(IONOSPHERIC PROPAGATION - Storming Media

A Review of Satellite Signal Scintillations - Observations and Research.

16 NOV 1973

Authors: Richard K. Stevens; ESL INC SUNNYVALE CALIF

The full text of this report is not available and therefore is not for sale. This information is provided for reference purposes only.

Naturally occurring ionospheric irregularities can significantly affect the performance of communication and navigation satellite systems. Both amplitude and phase fluctuations (scintillations) are produced by ionospheric irregularities at heights from 200 to 600 km. Scintillations are most frequently observed on paths traversing the ionosphere at high latitudes and near the geomagnetic equator, although at times they are also observed at mid-latitudes as well. This report summarizes the current state-of-knowledge concerning ionospheric ...

HF Backscatter Echoes from White Sands Spread F Experiment.

DEC 1970

Authors: George D. Thome; David W. Blood; RAYTHEON CO SUDBURY MASS

A series of experiments were run during the period 5-16 October 1970 in which HF radars at the White Sands Missile Range (WSMR) were used to search for direct backscatter from ionospheric irregularities produced by the Boulder heater. The observations were made from White Sands because radars at this location view the heated volume normal to the earth's magnetic field. If the irregularities are field aligned (as might be expected ...

Solar Influences on HF Absorption and the Resulting Hawaii to California Lowest Observed Frequency.

MAY 1970

Authors: Max P. Bleiweiss; NAVAL WEAPONS CENTER CHINA LAKE CA

The theory of the absorption of high frequency (HF) radio waves is presented and used to determine the expected lowest observed frequency (LOF). Next, experimental LOFs obtained with an HF oblique incidence sounder receiver on the Hawaii-California propagation path are presented and compared with the absorption theory. The LOFs are also compared with the CNO predictions. The conclusions are that the LOF is not influenced appreciably by a varying component ...

Coherent Aperture Study.

DEC 1968

Authors: Franklin M. Fletcher; Joseph A. Green; Ronald N. DeWitt; ITT ELECTRO-PHYSICS LABS INC COLUMBIA MD

The problem of determining the median response of an array immersed in a hypothetical distorted wave field has been considered using the Monte Carlo technique as well as by means of a more formal analysis. Wave-front fluctuations specifically considered include those producing individual element outputs in which both the amplitude and phase variations can be described by Gaussian statistics, and also the physically more likely case in which individual phase-quadrature ...

COMPUTATIONS OF VLF FIELDS FOR DETERMINATION OF ELECTRON DENSITY PROFILES USING OBLIQUE SOUNDER DATA,

OCT 1968

Authors: Verne E. Hildebrand; David G. Morfitt; NAVAL WEAPONS CENTER CORONA LABS CA

Electric field strength levels have been recorded by a VLF multiple-frequency oblique-incidence ionospheric sounder over a low latitude path from Hawaii to Southern California. These field strength values are compared with predicted fields obtained from a mathematical propagation mode, in order to investigate the propagation characteristics of various electron density profiles representative of the D-region of the ionosphere. A procedure for determining a 'best-fit' profile to the sounder data is ...

An Atlas of Reduced Data Obtained in a Cooperative HF Directional Propagation Experiment Over a 1330 Kilometer Path (March 1967 - March 1968).

SEP 1968

Authors: Albert D. Bailey; Edward W. Ernst; Leon J. Miller; Walter W. Wood; ILLINOIS UNIV AT URBANA RADIO RESEARCH LAB

This is a collection of reduced data, arranged in chronological order. The data were obtained on a 1330 km propagation path between Alta Loma, Texas and Bondville, Illinois. Data for 13 months, 5 days per month are included (65 days). Each daily chart contains: oblique ionograms (propagation modes), bearing deviation plots (azimuth), average deviation plots (20 minute and 2 hour), elevation angle of arrival, doppler data, vertical ionograms (availability information). ...

EXPANDED LITTLE IDA - EXPERIMENTAL RESULTS.

AUG 1968

Authors: Roger W. Swanson; T. C. Matsumoto; Donald T. Olmsted; Stephen G. Engle; John M. Jeffords; GENERAL ELECTRIC CO SYRACUSE NY HEAVY MILITARY ELECTRONIC SYSTEMS

This report discusses the effort performed in the areas of data collection, reduction, and analysis involving five major HF propagation experiments. These experiments were concerned with determining HF propagation mode reliability, mode loss, azimuth of arrival and spectrum characteristics of individual modes. In addition a noise/interference measurement experiment was performed. Under this effort three propagation circuits were instrumented with transmitting terminals located at Thule, Greenland; Keflavik, Iceland; and Coco Solo, ...

