Abstract: An antenna enclosure and mounting arrangement for transmitting meter-related information from a remotely readable commodity meter positioned within a subterraneous pit to a remote reading station. The antenna arrangement includes an antenna housing having an outwardly tapered support portion that contacts an inwardly tapered support surface formed in the pit lid. When the antenna housing is mounted within the pit lid, the top surface of the antenna enclosure is flush with the top surface of the pit lid, while the antenna contained within the antenna housing is positioned slightly below the top surface of the pit lid.

Abstract: An antenna assembly (10) for subsurface utility metering equipment includes a disk-shaped radiating element (50) which is connected through a wire (51) having a self-inductance to a capacitor C and then to a ground plane (41) and a connector (31) for a coaxial cable (30) to provide an LC circuit for impedance matching of the antenna assembly (10) to a transmitter.

Abstract: A system for establishing radio communications between an in-vehicle unit and a road unit, including a signal controller in response to an output of an approaching vehicle detector, includes an on-board antenna forming part of the in-vehicle unit and provided to have directivity toward a road surface, a plurality of stationary devices, which form part of the road unit, provided in series between the signal controller and a terminator, and respectively coupled to the plurality of stationary antennas, and a plurality of stationary devices forming part of the road unit and provided in series between the signal controller and a terminator, and respectively coupled to the plurality of stationary antennas. Each of the plurality of stationary devices branches a signal transmitted thereto from the signal controller and applies the signal to the corresponding stationary antenna, and applies a signal transmitted thereto from the on-board antenna to the signal controller.

Abstract: A device for electronically marking a buried closure has a transponder and a shield or cover affixed to the transponder in such a manner that, when attached to the buried closure, the transponder is positioned at a predetermined location and orientation with respect to the known position and orientation of the buried closure. The shield can have a raised portion housing the transponder, and is preferably elongated with an arcuate cross-section, generally larger than the buried closure.

Abstract: An ERT (Encoder, Receiver, Transmitter) for monitoring the consumption of a metered commodity and having an ERT transmitter for transmitting a signal related to commodity consumption, the ERT transmitter being disposed internally in an ERT housing, the ERT housing providing for the transmission of RF energy therethrough, includes a passive radiator being disposed external to the ERT housing and being communicatively, capacitively coupled to the ERT transmitter and receiving RF wireless communications from the ERT transmitter for wireless transmission. The passive radiator includes a radiator device being disposed spaced apart from an ERT antenna and being communicatively, capacitively coupled to the ERT antenna for enhancing the reception and transmission of RF wireless communications by an ERT transmitter/receiver. A method of enhancing transmission and reception of wireless RF energy communications is also included.

Abstract: For use with an electric meter chassis having a dielectric housing protruding therefrom, an antenna for allowing electric meter circuitry within the chassis to communicate wirelessly through the dielectric housing and a method of manufacturing the same. In one embodiment, the antenna includes: (1) antenna elements, located within the dielectric housing and adapted to transmit and receive electromagnetic radiation and (2) a balance circuit, coupled to the antenna elements to cause the antenna elements to act as an antenna and couplable to an unbalanced output port of a wireless communication circuit, that balances an impedance of the unbalanced output port thereby to balance the antenna.

Abstract: A telemetry antenna system for transmitting data from underground utility meters includes a telemetry board, a radiator assembly connected to the telemetry board and a housing assembly for housing both the telemetry board and the radiator assembly. The radiator assembly preferably includes two metallic plates separated by an air gap dielectric and connected by a plurality of inductive shunts. Capacitive tuning pads are also included on the plates and are connected by shunts. The housing assembly preferably includes a cylindrical base having an integral annular ring. The base houses the telemetry board. The radiator assembly is operably connected to the telemetry board and is housed and located within a radome which sealingly engages the annular ring. The radome is sealingly secured to the annular ring of the base by a retaining ring which is tightly, releasably fastened to the annular ring of the base. The housing assembly may include additional elements such as an end cap, base lock, spine and/or bulkhead.

Abstract: The invention described herein relates to an antenna system which makes use of the waveguide properties of sea ice. The antenna system broadly includes at least one antenna wire extending along and preferably in contact with a sea ice surface for transmitting and receiving substantially vertically polarized radio waves. In a first embodiment, the antenna system has a single antenna wire connected to a tuner at one end and grounded to seawater at a second end. The antenna system also has a second length of wire attached to the tuner. The second wire passes through a hole in the sea ice and is also grounded to the seawater beneath the sea ice. In an alternative embodiment, only the second wire is grounded to the seawater beneath the sea ice. The single antenna wire in this embodiment is ungrounded. In yet another embodiment, the antenna system comprises a dipole antenna wire laying on the surface of the sea ice and being connected to a radio for transmitting and receiving radio signals.

