Here’s a great resource for amateur radio operators. The best thing about it is that it’s free! Unfortunately, it only runs on PCs, but since the FORTRAN source code is also free, perhaps I can figure out a way to adapt it to the Mac.
VOACAP is a free professional HF prediction program from NTIA/ITS, originally developed for Voice of America (VOA) and is the result of 50+ years of U.S. HF research and development. Considered by many to be the most professional HF system performance prediction tool available, VOA and a number of other international HF broadcasters and institutions all over the world currently use it for HF frequency planning.
- Easy to use graphical user interface and, for advanced users, powerful command line options
- Detailed Point-to-Point graphs and Area Coverage maps for 22 parameters of circuit quality such as:
- SNR (Signal-to-Noise Ratio)
- Required Power Gain
- Signal Power
- Takeoff/Arrival Angle, and more
- Accurate predictions of the distribution of Worldwide Atmospheric and Man-made radio noise using the latest ITU-R recommendations and a unique combination methodology developed by the late A. D. Spaulding, a world authority in the modeling of noise distributions
- Detailed hourly and 24-hour predictions for the entire HF spectrum [2 to 30 MHz] with user assigned frequencies, such as:
- Point-to-Point Performance vs Distance at the given hour for the given parameter at one or all user assigned frequencies
- Point-to-Point Performance vs Time for the given parameter at one or all user assigned frequencies on the 24-hour scale
- User defined circuit databases for repeated or batch calculations
- Thirty calculation Methods for:
- antenna patterns
- complete system performance
- Versatile coverage maps: one transmitter to many receivers [VOAAREA], or many transmitters to one receiver [VOAAREA Inverse] for bi-directional circuit studies
- Freely adjustable geographical maps to be plotted on
- Adjustable precision in coverage map calculations
- Huge databases of more than 35,000 U.S. and world locations, including DXCC, NCDXF beacons, and HF broadcasting stations, to name a few
- Accepts unlimited number of user defined location databases
Database of hundreds of transmit and receive antennas, with ability to user adjustments using HFANT, for:
- amateur radio
- SWL, and more
- Accepts unlimited number of user defined antenna files (HFANT and Type 11 & 13)
- Comprehensive, user-community supported online VOACAP Quick Guide available for beginners and advanced users
- FORTRAN source code freely available for the prediction module of VOACAP [VOACAPW]
- Not subject to copyright protection in the U.S.
- Available for free downloading from the U.S. Department of Commerce (NTIA/Institute for Telecommunication Sciences; Boulder, Colorado).