SWS GRAFEX HF FREQUENCY PREDICTIONS ADDRESS NO. 1234 =============================================================================== Circuit: Geraldton Perth Date: 28 October, 2025 T-index: 90 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 6.8 5.1 3.2 BBF%%.. 00 01 7.1 5.6 3.5 ABFF%.. 01 02 7.6 6.0 3.6 ABBF%%. . 02 03 8.1 6.2 3.8 ABBFF%. . 03 04 8.4 6.3 3.8 ABBFF%% .. 04 05 8.6 6.3 3.8 ABBFF%% .. 05 06 8.3 6.1 3.7 ABBFF%% .. 06 07 7.9 5.8 3.6 ABFF%%% . 07 08 7.7 5.4 3.4 BBFF%%. . 08 09 7.5 4.8 3.0 ABFFF%%. . 09 10 7.1 3.8 2.5 AFFFF%%. . 10 11 6.6 0.8 0.0 FFFFFF%%.. 11 12 6.1 0.8 0.0 FFFFFF%%. 12 13 5.6 0.8 0.0 FFFFF%%. 13 14 5.4 0.8 0.0 FFFFF%.. 14 15 5.3 0.8 0.0 FFFFF%.. 15 16 5.1 0.8 0.0 FFFFF%.. 16 17 4.9 0.8 0.0 FFFF%%. 17 18 4.6 0.8 0.0 FFFF%.. 18 19 4.3 0.8 0.0 FFFF%. 19 20 4.1 0.8 0.0 FFFF%. 20 21 4.3 0.8 0.0 FFFF%. 21 22 5.2 2.4 1.7 AFFF%. 22 23 6.2 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) 28-Oct-2025 BoM Space Weather Services, Sydney Australia +61-2-9213-8000