SWS GRAFEX HF FREQUENCY PREDICTIONS ADDRESS NO. 1234 =============================================================================== Circuit: Karratha Perth Date: 15 September, 2025 T-index: 80 Bearings: 184 5 Distance: 1251 km First Mode |--------F r e q u e n c y (MHz)---------| Second Mode 1F 19-23 1E 5 1 5 10 15 20 25 30 35 40 2F 37-43 2E 14 UT OWF EMUF ALF |...|....| ....|....| ....|....| ....|....| OWF EMUF ALF UT 00 13.9 12.1 6.3 ASSXMMM MBF%%%... 9.1 7.4 3.9 00 01 14.8 13.7 7.0 SSXXMM MBBF%%%... 9.6 8.5 4.3 01 02 14.7 14.7 7.5 ASSXXM MBBB%%%... 9.7 9.1 4.5 02 03 14.5 15.3 7.7 ASSXXM MBBBP%%... 9.9 9.5 4.7 03 04 14.5 15.5 7.8 ASSXXM MMBBP%%... 10.0 9.6 4.8 04 05 14.4 15.4 7.8 ASSXXM MMBBP%%... 10.0 9.6 4.7 05 06 13.5 15.0 7.6 ASSXXM MBBPP%... 9.4 9.3 4.6 06 07 12.9 14.2 7.3 SSSXMM MBPP%%.. 9.0 8.8 4.4 07 08 12.8 12.9 6.7 SSXMMM MB%%%%.. 8.9 8.0 4.1 08 09 12.5 10.8 5.8 ASXMMMM FF%%%%.. 8.6 6.7 3.5 09 10 11.6 5.8 3.4 SMMMMMMM F%%%%... 7.9 3.6 2.1 10 11 9.6 2.0 0.0 XMMMMMMMM% %%%... 6.7 1.3 0.0 11 12 8.3 2.0 0.0 XMMMMMMM%% %... 6.0 1.3 0.0 12 13 7.6 2.0 0.0 XMMMMMM%%% ... 5.5 1.3 0.0 13 14 7.4 2.0 0.0 XMMMMMM%%% .. 5.4 1.3 0.0 14 15 7.3 2.0 0.0 XMMMMMF%%. .. 5.2 1.3 0.0 15 16 7.0 2.0 0.0 XMMMMM%%%. . 5.1 1.3 0.0 16 17 6.6 2.0 0.0 XMMMMM%%.. . 4.9 1.3 0.0 17 18 6.2 2.0 0.0 XMMMMM%%.. 4.6 1.3 0.0 18 19 5.8 2.0 0.0 XMMMM%%.. 4.3 1.3 0.0 19 20 5.3 2.0 0.0 XMMMM%%. 4.0 1.3 0.0 20 21 5.1 2.0 0.0 XMMMM%.. 3.8 1.3 0.0 21 22 6.7 2.0 0.0 XMMMMM%%.. 5.0 1.3 0.0 22 23 10.9 9.2 5.1 SSMMMMF %%%.. 7.5 5.6 3.1 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) 15-Sep-2025 BoM Space Weather Services, Sydney Australia +61-2-9213-8000