Communication System Performance Model for VHF and Higher Frequencies,
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 considers these terrain influences, along with other commonly considered influences, by automatically accessing digitized topographic data files to develop the path data needed to computer 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.
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 01, 1977
- Accession Number
- ADA049174
Entities
People
- R. D. Jennings
- S. J. Paulson