Abstract: A low cost, high efficiency, end fed half wave folded dipole radio frequency antenna. The antenna includes an improved balun including a conductive tubular base secured to a conventional coaxial cable connector, a conductive tube telescoped relative to the base with a slot between the base and tube having an area corresponding to the extent the tube and base are telescoped together and two wires within the tube connected to the coaxial connector and each having an insulating sleeve. A folded wire loop antenna is connected to the wires and extends away from the balun. The loop may include coils to improve the gain of the antenna. A tubular insulating housing encapsulates the antenna.

Abstract: A panel shaped mesh-type structure is provided as one of the conductive or radiating members of a radio frequency mobile antenna fed by a coaxial cable. The mesh-type structure appears to decouple antenna currents in the coaxial cable at short distances, while maintaining performance as a transmitter at long distances. The radiating elements are surrounded by an insulating material which serves as a dielectric, further improving antenna performance and also serving as environmental protection. The radiating elements are made from readily available mesh and sheet stock materials aligned in a generally planar configuration attached to a either the shield or center lead of the coaxial cable. A small section of the central cable conductor is stripped of insulation and shielding, to serve as a miniature loading coil for the first plate-type conductive element. Shielding of the coaxial cable is attached directly to a mesh-type element serving as the counterpoise.

Abstract: A discontinuous panel shaped element forms one of the radiating dipole members of a radio frequency mobile antenna fed by a coaxial cable. The discontinuous element decouples antenna currents in the coaxial cable placed at short to medium distances from the element, while maintaining matched element performance as a long distance transmitter. The radiating elements are surrounded by an insulating material which serves as a dielectric, further improving antenna performance and also serving as environmental protection. The radiating elements are made from readily available sheet stock materials aligned in a generally planar configuration. The discontinuous dipole member is attached to the shield and the other dipole member is connected to the center lead of the coaxial cable. A small section of the central cable conductor is stripped of insulation and shielding, to serve as a miniature loading coil for loading the first plate-type conductive element.

Abstract: An alarm device for monitoring the watering needs of a plant which comprises a stick surmounted by a cylindrical box containing the electrical elements. The stick is buried in the soil of a pot holding a plant. The alarm device is powered by a battery easily installable and consists of a conductive probe detector located at the buried end of the stick. It also comprises a first integrated circuit which is switched by a backwards connected amplifier acting as a very high impedance switch which minimizes power consumption. The circuit emits a series of pulses when a threshold resistance level is reached. These pulses trigger a melody integrated circuit which produces a pleasant singing melody destined to draw the attention of the plant grower to the watering needs of a plant. The tune is repeatedly reproduced until the soil resistance detected by the probe detector has exceeded a threshold resistance level.

Abstract: An antenna system which operates over a wide spectrum of radio frequencies by utilizing a body of a vehicle as an antenna. The antenna system comprises a tuned impedance-matching coupler and a uniquely-configured floating, low-capacitance coaxial transmission line. In this arrangement, the outer conductor of the transmission line connecting the coupler to the vehicular body is severed at both ends. Thus, electrical connection between the coupler and the vehicle body is provided only by the transmission line's center conductor and the line's capacitive coupling. Antenna performance with the instant configuration exhibits improved voltage standing wave ratios and field strength as compared to conventional radio antennas.

Abstract: A radio antenna which operates over a broad frequency band, comprising a half-wave antenna tuned to a frequency beyond one cut-off frequency of the desired frequency band and a quarter-wave transformer tuned to a frequency beyond the other cut-off frequency at the other end of said band. The quarter-wave transformer acts as an impedance compensation device by canceling the reactive components of the half-wave antenna such novel reactive cancellation technique provides broadband performance while maintaining the antenna's gain and impedance characteristics.