R&D Report 1991-11 : Field strength prediction for VHF/UHF terrestrial broadcasting and mobile radio services R.S. Sandell, R.W. Lee, C.P. Bell The propagation curves used internationally for the planning of services in the VHF and UHF Broadcast Bands are those of CCIR Recommendation 370 and associated Report 239. Derivations from these are also used for Mobile Radio planning in this frequency range. These curves, first produced some 30 years ago, have subsequently been the subject of...
Topics: terrain, ccir, prediction, curves, propagation, antenna, height, measurements, receiving, bbc,...
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,...
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,...
R&D Report 1973-08 : Computer program: MF sky-wave interference J.L. Eaton, A.M. Bunting A short self-contained computer program for calculating sky-wave interference at MF has been written. The program employs a simple empirical law for calculating field-strength and makes a correction for the transmitting aerial vertical radiation pattern, the take-off angle being derived from the great circle distance and the number of 'hops'. Protected field-strengths are calculated for each wanted...
Topics: transmitter, frequency, transmitters, interference, bbc, weighting, program, interfering, ccir,...
R&D Report 1974-03 : LF and MF propagation: Sky-wave field-strength prediction P. Knight During the night, medium-frequency sky-waves propagate to great distances via the ionosphere. The report describes the various factors which affect the waves as they travel from transmitter to receiver. Several methods which can be used for estimating the strength of sky-wave signals are compared.
Topics: curves, propagation, loss, ionospheric, wave, magnetic, coupling, polarisation, ccir, variation,...
R&D Report 1980-05 : The use of the 26 MHz band for satellite broadcasting. G.J. Phillips, P. Knight The existing top hf band (25.6 - 26.1 MHz) might be more effectively used than at present for international broadcasting if transmissions from satellites were permitted. Although the World Administrative Radio Conference, Geneva, 1979 did not extend the use of the band in this way, the report gives a useful record of the technical studies made in the preparation for the Conference....
Topics: mhz, satellite, ionosphere, ccir, transmissions, critical, aerial, layer, broadcasting,...
R&D Report 1981-13 : Planning standards for v.h.f. and u.h.f. receiving aerial discrimination and height gains at domestic receiving locations. C.P. Bell, R.I. Black This report summarizes the results of a limited investigation to study the validity of existing standards used in frequency planning of broadcast services for the protection afforded by the characteristics of receiving aerials against interfering transmissions. Although internationally agreed standards have been provided by the...
Topics: discrimination, ccir, band, receiving, directivity, relative, polarization, aerial, horizontally,...
R&D Report 1966-07 : C.W. Interference with monachrome UHF television reception R V Harvey The protection ratios for a monochrome a television transmission against an interfering c.w. signal, as given in CCIR Recommendation 418, 1963, in the case of Standard 1 (the current U.K. standard on u.h.f.), were confined to frequency offsets between -2 Mc/s and +5 Mc/s from the vision carrier frequency. The work described in this report extends this data to offsets of up to 6.5 Mc/s, including the...
Topics: impairment, interference, sound, carrier, vision, signal, ratios, offsets, ccir, monochrome,...
R&D Report 1987-13 : Band II VHF antenna for home construction. S. Wakeling A wideband Band II Yagi antenna, suitable for home construction, has been designed using computer techniques. The antenna is intended for use as a domestic receiving antenna for VHF/FM sound broadcasting at frequencies in the range 88 to 108 MHz. Scale-model antennas were constructed and measured to verify the performance predicted by the computer. Finally, a full-scale Yagi antenna was constructed and its radiation...
Topics: antenna, yagi, dipole, vhf, antennas, ccir, design, impedance, element, folded, single dipole,...
R&D Report 1993-04 : Alleviation of co-channel interference at Poole relay station J.H. Moore, A.I.E. Booker The Rowridge UHF television transmitting station, situated on the Isle of Wight, radiates the four principal UK domestic television channels to the south coast of England, and provides an off-air feed to a number of dependent relays. At one relay station (Poole), occasional Co-channel Interference (CCI) is known to occur. It is particularly noticeable during the summer and autumn...
Topics: offset, precision, channel, rowridge, relay, frequency, poole, interference, impairment, cci, total...
R&D Report 1966-46 : Long-distance tropospheric propagation measurements over the North Sea at 774 MHz. J.W. Stark, C.P. Bell This report presents the results of field strength measurements on horizontally polarized u.h.f. transmissions at 774 MHz over North Sea at distances from 198 km to 950 km. These measurements extended over a period of 2 1/4 years and have been used in the preparation of curves showing field strength as a function of distance for specified percentages of the total...
