Bell System Technical Journal, 10: 2. April 1931 pp 243-264. Overseas Radio Extentions to Wire Telephone Networks. (Espenschied, Lloyd; Wilson, William)
Topics: transmission, radio, telephone, circuits, circuit, wire, atlantic, transmitting, transatlantic,...
R&D Report 1970-07 : Medium-frequency sky-wave broadcasting: Effect of polarization on interference P. Knight Horizontal transmitting aerials may be used at medium frequencies for short-distance broadcasting via the ionosphere. The use of horizontal rather than vertical aerials affects the strength of interfering signals which propagate at night to greater distances. It is shown that less interference is caused in temperate latitudes when horizontal aerials are used, while in tropical...
Topics: horizontal, polarization, aerial, coupling, wave, radiated, aerials, vertical, ionosphere,...
R&D Report 1955-01 : Mutual interference between naval radar and VHF FM broadcasting in Band II -- B.B.C. and A.S.R.E. tests R.A. Rowden, D.G. Beadle, G.I. Ross, D.E. Susans, K.H. Green Tests were carried out by the Admiralty Signal and Radar Establishment and the B.B.C. Research Department to investigate the mutual interference likely to arise from the co-channel operation of naval radar sets Type 281 and Type 960 with VHF FM broadcasting stations. Specific measurements and observations on...
Topics: interference, type, radar, wrotham, strength, broadcasting, tests, field, set, naval, radar sets,...
Bell System Technical Journal, 12: 2. April 1933 pp 197-227. Some Results of a Study of Ultra-Short-Wave Transmission Phenomena. (Englund, C.R.; Crawford, A.B.; Mumford, W.W.)
Topics: antenna, transmission, field, intensity, hill, polarization, transmitter, reflection, airplane,...
R&D Report 1963-17 : Method for estimating the protection requred by a television service against interference from several sources. E. Sofaer An engineer planning a television service in a channel already occupied by other transmissions must be able to estimate the combined effect of interference from several sources Severity of interference is judged subjectively, and an ideal method of making the estimate would be one which gave the answer directly in terms of a subjective judgement....
Topics: probability, deviation, logarithmic, location, interference, variations, tion, standard, field,...
R&D Report 1954-18 : Channel Islands television site test. R.D. Pittilo, S.J. Ashdown, J. Hall Tests have been made from a site at Les Platons on the north coast of Jersey. It was found that a transmitter sited here would serve both Jersey and Guernsey adequately.
Topics: strength, guernsey, field, transmitter, contours, islands, jersey, channel, les, site, islands...
R&D Report 1964-35 : Service areas of the Holme Moss television and VHF sound transmitters J.H. Causebrook, J.A. Carter A brief summary of the installation of Holme Moss Relay Station
Topics: field, vision, sound, strength, medi, median, holme, transmitters, town, moss, moss television,...
R&D Report 1966-24 : Re-radiation from masts and similar obstacles at radio frequencies P. Knight Transmissions from v.h.f. and u.h.f. aerials may be distorted by re-radiated signals if tall obstacles such as masts or towers are situated in the service area. The amplitudes of these re-radiated signals are governed by factors discussed in this report.
Topics: obstacle, aerial, cylinder, reflexion, field, phase, values, coefficient, equation, radiation,...
R&D Report 1956-34 : Investigation of poor reception from Crystal Palace in the Reigate and Horsham areas B. Davis, G.D. Monteath, G.I. Ross An investigation has been made into complaints of poor reception, in the Reigate, Redhill and Crawley and Horsham districts, of the Crystal Palace television transmitter installation, in its temporary conditions. The field strength in these areas is lower than the value predicted from site test measurements and the prevalence of flutter fading due to...
Topics: palace, crystal, strength, field, tower, alexandra, flutter, horsham, measurements, aircraft, site...
R&D Report 1956-31 : A comparison between Band I and Band III reception in the London area. B. Davis This report presents all relevant data obtained during tests which have recently been carried out by the BBC Research Department on Band III transmissions and gives comparisons between the useful service areas of Band III and Band I transmitters using present techniques.
