Station List

How to use this map

Reading the map

Each colored circle represents a real ionosonde station measuring the ionosphere. The number in the center shows the foF2 value in MHz. The color indicates how high the critical frequency is:

< 3 MHz: Very low foF2 - only low bands (80m-160m) usable

3-5 MHz: Moderate foF2 - bands up to 40m usable

5-7 MHz: Good foF2 - bands up to 20m open

7-9 MHz: High foF2 - high bands (15m-17m) open

> 9 MHz: Excellent foF2 - all bands including 10m-12m

Practical use for contacts

The foF2 indicates the maximum frequency reflected vertically. For oblique DX contacts (long distance), the actual MUF is about 3 times the foF2. Look at stations near your location to understand local conditions.

Practical example

If you see foF2 = 7 MHz on a station near you:

Estimated MUF for 3000 km = about 21 MHz
20m, 17m and 15m bands should be open
10m and 12m bands probably closed

Interacting with the map

Click on a marker to see all station details (MUF, F2 layer height, confidence)
Hover over a marker for a quick summary
Use the table below to compare all stations sorted by foF2

What is foF2?

The foF2 (F2 layer critical frequency) is the maximum frequency that is reflected vertically by the ionosphere. It's a fundamental parameter for understanding which HF bands are usable.

Ionospheric Parameters

foF2: F2 critical frequency - maximum vertically reflected frequency
hmF2: Height of F2 layer peak in km
MUF(3000): Maximum Usable Frequency for a 3000 km path
foE: E layer critical frequency

Data Sources

Data comes from GIRO (Global Ionospheric Radio Observatory), NOAA and SWS Australia networks, aggregated via KC2G.

Ionosonde foF2 Map