SWS GRAFEX HF FREQUENCY PREDICTIONS ADDRESS NO. 1234 =============================================================================== Circuit: Karratha Perth Date: 16 October, 2025 T-index: 95 Bearings: 184 5 Distance: 1251 km First Mode |--------F r e q u e n c y (MHz)---------| Second Mode 1F 19-26 1E 5 1 5 10 15 20 25 30 35 40 2F 37-47 2E 14 UT OWF EMUF ALF |...|....| ....|....| ....|....| ....|....| OWF EMUF ALF UT 00 13.3 13.0 6.9 SSXXMM BBB%%... 8.9 8.1 4.1 00 01 13.7 14.4 7.5 ASSXMM BBBP%%.. 9.2 8.9 4.5 01 02 14.0 15.3 7.9 ASSXXM MBBPP%... 9.6 9.5 4.8 02 03 14.5 15.9 8.1 ASSSXM MBBBP%%.. 10.1 9.9 4.9 03 04 14.9 16.1 8.2 ASSSXM MMBBPP%... 10.4 10.0 5.0 04 05 15.0 16.1 8.2 ASSSXM MMBBPP%... 10.6 10.0 5.0 05 06 14.3 15.7 8.0 ASSXXM MMBBP%%.. 10.2 9.7 4.9 06 07 13.6 14.9 7.7 ASSXXM MBBP%%... 9.7 9.3 4.7 07 08 13.2 13.7 7.2 SSSXMM MBB%%%.. 9.4 8.6 4.3 08 09 13.4 11.9 6.4 ASSXMMM MFF%%%.. 9.3 7.5 3.9 09 10 12.6 8.7 4.9 ASXMMMMM MF%%%... 8.9 5.3 3.0 10 11 11.4 2.1 0.0 XMMMMMMMMM F%%%... 8.0 1.3 0.0 11 12 10.3 2.1 0.0 XMMMMMMMMF %%%... 7.4 1.3 0.0 12 13 9.7 2.1 0.0 XMMMMMMMF% %%... 6.8 1.3 0.0 13 14 9.2 2.1 0.0 XMMMMMMMF% %%.. 6.5 1.3 0.0 14 15 9.0 2.1 0.0 XMMMMMMM%% %... 6.3 1.3 0.0 15 16 8.5 2.1 0.0 XMMMMMMF%% ... 6.0 1.3 0.0 16 17 8.1 2.1 0.0 XMMMMMMF%% ... 5.8 1.3 0.0 17 18 7.3 2.1 0.0 XMMMMMM%%. . 5.4 1.3 0.0 18 19 6.6 2.1 0.0 XMMMMM%%.. 5.0 1.3 0.0 19 20 6.1 2.1 0.0 XMMMMM%.. 4.8 1.3 0.0 20 21 6.5 2.1 0.0 XMMMMM%%.. 5.0 1.3 0.0 21 22 9.0 4.1 2.6 AMMMMMF%% %.. 6.5 2.2 1.7 22 23 12.3 10.7 5.8 ASXMMMB FF%%.. 8.1 6.6 3.5 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-Oct-2025 BoM Space Weather Services, Sydney Australia +61-2-9213-8000