Abstract: A calibrator circuit for a self-contained device for vertification of open field test site accuracy. This device generates a broadband width of discrete frequencies from 10 MHz to 1000 MHz which is then radiated into space. The circuit contains a power supply subcircuit, an oscillator subcircuit which generates an output signal rich in harmonics, an antenna radiating element and a balun network to couple the output from the oscillator subcircuit to the antenna element.

Abstract: A radio frequency transmitter of the type that is adapted to be powered from an internal battery power source, or from an external power supply that is connected to the transmitter by an electrical conductor, which conductor acts as a part of the antenna system for such transmitter and increases the strength of the signal radiated by the transmitter when the transmitter is powered from the external power supply, and which includes a circuit for reducing the power output of the transmitter, when the transmitter is connected to the external power supply.

Abstract: An oscillator (10) operational in the millimeter wave range including frequencies greater than 30 GHz includes a lumped element active circuit (12) including an active element (14) with a negative resistance, a lumped element resonator circuit (16) in parallel therewith, and an antenna (18) extending directly from the oscillator without an intermediate impedance matching section therebetween and without an isolation element therebetween. The antenna has a length of nominally a quarter wavelength at the desired fundamental frequency, and has zero connection length from the oscillator. The antenna serves a dual function of radiating the energy generated by the oscillator and also transforming the output impedance of the oscillator to the impedance of transmission media providing a load, such as free space or a wave guide.

Abstract: A microphone is provided in which two circuit boards are held in spaced parallel position by each being connected at one end to a supporting member and by each resting at the other end in a pair of stabilizing grooves located within the microphone head. A battery holding assembly has attached at one end the supporting member, and at the other end an antenna mounting surface onto which a coiled antenna is placed. A battery holding compartment is located between the supporting member and the antenna so that a battery held in the compartment acts as an addition to the antenna itself. A power and battery level indicator flashes on and off to warn that the charge of the battery is reaching a predetermined low point. The electronic circuitry for the indicator is also provided.

Abstract: A short distance, battery powered, amplitude modulated, crystal controlled RF transmitter for transmitting encoded security information. In its preferred embodiments, the transmitter comprises a novel fifth overtone crystal oscillator which self-produces a carrier frequency at the third harmonic of the fifth overtone of the crystal's fundamental frequency, which carrier frequency is coupled by a series resonant trap, or a pi network, tuned to the carrier frequency to an amplifier stage where the carrier is amplitude modulated via pulse position encoded binary security data. In an alternative embodiment, the transmitter comprises matched crystal oscillator, tripler and amplifier stages. Also disclosed is an antenna including a battery clip contact.

Abstract: The invention pertains to a method and apparatus for generating and radiating electromagnetic energy for use in heating the upper atmosphere. For such an application, the cost per watt is a dominant design factor. The invention minimizes the cost per watt by minimizing the number of active devices utilized. A single active device is used to charge and discharge a short circuited antenna at a rate which is essentially the same as the antenna's resonant frequency.

Abstract: A high power TV antenna for operation at the ultra high frequency (UHF) frequency F includes a radiating antenna located at the top of a tower structure (often hundreds of feet high), a transmitter at the bottom of the tower and a main circular waveguide transmission line of diameter D1 between the transmitter and the antenna carried by the tower; the feed to and/or from the transmission line including transition sections such that wave propagation in the transition sections is below cutoff for the TM01 mode while it is above cutoff for the dominant TE11 mode while wave propagation in the main circular waveguide transmission line of diameter D1 is substantially totally in the dominent TE11 mode even while it is above cutoff for the TM01 mode, whereby the transition sections tend to inhibit wave propagation in the system in the undesired TM01 mode.

Abstract: A radio control transmitter which suppressed harmonics includes an oscillator which is coded by code selecting switches and in which undesired harmonics are reduced from the output of the transmitter by adding inductors into the emitter, the collector or the base of the radio frequency oscillator.

