VOACAP

VOACAP (Voice of America Coverage Analysis Program)^[1] is a radio propagation model that uses empirical data to predict the point-to-point path loss and coverage of a given transceiver if given as inputs: two antennas (configuration and position), solar weather, and time/date. Written in Fortran, it was originally designed for Voice of America.

VOACAP HF coverage prediction

VOACAP HF propagation prediction

Some movies on the coverage during daytime can be found here.^[2]

Simulating HF propagation conditions

Currently versions based on the original source tree exist for Windows, Linux (voacapl)^[3] and OSX.^[4] The program core uses text files for I/O and a bunch of wrappers now exist.

Besides commercial visualization tools, there are also Open Source implementations with GUI:

• VOACAP online using ITS' IONCAP model, available at http://www.voacap.com/prediction.html
• the PropagationPython Project.^[5] aka "Proppy" which is an evolution and alternate to VOACAP using the new ITURHFProp prediction model (formerly REC533) and always in development by James Watson^[6]

For immediate results, VOACAP provides a web interface for both the coverage^[7] and the prediction.^[8]

See also

• Shortwave
• Radio propagation model
• Radio propagation