Abstract: A compact transmitting device located in an exploding projectile transmits an RF pulse upon explosion of the projectile. Receipt of the RF pulse, through triangulation or equivalent techniques, identifies the burst point of the projectile. The transmitting device comprises a magnetic circuit that includes a permanent magnet, a ferromagnetic core having an air gap some distance from the permanent magnet, and a coil in the air gap. Stored energy in the permanent magnet is converted into a high power electrical pulse when the permanent magnet is destroyed. Prior to destruction of the magnet, a constant high magnetic flux exists in the air gap, but induces no current in the coil because it is a constant flux. Upon destruction of the permanent magnet, the magnetic flux changes rapidly, causing a high power electrical pulse to be generated.

Abstract: A crash survivable enclosure for flight data recorders used in aircraft and other vehicles operating over land and water includes a strong, light-weight metal shell for enclosing and protecting an information storage device having power, signal, and address lines connected thereto. The memory device is supported inside the shell in a wax filler of the type having a high melting temperature and a high heat of fusion to act as a heat sink for absorbing a large quantity of heat to minimize possible damage to the memory device because of excessive heat, flames and/or high temperature. A strong lightweight metal shell is provided to enclose and protect the inner shell and contents against substantial, external mechanical forces commonly occurring in a crash and flames, heat and fire resulting therefrom.

Abstract: A miniaturized electronic transmitter tracking device (10) for mounting on the shaft of a hunting arrow (12) is provided. An integral membrane or diaphragm (38) attaches the transmitter to the arrow (12) in the preferred embodiment and allows the transmitter to break away from the arrow when the arrow strikes some object. A membrane switch (32) is activated when the face plate (40) of the device (10) impacts the animal. Barbed points (42) are driven into the surface of the struck animal by the force of the impact, thus firmly attaching the device (10) to the object. In its preferred embodiment, the transmitter device (10) is used in conjunction with a base receiver (16) to determine the transmitter's location after the arrow (12) has been fired.

Abstract: A data communication system for an aircraft includes a voice encryption unit that is selectably included in the audio path between a user and a radio. The data communication system is interconnected so that the unencrypted audio path of a user is isolated from other users, thus providing the user with a secure, private communications link within the aircraft, as well as between the aircraft and a ground station. The system includes an audio path from the cockpit to the encryption unit and an audio path from the passenger cabin to the encryption unit, and further includes a control unit in each of the cockpit and the cabin so that control of the encryption unit can be selectably switched between the cockpit and the passenger cabin.

Abstract: A transmitter attachment for hunting arrows includes a hollow tubular member which is removably mounted between the arrowhead and shaft of a conventional hunting arrow. The tubular member has a transmitter mounted in one end, and a battery slidably mounted between a pair of spring contacts in the other end. The battery is mounted so as to slide forward into electrical contact with a coil spring, which closes an electrical circuit to energize the transmitter, when the arrow hits the target or the ground. Thus, the combination of battery and contacts forms a type of inertia switch. A directional receiver is utilized to locate the arrow. The transmitter is deactivated by tapping the nock-end of the arrow against the ground--which slides the battery out of contact with the coil spring.

Abstract: A system for detecting unintentional operation of a radio transmitter includes an antenna for receiving a r.f. signal and a detector for detecting the absence of presence of a component in the received signal that is indicative of a transmission from a radio transmitter keyed in an operating condition but not being used. In response to detection of such signal component, the detector produces a trigger signal. A delay timer times the duration of the trigger sigal and produces a delayed signal in response to the duration of the trigger signal exceeding a preset time period. An indication circuit produces an operator-alerting indication in response to receipt of the delayed signal informing the operator that the transmitter is unintentionally keyed in an "on" condition. The system also has a d.c. power source for supplying power to the detector, delay timer and indication circuit to operate the same.

Abstract: An emergency locating transmitting (ELT) system comprising a legislated ELT modified with an interface unit and connected by a multiwire cable to a remote control monitor (RCM), typically located at the pilot position. The RCM can remotely (1) test the ELT by disabling the legislated swept tone and allowing transmission of a single tone, (2) turn the ELT "on" for legislated ELT transmission, and (3) reset the ELT to an "armed" condition. The RCM also provides visual and audio indications of transmitter operating condition as well as ELT battery condition. Removing the RCM or shorting or opening the interface input connections will not affect traditional ELT operation.

Abstract: An arrow that accepts standard target or hunting tips includes a radio signalling transmitter which emits a carrier signal that is receivable by a directional receiver for tracking and locating the arrow when released from a bow. The transmitter includes a carrier interrupting circuit operating at a rate that is inversely proportional to battery voltage which permits dynamically testing the battery prior to releasing the arrow. This provides reliable operation of the transmitter by insuring an adequate minimum charge in the battery. An electrical switch embodying the arrow tip as an actuator permits selectively connecting or disconnecting the battery from the transmitter to conserve the battery charge.

