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The search returned 1,243 publication(s) on its.ntia.gov.
The subject computer programs are described and the FORTRAN source decks are Listed. The physical problem solved by the computer program is described. It allows an anisotropic ionospheric model, and variations in the model along the propagation path....
A computer based simulation model (Hatfield and Adams, 1970) was used to analyze the coverage obtained in the Command and Control and Arctic areas when transmitting CW and FAX from the U.S. Coast Guard’s Otis AFB, Cape Cod, Massachusetts facility. T...
The three sites selected by USCS as a result of Part 1 have been simulated in combination with the seven existing radio stations. The HF (4–22 MHz) predicted performance for all such combinations has been computed for the worst case propagation cond...
This report supplements information previously developed by the authors on interference predictions for VHF/UHF air navigation aids, Included are (a) radiation patterns needed to adapt curves previously developed for the Instrument Landing System (IL...
Some factors which could or should affect frequency allocations and assignments in the future are considered. These include propagation predictions, modulation, coding and information processing. In addition a forecast of the use of cables as replace...
The critically increasing demand for radio frequency allocations has stimulated development of information needed to reexamine efficient use of the radio spectrum. The characteristics and limitations, of the radio channel, with emphasis on the transm...
Several examples of the numerical evaluation of an integral equation for the calculation of the attenuation of a radio wave are given. These waves are assumed to be propagated over realistic, smoothly varying irregular, inhomogeneous terrain. Results...
During the Engineering Experimental Phase (1971–73) of the National Data Buoy Development Project, the U.S. Coast Guard (USCG) will deploy a network of automatic buoys in the Gulf of Mexico. They will gather oceanographic and meteorological data tha...
Azimuth and spectrum spread was measured from sidescatter and great circle signals over two transmission paths: Washington, D. C. to Boulder, Colorado, and Long Branch, Illinois, to Boulder. Both Doppler and fading spread were measured. The effective...
An ideal dispersion filter for simulating ionospheric dispersion is defined as one with constant dispersion in a channel frequency band and zero dispersion outside the band. An optimum lumped-element all-pass filter that approximates this ideal has a...
Worldwide atmospheric noise at 1 MHz, as presented in CCIR Report 3 22 (1963), has been numerically mapped in universal time. The mapping technique and representative contour maps for January and July, are presented. Fourier analyses were performed s...
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....
A new mathematical method is developed for interpolation from a given set of data points in a plane and for fitting a smooth curve to the points. This method is devised in such a way that the resultant curve will pass through the given points and wi...
Tests of the radiation efficiency of a dipole antenna 100 ft. long and buried in Sherman granite are described. The measurements were taken under winter conditions as a comparison with earlier measurements made in summertime; this determines whether...
Typical amplitude and time statistics of atmospheric radio noise for the four seasons, spring, summer fall, and winter, are given. The statistics were obtained from detailed computer analysis of high-dynamic range tape recordings of the noise process...
A total of six possible pairs of sites for a new U.S. Coast Guard, long range, HF radio station is evaluated. These six pairs of sites are made up of different combinations of four different transmitter sites and six different receiver sites. The a...
The F1 layer is not explicitly included in current ITS high frequency radio propagation predictions. Numerical maps of F1 layer characteristics, similar to those for F2, E, and Es characteristics now in use, were rejected in favor of a more concise ...
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...
The present 2182 kHz communication between Ketchikan, Alaska, and ships or boats within 300 nautical miles of Ketchikan Coast Guard Station is poor. Calculations have been made of predicted sky-wave mode performance for representative circuits with s...
The area in the Gulf of Mexico covered 85 percent of the time in the noisiest CCIR time block by the Coast Guard is calculated based on standard ground wave propagation and CCIR noise predictions. Most of the Gulf within 300 miles of the shore is cov...