HF Systems
FORECAST SOL: Disturbed red MAG: Normal green ION: Normal green
HomeHF SystemsGlobal HFHAP ChartsHourly HAP Charts Friday, Jul 19 2024 19:19 UT
Global HF

Hourly HAP Charts

These are Hourly Area Predictions (HAP) of communication frequencies based on the previous hours observed conditions for the Global HF ionosphere. As this product depends on global data it can currently only be made for the previous UT hour.


HAP charts are designed for communications between a specified base and mobile within a nominated area.

Features of SWS HAP charts:

  • Each chart shows colours which represent the recommended HF frequencies for contacting the base or mobile within the area bounded by the chart for a particular hour.
  • The geographic zone, which is variable, is represented by a map showing latitude and longitude.
  • Charts are in Universal Time (UT).

go to top of page