VOACAP propagation calculator information |
VOACAP (Voice of America Coverage Analysis Program) 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.
DXMAPS doesn't make use the VOACAP on-line scripts, but it runs its own calculations using the VOACAP model and making some assumptions in order to bypass the complexity of the input parameters required and showing the results in an intuitive way for any radio amateur. The assumed values are based on an average amateur radio station, with an average antenna and power. You have to understand that if your station is far above or below the average, these calculations could not match the SNR (Signal to Noise Ratio) that you could expect, but even so you could use them as a guidance for knowing the best times and frequencies for a given path.
Explanation of the graph: