October 1977 | Technical Report TR 77-128
Communication and System Performance Model for VHF and Higher Frequencies
Cite This Publication
R. D. Jennings and S. J. Paulson, “Communication and System Performance Model for VHF and Higher Frequencies,” Technical Report TR 77-128, U.S. Department of Commerce, Office of Telecommunications, Institute for Telecommunication Sciences, October 1977.
Abstract:
Communication system designers and engineers often must decide whether to use design-aid models not well suited to the problem at hand or to perform many tedious and laborious hand calculations which, coupled with certain “rules of thumb,” provide an estimate of system performance. The model documented in this report provides relief from such problems. For communication systems which operate at VHF and higher frequencies, the character of the terrain between the transmitting and receiving antennas, as well as the heights of the antennas above immediate terrain, will affect significantly the attenuation of the radio signals. The model reported herein consi9ers these terrain influences, along with other commonly considered influences, by automatically accessing digitized topographic data files to develop the path data needed to compute the basic transmission loss. Computation of the basic transmission loss is accomplished using the Longley-Rice formulation for point-to-point paths. The statistical character of the basic transmission loss results from long-term fading (time availability),
path to path differences (location variability), and prediction confidence considered in the model. The type of model output data is selected by the user. Options range from simple path terrain information to basic transmission losses to utilizations of the basic transmission loss in computing power density or received signal level. There is, in addition, an output option which portrays predicted communication reliability as the probability that received signal level will exceed a specified threshold for specified conditions of time availability and location variability. All output options will provide data in either tabular or plotted form. Plotted output data are contoured over a geographical area not to exceed two degrees latitude by two degrees longitude.
Keywords: basic transmission loss; propagation; communication; computer model; communication system; received signal level; propagation loss; communication reliability; communication system performance; path profile; power density
For funding information concerning this report, click this link.
Funding Information
Performing Agency
U.S. Department of Commerce
Office of Telecommunications
1325 G Street, N. W.
Washington, D. C. 20005
Funding Agency
U.S. Department of Defense
U.S. Department of the Army
U.S. Army Communications Command, Ft. Huachuca, AZ 86513
https://ror.org/035w1gb98
Disclaimer:
Certain commercial equipment, components, and software may be identified in this report to specify adequately the technical aspects of the reported results. In no case does such identification imply recommendation or endorsement by the National Telecommunications and Information Administration, nor does it imply that the equipment or software identified is necessarily the best available for the particular application or uses.
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