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The use of the SLAC VHF and UHF Radio Systems and the Tunnel Antenna Systems as they are presently configured is described. The original radio system was built in 1966 and has grown in scope over the years. The Tunnel Antenna Systems were developed for, and first installed in, the PEP ring, and later added to other tunnels and redesigned to cover the UHF range, as well as VHF. The UHF radio system was designed and built for SLC use, and was first used in the SLC Arcs. The three radio systems will be described and the capabilities of each system will be defined.

In Japan, as road vehicles become more popular as transportation media and the roads improve, the percentage of transportation relying on vehicles has been increasing constantly and this increasing trend continues For this reason, a new emphasis is being placed on the accurate and rapid supply of traffic information as well as improvement of road networks. The roadside radio system was developed to respond to these requirements of the age. This system is characterized by the following features. • Supply of traffic information automatically edited by computers. • Voice output by the synthesizer which has 24-channel multiplex output. • Information supply from 24 individual medium-wave radio stations respectively to 24 broadcasting zones at a transmitting frequency of 1,620 kHz. • Use of a special cable antenna to minimize radio interference into adjacent broadcasting zones as well as other radio broadcasts.

This paper will describe the design, installation and operation of a multi-frequency rapid transit radio system utilized by the Washington Metropolitan Area Transit Authority. It will contain discussions of the civil construction considerations, operational constraints and technical engineering detail that has gone into the implementation of the system. It will also touch briefly on those elements that might be changed or modified in light of actual operating experience.

The purpose of this report is to develop an engineering design package to protect the federal Emergency Management Agency (FEMA) National Radio System (FNARS) facilities from the effects of high-altitude electromagnetic pulses (HEMP). This report refers to the Louisiana State Emergency Operating Center (EOC) in Baton Rouge, Louisiana. This report addresses electromagnetic pulse (EMP) effects only, and disregards any condition in which radiation effects may be a factor. It has been established that, except for the source region of a surface burst, EMP effects of high-altitude bursts are more severe than comparable detonations in either air or surface regions. Any system hardened to withstand the more extreme EMP environment will survive the less severe conditions. The threatening environment will therefore be limited to HEMP situations. 76 figs., 2 tabs.

SRI International (formerly Stanford Research Institute) has developed a VHF communication system performance model which predicts the probability of successful communications (P s ) in irregular terrain for both analog voice and digital systems. The Longley-Rice model is used to predict the propagation effects. A new noise model, based upon information in CCIR Report 258, is used to help estimate predetection signal-to-noise ratios (R). A communication success is achieved when R ≥ R r , where R r is a value of R required for acceptable performance. The value of R r for a given system is either estimated analytically or determined empirically for a given application. Therefore, the model predicts the probability that R ≥ R r versus range (or other variables of interest). After a user has established an operationally required probability of successful communication (P sr ), the operational range (OR) of a radio system in irregular terrain can be defined as the range where P s = P sr . The model was used to compute OR for VHF-FM voice systems for several example cases, and the results were compared with measured data. Reasonable agreement between the predictions and observations was obtained.

The FCC has always stressed the importance of frequency coordination in all of the radio services. Good frequency coordination minimizes interference and enhances the quality of the radio system. With the advent of cellular systems, new forms of coordination are needed to predict and avoid interference both within and between systems. In several ways, cellular frequency coordination is more complex than coordination in other services. Close cooperation between carriers is required to ensure compatible frequency usage and maximum growth potential. This paper discusses the tools and techniques used in developing a frequency plan that minimizes intra- and inter-system frequency interference. Frequency reuse and close geographic proximity of cellular systems mandates careful coordination to maintain good call quality.