Abstract: In an emergency locator transmitter of a type wherein a standard distress signal is transmitted following a distress incident, the distress signal is encoded with data identifying the absolute time of the incident or the amount of time that has elapsed since the incident occurred. Distress waveform modulation of the carrier is periodically interrupted for insertion of the time signal. In a preferred embodiment, wherein the distress signal includes information burst signals that are periodically transmitted, e.g., every 50 seconds, timing pulses generated synchronously with the burst signals are supplied to a divider circuit for division by a predetermined integer to develop extended time base pulses, e.g., one hour pulse intervals. The extended pulses are accumulated in a binary counter and combined with the information burst signals.

Abstract: An emergency transmitter provided with separate devices for the transmission of a first frequency and a second frequency. The transmitter is contained within a floatable housing. The transmission devices are connected via a switch to a battery. The transmission devices are comprised of a common quartz or crystal oscillator connected with frequency multipliers which are connected to drive stages and to high frequency final stages. The latter are connected to a transmission antenna which extends from the housing. Also provided is a signal generator for modulating the transmitted frequencies. A fixed-cycle control device is associated with the first and second transmission devices and alternately sets the two transmission devices into operation.

Abstract: A method and apparatus for determining the position of a vessel in distress and transmitting an auditory distress message containing the position of the vessel. The apparatus obtains the position of the vessel as determined by a LORAN-C type receiver from either a cassette or directly from the LORAN-C receiver and generates a "Mayday" message including the identification of a vessel, the position of the vessel and the nature of the emergency. The "Mayday" message is synthesized into an auditory human or Morse code message. The language of the auditory message is preferably chosen to correspond with the most likely language used by a possible receiver of the "Mayday" message. Also preferably, the apparatus determines whether the primary distress radio frequency is clear; should the primary distress frequency be in use, the apparatus automatically shifts to a secondary frequency and transmits the "Mayday" message.

Abstract: A radiosonde for measuring atmospheric parameters, such as pressure, temperature, and humidity, includes a microprocessor interfaced with an analog-to-digital converter, which, in turn, receives sequential input signals representing the sensed atmospheric parameters, and converts those signals to corresponding digital data. This digital data is processed in the microprocessor, and applied as a digital data stream to an RF transmitter from where the data is transmitted to a remote ground processing station. A flap member on the radiosonde housing, which is movable between an open and a closed position in response to air flow, cooperates with a switch to provide a signal to the microprocessor indicating the launch and descent of the radiosonde. A preset input to the microprocessor is provided to automatically terminate transmission of meteorological data when the radiosonde has reached a predetermined altitude.

Abstract: A housing for electrical components and equipment sent aloft with a weather balloon to measure atmospheric parameters comprises a light-weight polystyrene case that serves as a shipping container and flight package. The housing also includes an air duct and a humidity sensor in the duct. Means in the duct minimize the reflection of sunlight onto the sensor to maintain at ambient temperature the air which flows over a humidity sensor.

Abstract: A low frequency air-to-air and air-to-ground communication system is described. The propagation characteristics of low frequencies and very low frequencies are such that less signal attenuation is encountered at intercontinental ranges when the system is operating in the TE mode as compared to the TM mode. The TE mode is defined as having a dominant vertical magnetic field component and the TM mode is defined as having a dominant vertical electric field. Also, the receiver in an aircraft is subjected to less ambient noise when it is positioned to receive the TE mode. However, ground transmitters are inefficient at transmitting and receiving the TE mode because the ground image tends to cancel out the transmitted and received signals.

Abstract: A radio communications system for aircraft, particularly useful at UHF frequencies and in aircraft travelling at high speed and low level where rapid phase and amplitude fluctuations degrade intelligible speech transmission. The system comprises a transmitter in a first aircraft, the transmitter including an upshift frequency translator for transferring the frequency band of an input signal from a microphone to a higher band, and further including an amplitude modulator for modulating the frequency translated signals; and a receiver in a second aircraft arranged to receive and demodulate the transmitted signals, the receiver including a high pass filter for removing noise from the demodulated signal, and a downshift frequency translator for transferring the frequency band of the filter output to a lower band.

Abstract: A telemetric system has a conductive coil positioned adjacent to a muzzle. burst of transducer data is electromagnetically relayed to the conductive coil from a missile after it is fired. This conductive coil has longitudinally spaced windings distributed alongside the trajectory of the missile. The effective length of the conductive coil is at least in the order of magnitude of the distance traveled by the missile while the burst of transducer data is being transmitted. Data thus received can be utilized to drive recorders or similar equipment. The missile has on its outside an associated missile coil for transmitting the burst of transducer data. The coil is driven by a modulated carrier. This modulation is provided by a delay device that is driven by a transducer. This arrangement allows transmission of data corresponding to an operating parameter of the missile after a predetermined delay.

Abstract: A capacitive signal dependent upon a quantity being measured is produced by capacitive sensors of a radiosonde. An oscillator in the radiosonde has an output frequency, controlled by the capacitive signal, in the order of 1 to 10 MHz. The output frequency of the oscillator is divided by a factor of 2.sup.7. A high frequency transmitter in the radiosonde is frequency modulated by a frequencyf.sub.M1 =f.sub.M0 /dwherein f.sub.M1 is the output frequency of the divider and f.sub.M0 is the input frequency of the divider.