Abstract: For use with an electric meter chassis having a dielectric housing protruding therefrom, an antenna for allowing electric meter circuitry within the chassis to communicate wirelessly through the dielectric housing and a method of manufacturing the same. In one embodiment, the antenna includes: (1) antenna elements, located within the dielectric housing and adapted to transmit and receive electromagnetic radiation and (2) a balance circuit, coupled to the antenna elements to cause the antenna elements to act as an antenna and couplable to an unbalanced output port of a wireless communication circuit, that balances an impedance of the unbalanced output port thereby to balance the antenna.

Abstract: An arrangement for radio utility meter reading processing of data acquisition for use with an automatic billing system involves a water meter transmitter antenna system installed at or near ground level in an outdoor environment. A radio frequency utility meter communication apparatus transmits utility meter data to a remote utility meter data collection unit from an underground pit box. The pit box receives a utility meter and has a generally ground level pit lid with an opening therethrough. An antenna element has an upper member extending at least partly through the pit lid opening and received thereabove. A depending base of the antenna element extends from the upper element and passes through the pit lid opening into the underground pit box. The antenna element is at least partly exposed to its surrounding environment.

Abstract: An identification and telemetry system including an interrogator (1) containing an interrogator antenna (2) for generating at an interrogation frequency, an interrogtion signal. The interrogation signal is adapted to excite over an electromagnetic coupling path (M1) at least one coded label (3) containing a label antenna (4) and a label microcircuit (5). The coded label is adapted to extract energy from the label antenna and to generate a label reply signal. The label reply signal is adapted to be conveyed to a label reply antenna and, via an electromagnetic coupling path, to a receiver in the interrogator. The label antenna is placed in proximity to a further antenna (6) being a parasitic antenna coupled electromagnetically (M2, M3) with the interrogator antenna and with the label antenna so as to enhance transfer of power between the interrogator and the coded label.

Abstract: A high dielectric is fixed to the side of an opening of a casing made from a good electroconductive material or is fixed to the side of an opening of an outer shell made from an insulator such as ferrite, and an antenna element is fixed on the back surface of the high dielectric. A material body, which has a small relative dielectric constant such as air is stored in the casing or the outer shell. The antenna element is sandwiched between the material body having the small relative dielectric constant and the high dielectric. The high dielectric is formed from a material having a relative dielectric constant that is close to the relative dielectric constant of a medium material such as clay, sand, water and the like in the underground or the underwater.

Abstract: A method for controlling the navigation of a towed linear acoustic antenna. Birds equipped with variable-incidence wings are fixed onto the antenna. Through a differential action, the wings allow the birds to be turned about the longitudinal axis of the antenna so that a hydrodynamic force oriented in any given direction about the longitudinal axis of the antenna is obtained. Power and control signals are transmitted between the antenna and the bird by rotary transformers. The bird is fixed to the antenna by a bore closed by a cover. The bird can be detached automatically as the antenna is raised so that the antenna can be wound freely onto a drum. This method allows the full control of the deformation, immersion and heading of the antenna.

Abstract: An antenna adapted for surface deployment is provided. A coaxial feedline, erminated at one end thereof at a feedpoint, has a center conductor and a shield at ground potential. A continuous length of antenna wire having first and second ends is electrically connected at its first end to the center conductor at the feedpoint. A first portion of the continuous length is spooled adjacent the first end. A second portion of the continuous length is deployed from the first portion by means of tension at the second end. The second portion extends to the second end along a substantially straight line away from the first portion. The second portion is typically at least as long as the first portion. The first portion serves as a variable tuning inductor for the antenna as the second portion is deployed therefrom.

Abstract: An enclosed antenna assembly having a non-rigid, floating connection between an aluminum tray and a radome along the length of the assembly. The non-rigid, floating connection along the length of the antenna assembly provides a seal that is not damaged or degraded as a result of thermal expansion and contraction of the dissimilar materials. The tray and radome are joined along their length by a tongue and groove type connection, which allows free movement along the major axis. A top end cap provides the only rigid connection between the tray and the radome. A bottom end cap is fastened only to the radome. The design of the keyway and the top end cap prevent direct water intrusion. The bottom end cap includes weep holes to allow condensation to escape from the interior of the antenna assembly.

