From AMS Glossary
A term normally referring to the measured solar radio flux at 10.7 cm (2800 MHz) and is reported in solar flux units (sfu). The F10.7 solar flux is an excellent indicator of solar activity and originates high in the chromosphere and lower corona of the sun. The F10.7 has been measured consistently in Canada since 1947, first at Ottawa, Ontario, and now the Penticton Radio Observatory in British Columbia. The solar flux generally can reach as low as 65 sfu during extremely quiet sun periods and approach 300 sfu during periods of maximum solar activity.
Space Weather Prediction Center, 2018: F10.7 cm radio emissions. Accessed 1 October 2018. Available at https://www.swpc.noaa.gov/phenomena/f107-cm-radio-emissions.
Term edited 1 October 2018.