The National Aeronautics and Space Administration (NASA), through the Jet Propulsion Laboratory (JPL), has developed a commercially oriented ACTS Mobile Terminal (AMT). This vehicular terminal employs a mechanically-steered antenna, and can support either digital links up to 64 kbps or analog links. The Army has now contracted JPL to modify this terminal for Army demonstration purposes. The AMT hardware will be mounted on a High Mobility Multi-purpose Wheeled Vehicle (HMMWV). In addition to providing standard baseline AMT capabilities, a coupling to a Single Channel Ground Air Radio System (SINCGARS) radio will enable secure command and control on the move. The rationale, design, features, and planned demonstration program for this Army AMT (AAMT) are discussed in this paper. >

Building penetration loss was measured at 937 MHz in an urban environment using a new method which unlike previous methods takes into account many of the variables present in an actual portable radio system. A 900 MHz portable transceiver was used to transmit a signal to a calibrated receiver connected to a 8.5 dB gain base station antenna. Measurements were made in buildings of the class 1 type (greater than 100' x 100' or higher than 4 floors). The buildings varied in age from 1 to 50 years. A comparison was made between signal strengths at the same height inside and outside the building, as well as comparing outside street level signals with signals in the building at different floor levels. Conclusions are drawn as to the effects of height above street level, type of building construction, and outside environment with respect to the base station, on building penetration loss.

The research reported contributes to the understanding of communication system performance with Thai speech, a tonal language having phonemic values in vowel duration and aspiration. Research results are attained by constructing a 250-word Thai intelligibility test in five similar 50-word forms. Laboratory system simulations and a standard military radio system are used to compare English and Thai work intelligibility under identical communication conditions. The research indicates that Thai speech transmission does not imply unusual system requirements. Thai intelligibility seems to depend on factors different from those in English, and further research is required to establish the nature of these factors.

Precision aiming method for antennas of wide-band high-power forward tropospheric scatter radio system, which was constructed to provide additional public overseas telephone service and television network link between United States and Cuba; type of geodetic surveys used to control aiming of antennas serve also to furnish State Plane Coordinates and to control boundary, topographic and construction surveys.

op measurements previously reported) are converted to radio system loss. Conversion from received voltage to system loss for a system using half- wave dipoles is also possible through relationships derived here, and an approximate formula is given for conversion to basic transmission loss. The use of horizontal polarization produces a much lower system loss than does the use of vertical polarization in the forest for the cases studied, with the exception of very low antanna heights. Tests made with a balloon-borne Xeledop elevated several hundred feet indicated the operational superiority of vertical dipoles over horizontal dipoles for balloon-elevated relays used in jungle terrain. The system loss for vertical polarization exceeded that obtained with horizontal polarization and optimum geometry, but optimum geometry for horizontal polarization was difficult to maintain.

1. Abstract The marine science and technology area is characterized by a continually increasing number of users who require position location with varying degrees of accuracy and frequency. These users include (but are not restricted to):commercial ships (for navigation aid, harbor traffic control, search and rescue, and offshore drilling);unmoored buoys (for correlation of collected data and position information in order to develop environmental profiles); andunmanned instrumentation at offshore locations (for survey purposes). The required accuracies range from a few feet for survey applications to one and one-half miles or more for commerical ship navigation, and frequencies of position finding from almost continuously to once a day or more are needed. This paper treats the design and position accuracy analysis of a promising satellite-based position location system which can satisfy, in an economical fashion, the performance requirements of the various marine science and technology users. Position location is carried out by means of a single satellite employing an original range and range rate measurement method. Active participation of satellite ground control station, satellite, and user is required. The system design was executed under the important practical constraint of simple measurement instrumentation at the user in order to minimize the per unit user investment. The material in the paper is divided into four sections:description of position location system and the role of ground station, satellite, and user in the position determination procedure;probabilistic analysis of position location accuracy with emphasis of evolution of criteria for instrumentation measurement accuracy;design of measurement instrumentation with emphasis on user equipment; andapplications to marine science and technology users. Two new analytical techniques, developed specifically for the study of the range and range rate problem but applicable to position location systems in general, will be emphasized. Briefly, these techniques deal with:the notion of "distribution-free" accuracy for evaluating position accuracy in situations where the error distribution is unknown; andthe inclusion and statistical treatment of bias errors in the probabilistic analysis of position accuracy. II. Description of the Range and Range Rate Position Location System All position location systems can be unified in terms of the geometry of quadric surfaces, i.e., three-dimensional surfaces. Measurements are made which determine -distance and/or angle variables. These measurements are relative to positions or orientations either known or determined by other measurements. Each variable generates a quadric surface on which the measurement-determined position is located. An example of a quadric surface is the sphere generated by the measurement determined range between a user-and a satellite. Solution of the equations of three quadric surfaces yields the position (in general the solution yields a number of positions and the ambiguities must be resolved). A spherical or ellipsoidal approximation to the Earth's figure is often used as one of the surfaces (suitably extended to take into account user altitude above mean sea level). The position location concept considered in this paper is based on the measurement of the range and range rate between a single satellite and the user as well as a knowledge of user altitude and velocity and satellite position and

