In situ measurements of radio frequency (RF) spectrum activity provide insight into the physics of radio frequency wave propagation and validate existing and new spectrum propagation models. Both of these parameters are essential to supporting and pr...
Propagation models are used to inform scientists and engineers on how radio propagation through an environment will affect the radio signal received on the other end of the link. Many propagation models have been developed: some are curve-fitting mod...
Geopositioning uncertainty degrades the usefulness of the data collected while conducting propagation measurements in the field. Researchers currently have access to highly detailed terrain, propagation, and locational data sets, but these data are u...
This report describes a set of best practices for the preparation and verification of radio propagation measurement systems. We discuss advantages and disadvantages of various channel sounders, the common components used in these systems, and measure...
This report describes one of three free-field radio frequency (RF) measurement systems that are currently being developed by engineers at the Institute for Telecommunication Sciences (NTIA/ITS). The objective is to provide estimates of the electrical...
This report describes a recent measurement effort conducted by the Institute for Telecommunication Sciences at a chamber located at the NASA Space Power Facility (SPF) in Sandusky, Ohio. The report describes the chamber and the measurement system, a...
This paper describes a mobile-to-mobile propagation measurement system that is currently being developed at the Institute for Telecommunication Sciences under the sponsorship of the Office of Spectrum Measurement. This system uses a fixed transmitter...
An investigation of different propagation modeling methods to meet the special requirements of a short-range propagation model with low antenna heights was performed, and has resulted in the development of approaches to be taken to accurately model r...
Radiowave propagation measurements made in an urban area of Denver, Colorado, are described. Wideband, impulse response measurements were made at 4 carrier frequencies from 430 MHz to 5750 MHz. These measurements were made using a mobile measurement...
Radiowave propagation measurements at Ft. Hood, Texas are described. These measurements were made as part of the Flexible Interoperable Transceiver (FIT) Program. The objective of the measurements is to define communication link requirements at 440,...
Radiowave propagation measurements at Edwards Air Force Base, CA are described. These measurements were made as part of the Flexible Interoperable Transceiver (FIT) Program. The objective of the measurements is to define communication link requireme...
This paper discusses the basic aspects of radio-wave propagation and antenna modeling in the medium frequency (MF) band. This band covers the frequencies of 300 to 3000 kHz. More specifically, we are concerned with the ground wave and the sky wave in...
Multipath channels in indoor wireless communication systems exhibit a characteristic power delay profile, which can be a detriment to system performance. In this paper, we present a simplified model for calculating the decay rate of the power delay p...
A local multipoint distribution system will essentially broadcast television signals (and perhaps more) to subscribers in small cells. It has been proposed to put such systems in the frequency band from 27.5 to 29.5 GHz where the wave length is only ...
For short propagation paths, correctly representing reflections of electromagnetic energy from surfaces is critical for accurate signal level predictions. In this paper, the method of homogenization is used to determine the effective material propert...
Propagation characteristics of the atmosphere are modeled for the frequency range from 1 to 1000 GHz (1 THz) by the modular millimeter-wave propagation model MPM. Refractivity spectra of the main natural absorbers (i.e., oxygen, water-vapor, suspend...
Impulse response measurements were taken simultaneously in both the 902–928 and 1850–1990 MHz bands using a wideband measurement system consisting of a fixed transmitter and a mobile receiver. Four different macrocells representing typical semi-rural...
Wideband impulse response measurements were made to characterize proposed radio data channels in three indoor environments. The measurement system employed a 1.5 GHz carrier which was biphase shift key (BPSK) modulated using a 100 Mb/s pseudo-random ...
Millimeter-wave propagation through the nonprecipitating atmosphere is modeled for frequencies below 1000 GHz. Complex refractivities represent the spectral properties of four natural absorbers; that is, oxygen, water-vapor, suspended droplets and i...
Wideband propagation measurements were made in a pecan orchard in Texas during April and August of 1990 to examine the propagation characteristics of millimeter–wave signals through vegetation. Measurements were made on tree obstructed paths with and...
This is a supplementary fifth part to a series of reports containing tabulations and graphs of transmission loss data resulting from propagation experiments which have emphasized the UHF frequency band. The first four reports described data taken in...
Rapid development of personal, portable, radio communications is expected during this decade. A primary example of this is the emergence of personal communication networks (PCN). These networks are similar to today's cellular telephone technology. Ho...
This report describes the results of an 18-month digital microwave radio performance and propagation measurement project that was conducted on a portion of the Defense Communications System in Germany. More than 6 gigabytes of data were collected...
