes a tuner circuit directly connected to the antenna element, a high-frequency amplifier circuit for amplifying the reception signal tuned into by the tuner circuit, and an audio signal converter for detecting and low-frequency amplifying a high-frequency amplified signal and for producing an audio signal. A tuning control signal and a volume control signal are respectively supplied from a control unit to the tuning circuit and the audio signal converter circuit of the radio receiver. This control unit is arranged separately from the radio receiver and receives volume control and tuning control operating signals from an operating section which has a tuning control knob, a volume control knob and the like.