RAY TRACING INVESTIGATION OF THE MAGNETOIONIC EFFECT ON BEARING DEVIATION IN HF TRANSIONOSPHERIC PROPAGATION.

AUG 1968

Authors: N. Narayana Rao; ILLINOIS UNIV AT URBANA RADIO RESEARCH LAB

The influence of an earth centered dipole magnetic field upon bearing deviation of medium range hf ray paths in the ionosphere is investigated by using the ESSA three dimensional computer ray tracing program for a variety of conditions involving quasi-parabolic layer models and actual electron density profiles deduced from ionograms gathered during a direction finding experiment. The adequacy of the dipole model is examined by comparing the bearing deviations obtained ...

BEARING DEVIATION IN HF TRANSIONOSPHERIC PROPAGATION.

MAY 1968

Authors: N. Narayana Rao; ILLINOIS UNIV AT URBANA RADIO RESEARCH LAB

Expressions are derived for the exact computation of bearing deviation and other high frequency radio ray path parameters in a model ionosphere with no magnetic field but with electron density varying in three dimensions. The three dimensional variation is simulated by assuming a spherically symmetric ionospheric model but with its center of curvature displaced from the center of the earth and by launching the ray out of the plane containing ...

IONOSPHERIC MORPHOLOGY.

MAR 1968

Authors: R. A. Kupferman; G. Kantor; A. H. Katz; C. Rush; AVCO MISSILES SPACE AND ELECTRONICS GROUP LOWELL MA AVCO SPACE SYSTEMS DIV

This report outlines a program of research the aim of which is to predict electron density profiles for the North American continent and surrounding waters in order to perform high-resolution ray tracing of HF radio waves. A prediction scheme for ionospheric parameters, such as f0F2 at selected locations, is outlined; and for the extension of these to all areas of interest, a new computer synoptic mapping technique has been devised. ...

RESEARCH WORKS RELATED TO SOLAR RADIO EMISSION AND V.L.F. PROPAGATION IN THE LOWER IONOSPHERE.

JAN 1968

Authors: Pierre Kaufmann; UNIVERSIDADE MACKENZIE SAO PAULO (BRAZIL) GRUPO DE RADIO-ASTRONOMIA

The report consists of the following abstracts: (1) Some Results Obtained with VLF Atmospheric Measurements at Sao Paulo, Brazil, (2) VLF Propagation Across the Geomagnetic Anomaly during SID's, (3) Characteristics of VLF Tracking Stations for Ionospheric Researches, (4) Note on the Establishment of Solar Activity Indices through Measurements at 300 MHz, (5) Experimental Results from Measurements Performed during the 12 November 1966 Total Solar Eclipse with a 4.28 cm Radio ...

RECEIVED POLARIZATION OF IONOSPHERICALLY PROPAGATED WAVES AS A FUNCTION OF TIME AND FREQUENCY.

JAN 1968

Authors: M. R. Epstein; O. G. Villard Jr; STANFORD UNIV CA STANFORD ELECTRONICS LABS

The incoming wave polarization of sweep-frequency CW radio transmissions was measured as a function of HF frequency and time of day for one-hop F-layer propagation over 1300 km N-S and 1900 km E-W temperate-latitude paths. Daytime rates of polarization rotation with frequency (at an instant of time) average 2 turns/MHz (equivalent to a null-to-null spacing of 250 MHz) over the N-S path, and 0.25 turn/MHz over the E-W path. These ...

EXPANDED LITTLE IDA, EXPERIMENTAL RESULTS.

DEC 1967

Authors: Donald T. Olmsted; Joseph A. Reeve; Bohdan Shepelavey; GENERAL ELECTRIC CO SYRACUSE NY HEAVY MILITARY ELECTRONIC SYSTEMS

The report presents the results of four major experiments involved in the Expanded Little IDA (ELIDA) Program. The objective of this program is the collection and analysis of HF propagation data that will aid in the design and operation of OHD systems. The data discussed was collected over two propagation paths: (1) Thule, Greenland to Central New York, and (2) Coco Solo, Panama Canal Zone to Central New York. Data ...

THE INTERPRETATION OF HF SWEEP-FREQUENCY BACKSCATTER SOUNDINGS TO DEDUCE THE STRUCTURE OF LOCALIZED IONOSPHERIC ANOMALIES.