This report describes the results of an 18-month digital microwave radio performance and propagation measurement project· that was conducted on a portion of the Defense Communications System in Germany. More than 6 gigabytes of data were collecte...
This report describes the results of an 18-month digital microwave radio performance and propagation measurement project that was conducted on a portion I of the Defense Communications System in Germany. More than 6 gigabytes of data were collect...
Two millimeter-wave propagation models, called MPM and MZM, are discussed. The first one predicts, at frequencies up to 1000 GHz, loss and delay effects for a nonprecipitating atmosphere. Contributions from dry air and vapor are addressed, as well a...
At heights between 30 and 100 km above Earth, the oxygen absorption lines near 60 GHz together with the geomagnetic field cause the atmosphere to become an anisotropic medium. This report discusses why this is so and how to compute the consequent eff...
A broadband model for complex refractivity is presented to predict propagation effects of loss and delay for the neutral atmosphere at frequencies up to 1000 GHz. Contributions from dry air, water vapor, suspended water droplets (haze, fog, cloud), a...
This handbook is intended to provide estimates of radio wave propagation loss between transmitting and receiving antennas of various heights and transmission frequencies above the assumed smooth–earth surface calculated using the NLAMBDA computer mod...
Measurements were performed in an urban-suburban environment with narrowband and wideband RF probes, which include millimeter-wave frequencies, in order to study propagation characteristics for street level paths. The primary objective of this report...
This report discusses propagation and performance measurements that were obtained over a digital troposcatter communication link between Bocksberg, West Germany, and West Berlin. The measurements were unusual because three general types of data were ...
Laboratory measurements have been performed at 138 GHz of water vapor attenuation αx for pure vapor (H2O) and its mixtures with air, nitrogen (N2), oxygen (O2), and Argon (Ar). Temperatures ranged from 8 to 43 °C, relative humidities from 0 to 95% a...
When wave propagation through a stratified atmosphere is formulated in operator theoretic terms, it becomes evident that the problem does not follow the guide of the usual examples of mathematical physics. Nevertheless, such a formulation is useful t...
Prediction of propagation effects (i.e., path attenuation, phase delay, ray bending and medium noise) over the 1 to 300 GHz frequency range through the clear, nonturbulent atmosphere is accomplished by combining a spectroscopic data base with a compu...
The distribution of raindrop sizes in a given volume of air remains an unknown aspect of critical importance to the prediction of rain attenuation at millimeter–wave frequencies. Thus, in this report, the search continues for a methodology of predict...
Measurements reported are part of a study of propagation characteristics for millimeter-wave communication links operating in an urban-suburban environment. Absorption data were collected for signals propagated through some common building materials...
A practical atmospheric Millimeter-Wave Propagation Model (MPM) is formulated that predicts attenuation. delay, and noise properties of moist air for frequencies up to 1000 GHz. Input variables are height distributions (0–30 km) of pressure, temperat...
A practical atmospheric millimeter-wave propagation model (MPM) is updated and tested with experimental data from horizontal, line–of–sight links when there is no precipitation. The MPM computer program predicts attenuation and delay properties of mo...
This handbook is intended to assist in manual analysis techniques that must be used when an automated analysis is not possible. It provides estimates of radio wave propagation loss between transmitting and receiving antennas above the assumed smooth-...
In the presence of rain, millimeter–wave propagation is acutely sensitive to the distribution of raindrop sizes along a given propagation link. This report analyzes the variability of rain attenuation prediction at microwave/millimeter wave frequenci...
Measurements of radio propagation path loss were made over four paths in the 3 to 30 MHz band. The paths were of lengths up to 45 km in the Boulder, CO, area. They ranged from smooth to mountainous terrain, from open areas with few or no man-made str...
The neutral atmosphere is characterized for the frequency range from 1 to 300 GHz as a nonturbulent propagation medium. Attenuation and propagation delay effects are predicted from meteorological data sets: pressure, temperature, humidity, suspended...
This report provides a description of the computational details in the IF-77 (ITS-FAA-1977) radio wave propagation model. The IF-77 model is useful in estimating service coverage for radio systems operating in the 0.1 to 20 GHz frequency range. It is...
A diagnostic probe used to fully describe the propagation characteristics of a millimeter wave channel by nearly simultaneous recording of an impulse response, frequency spectra, amplitude response, and bit error rate is discussed. A 30.3 GHz carrier...
A radio propagation prediction computer code has been developed to permit rapid simulation of HF air-to-ground telecommunication circuits. This prediction program provides estimates of both skywave and groundwave HF propagation parameters. The skywav...