Topics: measurements, mhz, curves, band, propagation, ccir, strength, field, values, receiving,...
R&D Report 1976-33 : UHF field strength measurement of the ATS-6 satellite J. Middleton Space technology can now provide a geosynchronous satellite capable of radiating over 100 kW EIRP within the UHF band. Therefore the question of interference to existing or planned television services sharing this band merits investigation whenever the opportunity arises. The report describes a series of measurements undertaken to establish whether the ATS-6 UHF aerial used for transmitting an...
Topics: bbc, strength, mhz, field, signal, receiver, aerial, satellite, broadcasting, measurement, field...
R&D Report 1977-42 : LF and MF sky-wave propagation: the origin of the Cairo Curves. P. Knight The report describes the measurements from which the Cairo curves were derived. Both curves appear to be 10 dB higher than the measurements indicate, at the greatest distance for which they are drawn. The North-South curve may have been influenced by sea gain and the East-West curve by solar activity.
Topics: measurements, curves, buenos, strengths, aires, ccir, propagation, cairo, field, paths, north...
R&D Report 1977-12 : LF and MF propagation: a study of sky-wave field-strength variation. P. Knight LF and MF sky-waves vary in strength during periods which may be as short as a minute or as long as 11 years; this range includes day-to-day, diurnal, seasonal and solar-cycle variations. A detailed study has been made of all that is known about LF and MF sky-wave field-strength variation and this has been supplemented by further analysis of measured data.
Topics: variation, measurements, field, propagation, strengths, strength, seasonal, median, frequency,...
R&D Report 1968-01 : Long distance tropospheric propagation measurements over mixed land and sea paths at 774 MHz C.P. Bell Field-strength measurements of a transmission at 774 MHz were carried out over mixed land and sea paths ranging from 196 km to 365 km in length. The results show that the attenuation relative to an all-sea path, introduced by sections of land at the end of the path increases substantially with proportion of land path. The results of the measurements are compared with...
Topics: aerial, measurements, height, bawdsey, ccir, strength, receiving, propagation, manningtree, field,...
R&D Report 1993-01 : Digital sound: the selection of critical programme material and preparation of recordings for CCIR tests on low bit-rate codecs. N.H.C. Gilchrist A draft new recommendation on low bit-rate digital audio coding for broadcasting is in preparation within CCIR Study Group 10. As part of this work, subjective tests are being conducted to determine the preferred coding systems to be used in the various applications, and at which bit rates they should be used. The BBC has been...
Topics: codecs, audio, material, contribution, broadcasting, digital, recordings, codec, ccir, bbc,...
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Topics: iec, khz, ccir, und, din, supercardioide, bij, limite, module, gewicht, din iec
R&D Report 1966-45 : UHF service area prediction: an investigation using relief map photography E. Sofaer, R. Sims An experiment was undertaken to determine whether the service areas of u.h.f. broadcasting transmitters could be reliably predicted by photographing a three-dimensional relief map suitably illuminated. The results obtained are discussed.
Topics: predicted, map, ccir, contour, lamp, errors, field, prediction, service area, measured, service...
R&D Report 1972-06 : UHF medium distance tropospheric propagation measurements over the English channel C.P. Bell, S.J. Ashdown In extending the UHF television network, consideration must be given to the most suitable means of providing a programme feed to the Channel Islands. Any direct re-broadcast link from the mainland of the United Kingdom must be at least 95 km in length and will thus be subject to a considerable degree of fading. This report summarises the statistical results of a...
Topics: receiving, field, strength, alderney, rowridge, propagation, measurements, aerial, torteval, ccir,...
R&D Report 1991-08 : VHF (Band II) propagation tests across the Irish Sea. J. Middleton Measurements of Band II transmissions across the Irish Sea over a 13-month period between 1983 and 1984 have been analysed and compared with prediction methods normally used to calculate interference from broadcast transmissions (BBC and CCIR methods). They were also compared with North Sea measurements made in 1954. The measurements show that both methods predict interference levels which are not...
Topics: bbc, measurements, ccir, strength, propagation, antenna, field, transmitter, sea, height, antenna...
R&D Report 1971-31 : Long distance tropospheric propagation measurements at UHF over mixed land and sea paths crossing the English Channel C.P. Bell, S.J. Ashdown This report gives the results of a series of long-term tropospheric propagation measurements carried out at UHF over a number of mixed land and sea paths of lengths ranging from 195 km to 330 km. These measurements, which supplement the data available for frequency planning, are compared with values estimated by two prediction...