Topics: band, iii, interference, aircraft, frequency, field, strength, flutter, vehicles, receiving,...
R&D Report 1957-09 : The service area of the temporary television transmitter at Sandale. D.W. Taplin, D.F. Cooney The report gives the results of a survey of the service area of the temporary television transmitter at Sandale, Cumberland. It is shown that a service is provided to many parts of Cumberland and to a small area of south-west Scotland.
Topics: transmitter, temporary, sandale, horizontal, television, aerial, penrith, tbe, television...
R&D Report 1956-36 : The Service area of the Les Platons Television Transmitter G.I. Ross, A.R. Williams This report gives the results of field strength survey of the Les Platons television transmitter. The service provided in Jersey is very good. Guernsey, on the whole, has a good service, although a small area in the west of the island receivers a field strength of less than 100 uV/m. Ninety-seven per cent of the population of the Channel Isles is within the 0.1 mV/m field strength...
Topics: les, platons, strength, guernsey, median, jersey, transmitter, field, field strength, channel, les...
R&D Report 1960-30 : Long distance overland tropospheric propagation measurements at 495 and 560 Mc/s D.W. Taplin, K.H. Green, S.J. Ashdown, I. Rhodes, J.W. Stark This report presents the results of field strength measurements on uhf transmissions on 495 Mc/s and 560 Mc/s over land paths at distances up to 294 miles (473 km). These measurements extended over a period of approximately three years and have been used in the preparation of field strength/distance curves for various percentages...
Topics: field, measurements, strength, transmissions, iii, beddingham, receiving, mursley, pike, pontop,...
R&D Report 1960-04 : Television and VHF sound transmitter site tests at Nether Button, Orkney. D.W. Taplin This report gives the results of television and v.h.f. sound transmitter site tests at Nether Button, Orkney. With the effective radiated powers (e.r.p.s) proposed at Nether Button a satisfactory service will be provided to a very large proportion of the population of Orkney and the north coast of Caithness, including most of Thurso. Reception tests of the Meldrum television...
Topics: nether, orkney, transmitter, strength, television, tests, site, field, transmission, meldrum,...
R&D Report 1970-11 : Combined effect of several interfering signals J.W. Head When a site is considered for a new radio or television transmitter the best available assessment of interference expected from existing transmitters operating on or near the same frequency is required. This involves calculation of the combined effect of two or more interfering signals simultaneously present. The information available about each interfering signal is its distribution in time, that is, the...
Topics: signals, signal, distribution, quantized, correlation, probability, resultant, interfering,...
R&D Report 1977-05 : Airborne television transmission M.W. Harman, J. Middleton Certain countries with favourable climates have already obtained satisfactory results using high flying aircraft and captive balloons to provide a rapid solution to their television coverage problems. In general, these techniques have been considered or applied in situations with no existing ground station network or where unused parts of the radio spectrum are available for broadcasting. While the United...
Topics: aircraft, airborne, aerial, transmitting, field, strength, transmitter, ground, flight,...
R&D Report 1975-33 : A field strength measuring receiver for Band II D.G. Beadle, J.A. Fox This Report describes a receiver designed for the investigation of reception conditions for both monophonic and stereophonic broadcasts using the pilot tone stereo system in the band 87-108 MHz. The design is intended to replace two earlier receivers and, in addition, provides commercial quality stereo reception for assessment of the stereo service provided in any area. These requirements are somewhat...
Topics: receiver, khz, multipath, calibration, mhz, output, oscillator, frequency, display, strength,...
R&D Report 1982-16 : Radio-frequency ignition hazards: the choice of reference aerial for available-power calculations. P. Knight Structures in petrochemical plants can act as receiving aerials and extract power from radio waves; if a spark is generated there is a risk that flammable vapours might be ignited. The power available from a structure is closely related to that available from a small loss-free reference aerial in the same location, the ratio of the two powers being known as the...
Topics: aerial, power, ground, extracted, equation, flux, aerials, small, loop, dipole, radiation...
