SWS GRAFEX HF FREQUENCY PREDICTIONS ADDRESS NO. 1234 =============================================================================== Circuit: Geraldton Perth Date: 11 September, 2026 T-index: 58 Bearings: 162 341 Distance: 373 km First Mode |--------F r e q u e n c y (MHz)---------| Second Mode 1F 52-57 1E 24 1 5 10 15 20 25 30 35 40 UT OWF EMUF ALF |...|....| ....|....| ....|....| ....|....| OWF EMUF ALF UT 00 6.4 4.4 2.7 ABFF%.. 00 01 6.9 5.1 3.1 BBF%%. 01 02 7.2 5.5 3.3 BBFF%.. 02 03 7.5 5.7 3.4 BBFF%%. 03 04 7.6 5.8 3.5 ABFF%%. . 04 05 7.7 5.8 3.4 BBFF%%. . 05 06 7.3 5.7 3.4 BBFF%%. 06 07 7.1 5.4 3.2 BBFF%.. 07 08 6.9 4.9 3.0 ABFF%%.. 08 09 6.6 4.1 2.6 ABFF%%. 09 10 5.8 2.2 1.5 AFFF%%.. 10 11 4.9 0.7 0.0 FFFF%%.. 11 12 4.3 0.7 0.0 FFFF%.. 12 13 3.9 0.7 0.0 FFF%%.. 13 14 3.8 0.7 0.0 FFF%%. 14 15 3.8 0.7 0.0 FFF%.. 15 16 3.7 0.7 0.0 FFF%.. 16 17 3.6 0.7 0.0 FFF%. 17 18 3.5 0.7 0.0 FFF%. 18 19 3.3 0.7 0.0 FFF%. 19 20 3.2 0.7 0.0 FFF%. 20 21 3.1 0.7 0.0 FFF%. 21 22 3.5 0.7 0.0 FFF%. 22 23 5.2 3.2 2.1 BFF%. 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) 11-Sep-2026 BoM Space Weather Services, Sydney Australia +61-2-9213-8000