Topics: measurements, propagation, prediction, bbc, paths, method, caen, receiving, field, sea, ccir...
R&D Report 1970-27 : Satellite broadcasting: An aerial design for domestic reception in the 12 GHz band G.H. Millard A design of aerial suitable for use in Television Band VI (11.7 GHz - 12.7 GHz) is described. The aerial should be capable of mass-production at low cost to meet a possible domestic requirement.
Topics: aerial, ghz, gain, isotropic, satellite, log, broadcasting, aperture, ccir, relative, effective...
R&D Report 1975-32 : LF and MF propagation: An approximate formula for estimating sea gain. P. Knight The strength of waves propagated via the ionosphere at LF and MF may be increased if either path terminal is situated near the sea. This increase, which is known as sea gain, depends both on the distance of the terminal from the coast and on the extent of the sea beyond the coastline. An approximate formula is derived for estimating sea gain for all geographical situations which are likely...
Topics: sea, terminal, gain, radiation, inland, ccir, formula, distance, path, approximate, path length,...
R&D Report 1989-15 : Long-distance propagation measurements at UHF: Comparisons between results using BBC and CCIR prediction methods C.P. Bell This report gathers together available data on measurements over long distance propagation paths in the UHF Broadcast Band made by the BBC and other UK organizations, and uses them to test the accuracy of both BBC and CCIR field strength prediction methods. The former makes use of terrain database, and the latter, as contained in CCIR...
Topics: bbc, ccir, path, prediction, predictions, measurements, method, paths, clutter, receiving, field...
R&D Report 1969-08 : Medium-distance overland tropospheric propagation measurements at UHF C.P. Bell This report gives the results of a series of long-term tropospheric propagation measurements carried out at UHF over a number of overland transmission paths of lengths ranging from 60 km to 150 km. These measurements, which supplement the data available for frequency planning, are compared with values estimated by two prediction methods. Comparisons of measurements over similar path lengths...
Topics: measurements, receiving, ccir, paths, correction, path, bbc, crystal, field, palace, protected...
R&D Report 1975-23 : Digital sound: Baseband filtering to improve the fading margin for 13-channel system operating over existing FM links. N.H.C Gilchrist, W.I. Manson, T.A. Moore In order to realise as rapidly as possible the potential advantages of pulse code modulation, microwave frequency-modulation links, originally intended for monochrome video signals, are being used to distribute sound programmes to transmitters by multiplexed PCM signals. However, for instrumental reasons the...
Topics: mhz, filter, deviation, baseband, margin, bbc, fading, carrier, noise, ccir, carrier deviation,...
R&D Report 1983-15 : Ionospheric propagation in the l.f. broadcasting band. P. Knight Continuous field-strength recordings made in the UK of l.f. transmissions from Poland and Algeria are described. The results show that sky waves propagate strongly during the day in winter, giving field strengths which are only about 15 dB less than night-time values. IN winter, the transition from day to night is very gradual, with the signal strength increasing steadily for several hours. In summer,...
Topics: median, field, strength, warsaw, ccir, values, variation, tipasa, broadcasting, bbc, path length,...
R&D Report 1978-13 : Computer programs for v.h.f. interference prediction using a terrain data bank. J.H. Causebrook, B. Tait A set of computer programs has been written to aid broadcast service planning work in the VHF bands. They are intended for FM sound in Band II as well as new television and other possible services in Bands I and III. The prime object is the prediction of interference levels from other transmitters into a service area. The methods are an extension of those employed...
Topics: interference, transmitter, receiver, iii, protection, data, interfering, programs, bands, band,...
R&D Report 1988-12 : The visibility of noise in System I PAL colour television. A. Oliphant, K.J. Taylor, N.T. Misson The results of new subjective tests on the visibility of noise in System I PAL colour television are reported. Three forms of noise are considered: white (flat) noise; de-emphasised triangular noise; the noise resulting from vestigial sideband demodulation (VSB noise). The results are compared with those given by work published 20 years ago and it is concluded that observers...
Topics: noise, tests, impairment, triangular, pal, series, vsb, chrominance, weighting, test, impairment...
Bell System Technical Journal, 50: 1. January 1971 pp 81-102. Model for Computation of Interference to Radio-Relay Systems From Geostationary Satellites. (May, A.S.; Pagones, M.J.)
Topics: interference, satellite, latitude, antenna, system, separation, ccir, orbit, geostationary,...