Rain is the dominant attenuator for radio systems operating above 10 GHz. Correctly configuring systems that can dynamically compensate for rain fading requires a detailed knowledge of spatial and temporal rain field variation. Ideally, this would be provided by a database of meteorological radar measurements. Unfortunately, such data is scarce. Alternatives to radar measurements are methods for simulating rain fields in time and space. This paper discusses a monofractal, additive (in the logarithmic domain) discrete cascade model for simulating rain fields in two spatial dimensions. The model produces events-on-demand, customised to an input rain rate parameter and desired rain event type (stratiform or convective). In order to test the long term statistics of a proposed radio system, simulated rain field datasets are required which will reproduce the annual rain statistics for the average year. Work towards a method to convert from a set of single events into a set capable of reproducing annual statistics is presented in this paper.

The context refers to “any information that can be used to characterize the situation of an entity, where an entity can be a person, place, or physical object.” Radio context awareness is defined as the ability of detecting and estimating a system state or parameter, either globally or concerning one of its components, in a radio system for enhancing performance at the physical, network, or application layers. In this paper, we review the fundamentals of context awareness and the recent advances in the main radio techniques that increase the context awareness and smartness, posing challenges and renewed opportunities to added-value applications in the context of the next generation of wireless networks.

The Distant Early Warning System (DEWLine) is a network of radar and communications stations stretching for some 3600 miles along the 69th parallel from Cape Lisburne, Alaska, to Cape Dyer, Baffin Island, and continuing across Davis Strait and the Greenland ice sheet to the east coast of Greenland. Thence it maintains communication with the North Atlantic Radio System from Keflavfk, Iceland, to Fylingdales Moor, England. The DEWDrop system, a tropospheric scatter communications system links Cape Dyer with the Inter-Continental Ballistic Missile Station at Thule, Greenland and another connects Thule with the DEWLine station FOX, on Foxe Basin. DEWLine stations are supervised and controlled by the US Air Force, by agreement with the Canadian and Danish Governments.

Evidence has been found for correlation between optical and radio emission from extensive air showers at large zenith angles, using a Cerenkov optical detector and wide-band radio system.

Interest in the use of the millimetre wavebands is increasing as the conventional radio spectrum becomes more congested. However, a system designer using these frequency bands must contend with the variability of the weather as well as possess an understanding of the effects of specific weather structures on radio propagation

A large hybrid computer has been used to simulate modern communication systems, particularly those using digital radio techniques. This paper describes the basic thinking behind these models, outlines some of the techniques used and takes, as an example, a digital f.s.k. radio system. The unique results obtained, especially with regard to co-channel interference show the versatility and power of the simulation technique used.

By studying the rate of coincident detection of meteors at two widely separated locations, as a function of the differential time of first detection, it is possible to deduce the distribution in length of the meteoric ionization columns. A precise determination would require, in addition, that the velocity of the individual meteors used in the test be known. However, in the absence of such data, an approximate distribution of trail lengths whose mean value is probably representative of actual conditions, can still be deduced. For equipment generating about a kilowatt of continuous wave output, and capable of detecting meteors at a total rate of 450 meteors per hour, the mean trail length was found to be 25 or 30 km. Calculations based upon this value of trail length, and upon the use of a corrected rate of meteoric arrival, show that meteors up to the sixth magnitude were detected during the test. The method described provides a measure of trail length dependent upon the ability of the trail to reflect a signal at normal incidence. The accuracy of the determination of frequency of occurrence of trails of various lengths is independent of the rate of detection, but is proportional to the square root of the period of observation.