Abstract: An antenna switch (302) includes a radio terminal (R) and first and second antenna terminals (A1 and A2). When the second antenna terminal (A2) is unterminated, the radio terminal (R) is coupled to the first antenna terminal (A1). When the second antenna terminal (A2) is connected to a remote antenna system (304), the switch automatically couples the radio terminal (R) to the second antenna terminal (A2). Thus, the switch does not require a separate control terminal (C) and control signal to switch between the first and second antenna terminals. Instead, the switch is controlled by the presence or absence of a DC current at the second antenna terminal (A2). The remote antenna system includes a remote antenna (308) and a low pass filter (310) coupled between the remote antenna and ground. An alternate embodiment is described which includes a DC amplifier (402).

Abstract: A three-element active device is physically and electrically integrated (e.g., by soldering) onto shaped conductive areas in a thin conformable microstrip structure which includes a microstrip antenna radiator. Two of the elements of the active device are connected to microstrip reactance structures which form a series-resonant partial oscillator circuit. The third (output) element of the active device is connected directly to the microstrip antenna radiator via a microstrip transmission line which, together, directly provide the r.f. load impedance for the thus completed oscillator circuit. Quarter wavelength r.f. microstrip segments are also provided to facilitate the feeding of d.c. bias to the active device without disturbing the r.f. circuitry. The oscillator load impedance to be provided by the microstrip radiator is predetermined in accordance with conventional device-line or loadpull impedance measurements so as to maximize the power output of the active device.

Abstract: A noncontact switch couples power from A and B radio frequency sources to a load and an antenna in three modes. Mode I couples the A source to the antenna and the B source to the load; Mode III is B to antenna and A to load, and Mode II couples both A and B sources to the antenna. The structure includes a first 3dB, 90.degree. coupler coupled to the sources and a second 3db, 90.degree. coupler coupled to the load and the antenna. A third 3dB, 90.degree. coupler is coupled in a first path between the first and second couplers. A pair of reflective terminations coupled to ports of the third coupler are mechanically controllable to one of three phase-shift conditions; 0.degree. for mode I, 90.degree. for mode II and 180.degree. for mode III. A fixed phase shifter couples the first and second 3dB, 90.degree. couplers by a second path. Each reflective phase shifter is a coaxial circuit including the parallel combination of first and second series inductance-capacitance circuits.

Abstract: The invention relates to a high frequency antenna tuning device. The antenna is connected to a power transmitter, which periodically supplies power signals at predetermined high frequencies. For each frequency, the tuning device comprises a tuning capacitor connected to a switch. These switches are connected to control means, which are in turn connected to identification outputs of the frequencies of the signals supplied by the generator. The device also comprises means for detecting power signals transmitted by the antenna, so as to prevent any switching throughout the duration of a power transmission by the antenna on one of the predetermined frequencies.

Abstract: A technique for reducing the average fade duration of signals in a radio system by simulating motion of a plurality of transmitting antennas is disclosed. This simulation is accomplished by slowly and continuously varying a characteristic of the modulated carrier signal supplied to the antennas. The altered characteristic can either be the power of the modulated carrier signal supplied to each of the antennas or the phase between modulated carrier signals coupled to the antennas. This technique can also be applied at a receiver to reduce the average fade duration of signals arriving thereat by simulating motion of a plurality of receiving antennas.

Abstract: A portable radio transceiver and mobile mount housing are disclosed which utilize a switchless connector for connecting the portable unit to an external antenna which is electrically coupled to the mobile mount. In the preferred embodiment, the portable radio is equipped with an internal antenna which is either coupled to an electrical contact on the exterior of the portable unit adaptable to making electrical contact with a similar contact on the inside of the mobile housing when the portable radio is inserted therein. The internal antenna in the portable unit is shielded by the metallic mobile mount housing which obviates the need to disconnect the same. In one embodiment the contact disposed on the portable unit exterior is connected to a predetermined point on the internal antenna for impedance matching with the external antenna when the portable unit is inserted into the mobile mount housing.