Abstract: A sealed housing for a transponder unit (10) in a utility meter pit enclosure has a tube (28), approximately 33/4 inches long and 11/2 inches in diameter, in which transponder electronics carried by a circuit board and an antenna are inserted from the bottom and fitted into guide structures (42, 47) and then a body of epoxy sealant (50) is used to seal and form a recessed lower end of the tube (28) which, in use, may be immersed in water within a subsurface pit enclosure (11). The tube (28) is attached to a cap (22) and suspended through a hole (29) in the pit lid (15). A clamping member (38) is threaded onto the lower end of the tube (28) for trapping a portion of the pit lid (15) between said clamping member (38) and the cap (22). A method of assembling and sealing the unit (10) is also disclosed.

Abstract: A preferred embodiment of the invention includes a passive type marker device (10) with a stem (11) placed in contact with or adjacent to a hidden object (14) or other particular point, providing for visual and/or electronic identification of such. Measurements (20) and directional markings (24) imprinted along the stem face indicate distance to the object. An alignment saddle (12) astride the object self aligns an arrow opening (18) through the stem defines the object's orientation relative to its surroundings. The device's color indicates object type such as red for electric, blue for water, etc. A marker dial (46) for optional placement in a finished surface also defines the object depth. The dial is indexedly installed atop an alignment indicating adapter (44) which is self aligned by insertion into the arrow opening of the stem. An arrow and indicia atop the adapter indicates the orientation and size of the object.

Abstract: A passive electronic marker uses a plurality of ferrite cores to increase locating range, and the cores are attached in such a manner that a slight bend of the marker at a junction between the cores does not significantly affect the markers performance. Stable locating range and tuned frequency are achieved by controlling the air gap between the cores, using specially shaped ends or a sphere which is positioned between the cores. By selecting the appropriate geometry for the core ends and winding interconnections, the first order permeability across the air gap is held constant during bending of the marker.

Abstract: An RF control system characterized by the use of remotely located low profile radio frequency antennas which are concealed in conventionally appearing valve boxes or similar housings. The system includes a central control station, including a central RF transmitter, and a plurality of remote station, each including an RF receiver and antenna. A preferred remote station includes a valve box or similar housing of the type intended to be at least partially buried in the earth. The housing has a peripheral wall defining an access opening and a removable cover for bridging the opening. A directional discontinuity ring radiator (DDRR) antenna is physically mounted in the valve box housing on the interior side of the cover and is connected to a receiver, preferably also physically mounted on the cover.

Abstract: An antenna is described having a generally elongate radiating part (10) and a reflective plane (11)juxtaposed and generally parallel to the elongate radiating part. The radiating part has a free end (15), a ground connection (13) remote from the free end and a feed connection (16) between the free end and the ground connection. The ground connection is mounted on the reflective plane (11), giving electrical ground connection and mechanical support. A method of manufacture of an antenna is also described involving breaking off an extension portion to suit the required frequency of operation.

Abstract: A radio antenna for mounting in the lid of a water meter box and forming part of a remote meter reading system comprises an annular conductive plate and a circular conductive plate which are coaxial with and parallel to each other and spaced apart to define a slot, the circular plate serving as a ground plate. The antenna has an input in the form of a conductive pillar interconnecting the two members, with a drive input at a selected point along the length of the pillar and a second input on the ground plate. A variable tuning capacitance is disposed between the plates diametrically opposite the conductive pillar. The ground plate also serves for locating the lid in undergrowth or under snow using a metal detector.

Abstract: There is presented an antenna assembly comprising an elongated mast slida mounted in a support structure. A first electric motor is disposed at a proximal end of the mast for moving the mast along the axis of the mast, and a second electric motor is disposed at a distal end of the mast for moving the mast rotatively about its axis.

Abstract: Maintenance information is collected by a sensor on an electric power cable installed in a manhole. The information is transmitted to a radio transmitter which is positioned in a vicinity of a bottom plane of an inner lid in an opening of the manhole. The information is transmitted by the radio transmitter, and received by a receiving antenna mounted on a bottom plane of the inner lid. On a top plane of the inner lid, an electrode, a connecting lead or a transmitting antenna is provided to be connected to the receiving antenna by an impedance matching circuit. The information is supplied to an outer lid in the opening of the manhole by the opening of the manhole by the electrode using a spatial coupling capacitance relative to the outer lid, or the connecting lead directly connected to the outer lid. Thus, the information is transmitted as a radio signal by the outer lid functioning as an antenna. Otherwise, the information is radiated below the outer lid by the transmitting antenna.

