SWS GRAFEX HF FREQUENCY PREDICTIONS ADDRESS NO. 1234 =============================================================================== Circuit: Perth district Date: 1 August, 2026 T-index: 80 Bearings: 0 180 Distance: 0-300 km First Mode |--------F r e q u e n c y (MHz)---------| Second Mode 1F 60-90 1E 40-90 1 5 10 15 20 25 30 35 40 ** NONE ** UT OWF EMUF ALF |...|....| ....|....| ....|....| ....|....| OWF EMUF ALF UT 00 5.8 2.3 2.0 AFFF%.. 00 01 6.7 2.8 2.3 FFFF%.. 01 02 7.1 3.1 2.5 AFFFF%. 02 03 7.4 3.2 2.6 AFFFF%.. 03 04 7.5 3.3 2.7 AFFFF%.. 04 05 7.5 3.3 2.7 AFFFF%.. 05 06 7.5 3.2 2.6 AFFFF%.. 06 07 7.4 3.0 2.5 AFFFF%.. 07 08 7.3 2.6 2.2 FFFFF%.. 08 09 6.7 1.9 1.7 AFFFF%.. 09 10 5.6 0.4 0.0 FFFFF%.. 10 11 4.5 0.4 0.0 FFFF%.. 11 12 3.8 0.4 0.0 FFF%.. 12 13 3.5 0.4 0.0 FFF%. 13 14 3.3 0.4 0.0 FFF%. 14 15 3.3 0.4 0.0 FFF%. 15 16 3.2 0.4 0.0 FFF%. 16 17 3.2 0.4 0.0 FFF%. 17 18 3.1 0.4 0.0 FFF%. 18 19 3.0 0.4 0.0 FF%.. 19 20 3.0 0.4 0.0 FF%.. 20 21 2.9 0.4 0.0 FF%.. 21 22 2.9 0.4 0.0 FF%. 22 23 4.3 0.4 0.0 FFFF% 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) 1-Aug-2026 BoM Space Weather Services, Sydney Australia +61-2-9213-8000