R&D Report 1978-08 : Channel Islands link for BBC television programmes: the Alderney receiving installation. G.H. Millard Colour television programmes for the Channel Islands are obtained from the mainland by direct reception of UHF transmissions on a long oversea path. The consequent variability and distortion of the signal has demanded special features of the receiving installation which are described in this report.
Topics: aerial, channel, bbc, interference, array, alderney, signal, aerials, parabolic, diversity, aerial...
Data waveforms of the rate of change of electric flux density obtained during two lightning strikes to an aircraft specially instrumented for lightning electromagnetic measurements are presented. The aircraft was operating in a thunderstorm environment to elicit strikes. The instrumentation system configuration, flight conditions, and strike scenario showing probable lightning path on the aircraft are described. The waveforms, which were obtained at a 10 nanosecond sample interval, indicate...
Topics: NASA Technical Reports Server (NTRS), ELECTROMAGNETIC MEASUREMENT, ELECTROMAGNETISM, FLIGHT...
R&D Report 1956-09 : Low power television transmitters -- Site tests in Londonderry. C.J. White, D.W. Taplin, R.S. Sandell, J. Hall Two sites, Sheriffs Mountain and Lisdillon, have been tested. Of these the Sheriffs Mountain site will provide the better service and, in conjunction with the Divis transmitter, coverage over most of Northern Ireland will be achieved with the exception of the Enniskillen area. Reception tests indicate that the field strength of Divis at Sheriffs Mountain should...
Topics: sheriffs, divis, mountain, site, lisdillon, contour, tests, londonderry, aerial, field, principal...
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201
Jun 1, 2010
06/10
by
Mayaud, P. N
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Estimate of decrease with altitude in field S due to diurnal variation
Topics: DIURNAL VARIATIONS, FIELD STRENGTH, DIURNAL VARIATION, FIELD STRENGTH
R&D Report 1962-07 : The use of overhead power lines to provide a VHF broadcasting service. R.G. Manton, P. Knight The provision of an adequate television or v.h.f. f.m. service in a mountainous area presents considerable difficulty since a large number of low-power relay stations is required. A possible alternative is the use of existing over-head power lines for the both the transmission and radiation of the services throughout an area. In this report, the service area which could be...
Topics: power, radiation, lines, propagation, cross, spaced, dipole, field, currents, dipoles, power flow,...
R&D Report 1956-37 : Temporal variation of the ground-wave field strength of medium frequency broadcasting transmitters. M. Deakin, E. Sofaer, R.A. Rowden This report surveys the results of measurements made by the BBC Research Department and comments on earlier work by others. It is concluded that the effect, which is due apparently to a variety of factors not yet fully investigated, is no longer of significant importance in broadcasting.
Topics: strength, variation, field, variations, temporal, wave, conductivity, transmitters, signal,...
R&D Report 1977-45 : The relationship of VHF car radio reception quality to field strength at 10 metres. D. Vinnell The results of practical tests of reception in cars have been used to estimate the field-strength at 10m above ground required for a satisfactory service. They showed considerable receiver-to-receiver variations, with more recent receivers incorporating active interference-limiting circuits showing a marked advantage. The suggested limit for a satisfactory service is 60...
Topics: field, strength, polarized, aerial, radio, assessments, transmissions, grade, receiver, subjective,...
R&D Report 1974-36 : A fixed-tuned medium-wave receiver suitable for a road traffic information service D.E. Susans This report describes a medium-wave fixed-tuned receiver intended for use in a motorcar for the reception of a road traffic information service. Its main features are long-term tuning stability, good automatic gain control over the working signal-level range, and a carrier-level-operated muting circuit to suppress the output on weak input signals. The receiver and loudspeaker...
Topics: receiver, mute, circuit, input, amplifier, traffic, output, muting, traffic service, khz, muting...
