While the Club repeater system provides wide-area VHF communications, HF NVIS propagation is also used to maintain communications in the event the repeater system is inoperative.
HF NVIS MAP
HF NVIS propagation frequencies vary with time of year and the current solar cycle. The Australian Bureau of Meteorology maintains a near-real time map of the ionosphere which indicates which frequencies may be suitable for NVIS propagation. To use the map below, simply find your location and match the chart color to the legend to see the maximum usable frequency for NVIS propagation at that location.