SWS GRAFEX HF FREQUENCY PREDICTIONS ADDRESS NO. 1234 =============================================================================== Circuit: Albany Perth Date: 18 August, 2026 T-index: 60 Bearings: 331 152 Distance: 386 km First Mode |--------F r e q u e n c y (MHz)---------| Second Mode 1F 50-55 1E 24 1 5 10 15 20 25 30 35 40 UT OWF EMUF ALF |...|....| ....|....| ....|....| ....|....| OWF EMUF ALF UT 00 6.3 4.6 2.6 ABFF%. 00 01 6.9 5.4 3.0 ABBF%%. 01 02 7.3 5.9 3.2 BBFF%.. 02 03 7.5 6.2 3.3 BBBF%.. 03 04 7.6 6.3 3.4 BBBF%%. 04 05 7.6 6.2 3.4 BBBF%%. 05 06 7.6 6.0 3.3 BBBF%%. 06 07 7.5 5.6 3.1 BBFF%.. 07 08 7.4 5.0 2.8 ABBFF%.. 08 09 6.8 3.8 2.2 BFFF%%. 09 10 5.7 0.8 0.0 FFFFF%%.. 10 11 4.6 0.8 0.0 FFFF%%.. 11 12 3.9 0.8 0.0 FFF%%. 12 13 3.6 0.8 0.0 FFF%.. 13 14 3.4 0.8 0.0 FFF%. 14 15 3.3 0.8 0.0 FFF%. 15 16 3.3 0.8 0.0 FFF%. 16 17 3.2 0.8 0.0 FFF%. 17 18 3.1 0.8 0.0 FFF%. 18 19 3.0 0.8 0.0 FF%%. 19 20 2.9 0.8 0.0 FF%.. 20 21 2.8 0.8 0.0 FF%.. 21 22 2.9 0.8 0.0 FF%. 22 23 4.7 2.7 1.6 AFF%. 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) 18-Aug-2026 BoM Space Weather Services, Sydney Australia +61-2-9213-8000