DEC 1967

Authors: Thomas A. Croft; STANFORD UNIV CA STANFORD ELECTRONICS LABS

By use of computer simulation, it is possible to predict the effect of traveling ionospheric irregularities upon the data obtained by HF sweep-frequency ground-backscatter sounders. The simulation process makes use of an ionospheric model in which radio rays are traced to determine the time distribution of energy along the distant ground after skywave travel. Subsequent computation yields a synthetic record of the echo amplitude as a function of radio frequency ...

HIGH FREQUENCY RADIO COMMUNICATIONS WITH EMPHASIS ON POLAR PROBLEMS,

NOV 1967

Authors: Knut W. Eriksen; Bjoern Landmark; Finn Lied; Bernt Machlum; Eivind V. Thrane; ADVISORY GROUP FOR AERONAUTICAL RESEARCH AND DEVELOPMENT PARIS (FRANCE)

The aim of the book is to assist the practical Communication Officer and Engineer in radio communication, particularly when working in Polar Regions. All signalling by means of radio, occurs as the result of waves, that travel from the transmitter to a receiver. Of the two types of waves, the sky-wave and the ground-wave, we deal here only with the sky wave, which is particularly important for long-range communication. The ...

STATISTICAL INVESTIGATION OF IONOSPHERIC DRIFT.

31 MAY 1967

Authors: E. HARNISCHMACHER; K. Rawer; IONOSPHAREN-INSTITUT BREISACH (GERMANY)

Drift data obtained with the three antennas fading method have been analyzed with a simple 'digitized' method using 12 steps for direction and 14 for the speed value. The reduction method has been applied to observations at (A) Breisach, 1958/64, (B) Puerto Rico, 1954/60, (C) Eglin AFB, fall 1962. (A) concerns observations with 6 antennas i.e. in four triangles. By comparison it is stated that in spite of the rather ...

MEASUREMENTS OF EQUATORIAL MAGNETIC DIP ANGLE AT IONOSPHERIC HEIGHTS.

MAY 1967

Authors: Vichai T. Nimit; STANFORD RESEARCH INST MENLO PARK CALIF

Data collected for calculating electron content of the ionosphere by the Faraday rotation technique can be used to calculate the magnetic dip angle at ionospheric height near the geomagnetic dip equator. In this report the magnetic dip angle at ionospheric height was determined at the position where the angle between the ray path from the satellite to the ground station and the geomagnetic field vector is 90 degrees (transverse position). ...

A COMPUTER PROGRAM FOR VLF RAY TRACING IN A MODEL IONOSPHERE,

MAY 1967

Authors: Stanley D. Shawhan; IOWA UNIV IOWA CITY DEPT OF PHYSICS AND ASTRONOMY

The ray tracing equations and expressions necessary to evaluate these equations for a model ionosphere with a centered dipole magnetic field and an H+, He+, O+, e- diffusive equilibrium concentration model are given and discussed. A basic computer program for the numerical calculation of ray paths in a meridian plane is listed and explained. An additional routine to calculate point-to-point ray paths is briefly described. Examples are given of the ...

ON THE MEASUREMENT OF IONOSPHERIC DRIFTS,

07 DEC 1966

Authors: L. K. Nerovnya; A. A. Kashin; E. G. Andreev; FOREIGN TECHNOLOGY DIV WRIGHT-PATTERSON AFB OHIO

Over the years in the Department of Physics of the Atmosphere (Moscow University) two-frequency ionsphere stations have been developed for the investigation of drifts, absorption of radio waves, and non-linear effects. The station there at present is for the investigation of drifts of small-scale nonuniformities. A schematic diagram is given of the station consisting of a transmitter and two receivers operating in the range of 1--15 megacycles. The authors discuss ...

TRANSEQUATORIAL F-LAYER PROPAGATION STUDY.

SEP 1966

Authors: E. D. Bowen; W. J. Fay; J. L. Heritage; J. R. Buss; K. J. B. Andersen; SMYTH RESEARCH ASSOCIATES SAN DIEGO CA

This final report describes an experimental research program on the transequatorial, log range, VHF propagation in the Far East during the sun spot minimum. Four VHF frequencies, 34, 45.1, 54, and 77 MHz were transmitted from Okinawa and received at Darwin, Australia, and Lautoka, Fiji Islands. The Okinawa-Darwin path was 4300 km and oriented along a magnetic meridian, while the Okinawa-Fiji path was 7200 km long and formed an angle ...

LONG RANGE PROPAGATION STUDIES.

SEP 1966

Authors: Kristen Folkestad; FORSVARETS FORSKNINGSINSTITUTT KJELLER (NORWAY)

The report describes activity associated with step frequency oblique soundings in Northern Norway. Pertinent operational parameters are given. Various representative samples of backscatter recordings, together with appropriate deductions are displayed. Results from comparing measured data with the outcome of theoretical computations are dealt with in one of the chapters. A brief description of two general ray-tracing methods, with worked examples, has been inserted. Some aspects of fading are treated. Experimental ...