Abstract: A structure comprises a first component subject to loading and connected to a second component via a load transmitting member so that the loading exerted by the first component is imposed on the second component. The first component includes a surface secured to a complementary first surface of said load transmitting member and the second component includes a surface secured to a complementary second surface of said load transmitting member. The load transmitting member and the second component are formed of materials having relatively superior and inferior mechanical properties, respectively and the area of said surface of the second component is greater than the area of said surface of the first component. The first component may be an antenna and the second component a radome for a submarine formed of, for example, syntactic foam. The load transmitting member may be formed from fibre-reinforced plastics material.

Abstract: A method and apparatus is provided for measurement-while-drilling utilizing improved antennas. An elongated tubular member is provided with an outer peripheral surface having a contoured portion defining a plurality of discrete communication regions of reduced radial dimension. An antenna pathway is defined in the elongated member substantially transverse to the plurality of discrete communication regions. An antenna member is partially disposed in the antenna pathway with portions of the antenna member extending out of the elongated member at the plurality of discrete communication regions to facilitate communication of electromagnetic energy. In a reception mode of operation, the antenna member detects electromagnetic energy in the wellbore and generates a current corresponding thereto. If operated in a transmission mode of operation, the antenna member emits electromagnetic energy in the wellbore in response to an energizing current.

Abstract: An electromagnetic propagation tool using magnetic dipole antennas comprising small current loops having characteristics of a point dipole is presented. The electromagnetic tool comprises a drill collar segment having at least one dipole antenna for each transmitter and/or receiver antenna. The dipole antennas are disposed within pockets formed in the drill collar segment.

Abstract: An electromagnetic propagation tool using magnetic dipole antennas comprising small current loops having characteristics of a point dipole is presented. The electromagnetic tool comprises a drill collar segment having at least one dipole antenna for each transmitter and receiver antenna. The dipole antennas are disposed within pockets formed in the drill collar segment.

Abstract: A remote meter reading arrangement in which utility consumption data accumulated in an electronic metering unit located within an underground enclosure is transmitted via radio frequency signals to a handheld data collection unit or to a mobile data collection unit carried in a vehicle. An assembly for installation in the underground enclosure includes an antenna enclosure, a transponder enclosure and means for enclosing and protecting an antenna within the antenna enclosure and a transponder within the transponder enclosure. Two embodiments are disclosed.

Abstract: An apparatus is provided for erecting and stowing a communications antenna rom an underwater buoyant cable. In its stowed position, the antenna is approximately parallel to the cable. In its erected position, the antenna is approximately perpendicular to the cable. A hinge, spring biased to maintain the antenna in its stowed position, is connected to the cable and to one end of the antenna. A shape memory alloy actuator is connected to the cable and the antenna. The actuator overcomes the spring bias of the hinge to raise the antenna to its erected position when energy of activation is supplied thereto. Further, the actuator allows the spring bias of the hinge to return the antenna to its stowed position when the energy of activation is removed therefrom.

Abstract: A fiber reinforced polymer matrix composite shell for covering the elastomeric layer surrounding the antenna of a measurement-while-drilling borehole formation evaluation tool is disclosed. The shell protects the elastomeric layer and associated antenna from wear and abrasion. If damaged during drilling, the shell may be replaced at the drillsite with minimal downtime.

Abstract: Antennas designed for use in producing effective electromagnetic capture zones for transponders mounted on moving vehicles. The antenna systems disclosed are principally designed to be mounted at or near the surface of a roadway carrying the vehicle whose transponder is to be interrogated. A principal advantage of the antennas of the invention is minimal interference with normal operation of the road and greatly reduced cost of installation when used in providing vehicle identification, toll collection, or communication with the transponder carrying vehicle.

Abstract: Electrode used for one pole in underwater transmission of high-voltage direct current, an insulated cable being used for the other pole, such electrodes being adapted to be stationary on the bottom of the sea to serve as the anode and the cathode, respectively, while the sea-water constitutes the electric conductor therebetween. What characterises the invention is that the electrode comprises at least one layer (1) of a flexible, electrically conductive material which preferably is resistant to chlorine-alkali, said layer (1) being enclosed between protective structures (2,3) of a flexible, mechanically resistant material which preferably is resistant to chlorine-alkali, at least one protective structure (2) having openings (4) which are positioned across the surface thereof and through which the sea-water comes into contact with the layer (1).

