SWS GRAFEX HF FREQUENCY PREDICTIONS ADDRESS NO. 1234 =============================================================================== Circuit: Perth district Date: 20 October, 2026 T-index: 45 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 5.3 2.8 2.3 FFF%. 00 01 5.6 3.1 2.5 AFF%.. 01 02 5.8 3.3 2.7 AFF%%. 02 03 6.2 3.4 2.7 AFFF%.. 03 04 6.5 3.4 2.8 AFFF%%. 04 05 6.6 3.4 2.8 AFFF%%. 05 06 6.6 3.3 2.7 AFFF%%. 06 07 6.3 3.2 2.6 AFFF%.. 07 08 6.1 3.0 2.4 BFFF%. 08 09 5.9 2.6 2.2 FFF%%. 09 10 5.5 2.0 1.8 AFFF%%. 10 11 5.0 0.4 0.0 FFFF%%.. 11 12 4.5 0.4 0.0 FFFF%%. 12 13 4.0 0.4 0.0 FFF%%. 13 14 3.9 0.4 0.0 FFF%%. 14 15 3.9 0.4 0.0 FFF%.. 15 16 3.8 0.4 0.0 FFF%. 16 17 3.7 0.4 0.0 FFF%. 17 18 3.5 0.4 0.0 FFF%. 18 19 3.3 0.4 0.0 FFF%. 19 20 3.1 0.4 0.0 FFF.. 20 21 3.2 0.4 0.0 FFF%. 21 22 4.1 1.2 1.2 FFF%. 22 23 4.8 2.3 2.0 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) 20-Oct-2026 BoM Space Weather Services, Sydney Australia +61-2-9213-8000