R&D Report 1970-22 : Television reception over sea paths: The effect of the tide P.A. Levan, D.W. Taplin, C.P. Bell On oversea paths within the horizon, the received field strength is the vector sum of a direct component and a component reflected from the surface of the sea. If the level of the sea varies, the relative phase of the reflected component alters and causes field strength variations. To determine the effect of these variations on UHF television reception, a series of...
Topics: fading, aerial, field, strength, receiving, reflection, path, vertical, tidal, variations, path...
R&D Report 1957-04 : The service area of the Pontop Pike television transmitter. D.W. Taplin, D.F. Cooney, I. Rhodes A field strength survey of the Pontop Pike television transmission has been carried out. The service provided conforms well with that expected from site test measurements. The heavily populated industrial areas of Tyneside area well served. The Tees-side area is provided with a fair service.
Topics: pontop, pike, transmitter, transmission, strength, contours, field, median, pontop pike, populated,...
R&D Report 1986-04 : Review of VHF Band I field strength prediction. R.S. Sandell, J. Malcolm-Coe The report describes the results of a review of VHF Band I field strength measurements and prediction methods. Most of the measurements were made by the BBC, and many were used in the early Nineteen-sixties to prepare CCIR propagation curves. Modern computational methods have permitted a fuller analysis of the data than has been possible previously. This has led to conclusions about the...
Topics: ccir, prediction, terrain, bbc, antenna, propagation, field, measurements, strength, height,...
Preliminary results of observations of solar coronal bright points acquired simultaneously from ground based observatories at the radio wavelength of 20 cm and in the He I wavelength 10830 line on September 8, 1985, are reported. The impetus for obtaining simultaneous radio and optical data is to identify correlations, if any, in changes of the low transition-coronal signatures of bright points with the evolution of the magnetic field, and to distinguish between intermittent heating and changes...
Topics: NASA Technical Reports Server (NTRS), HEATING, RADIO ASTRONOMY, SOLAR CORONA, SOLAR GRANULATION,...
A novel type of lightweight space radiator has been proposed which employs internal electrostatic fields to stop coolant leaks from punctures caused by micrometeorites or space debris. Extensive calculations have indicated the feasibility of leak stoppage without film destabilization for both stationary and rotating designs. Solutions of the evolution equation for a liquid-metal film on an inclined plate, using lubrication theory for low Reynolds numbers, Karman-Pohlhausen quadratic velocity...
Topics: NASA Technical Reports Server (NTRS), ELECTROSTATIC CHARGE, FLOW MEASUREMENT, VELOCITY...
R&D Report 1963-34 : Service areas of the Redruth television and VHF sound transmitters. R.C. Vercoe, J.H. Causebrook, J.A. Carter The results of field strength surveys of the television and v.h.f. sound transmission are given in this report.
Topics: redruth, transmitters, television, sound, aerial, exceeded, field, strength, field strength, tiers,...
R&D Report 1986-18 : LF and MF sky-wave propagation: a comparison of measurements made at sunset and sunrise P. Knight, W.F. Williams The strength of LF and MF sky-wave signals is greatest at night and weakest during the day. The increase in field-strength which occurs at sunset has been extensively studied but less is known about the decrease which occurs at sunrise. This Report describes a series of measurements made by members of the European Broadcasting Union (EBU) which covers both...
Topics: measurements, sunrise, sunset, field, strength, seasonal, curve, ccir, khz, curves, ccir diurnal,...
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209
May 28, 2011
05/11
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NON
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A method for fabricating soft tissue implants using a mold. The cavity surface of an initially untextured mold. made of an organic material such as epoxy. is given a thin film coating of material that has pinholes and is resistant to atomic particle bombardment. The mold cavity surface is then subjected to atomic particle bombardment, such as when placed in an isotropic atomic oxygen environment. Microscopic depressions in the mold cavity surface are created at the pinhole sites on the thin...
Topics: MAGNETIC FIELDS, VAPORS, SPACE TRANSPORTATION, SIMPLIFICATION, SENSITIVITY, POSITIONING, LIQUID...