COMPARISON OF C-2 IONOSPHERIC SOUNDER DATA WITH FREQUENCY PREDICTIONS FOR SHORT-RANGE COMMUNICATION WITH MAN-PACK TRANSCEIVERS IN THAILAND.

AUG 1966

Authors: Clifford L. Rufenach; George H. Hagn; STANFORD RESEARCH INST MENLO PARK CALIF

The report briefly discusses several ionospheric parameter prediction techniques and compares values of f sub oF2, f sub min, and F-layer height (h sub L) predicted using several of these techniques with observed data taken by the C-2 ionospheric sounder at Bangkok, Thailand from its initial operation in September 1963 through March 1965. The sounder data was used to calculate a correction function for f sub oF2, and corrected predictions ...

VLF RAY TRACING IN A MODEL IONOSPHERE.

AUG 1966

Authors: Stanley D. Shawhan; IOWA UNIV IOWA CITY DEPT OF PHYSICS AND ASTRONOMY

A VLF ray tracing study in a model ionosphere including ions is presented. A review of previous VLF ray tracing methods is given. The physical meaning of rays and ray paths is discussed and it is concluded that for ray tracing in the ionosphere the wave packet and Poynting vector approaches give the same results. Two-dimensional ray tracing equations are derived for the case of a horizontally stratified ionosphere and ...

VLF IONOSPHERIC SOUNDER PROGRAM.

18 MAR 1966

Authors: David J. Shamp; Lawrence E. Christensen; Andres Farkas; AERO GEO ASTRO CORP CORONA CALIF

The VLF pulse sounder is a new basic tool for studying the lower ionosphere. The system is a combination pulse sounder, phase sounder, and polarimeter. A concurrent program of system improvement and experimental study of the ionosphere has been conducted. The results of this program as presented here should be of use in planning various types of communication, navigation, and detection systems which make use of VLF propagation or distribution ...

IONOSPHERIC DATA: BANGKOK, THAILAND.

FEB 1966

Authors: Vichai T. Nimit; STANFORD RESEARCH INST MENLO PARK CA

SOME CONSIDERATIONS IN THE OPERATIONAL CLASSIFICATION OF SUDDEN IONOSPHERIC DISTURBANCES AND COMPUTATION OF PEAK INCREASED ABSORPTION ON HF CIRCUITS.

17 JAN 1966

Authors: BOOZ-ALLEN APPLIED RESEARCH INC BETHESDA MD

The report reviews various approaches to the application of sudden phase anomaly (SPA) data derived at very low frequency (VLF) to the operational estimation of increased high frequency (HF) absorption resulting from solar flares. The means of categorizing 'weak' and 'strong' SPA events originally devised by Chilton is described. Within the 'strong' category, five further classifications relative to the ratio of D-layer ionization densities before and at the peak of ...

IONOSPHERIC DATA: BANGKOK, THAILAND.

OCT 1965

Authors: Vichai T. Nimit; STANFORD RESEARCH INST MENLO PARK CA

Ionospheric observations are being carried out at the Laboratory of the Military Research and Development Center at Bangkok, Thailand, a joint United States-Thailand organization. A Model C-2 vertical-incidence sounder supplied and operated by the United States Army Radio Propagation Agency has been used.

ON WAVE PROPAGATION IN A LINEARIZED, VERTICALLY INHOMOGENEOUS PARTIALLY IONIZED GAS; FORMULATION AND MATHEMATICAL METHODOLOGY,

30 SEP 1965

Authors: Harold R. Raemer; NORTHEASTERN UNIV BOSTON MASS DEPT OF ELECTRICAL ENGINEERING

The problem of wave propagation in a linearized 3-component (electron, ion, neutral) gas is discussed for the case where the ambient gas parameters are arbitrary functions of the vertical coordinate in z and uniform with respect to time and the horizontal coordinates. The formulation of the problem from the Boltzmann equation to a system of simultaneous coupled linear algebraic and first order differential equations in z is discussed in some ...

IONOSPHERIC DATA: BANGKOK, THAILAND.

AUG 1965

Authors: Vichai T. Nimit; STANFORD RESEARCH INST MENLO PARK CA

IONOSPHERIC DATA: BANGKOK, THAILAND.

