SWS GRAFEX HF FREQUENCY PREDICTIONS ADDRESS NO. 1234 =============================================================================== Circuit: Perth district Date: 4 September, 2026 T-index: 70 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 6.0 2.6 2.2 FFF%%. 00 01 6.6 3.0 2.5 AFFF%.. 01 02 6.9 3.2 2.6 AFFF%%. 02 03 7.2 3.3 2.7 AFFFF%.. 03 04 7.3 3.4 2.8 AFFFF%.. 04 05 7.4 3.4 2.8 AFFFF%.. 05 06 7.1 3.3 2.7 AFFFF%.. 06 07 6.9 3.1 2.6 AFFF%%. 07 08 6.7 2.8 2.4 FFFF%%. 08 09 6.4 2.3 2.0 AFFFF%.. 09 10 5.6 0.4 0.0 FFFFF%%. 10 11 4.7 0.4 0.0 FFFF%%.. 11 12 4.1 0.4 0.0 FFFF%.. 12 13 3.8 0.4 0.0 FFF%%. 13 14 3.7 0.4 0.0 FFF%.. 14 15 3.7 0.4 0.0 FFF%. 15 16 3.5 0.4 0.0 FFF%. 16 17 3.5 0.4 0.0 FFF%. 17 18 3.3 0.4 0.0 FFF%. 18 19 3.2 0.4 0.0 FFF%. 19 20 3.1 0.4 0.0 FFF.. 20 21 3.0 0.4 0.0 FF%.. 21 22 3.3 0.4 0.0 FFF%. 22 23 4.9 1.8 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) 4-Sep-2026 BoM Space Weather Services, Sydney Australia +61-2-9213-8000