Abstract: An all-dielectric cable (20) or object which is destined to be buried is provided with at least one electronically resonant marker (44). After the cable or object is buried, a tradesperson may locate the cable or object by causing an electromagnetic signal (71), which comprises at least one frequency to be transmitted by a transceiver (60) and to be induced into the electronically resonant marker associated with the cable or object. A return signal (73), which is radiated by the electronically resonant marker at a frequency different from the at least frequency, is received by the transceiver. Characteristics of the return signal provide useful information for the determination of the location of the buried cable or object.

Abstract: A passive inductively and capacitively loaded antenna is shown which is retained within a closed cel styrene foam enclosure. A method for detecting buried utility components utilizing such in combination with underground radar is also shown.

Abstract: A modified subterranean antenna structure for use in boreholes that pivotally balances a separate core member within the hollow interior of a fixed winding member in order to filter out mechanically induced vibrations from the core. The mechanical natural resonant frequency of the core is reduced and becomes less than the lowest electromagnetic signal frequency intended to be transmitted to and received by the subterranean antenna. In this way, mechanically induced vibrations will not create mechanically generated frequency signals sympathetic to the frequencies chosen for the antenna communication band frequencies.

Abstract: A peak radiated energy locator includes a plurality of broadband antennas mounted on a mast positioned between the radiating device and a calibrated antenna located to receive the radiated energy. The vertical angle at which peak radiated energy occurs is determined by establishing the broadband antenna receiving energy at a level that exceeds the levels of all the other broadband antennas and providing the vertical angle corresponding to the height of that antenna. The mast and broadband antennas are then removed, the calibrated antenna is positioned at a height corresponding to the determined vertical angle and an accurate measurement of the peak radiated energy is made.

Abstract: A modified subterranean antenna structure for use in boreholes that pivotally balances a separate core member within the hollow interior of a fixed winding member in order to filter out mechanically induced vibrations from the core. The mechanical natural resonant frequency of the core is reduced and becomes less than the lowest electromagnetic signal frequency intended to be transmitted to and received by the subterranean antenna. In this way, mechanically induced vibrations will not create mechanically generated frequency signals sympathetic to the frequencies chosen for the antenna communication band frequencies.

Abstract: The homing technique for directing an in-ground boring device through the ground from its particular location to a specific target point is disclosed herein. In accordance with this technique, an electromagnetic dipole field containing a predetermined homing signal is generated at the boring device and detected by a specifically configured receiving antenna arrangement at the target point or, in a preferred embodiment where the target point is below ground, at a ground level point directly above or beyond the target point. Means are provided in response to detection of the homing signal for producing an internal electrical signal containing certain information relating to the actual path taken by the boring device as compared to the path or course leading to the target point. The information from this latter signal is then transmitted by means of electromagnetic waves to a remote location where it is used to steer the boring device on a course toward the target.

Abstract: A marker for positioning near a buried object wherein the marker can be detected to locate the buried object. The marker includes a passive resonant type antenna which becomes inoperative when the initial position for the buried marker is changed. A lead wire and/or a mercury switch that is a part of the antenna serve to make the antenna inoperative due to such change in the initial position of the marker.

Abstract: A novel underground guided wave antenna system and method. The system comprises at least one substantially linear, electrically insulated radiating element which is buried in the earth so as to lie no more than approximately one skin depth below the earth's surface. The effective electrical length of each radiating element is equal to at least one-third of the wavelength, as measured in the earth, of the electromagnetic signals being propagated; and the effective electrical length of a radiating element may be made greater than its actual physical length, if desired, by providing tree terminations at the ends of such radiating element.The efficiency of the system can be increased, particularly when operating at high frequencies, by surrounding the radiating elements with a low loss dielectric substance, such as, for example, crushed rock.

Abstract: An antenna element such as a monopole, dipole or loop antenna is located in the earth or on the floor of the sea so as to receive pre-earthquake electromagnetic waves generated prior to the occurrence of an earthquake. Unwanted noise waves propagating in the air such as man-made noise are effectively eliminated by a reflector laid on the surface of the earth or by the sea water and only the required pre-earthquake waves are detected by the antenna element, whereby earthquakes can be predicted reliably.

