SWS GRAFEX HF FREQUENCY PREDICTIONS ADDRESS NO. 1234 =============================================================================== Circuit: Geraldton Perth Date: 16 September, 2025 T-index: 100 Bearings: 162 341 Distance: 373 km First Mode |--------F r e q u e n c y (MHz)---------| Second Mode 1F 52-58 1E 24 1 5 10 15 20 25 30 35 40 UT OWF EMUF ALF |...|....| ....|....| ....|....| ....|....| OWF EMUF ALF UT 00 8.3 4.7 3.0 ABFFFF%. . 00 01 8.8 5.4 3.3 BBFFF%% . 01 02 9.2 5.8 3.6 ABFFFF% .. 02 03 9.4 6.0 3.7 ABBFFF% %. 03 04 9.6 6.1 3.7 ABBFFF% %. 04 05 9.6 6.1 3.7 ABBFFF% %. 05 06 9.1 6.0 3.6 ABBFFF% .. 06 07 8.8 5.7 3.5 ABFFF%% .. 07 08 8.7 5.2 3.2 BBFFF%% .. 08 09 8.5 4.3 2.8 ABFFFF%% . 09 10 7.9 2.5 1.8 AFFFFF%%. . 10 11 6.8 0.8 0.0 FFFFFF%%.. 11 12 6.0 0.8 0.0 FFFFF%%.. 12 13 5.5 0.8 0.0 FFFFF%%. 13 14 5.1 0.8 0.0 FFFFF%.. 14 15 4.9 0.8 0.0 FFFF%%. 15 16 4.6 0.8 0.0 FFFF%.. 16 17 4.5 0.8 0.0 FFFF%.. 17 18 4.3 0.8 0.0 FFFF%. 18 19 4.0 0.8 0.0 FFF%%. 19 20 3.9 0.8 0.0 FFF%.. 20 21 3.7 0.8 0.0 FFF%. 21 22 4.5 0.8 0.0 FFFF%. 22 23 6.7 3.5 2.3 BFFF%.. 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) 16-Sep-2025 BoM Space Weather Services, Sydney Australia +61-2-9213-8000