Measurements of millimeter wave propagation in urban areas at 9.6, 28.8 and 57.6 GHz, and a determination of signal levels reflected from several building surfaces, were made to study wave propagation characteristics in a city environment. Principal...
An integral equation method is presented for computing the vertically polarized field strength over irregular terrain which is covered with forest, buildings, or snow. The terrain cover is modeled as an equivalent slab, and a general computer code, W...
Comparisons of theoretical attenuation based on multiple knifeedge diffraction with measured values of median propagation loss are presented for a number of different propagation paths. In general the knife-edge predictions tend to overestimate recei...
The burning of an Atlas-Centaur rocket in the ionospheric F–region was used to determine the extent of HF propagation anomalies associated with the resultant drop in ionospheric electron content. This "ionospheric hole" grew to encompass the control ...
This report presents an extensive bibliography, categorized by effect, of radio propagation through the atmosphere, for the frequency region of 10 to 300 GHz. Preceding the bibliographic presentation is an article-by-article synopsis of that literatu...
A study was conducted to determine the limiting propagation effects on the performance of a microwave system that could be used to detect the optical visibility between two vehicles, separated by up to 10 km, in irregular, obstructed terrain. The stu...
This report provides extensive comparisons of measured propagation data with predictions made by the IF-77 (ITS-FAA-77) and other propagation models. Although IF-77 was developed for aeronautical applications, it can be used for some point-to-point p...
An algorithm (PROGRAM WAGNER) that evaluates HF ground–wave attenuation over irregular, inhomogeneous terrain is used to compare calculated field strengths with observed measurements for 9 actual paths and frequencies ranging from 120 kHz to 50 MHz. ...
Measurements of radio propagation path loss and local ground conductivity were made over four paths in the 100 to 2000 kHz band. The paths were of lengths up to 50 km and were chosen to represent both extreme and typical topography and conductivity c...
The United States Department of Commerce (DOC) has been active in radio wave propagation research and prediction for several decades, and has provided the Federal Aviation Administration (FAA) with many propagation predictions relevant to the covera...
This report reviews much of the earlier work on radio propagation in urban areas, including a good deal of data from measurement programs, careful studies of multipath propagation, and techniques to reduce multipath fading. A number of investigators ...
This report covers ten computer programs useful in estimating the service coverage of radio systems operating in the frequency band from 0.1 to 20 GHz. These programs may be used to obtain a wide variety of computer-generated microfilm plots such as ...
This report presents some estimates of the enhanced fields deduced from the presently available theory and observational data. The fields of interest are the enhanced fields that are encountered in the presence of the stratified atmosphere, the ducti...
The data from a large measurement program at VHF and UHF are carefully evaluated , summarized and compared with values predicted from models of radio propagation over irregular terrain. Particular problems of low antennas and the effects of vegetatio...
A theoretical expression for the received signal by a radar is reduced to a utilitarian form by the introduction of feasible approximations and assumptions, with concern expressed for the need for evaluation of errors caused by these approximation...
This report is a study of the feasibility of applying numerical mapping techniques to the storage and handling of OMEGA propagation corrections. Using the techniques discussed in the report, it is possible to represent the 110,592 propagation corecti...
The extended offshore test range proposed for the Pacific Missile Range will use high altitude aircraft to relay signals for tracking, telemetry, and control. This report treats the reliability of the radio propagation paths between these relays and ...
A theoretical expression for the received signal by a radar is reduced to a utilitarian form by the introduction of feasible first order approximations, and specifying where other common assumptions are made, with concern expressed for the need for e...
References are presented on the subject of recent (1971 to mid-1974) work on radio propagation through the atmosphere at frequencies from 10 to 100 GHz. The references are separated into six major categories covering propagation through precipitati...
Estimates for the effects on a lateral wave of a clearing in a foliage layer are considered. A first-order solution to the integral equation for the mixed-path problem is derived and two examples are considered. They show that a m.id-path clearing ha...
HF radio propagation predictions are calculated for Voice of America circuits using the OT/ITS prediction program. Some of the parameter s given are maximum usable frequency (MUF), the optimum traffic frequency (FOT), the lowest useful frequency (LU...
VOLUME I: HF radio propagation predictions are calculated for Voice of America circuits using the OT/ITS prediction program. Some of the parameters given are maximum usable frequency, the optimum traffic frequency, the lowest useful frequency, availa...
This report reviews the available documentation for two links of the FACSFAC microwave system and the findings of on-site inspections. It is recommended that the present maintenance program be supplemented by additional performance monitoring. This s...
