RF Propagation Information
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 and highly technical topic of amateur radio operation.
Important Space Weather Data
| 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 |
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 below 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.
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.
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🔗 Paul L. Hermann Propagation Tools
Live Solar-Terrestrial Data Widget
showing only space weather data.
provided by Paul L. Hermann.
Propagation Tools
The Live Solar-Terrestrial Data Widget to the left shows 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
Radio beacons are another source of propagation information. These are available on pretty much all bands.
ⓘ Radio Beacons
References:
- QSL.net 🔗 How to Read Radio Propagation Banners
- ARRL Article 🔗 Propagation of RF Signals