MAR 1965

Authors: Vichai T. Nimit; STANFORD RESEARCH INST MENLO PARK CA

Ionospheric observations are being carried out at the Laboratory of the Military Research and Dvelopment Center at Bangkok, Thailand, a joint United States-Thailand organization. A Model C-2 vertical-incidence sounder supplied and operated by the United States Army Radio Propagation Agency has been installed there.

IONOSPHERIC DATA: BANGKOK, THAILAND.

MAR 1965

Authors: Vichai T. Nimit; STANFORD RESEARCH INST MENLO PARK CA

IONOSPHERIC DATA: BANGKOK, THAILAND.

MAR 1965

Authors: Vichai T. Nimit; STANFORD RESEARCH INST MENLO PARK CA

IONOSPHERIC DATA: BANGKOK, THAILAND.

MAR 1965

Authors: Vichai T. Nimit; STANFORD RESEARCH INST MENLO PARK CA

IONOSPHERIC DATA: BANGKOK, THAILAND.

JAN 1965

Authors: Vichai T. Nimit; STANFORD RESEARCH INST MENLO PARK CA

Ionospheric observations are being carried out at the Laboratory of the Military Research and Development Center at Bangkok, Thailand, a joint United States-Thailand organization. A model C-2 vertical-incidence sounder supplied and operated by the United States Army Radio Propagation Agency has been installed there.

IONOSPHERIC DATA: BANGKOK, THAILAND.

JAN 1965

Authors: Vichai T. Nimit; STANFORD RESEARCH INST MENLO PARK CA

IONOSPHERIC DATA: BANGKOK, THAILAND.

DEC 1964

Authors: Vichai T. Nimit; STANFORD RESEARCH INST MENLO PARK CA

IONOSPHERIC DATA: BANGKOK, THAILAND.

DEC 1964

Authors: Vichai T. Nimit; STANFORD RESEARCH INST MENLO PARK CA

IONOSPHERIC DATA: BANGKOK, THAILAND.

NOV 1964

Authors: Vichai T. Nimit; STANFORD RESEARCH INST MENLO PARK CA

IONOSPHERIC DATA: BANGKOK, THAILAND.

AUG 1964

Authors: Vichai T. Nimit; STANFORD RESEARCH INST MENLO PARK CA

IONOSPHERIC PROPAGATION STUDIES.

01 JUN 1964

Authors: Braulio Dueno; PUERTO RICO UNIV MAYAGUEZ

A relation for the condition of minimum time delay focussing for the spherical earth geometry is obtained assuming on ionosphere with a parabolic distribution of electron density. Theoretical curves for the case of sweepfrequency backscatter are obtained that agree well with experimental values. A qualitative explanation of frequency independent echoes is given in terms of the flat earth and ionosphere approximation. Unusual cases of motions of this frequency independent echoes ...

GREAT-CIRCLE AND DEVIATED-PATH OBSERVATIONS ON CW SIGNALS USING A SIMPLE TECHNIQUE,

MAY 1964

Authors: Frederic H. Dickson; Richard Silberstein; ARMY SIGNAL RADIO PROPAGATION AGENCY FORT MONMOUTH N J

A modification of the Pinwheel techniques of observing HF signals propagated over deviated paths was used over Pacific paths on 12, 18 and 30 Mc. Strip-chart records made of CW signals with directive receiving antennas rotating ten times as fast as similiar transmitting antennas gave distinct records of deviated scatter signals alone or co-existing with great-circle signals. By the use of precise program timers, combined receiving and transmitting azimuths for ...

MULTIPATH PROPAGATION ON TRANSARCTIC HF CIRCUITS,

30 OCT 1961

Authors: Johannes Ortner; Leif Owren; KIRUNA GEOPHYSICAL OBSERVATORY (SWEDEN)

Multipath observations of HF pulse transmissions are discussed as observed on the transpolar propagation path College, Alaska - Kiruna, Sweden. During the winter months the signal strength was unusually high at Kiruna. Furthermore, the signals received on 18 Mc/s showed usually 3 components, with time delays of 3 and 6-7 msec respectively. It is tried to explain the unusual propagation conditions by means of great-circle tilt modes. For the long ...

NORTHERN LATITUDE PROPAGATION RESEARCH.

20 OCT 1961

Authors: Alv Egeland; Bengt Hultqvist; Johannes Ortner; KIRUNA GEOPHYSICAL OBSERVATORY (SWEDEN)

Two year investigations of oblique auroral reflections in the VHF band are summarized. The behaviour of VLF propagation between Rugby and Kiruna, riometer observations at Kiruna and a transpolar HF propagation experiment are discussed. A symposium on PCA is reviewed. (Author)