Abstract: A radio communication device comprises a portable communication device and a power amplifier device adapted to accommodating the portable communication device thereinto for amplifying a transmitter output therefrom. The radio communication device further comprises a detector circuit for detecting that an electrical coupling between the portable communication device and the power amplifier device, thereby effecting a control such that the transmitter output power level is kept at a minimum input level required for the power amplifier device. Thus, this can suppress exceesive heat generation in the communication device when the portable communication device is used by being accomodated in the power amplifier device.

Abstract: A television transmission system for transmitting UHF signals from a UHF signal generator, the system comprising an antenna for radiating UHF signals generated by said UHF signal generator, an overmoded section of waveguide for carrying the signals at least part of the way between the UHF signal generator and the antenna with a low level of power loss, and a high-power mode filter coupled between the antenna and the overmoded section of waveguide.

Abstract: A FM wireless headphone transmitter which uses a novel technique of varying the transmitted frequency. Instead of the traditional methods of using a variably meshing multi-plate capacitor, the invention uses a printed circuit inductance with a tuning plate attached permanently to the inside of the case so that frequencies are changes by changing cases. An alternative embodiment uses interchangeable tuning plates attached to the inside of the case by hook and loop pile type fastener material. The printed circuit inductance also serves as a transmitting antenna.

Abstract: A system for adjusting the antenna matching network of a radio system in the presence of an interfering signal in the matching network being adjusted comprises a loop from which the interfering signal is cancelled by an adaptive interference cancellation (AIC) system. The AIC system receives an interference sensor signal having the frequency of the interfering signal. Means responsive to the interference sensor signal and phase and amplitude control signals provides a modified interference sensor signal having a phase and amplitude determined by the control signals. This modified interference sensor signal is combined with a mismatch signal which is derived from the signal in the matching network to produce a modified mismatch signal.

Abstract: In an ultra high frequency (UHF), high power broadcast television (TV) antenna system that includes a radiating antenna located at the top of a tower structure many hundreds of feet high, a transmitter at the bottom of the tower and a circular waveguide transmission line between the transmitter and the antenna carried by the tower, an undesired polarization mode that is transverse to the desired polarization mode for which the antenna system is adjusted is excluded at the top of the tower structure at the end of the circular waveguide transmission line so that the undesired polarization mode does not energize the radiating antenna and, in particular, the undesired polarization mode does not energize the antenna and produce a ghost image in a TV receiver after reflecting from the bottom end of the circular waveguide transmission line back up to the antenna and does not add a standing wave in the circular waveguide transmission line.

Abstract: A low-power transmitter for garage door operator systems and the like wherein harmonics of the fundamental frequency are suppressed by class A or AB oscillator operation and fundamental radiation is enhanced by way of a combined inductor/radiator having conductive printed circuit extrusions on the ends thereof to effectively form a center-fed dipole antenna.

Abstract: A warning and protection circuit arrangement suitable for use in conjunction with a two-way portable transceiver having a removable battery pack/antenna includes a battery enclosure containing an antenna structure. A circuit is enclosed inside the battery enclosure for providing information indicative of certain predetermined parameters of the antenna or the battery. This information may be used by the transceiver to provide the user with an alert in the event an inappropriate battery pack/antenna is being used. The information may also be used to modify the normal operation of the transceiver to avoid possible damage.

Abstract: A UHF broadcast antenna system uses circular waveguide for the run from the high-power final amplifier to the antenna. Undesired cross-polarization components are formed in the circular waveguide due to unavoidable tolerances. Correction of the cross-polarization components is accomplished by a correction apparatus for sampling the principal polarization-plane signal, and reinjecting the sample with controlled amplitude and phase into the circular waveguide in the plane of the cross-polarization component for cancelling the cross-polarization.

