Solar Conditions & Ham Radio Propagation
Solar radiation impacts radio wave propagation, with sunspots enhancing ionosphere reflection and low activity reducing global communication potential, making ham radio success dependent on selecting suitable frequency bands.
Amateur radio operators use solar indices to predict radio wave behavior and adjust communication strategies.
See for example the following banner:
The banner displays numerical indices, which are explained below:
SFI - Solar Flux, 2800MHz (10.7cm)
(SFU units) correlates with F2-layer ionization; higher value better HF conditions.
(SFU units) correlates with F2-layer ionization; higher value better HF conditions.SN - Daily Sunspot Number is a measure of the solar activity; like SFI it correlates with enhanced F2-layer i.e. better HF conditions
K-Index: Geomagnetic Disturbance; good conditions K < 3 | A -Index: 24 hours Average; good conditions A < 10
: Geomagnetic Disturbance; good conditions K < 3 | A -Index: 24 hours Average; good conditions A < 10304 Å: Total Solar Radiation SEM (Solar EUV Monitor) wavelenth: 304 Ångstroms (30.4nm) that affects F-layer ionization
Ptn - Proton Flux Density | Elc - Electron Flux Density in the Solar Wind;
both impact E-layer
Aurora indicates the strength of the ionization of the F-layer in the polar regionsMUF Boulder - Maximum Usable Frequency (MHz) at Boulder, CO, USA, updated every 15 minutes.
