Radio weather report from the HF department of the DARC

The HF department of the DARC publishes radio weather reports every working day with plain text, numbers, and abbreviations. But what do these abbreviations mean, and what information can be derived from them?

 

This can be easily understood using the radio weather report from January 14, 2026.

 

ZCZC 140415UT JAN26 QAM SFI117 SSN49 eSFI102 eSSN52 KIEL A12 K(3H)2 SWS528 BZ-2 BT6 HPI34 DST-6 KP4CAST(3D) MAX 3/4 2/3 2/3 MUF3000 MAX28+ (D) MIN6(N) DATA BY SWPC/NOAA SANSA WDC/KYOTO MET OFFICE UK GFZ POTSDAM FWBST RHB NNNN

 

Basic structure

ZCZC … NNNN

Classic telegraphy/WMO header

  • ZCZC = Start of message
  • NNNN = End of message

 

Time & place

  • 140415UT JAN26 → January 14, 2026, 04:15 UTC
  • QAM → Identifier for a space weather/geomagnetic product
  • KIEL → Issuing agency/regional reference (here Kiel)

 

Solar activity

  • SFI117 → Solar Flux Index = 117 (average solar activity)
  • SSN49 → Sunspot number 49 (from the previous day!)
  • eSFI102 / eSSN52 → Forecast values. eSSN (effective SunSpot Number) or eSFI (effective Solar Flux Index)

 

Geomagnetic activity

  • A12 → Daily A-index = 12 (from the previous day!) (quiet to slightly disturbed)
  • K(3H)2 → K index over 3 hours = 2 (quiet)
  • KP4CAST(3D) → 3-day forecast of the Kp index
    • Day 1: max 3 / 4
    • Day 2: 2 / 3
    • Day 3: 2 / 3

No severe geomagnetic storms expected

 

Solar wind & magnetic field

  • SWS528 → Solar wind speed 528 km/s (increased)
  • BZ-2 → Bz component −2 nT (slightly south → weak coupling possible)
  • BT6 → Total magnetic field strength 6 nT

 

Disturbance & index values

  • HPI34 → Hemispheric power index (aurora activity)
  • DST-6 → Dst index −6 nT (no storm phase)

 

Radio wave propagation (HF)

  • MUF3000 MAX28+(D) → Maximum usable frequency ~28 MHz during the day
  • MIN6(N) → Minimum MUF ~6 MHz at night

Very good shortwave conditions during the day, moderate at night

 

Data sources

  • SWPC/NOAA – US Space Weather Prediction Center
  • SANSA – South African National Space Agency
  • WDC/Kyoto – geomagnetic reference data
  • Met Office UK, GFZ Potsdam, FWBST, RHB

 

Overall assessment (simplified)

  • Calm to slightly active space weather
  • Good to very good HF radio conditions
  • No critical geomagnetic disturbances
  • No danger to power grids or GNSS expected