IONCAP/VOACAP Model 1983/1993

Author: L. R. Teters, J. L. Lloyd, G. W. Haydon, D. L. Lucas, F. G. Stewart
Institute for Telecommunication Sciences
National Telecommunications and Information Administration
325 Broadway, Boulder, Colorado 80303

Parameter: Electron density, maximum usable frequency, performance estimate for telecommunication systems

Brief Description:
The Ionospheric Communications Analysis and Prediction Program (IONCAP) provides the means to calculate HF propagation parameters at any location. Field strength, mode reliability, the maximum usable frequency (MUF) and the lowest useful frequency (LUF) are some of the parameters calculated by IONCAP. They enable the user to specify antenna gains as a function of take-off angle and to specify required system performance in terms of the signal-to- noise ratio evaluated at the receiving point of the circuit. Required inputs include the transmitter and receiver location, transmitter power, universal time, month, and sunspot number. The Voice of America Coverage Analysis Program (VOACAP) is a derivative of IONCAP specifically for broadcast relay station design and horizontal dipole curtain antenna specification. VOACAP has an interactive input menu.

- On IBM PC diskette from the National Technical Information Service, search for IONCAP or VOACAP
- IONCAP FORTRAN executable from the National Geophysical Data Center (

L. R. Teters, J. L. Lloyd, G. W. Haydon, and D. L. Lucas, Estimating the Performance of Telecommunication Systems Using the Ionospheric Transmission Channel-Ionospheric Communications Analysis and Prediction Program User's Manual, National Telecommunication and Information Administration, Report NTIA 83-127, Boulder, 1983.

C. M. Rush, Ionospheric Radio Propagation Models and Predictions-A Mini-Review, IEEE Trans. Antennas Propag. AP-34, 1163, 1986.

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