SWS GRAFEX HF FREQUENCY PREDICTIONS ADDRESS NO. 1234 =============================================================================== Circuit: Geraldton Perth Date: 12 August, 2026 T-index: 35 Bearings: 162 341 Distance: 373 km First Mode |--------F r e q u e n c y (MHz)---------| Second Mode 1F 51-56 1E 24 1 5 10 15 20 25 30 35 40 UT OWF EMUF ALF |...|....| ....|....| ....|....| ....|....| OWF EMUF ALF UT 00 5.6 3.9 2.4 BFF%. 00 01 6.1 4.6 2.8 ABFF%. 01 02 6.3 5.1 3.0 ABBF%. 02 03 6.4 5.3 3.1 BBF%.. 03 04 6.6 5.5 3.2 BBF%.. 04 05 6.6 5.4 3.2 BBF%.. 05 06 6.7 5.3 3.1 BBF%.. 06 07 6.7 4.9 2.9 ABFF%.. 07 08 6.4 4.4 2.7 ABFF%. 08 09 6.0 3.4 2.2 BFF%%. 09 10 4.9 0.7 0.0 FFFF%%. 10 11 3.9 0.7 0.0 FFF%%. 11 12 3.3 0.7 0.0 FFF%. 12 13 3.1 0.7 0.0 FFF%. 13 14 3.2 0.7 0.0 FFF%. 14 15 3.1 0.7 0.0 FFF.. 15 16 3.1 0.7 0.0 FFF.. 16 17 3.1 0.7 0.0 FFF.. 17 18 3.0 0.7 0.0 FF%.. 18 19 2.9 0.7 0.0 FF%%. 19 20 2.8 0.7 0.0 FF%.. 20 21 2.7 0.7 0.0 FF%. 21 22 2.8 0.7 0.0 FF%. 22 23 4.2 1.7 1.2 FFF. 23 UT OWF EMUF ALF |...|....| ....|....| ....|....| ....|....| OWF EMUF ALF UT =============================================================================== |. USABLE LESS THAN 50% OF DAYS |% USABLE 50% TO 90% OF DAYS | |B BOTH E and F MODES 90% OF DAYS |M MIXED FIRST AND SECOND F MODES | |F FIRST F MODE ONLY |E E-LAYER PROPAGATION |P 90% E and 50-90% F | |S SECOND MODES ONLY |A HIGH ABSORPTION |X COMPLEX MODES | (c) 12-Aug-2026 BoM Space Weather Services, Sydney Australia +61-2-9213-8000