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May 6, 2010
05/10
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Someroski, F. W.; Tischer, F. J
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Field intensity, guide wavelengths, and attenuation of grooved waveguide
Topics: ATTENUATION COEFFICIENTS, WAVEGUIDE, WAVELENGTH, FIELD EMISSION, FIELD STRENGTH, GROOVES,...
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Jun 21, 2010
06/10
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Boyko, L. V.; Korshak, V. V.; Pavlova, S. A.; Vinogradova, S. V.; Vygodskiy, Ya. S
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Synthesis and molecular structure of thermostable soluble polyimides
Topics: DIRAC EQUATION, PAIR PRODUCTION, PERTURBATION THEORY, WAVELENGTHS, ELECTROMAGNETIC FIELDS, MAXWELL...
R&D Report 1960-11 : A moblie laboratory used in the U.H.F. television survey of 1957/58 E.W. Taylor, L.C. Munn This report describes the mobile laboratory used by the B.B.C. Research Department for assessing the reception conditions during the Band I/Band V comparison tests carried out in 1957/8. The mobile laboratory was equipped for the measurement of vision field strength and test waveforms, and the subjective assessment of the picture quality resulting from the transmissions from...
Topics: series, tests, waveform, aerials, frequency, signal, band, aerial, receiver, laboratory, receiving...
No abstract available
Topics: NASA Technical Reports Server (NTRS), MAGNETIC FIELDS, SOLAR CYCLES, FIELD STRENGTH, MERIDIONAL...
Monthly and annual percent-of-time data on ground rain fall rate and attenuation on satellite downlinks at 11.7 GHz, 19.04 GHz, and 28.56 GHz is presented. Equal probability values of attenuation and rain rate are compared for monthly, quarterly, half-year periods and for the entire year. Regression equations relating cross polarization isolation to the logarithm of attenuation are also presented.
Topics: NASA Technical Reports Server (NTRS), COMMUNICATIONS TECHNOLOGY SATELLITE, DEPOLARIZATION, RADIO...
Previously we have reported carbonate liq./silicate liq. partition coefficients (D) for a standard suite of trace elements (Nb, Mo, Ba, Ce, Pb, Th, and U) and Ra and Pa as well. In brief, we have found that immiscible liquid partitioning is a strong function of temperature. As the critical temperature of the carbonate-silicate solvus is approached, all partition coefficients approach unity. Additionally, for the overwhelming majority of the partitioning elements, InD is a linear function of...
Topics: NASA Technical Reports Server (NTRS), CARBONATES, CRITICAL TEMPERATURE, LIQUIDS, SILICATES,...
A model for the prediction of the electromagnetic field strength in an urban environment is presented. The ray model, that is based on the Uniform Theory of Diffraction (UTD), includes effects of the non-perfect conductivity of the obstacles and their surface roughness. The urban environment is transformed into a list of standardized obstacles that have various shapes and material properties. The model is capable of accurately predicting the field strength in the urban environment by...
Topics: NASA Technical Reports Server (NTRS), CITIES, COMMUNICATION SATELLITES, DOPPLER EFFECT,...
The research deals mainly with Very Large Array and Solar Maximum Mission observations of the ubiquitous coronal loops that dominate the structure of the low corona. As illustrated, the observations of thermal cyclotron lines at microwave wavelengths provide a powerful new method of accurately specifying the coronal magnetic field strength. Processes are delineated that trigger solar eruptions from coronal loops, including preburst heating and the magnetic interaction of coronal loops. Evidence...
Topics: NASA Technical Reports Server (NTRS), ANTENNA ARRAYS, CORONAL LOOPS, MAGNETIC FIELDS, SOLAR...
The magnetic field geometries of Uranus and Neptune are superficially similar, and are similarly unlike those of other planets: the field strengths are similar, and they contain extraordinarily large non-dipolar components. As a corollary, the best dipolar field models of each of the two planets comprises a dipole that is considerably offset from the planetary center and tilted away from the rotational axis. However, in other respects the best field models of the two planets are quite...
Topics: NASA Technical Reports Server (NTRS), COMPUTER PROGRAMS, FIELD STRENGTH, INNER RADIATION BELT,...
