SWS GRAFEX HF FREQUENCY PREDICTIONS ADDRESS NO. 1234 =============================================================================== Circuit: Geraldton Perth Date: 18 October, 2025 T-index: 105 Bearings: 162 341 Distance: 373 km First Mode |--------F r e q u e n c y (MHz)---------| Second Mode 1F 52-62 1E 24 1 5 10 15 20 25 30 35 40 UT OWF EMUF ALF |...|....| ....|....| ....|....| ....|....| OWF EMUF ALF UT 00 7.7 5.1 3.2 BBFF%%. 00 01 8.0 5.6 3.5 ABFF%%. 01 02 8.4 6.0 3.7 ABBFF%% . 02 03 9.1 6.2 3.8 ABBFFF% .. 03 04 9.3 6.3 3.9 ABBFFF% .. 04 05 9.5 6.3 3.9 ABBFFF% %. 05 06 9.3 6.2 3.8 ABBFFF% %. 06 07 8.9 5.9 3.7 ABFFF%% .. 07 08 8.6 5.5 3.4 BBFFF%% . 08 09 8.4 4.8 3.1 BFFFF%% . 09 10 7.9 3.7 2.5 AFFFF%%. . 10 11 7.3 0.8 0.0 FFFFFFF%%. 11 12 6.7 0.8 0.0 FFFFFF%%.. 12 13 6.2 0.8 0.0 FFFFFF%.. 13 14 5.8 0.8 0.0 FFFFF%%. 14 15 5.6 0.8 0.0 FFFFF%%. 15 16 5.3 0.8 0.0 FFFFF%.. 16 17 5.1 0.8 0.0 FFFFF%.. 17 18 4.9 0.8 0.0 FFFF%%. 18 19 4.6 0.8 0.0 FFFF%.. 19 20 4.4 0.8 0.0 FFFF%. 20 21 4.5 0.8 0.0 FFFF%. 21 22 5.6 1.7 1.3 FFFF%.. 22 23 6.9 4.2 2.7 ABFF%%. 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) 18-Oct-2025 BoM Space Weather Services, Sydney Australia +61-2-9213-8000