Abstract: A wireless communication system and method for employing underground or low profile surface deployed current drivers for inducing ground currents in the earth which define loop antennas for sending and receiving electromagnetic signals propagated through the atmosphere over a wide bandwidth. The system uses a current driver whose impedance is adjusted so that it matches the impedance of a transmitter/receiver connected thereto. The current driver is capacitively coupled to the surrounding ground so that the current driver and the earth effectively function together as a vertical plane polarized antenna which propagates a vertically polarized electromagnetic signal. The system can be operated using either a single current driver or, where increased signal gain is desired, using an array of current drivers that are spaced in parallel. A undirectional vertically polarized signal may be produced by shortening the length of one current driver conductor with respect to the other arm.

Abstract: A geodetic fixpoint system comprising plural terrestrial fixpoints marked by subterranean fixpoint markers with resonance circuits. The markers reveal themselves by a virtual vertical axis searchable by a surface search detector and the fixpoints are found by intersection between the virtual vertical axis and the ground surface. The markers are mounted with spacing sufficient to allow any fixpoint, when marked visually, to be visible from at least one other fixpoint of the system. The surface search detector generates a frequency which is a nominal resonance frequency of the resonance circuits of the markers, and receives the generated frequency from the markers to search for the virtual vertical axis.

Abstract: A transportable wireless communication system and method for employing lightweight, compact, low profile surface deployed current drivers which are capable of rapid deployment and quick retrieval and which are used for inducing ground currents in the earth so as to send and receive electromagnetic signals propagated through the atmosphere over a wide bandwidth. The impedance of the current driver and earth is adjusted to match the impedance of a transmitter/receiver connected thereto. The current driver is capacitively coupled to the earth so that the current driver and the earth effectively function together as a vertical plane polarized antenna which propagates a vertically polarized electromagnetic signal. The system utilizes either a single current driver or, where increased signal gain is desired, an array of current drivers spaced in parallel. A unidirectional vertically polarized signal may be produced by shortening the length of one current driver conducting arm with respect to the other arm.

Abstract: A towable broadband submarine antenna system for deployment in the ocean ing operation comprises an antenna element including a metallic termination tip and a length of single conductor buoyant cable. A broadband amplifier connects to the antenna element and provides separate paths for the VLF/LF and the HF/VHF signals with amplification provided only to the HF/VHF signals. The signal from the broadband amplifier is further transmitted on a coaxial cable.

Abstract: A spokewheel convertible buoyant cable antenna is comprised of a multipliy of machined metal and molded or extruded plastic components. These parts are designed to be quickly assembled in such a way as to be watertight at all practical depths. They have sufficient tensile strength so as to be towed at reasonable speeds, either on the surface or submerged. The assembly may be disassembled in the field, for repairs. The design also allows it to be easily inserted into a conventional XU-4 type antenna thereby doubling the usefulness of the standard BCA system when this spokewheel capability is needed. The spokewheel version may be quickly converted back to the standard XU-4 version.

Abstract: An antenna structure for transmitting signals from a transmitter at the bottom of a drill well to the earth's surface which includes a drill collar extending in an axial direction and which is adapted to support a transmitter therein, a cylindrical metal sleeve for forming part of an antenna for electromagnetic wave transmission, the cylindrical metal sleeve being disposed around the drill collar and adapted to be connected electrically to the transmitter, an insulating sheath between the cylindrical metal sleeve and the drill collar and a plurality of metal rings disposed between each opposite axial end of the cylindrical metal sleeve and confronting opposite axial end of the insulating sheath. The cylindrical metal sleeve has a diameter greater than the diameter of the drill collar and the insulating sheath has an axial length longer than the axial length of the cylindrical metal sleeve.

Abstract: Radio frequency antenna is buried in the earth with its top substantially flush with the surface with a significant portion of the antenna buried therebelow. The antenna is configured so that, if much of the top is removed, as by blast, the remaining portion of the antenna remains operative without significant functional deterioration.

Abstract: A passive marker device including a tuned circuit enclosed in a housing which includes a base member with an upstanding rim with a cover member bonded to the rim and to a central portion of the base member. An opening is provided that extends through the housing at the central portion of the housing. A boss extends from the central portion of the base member to the cover member. The boss is recessed on the side of the base member that is away from the cover.

Abstract: A VLF-VHF broadband in-line amplifier forms a portion of a towable buoyant able antenna system that is deployed in seawater from submarines. The amplifier is located between an antenna system and a coaxial cable. The coaxial cable is connected to the submarine. The VLF-VHF broadband in-line amplifier provides substantially uniform amplification for the frequency range of 10 kHz-160 MHz on signals received from the antenna system. The amplified signals are then transmitted to the submarine over the coaxial cable.