HF Communications Warning

(last updated 20 Apr 2026 21:55 UT)

SUBJ: ASWFC HF RADIO COMMUNICATIONS WARNING 26/37 ISSUED AT 2220UT/19 APRIL 2026 BY THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE. Maximum Usable Frequencies (MUFs) are depressed by up to 30% due to geomagnetic activity induced by a coronal hole high speed wind stream. MUFs are expected to be depressed over the next UT day. DEGRADED HF PROPAGATION CONDITIONS EXPECTED FROM 19-20 APRIL 2026 IF COMMS DIFFICULTIES EXPERIENCED TRY A LOWER FREQUENCY BAND _____________________________________________________________ HF COMMUNICATIONS FORECAST (AUSTRALIAN/NEW ZEALAND REGION) FREQUENCY BANDS T-index MUFs 2 4 6 8 12 16 22 26 _____________________________________________________________ 19 Apr: 40 -30% 2 4 6 8 8 12 16 16 20 Apr: 50 -20% 2 4 6 8 12 12 16 22

Please note this icon refers to any current HF Depression Warning. For HF Fadeout Warnings, see here.