Abstract: Implementations of a flight termination system for unmanned aircraft systems are provided. The flight termination system comprises a ground-based flight termination transmitter (FTTx) located with an operator/observer, an airborne flight termination receiver (FTRx) located on an unmanned aircraft system (UAS), and a radio link connecting the FTTx and the FTRx. The FTTx is configured to communicate a TERMINATE FLIGHT message to the FTRx and, once the TERMINATE FLIGHT message has been confirmed, the FTRx is configured to terminate the flight of the UAS by disabling the propulsion system thereof. In this way, the UAS (e.g., a drone or other unmanned aerial vehicle) may be prevented from flying away in an uncontrolled fashion. The FTTx includes an arming switch that can be actuated by a provided key. The dedicated radio link connecting the FTTx and the FTRx is independent of any radio link used to operate the UAS.

Abstract: Implementations of a wearable radio frequency (RF) detector are provided. The wearable RF detector is configured to monitor environmental electromagnetic radiation and comprises a high sensitivity, high linearity RF detection circuit that is paired with a compact, broadband, non-resonant antenna. This combination enables a physically small, yet accurate, detector to be built. An exemplary implementation of the wearable radio frequency detector comprises: an electronic circuit configured to monitor environmental electromagnetic radiation within a frequency band of interest; the electronic circuit comprises a radio frequency detection circuit and a non-resonant antenna that lacks resonant modes in the frequency band of interest; wherein the radio frequency detection circuit, in conjunction with the non-resonant antenna, facilitates the monitoring of environmental electromagnetic radiation within the frequency band of interest.

Abstract: Implementations of a battery pack with reduced magnetic field emission are provided. The battery pack is configured to reduce or eliminate the magnetic field normally generated while electrical current is being drawn from cylindrical-steel electrochemical cells (e.g., AA batteries) by a connected electrical device. In some implementations, a battery pack with reduced magnetic field emission comprises two or more electrochemical cells positioned in a coaxial configuration. In this coaxial configuration, the supply path is through the center of each electrochemical cell, and the return path is through a conductive sleeve positioned about each electrochemical cell of the battery pack. In this way, the supply path and the return path are as close as is physically possible, thereby minimizing any magnetic field generated between the conductors (i.e., between the electrochemical cells and their conductive sleeves).

Abstract: Implementations of a battery pack with reduced magnetic field emission are provided. In some implementations, the battery pack may be configured to reduce and/or eliminate the magnetic field normally generated while electrical current is being drawn from one or more cylindrical-steel electrochemical cells (e.g., AA batteries) by a connected electrical device. In some implementations, each electrochemical cell of a battery pack may include a conductive sleeve comprised of four conductive strips that are separated from the electrochemical cell by a thin insulating layer of material. In this way, the conductive sleeve provides a return path for electrical current that minimizes the loop area between the electrochemical cell and the conductive sleeve thereof. In some implementations, the four conductive strips of a conductive sleeve may be equally spaced 90 degrees apart and/or positioned longitudinally on a cylindrical-steel electrochemical cell, separated therefrom by the insulating layer of material.

Abstract: Implementations of an unmanned aerial vehicle (UAV) fuselage are provided. In some implementations, the fuselage comprises a frame having a shell removably secured thereto. The frame of the fuselage is made of printed circuit board (PCB) material that includes conductive tracks configured to conductively connect electrical components of the UAV. Due to the inherent rigidity of PCB material, the transfer of vibration loads to electrical components secured to the frame of the fuselage is minimized. While the shell is secured to the frame, an enclosure for any electrical components on the topside of the frame is formed. In this way, the encased electrical components may be protected from the environment (e.g., rain) and direct impact during a crash. In some implementations, the frame of the UAV fuselage may include a plurality of stiffening inserts that are positioned and configured to increase the rigidity of the frame.

Abstract: Implementations of a flight termination system for unmanned aircraft systems are provided. The flight termination system may comprise a ground-based flight termination transmitter (FTTx) located with an operator/observer, an airborne flight termination receiver (FTRx) located on an unmanned aircraft system (UAS), and a radio link connecting the FTTx and the FTRx. The FTTx is configured to communicate a TERMINATE FLIGHT message to the FTRx, once the TERMINATE FLIGHT message has been confirmed, the FTRx is configured to terminate the flight of the UAS by disabling the propulsion system thereof. In this way, the UAS (e.g., a drone or other unmanned aerial vehicle) may be prevented from flying away in an uncontrolled fashion. In some implementations, the dedicated radio link connecting the FTTx and the FTRx is independent of any radio link used to operate the UAS.

Abstract: Implementations of a battery pack with reduced magnetic field emission are provided. In some implementations, the battery pack may be configured to reduce and/or eliminate the magnetic field normally generated while electrical current is being drawn from one or more cylindrical-steel electrochemical cells (e.g., AA batteries) by a connected electrical device. In some implementations, each electrochemical cell of a battery pack may include a conductive sleeve comprised of four conductive strips that are separated from the electrochemical cell by a thin insulating layer of material. In this way, the conductive sleeve provides a return path for electrical current that minimizes the loop area between the electrochemical cell and the conductive sleeve thereof. In some implementations, the four conductive strips of a conductive sleeve may be equally spaced 90 degrees apart and/or positioned longitudinally on a cylindrical-steel electrochemical cell, separated therefrom by the insulating layer of material.

Abstract: A wireless sound transmission system for musical instruments includes a transmitter which can be mounted within the hollow body of the instrument. The transmitter is provided with a clamp which positions it adjacent the sound hole through which it is inserted. The transmitter may have a face contained to follow the outline of the sound hole. In a first embodiment, the transmitter is adapted to be mounted through and proximate a round sound hole. In a second embodiment, the transmitter is adapted to be mounted through an f sound hole.