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VOACAP (Voice of America Coverage Analysis Program) is a 
Some movies on the coverage during daytime can be found here.
radio propagation model
Radio propagation is the behavior of radio waves as they travel, or are propagated, from one point to another in vacuum, or into various parts of the atmosphere.
As a form of electromagnetic radiation, like light waves, radio waves are affect ...
that uses empirical data to predict the point-to-point path loss
Path loss, or path attenuation, is the reduction in power density (attenuation) of an electromagnetic wave as it propagates through space. Path loss is a major component in the analysis and design of the link budget of a telecommunication system. ...
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
Voice of America (VOA or VoA) is an international broadcasting network funded by the federal government of the United States that by law has editorial independence from the government. It is the largest and oldest of the American internation ...
.
Some movies on the coverage during daytime can be found here.
Simulating HF propagation conditions
Currently versions based on the original source tree exist for Windows, Linux (voacapl) and OSX. 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. 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 For immediate results, VOACAP provides a web interface for both the coverage and the prediction.Online Voacap prediction http://www.voacap.com/prediction.htmlSee also
*Shortwave
Shortwave radio is radio transmission using radio frequencies in the shortwave bands (SW). There is no official definition of the band range, but it always includes all of the high frequency band (HF), which extends from 3 to 30 MHz (app ...
* Radio propagation model
Radio propagation is the behavior of radio waves as they travel, or are propagated, from one point to another in vacuum, or into various parts of the atmosphere.
As a form of electromagnetic radiation, like light waves, radio waves are affect ...
* Radio propagation
Radio propagation is the behavior of radio waves as they travel, or are wave propagation, propagated, from one point to another in vacuum, or into various parts of the atmosphere.
As a form of electromagnetic radiation, like light waves, radio w ...
References