The intermediate wavelength component of the Earth's magnetic field has been well documented by observations made by MAGSAT. It has been shown that some significant fraction of this component is likely to be caused within the core of the Earth. Evidence for this comes from analysis of the intermediate wavelength component revealed by spherical harmonics between degrees 14 and 23, in which it is shown that it is unlikely that all of this signal is crustal. Firstly, there is no difference between...
Topics: NASA Technical Reports Server (NTRS), EARTH CORE, FIELD STRENGTH, GEOMAGNETISM, MODELS,...
The effects of gravity on the free flow electrophoretic process was demonstrated. The free flow electrophoresis chamber used to demonstrate the effects of gravity on the process was of a proprietary design. This chamber was 120 cm long, 16 cm wide, and 0.15 cm thick. Flow in this chamber was in the upward direction and exited through 197 outlets at the top of the chamber. During electrophoresis a stream of sample was injected into the flow near the bottom of the chamber and an electrical field...
Topics: NASA Technical Reports Server (NTRS), ELECTRIC FIELD STRENGTH, ELECTROPHORESIS, FREE FLOW,...
Coronal holes appear brighter than the quiet Sun in microwave images, with a brightness enhancement of 500 to 2000 K. The brightness enhancement corresponds to the upper chromosphere, where the plasma temperature is about 10000 K. We constructed a microwave butterfly diagram using the synoptic images obtained by the Nobeyama radio-heliograph (NoRH) showing the evolution of the polar and low latitude brightness temperature. While the polar brightness reveals the chromospheric conditions, the low...
Topics: NASA Technical Reports Server (NTRS), BRIGHTNESS TEMPERATURE, CORONAL HOLES, FIELD STRENGTH,...
The field emission characteristics of niobium electrodes were compared to those of stainless steel electrodes using a DC high voltage field emission test apparatus. A total of eight electrodes were evaluated: two 304 stainless steel electrodes polished to mirror-like finish with diamond grit and six niobium electrodes (two single-crystal, two large-grain, and two fine-grain) that were chemically polished using a buffered-chemical acid solution. Upon the first application of high voltage, the...
Topics: NASA Technical Reports Server (NTRS), PHOTOELECTRONS, DIRECT CURRENT, ELECTRIC POTENTIAL,...
Palaeointensity determinations on Apollo 11, 16 and 17 rocks have indicated that 3.9 - 4.0 AE ago the strength of the surface lunar magnetic field was about 1.3 Oe while there is evidence from younger rocks that a field of about one quarter of this value was present at a later time (3.6 AE).
Topics: NASA Technical Reports Server (NTRS), LUNAR MAGNETIC FIELDS, LUNAR ROCKS, LUNAR SOIL, APOLLO...
The Observation and Analysis of Smectic Islands in Space (OASIS) project comprises a series of experiments that will probe the interfacial and hydrodynamic behavior of freely suspended liquid crystal films in space. These are the thinnest known stable condensed phase structures, making them ideal for studies of fluctuation and interface phenomena. The experiments seek to verify theories of coarsening dynamics, hydrodynamic flow, relaxation of hydrodynamic perturbations, and hydrodynamic...
Topics: NASA Technical Reports Server (NTRS), THERMOCAPILLARY MIGRATION, HYDRODYNAMICS, LIQUID CRYSTALS,...
The Fermi Gamma-Ray Space Telescope has revolutionized the study of pulsar physics with the discovery of new populations of radio quiet and millisecond gamma-ray pulsars. The Fermi Large Area Telescope has so far discovered approx.20 new gamma-ray millisecond pulsars (MSPs) by both folding at periods of known radio MSPs or by detecting them as gamma-ray sources that are followed up by radio pulsar searches. The second method has resulted in a phenomenally successful synergy, with -30 new radio...
Topics: NASA Technical Reports Server (NTRS), FIELD STRENGTH, GALACTIC COSMIC RAYS, GAMMA RAY TELESCOPES,...