Abstract: A portable advertising sign is positioned in proximity to a street and includes a message board. A low power transmitter is physically secured to the sign and generates a modulated RF output signal at a predetermined frequency within the broadcast band. An antenna colocated with the sign is coupled to the transmitter and radiates the transmitter output signal. A cassette tape player is positioned in a secure area physically spaced apart from the sign by a substantial distance and includes a colocated power supply for supplying a DC voltage. A cable conveys the audio output signal from the tape player and the DC voltage from the power supply to the transmitter. The sign message board displays the operating frequency of the transmitter to vehicles passing by the sign.

Abstract: An antenna matching apparatus tunable to different frequencies is disclosed for use with a high frequency transmitter that is rapidly switchable between different transmitting frequencies by a control unit according to a predetermined frequency scheme. This apparatus which is tunable as quickly as the transmitter, includes two or more antenna tuning means tuned to different frequencies which are tuned to different frequencies and switched rapidly by the control unit.

Abstract: A simple technique and circuit is disclosed to replace prior Z-.theta. type discriminators in supplying the loading and phasing control signals to the impedance matching network in an automatic antenna tuner. The new circuit samples forward and reflected voltage V.sub.f and V.sub.r (or equivalently I.sub.f and I.sub.r) in the RF input. The loading control signal is supplied according to the in-phase component of V.sub.r relative to V.sub.f. The phasing control signal is supplied according to the quadrature component of V.sub.r relative to V.sub.f. The magnitude of each of the in-phase and quadrature V.sub.r components is reduced to zero by the matching network to thus reduce the phasor amplitude of V.sub.r to zero and hence eliminate reflected voltage.

Abstract: A VLF communication system which utilizes the electrically conducting portions of an electromechanical cable connected to a deployed aerostat and acting as its tether so as to additionally serve as the VLF antenna.

Abstract: A device for detecting the optimum anode load impedence of a transmitter tube in a high frequency transmission chain. A phase shift circuit phase shifts by k.pi./2 (with k being a positive or negative uneven integer) the phase difference between the input and output voltages of the tube. The phase shifted voltages are multiplying together in a circuit, and the mean value of the product is then calculated. Cancellation of this mean value corresponds to the anode load impedance passing through a purely resistive value. Thus, the circuit allows the phase matching detection to be made, which is independent of any modulus matching detection.

Abstract: A remote unit for use in a wireless extension telephone system having a self-contained dipole antenna. Utilizing the unique construction of the telephone instrument housing one element of the dipole is included in a planar element that functions normally to direct sound to a self-contained microphone and the other element of the antenna is a static shield used to protect components on printed circuit board included within the extension unit.

Abstract: A device mounted on a power transmission device of a vehicle is utilized for transmitting an RF signal when a predetermined parameter exists in the power transmission device wherein the RF signal is capable of being received at a remote location. An electromagnetic transducer provides alternating voltage as power which is applied to an oscillator including a crystal filter, a junction field effect transistor and a resistor. The alternating voltage is applied across a drain and a source of the junction field effect transistor. The crystal filter is connected between the drain and the gate of the junction field effect transistor while the resistor is connected between the gate and the source of the junction field effect transistor. A wire antenna has a first end which is connected to the drain of the junction field effect transistor and a second end which is connected to the source of the junction field effect transistor to prevent transmission of any RF signal until the predetermined parameter is exceeded.

Abstract: A novel apparatus and method for improving the stability of an electrical circuit such as an oscillator and/or a radio frequency transmitter which is coupled to a radiating element wherein the radiating element such as a loop is coupled to the inductor or capacitor of the frequency determining circuit of the oscillator so that frequency shifts will not occur due to inductive or capacitive effects. The oscillator circuit is mounted on an insulating sheet which has a ground plane on the opposite side thereof so as to provide effective shielding and the radiating element is mounted on a portion of the insulating sheet where the grounding plane does not extend. The radiating element is also coupled symmetrically to the inductor or capacitors of the frequency determining circuit and is connected at tap points which do not have the entire inductance between them.

