Abstract:
A rod-shaped vehicle antenna according to the present invention, includes a rod-shaped antenna element having small- and large-diameter portions arranged alternately at regular pitches along the longitudinal direction of a rod-shaped conductor. When the outside diameter of each of the small-diameter portions is D1, that of each of the large-diameter portions is D2, and the pitch (length of each of the small- and large-diameter portions) is P, P is set within the following range:(D2.times.6).ltoreq.P.ltoreq.(D2.times.7). The ratioof D1 to D2, that is, D1/D2 is set within the following range:0.7.ltoreq.(D1/D2).ltoreq.0.85.
Abstract:
A parabolic, collapsible rooftop microwave antenna for direct satellite-to-consumer TV transmission pivots in the direction of the aperture axis about a horizontal pivot axis in response to excessive wind forces. The antenna has a cross-head theodolite-type mount adjustable for azimuth and elevation, with a horizontal pivot that provides axial displacement if the axial wind force exceeds a predetermined threshold force. This limits the torque transmitted to the roof on which the antenna is mounted to a reasonably low level. Various torque sensitive horizontal pivots are described including a torqued pivot bolt, torqued slide bolts disposed in arcuate slots for limit-stop action, shear pins for quick release action, and biased springs for collapse and self-restoration to the initial vertical position in response to transient wind force exceeding a threshold force set by the spring bias.
Abstract:
A microwave antenna has an elongated tubular radome made of a rigid nonconductive material, and an elongated unitary core made of a rigid dielectric material and telescoped within the radome in supporting engagement with the inner surface of said radome. A pair of conductive antenna elements are affixed to the surface of the core and extend along the length thereof. A microwave transmission line is connected to the antenna elements for transmitting electromagnetic energy to and from the elements.
Abstract:
Manually extendable telescoping antenna for a vehicle or vessel having a continuous core provided in the interior of the antenna to reduce mechanical/wind generated vibration noises. With the antenna extended, the core loosely touches the insides of the hollow telescoping elements and thus dampens and prevents creating a propagation of eigen-vibrations into the vehicle or vessel interior. The preferred core configuration may be a plastic band, plastic coated wire, or hollow or foam-filled plastic tube formed in a helical spiral secured at its lower end to a guide tube and at its upper end to the solid rod upper antenna section.
Abstract:
A rod-like protrusion of a vehicle body such as an antenna is provided with a projection at an outer peripheral portion intermediate the opposite ends thereof.
Abstract:
A shunt arrangement for processing the output current of an inductive current transformer having a wide dynamic range in which, in order to provide high-precision conversion with smaller currents, a power shunt is connected in series with a precision shunt which is connected in parallel with an overvoltage protection circuit containing a switchable semiconductor rectifier and a control circuit. The rectifier changes to a conductive state if the voltage at the precision shunt reaches a limit value. The control circuit contains a symmetric voltage limiting element which is constructed as a pair of limiting diodes or as a fullwave rectifier, the output of which is connected to a reference diode. In order to check the switching state of the overvoltage protection circuit, the series circuit including the power shunt and the precision shunt is connected in parallel with a series circuit consisting of a first bridge resistor and a second bridge resistor which, together with the shunts, form a balanced bridge circuit whereby, when the overvoltage protection circuit is inhibited, bridge circuit is monitored by a window discriminator.
Abstract:
A plurality of plates are rigidly affixed normal to forward and rearward surfaces along a major axis of a maximal diameter of an asymmetrical rotating antenna. In the presence of a wind, any aerodynamic forces tending to produce aerodynamic rotational moments on the antenna are reduced by the interaction between the wind, which produces a boundary layer on the antenna, and the plates, which affect the boundary layer.The net effects of the plates are to reduce the aerodynamic pressure difference between the forward and rearward surfaces of the antenna and to move the center of aerodynamic pressure closer to the center of rotation of the antenna. Due to these effects, the overall aerodynamic rotational movement on the antenna is reduced.
Abstract:
A pendulum for suspending a swinging article from a support structure includes an elongated core having longitudinal ends, enlarged tension heads disposed on each of the longitudinal ends and operable to be engaged and supported by the article and the support structure, a plurality of stiff toroidal elements strung on the elongated core, one of the toroidal elements being a first end toroidal element which is spaced from one of the tension heads, another of the toroidal elements being a second toroidal element which is spaced from the other of the tension heads.
Abstract:
A damper for detuning a vertical slender structure such as a monopole antenna, subject to wind induced vibrations, the damper having a ''''mushroom'''' shaped configuration with a cap mounted on one end of a flexible stem, the other end of the stem secured to the top of the structure enabling the cap to oscillate out-ofphase with the vibrating structure.