Amateur Radio Station
Operator: Herwig "Herb" Feichtinger
Petershausen, Bavaria, Germany
HF transceiver: Kenwood TS-590S - see my
More station details: DC1YB
image on the right shows the current HF propagation indices.
- SFI: Solar flux index, measured at a wave length of 10.7 cm. During
solar minimum (every ~11 years), this value is down to 65. Solar maximum values
are typically 150 or more. High values result in a higher MUF (maximum usable
frequency) and a better propagation especially on the higher bands
(20/17/15/12/10 m, sometimes even 6 m).
- SN: Sunspot number, calculated from the count of the visible darker areas on the sun's surface
plus ten times the number of spotted regions.
The solar flux follows this number more or less.
The higher the number, the better the HF propagation.
- A index: Linear value indicating the status of earth's magnetic
field, ranging from 0 (quiet) to 400 (severe storm). Low values result in a
better HF propagation.
- K index: Logarithmic value from 0 to 9, computed from a 3-hour
average of the A index. Low values result in a better HF propagation.
- X-ray: High values are typically caused by solar flares and can fade
out HF communications during daytime.
- 304 Å: The wave length of 304 Ångström is sometimes used as an
alternative to the 10.7 cm SFI because it is tracking HF propagation more
- Proton flux: High values are caused by solar radiation storms; they
are measured by the GOES satellite.
- Electron flux: High values can cause HF blackouts in polar regions.
- Aurora: A natural light typically in the high-latitude areas (south
pole, north pole) induced by solar wind. It can be used for VHF backscatter.