Palomar Amateur Radio Club STEM Experimentation Lab

One of the most important (and highly technical) considerations in HF operation is current propagation conditions. Understanding solar flux, K-indices, and A-indices helps predict whether long-distance signals will "skip" off the ionosphere effectively. It is a fascinating topic of amateur radio operation.

Paul L. Hermann N0NBH provides excellent real-time solar-terrestrial data. He offers a number of widgets that display useful data for RF propagation conditions and predictions.
  ⓘ  🔗 Paul L. Hermann Propagation Tools

So what does all this mean?
The propagation of RF signals is affected by the curvature of the earth, atmospheric conditions, geomagnetic activity and effects of the sun's activity, sometimes called "space weather".

The information shown in the widget to the right is used to determine how space weather affects RF propagation for various radio bands. This helps to predict what bands and frequencies will give us the best chance of successful operation.

This widget includes predictions for HF and VHF bands. It even gives you a nice current image of the sun.

This is just one of many available tools that a simple web search for "radio propagation" will lead you to.

Important Data	Description
SFI  SN	Solar Flux Index Sunsport Number → Higher numbers are better
K-Index	Disturbance of Earth's magnetic field
A-Index	Daily average of geomagnetic activity
X-ray	Solar Flare X-raay intensity affecting D-region absorption
304A	Relative strengh of solar radiation at 304 angstroms (the red in the solar image). Affects F-region ionization
Ptn Flx	Proton Flux density of the solar wind
Elc Flx	Electron Flux density of the solar wind
Aurora	Ionization strength of the atmospheric E-region in the polar regions

Propagation Tools

Live Solar-Terrestrial Data Widget
showing only space weather data.
provided by Paul L. Hermann.

Live Solar-Terrestrial Data Widget
showing space weather data and
band propagation predictions
for both HF and VHF bands.
provided by Paul L. Hermann.

The band prediction data gives a quick look at how good or bad the RF propagation conditions will be for day and night for the indicated band. The MUF value is the highest predicted usable frequency in the HF bands. The value shown here is that measured at Boulder, Colorado