HF radio propagation predictions are calculated for 35 circuits from the Voice of America transmitting facility at Tinang, P. I. and 30 circuits from their facility at Kava1a, Greece, using the OT/ITS prediction program. The program selects the optim...
HF radio propagation predictions are calculated for 35 circuits from the Voice of America transmitting facility at Tinang, P. I. and 30 circuits from their facility at Kavala, Greece, using the OT/ITS prediction program. The program selects the optim...
HF radio propagation predictions are calculated for Voice of America circuits using the OT/ITS prediction program. Some of the parameters given are maximum usable frequency, the optimum traffic frequency, the lowest useful frequency, available signal...
HF radio propagation predictions are calculated for Voice of America circuits using the OT/ITS prediction program. Some of the parameters given are maximum usable frequency, the optimum traffic frequency, the lowest useful frequency, available signal...
HF radio propagation predictions are calculated for 35 circuits from the Voice of America transmitting facility at Tinang, P. I. and 30 circuits from their facility at Kava1a, Greece, using the OT/ITS prediction program. The program selects the optim...
VOLUME I: HF radio propagation predictions are calculated for Voice of America circuits using the OT/ITS prediction program. Some of the parameters given are maximum usable frequency, the optimum traffic frequency, the lowest useful frequency, avail...
HF radio propagation predictions are calculated for Voice of America circuits using the OT/ITS prediction program. Some of the parameters given are maximum usable frequency (MUF), the optimum traffic frequency (FOT), the lowest useful frequency (LUF...
HF radio propagation predictions are calculated for Voice of America circuits using the OT/ITS prediction program. Some of the parameters given are maximum usable frequency (MUF), the· optimum traffic frequency (FOT), the lowest useful frequency (LU...
HF radio propagation predictions are calculated for circuits from the Voice of America transmitting facility at Tinang, P. I. and 25 circuits from their facility at Kavala, Greece, using the OT/ITS prediction program. The program selects the optimum...
HF radio propagation predictions are calculated for 35 circuits from the Voice of America transmitting facility at Tinang, p. I. and 30 circuits from their facility at Kavala, Greece, using the OT/ITS prediction program. The program selects the opti...
A bibliography is presented on the subject of electromagnetic wave propagation over line-of-sight paths through the troposphere at frequencies above 10 GHz. The references are divided into three main categories covering the areas of propagation throu...
An analysis is presented of air-ground radio wave propagation measurements, which were performed using an airborne transmission source at approximately 6,400 m above msl. Receiving antennas were slightly within and beyond line-of-sight of the airbor...
This is the fourth part of a four-part report containing tabulations and graphs of transmission loss data resulting from propagation experiments in the 230 - to 9200-MHz frequency range conducted over irregular terrain in Colorado. This part present...
This report documents a digital computer program for computing the propagation of LF and VLF radio waves using the wave hop theory. It supersedes NBS Report 8889. The documentation includes a description of the physical model, detailed mathematical f...
Published measured profiles of the lower ionosphere are used as the basis of an analytic model of the D-region electron density which varies with the sun’s zenith angle. The model is the sum of an exponential layer and a daytime Chapman-like C-layer....
This is the third part of a four–part report containing tabulations and graphs of transmission loss data resulting from propagation experiments in the 230- to 9200- MHz frequency range conducted over irregular terrain in Colorado. This part describe...
Predictions of tropospheric transmission loss over irregular terrain using the computer methods described by Longley and Rice (1968) are compared with measurements, to determine their limits of applicability and define the boundary conditions for the...
A computer program. for calculating ground wave propagation in an ionized atmosphere is documented and listed. The conductivity of the atmosphere can vary in an arbitrary way with altitude. The notion of continuous stratification of the profile has b...
This report describes many of the UHF propagation characteristics between aircraft or satellites and buried antennas. A vertical monopole was used as a reference antenna, and the propagation characteristics of an annular slot and other antennas, omni...
This report is a presentation in two volumes of measurement techniques, data, comparisons, and conclusions obtained from a UHF propagation measurement program at 230 and 415.9 MHz. Antenna heights were 3 m or less above ground. Vertical polarization ...
This report is a presentation in two volumes of measurement techniques, data, comparisons, and conclusions obtained from a UHF propagation measurement program at 230 and 415.9 MHz. Antenna heights were 3 m or less above ground. Vertical polarization ...
A method of estimating the basic transmission loss, Lb, for VHF/UHF links that have low or buried antennas surrounded by security fences is presented, Estimates of Lb obtained are compared with experimental data.
Received signal level recording on two long line-of-sight paths with a common terminal showed that a relatively steep path elevation angle will not eliminate occasional deep fading. Most of the deeper fading occurred during periods of weak winds when...