Abstract: An efficient circuit for coupling at least two radio frequency transmitters of arbitrary power and frequency to one antenna comprises a three-port ferrite circulator connected to the output of each transmitter, a tee connector with a predetermined impedance mismatch connected to the first output port of each circulator, a first in-phase power combiner connected to the second output port of each circulator, and a second in-phase power combiner connected to the outputs of the tee connector and first combiner for adding the RF power and feeding the attached antenna. The impedances of transmission lines connected to the tee connector are selected to present a 3 to 1 voltage standing wave ratio to input lines so that reflected power is equally divided and fed in segments of equal power, phase and amplitude to that of the original summation for recombining and delivery to the antenna. The circuit effectively isolates the transmitters from each other and combines their outputs with high efficiency and minimum loss.

Abstract: An efficient circuit for coupling at least three radio frequency transmitters of arbitrary power and frequency to one antenna comprises a three-port circulator connected to the output of each transmitter, a four-port connector and a five-port inphase power combiner, and transmission lines having the same characteristic impedances connecting the circulators through the connector and the combiner to the antenna. The transmission lines interconnecting the components of the circuit have electrical lengths selected to deliver energy in phase to the ports of the connector and to the combiner. In a three-transmitter embodiment, one output port of each circulator is connected to the connector, a second output port of each circulator is connected to the combiner, and the output port of the connector is connected to the combiner. In a four-transmitter embodiment, one output port of each circulator is connected to the connector and the second output port of each circulator is connected to the combiner.

Abstract: A method of establishing an ELF/VLF, vertical E-field transmitter loop antenna installation. The method comprises the steps of ascertaining a land region having contiguous areas of widely differing (by at least 4 to 1) subsurface conductivity, and positioning a closed loop wire antenna having a high-power, ELF/VLF transmitter in series electrical path therewith in a generally horizontal plane over the interface of the first and second contiguous areas. The closed loop wire antenna may be positioned above the surface of the contiguous areas, or on top or within the contiguous areas. The antenna may take the form of a rectangular, circular or elliptical loop and is positioned with respect to the interface of the contiguous areas as determined by the values of skin depths of the contiguous areas.

Abstract: A radio transmitter is protected against the possibility of initiating transmission without the radio being connected to a load by having a switch that controls a push-to-talk key line that is only enabled when the antenna load is connected to the transmitter.

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 wide band impedance matching device is described for matching the impedance of an antenna transmission line to a radio transceiver over a wide band of radio frequencies. The device includes an impedance matching network having an inductor and two capacitors that electrically interconnect in either a capacitance "T" mode or a capacitance ".pi." mode. The device also includes an efficient bypass circuit that is capable of electrically bypassing the impedance matching network to effectively directly interconnect the antenna transmission line to the transceiver.

Abstract: A method and apparatus for the automatic matching of a transmitter to an antenna is disclosed. A voltage signal proportional to the square root of the load impedance of the final stage of the transmitter is compared to a signal which is proportional to the square root of the nominal value of the final stage load impedance and the difference is used as the criteria for tuning a load coupling coil connecting the final stage of the transmitter to the antenna.

Abstract: Apparatus for the generation and radiation of microwave radiation including a microwave oscillator having a cavity resonator directly coupled with the input of a horn resonator by way of a first apertured diaphragm. There is arranged within the horn radiator a second apertured diaphragm disposed at a distance from the first apertured diaphragm such that together with the first diaphragm it forms a filter resonator.

Abstract: A reproducing stylus traces a track of a recording medium, in which track an information signal is recorded as variations of geometrical shape, and reproduces as variations in capacitance the information signal thus recorded. The reproducing stylus comprises a reproducing stylus main structure having a tip part with a flat sliding contact face for slidingly contacting at least one track of the recording medium at a time, and an electrode secured to the reproducing stylus main structure at the tip part thereof and adapted to trace one track and reproduce the information signal as the variations in capacitance in accordance with the variations in geometrical shape. The electrode has over a specific distance over the tip part of the stylus main structure from the extreme tip thereof, a width in the width direction of the track which is less than the width of the track. The extreme tip of the electrode has a flat or linear tip end contacting the track.