This paper poses, and attempts to answer, some of the questions involved when a UHF antenna is buried in the ground. A description of the basic theory is given, together with illustrative calculations for many situations of interest. Graphs are prese...
A hypothetical aircraft-to-ground communication channel is examined for frequencies in the 2 -30 MHz band, and in the 200 -400 band. The channel is characterized by its correlation function and scatter function. Particular attention is given to the e...
This is the second part of a four-part report containing tabulations and graphs of transmission loss data resulting from propagation experiments in the 230 to 9200 MHz frequency range conducted over irregular terrain in Colorado. This part describes...
This four-part report contains tabulations and graphs of transmission loss data resulting from propagation experiments in the 230 to 9200 MHz range conducted over irregular terrain in Colorado. Each part of the report deals with data obtained at a s...
This report contains tabulations of transmission loss data resulting from propagation experiments at 20, 50, and 100 MHz conducted over irregular and partly wooded terrain in northeastern Ohio. Raw data from measurements described in this report is...
This final report contains the results of an extensive study program, the development of a method for evaluating candidate communication systems, and the design of a test plan to supplement the information from the study program and provide realistic...
During October and November 1966, propagation measurements were made on two-line-of-sight paths between the islands of Maui and Hawaii, utilizing paths of a nominal 1-ns width at a carrier frequency of approximately 9 GHz. Prime objective was to de...
This report contains tabulations of transmission loss data resulting from propagation experiments at 20, 50, and 100 MHz conducted over irregular terrain in the Colorado Mountains primarily east of the Continental Divide. Raw data from measurements ...
This report contains tabulations of transmission loss data resulting from propagation experiments at 20, 50, and 100 MHz conducted over irregular terrain in the Colorado high plains east of the Continental Divide. Raw data from measurements describe...
The propagation factor for wave propagation over an impedance surface containing irregularities large compared to a wavelength is the solution of a certain integral equation. The equation is solved numerically for the special case of a two-dimension...
Numerical results concerning the disturbances caused by a typical category of slightly subrefractive or superrefractive thick tropospheric layers in line-of-sight propagation as well as the importance of total reflection from such layers. These refle...
Objective: To develop the concept for a system which will provide the Naval communication a capability for the selection of best operating frequencies for Navy HF circuits; and for predicting the time of onset, the intensity and duration of ionosphe...
This Technical note was originally given limited distribution as NBS Report No. 5092, dated July 25, 1957. Since that time part of this report have been published in the following references: (1) K. A. Norton, "Low and medium frequency radio pr...
Results of measurements of basin transmission loss over 400 and 600 miles paths are presented in the form of distributions of hourly medians for frequencies in the 100 to 1000 Mc range. The paths extend southeastward from the Front Range of the Colo...
A brief survey is given of results from an experimental program extending over the last five years to investigate the nature and characteristics of high-loss regular VHF propagation by means of scatteriung and other mechanisms in the lower ionosphere...
A discussion is given of the transmission loss expected in free space with various types of antennas, followed by a description of theoretical prediction curves for the transmission loss expected in tropospheric propagation on over-land paths. The B...
Initial results through December 1954 are reported from a continuing investigation of the extreme distance range of regular VHF propagation by scattering in the lower ionosphere. Signal strength observed at 36/Mc/s over an experimental path from New...
This report describes tropospheric propagation measurements taken over the Cheyenne Mountain paths on frequencies between 92 and 1046 Mc during February 1954. The results of the measurements are given in terms of cumulative distributions of hourly m...
The National Bureau of Standards has established extensive facilities for studies of tropospheric radio-wave propagation in the very-high frequency and ultra-high frequency portion of the frequency spectrum at Cheyenne Mountain, Colorado. These faci...
The Air Navigation Development Board asked the Central Radio Propagation Laboratory to investigate radio wave propagation in the 960–1600 Mc frequency banned. A primary focus was assessment of the reliability of air-to-grounds communications or radi...
A description is given of the facilities provided by the National Bureau of Standards on Cheyenne Mountain in Colorado and in its vicinity which are used for the measurement of the transmission loss on radio transmission circuits operated in the freq...
In this paper there is derived an approximate formulation of the problem of a scalar wave propagated over an irregular bounding surface. This formulation takes the form of a one-dimensional Volterra integral equation, which can, or so it appears, be...
Basic Radio Propagation Predictions are prepared by the staff of the Central Radio Propagation Laboratory of the National Bureau of Standards under the direction of J. Howard Dellinger, Chief, and Newbern Smith, Assistant Chief. The monthly reports o...