SWS GRAFEX HF FREQUENCY PREDICTIONS ADDRESS NO. 1234 =============================================================================== Circuit: Karratha Perth Date: 12 October, 2026 T-index: 20 Bearings: 184 5 Distance: 1251 km First Mode |--------F r e q u e n c y (MHz)---------| Second Mode 1F 18-24 1E 5 1 5 10 15 20 25 30 35 40 2F 36-44 2E 14 UT OWF EMUF ALF |...|....| ....|....| ....|....| ....|....| OWF EMUF ALF UT 00 10.0 11.7 5.9 ASXXMBP P%.. 6.6 7.3 3.6 00 01 10.3 13.1 6.5 ASSXXBB PPE.. 6.7 8.1 3.9 01 02 10.4 13.9 6.9 SSXXBB PPP.. 6.9 8.6 4.2 02 03 10.7 14.4 7.1 SSSXMB PPPE. 7.1 9.0 4.3 03 04 11.0 14.7 7.2 SSSXXB PPPP.. 7.4 9.1 4.3 04 05 11.2 14.6 7.1 SSSXXB BPPP.. 7.6 9.1 4.3 05 06 11.0 14.2 7.0 SSXXMB PPPP.. 7.5 8.8 4.2 06 07 10.8 13.5 6.7 ASSXXMB PPP.. 7.4 8.4 4.0 07 08 10.4 12.4 6.2 ASSXMBB PP%.. 7.1 7.8 3.8 08 09 10.4 10.8 5.5 SSXMMBB %%%.. 7.0 6.7 3.3 09 10 9.6 7.7 4.2 ASMMMMF% %%... 6.5 4.7 2.6 10 11 8.4 1.7 0.0 MMMMMMMF%% %.... 5.8 1.0 0.0 11 12 7.1 1.7 0.0 MMMMMMF%%. ... 5.0 1.0 0.0 12 13 6.2 1.7 0.0 MMMMMM%%.. . 4.5 1.0 0.0 13 14 5.8 1.7 0.0 MMMMM%%... 4.3 1.0 0.0 14 15 5.8 1.7 0.0 MMMMM%%.. 4.3 1.0 0.0 15 16 5.7 1.7 0.0 MMMMM%%.. 4.3 1.0 0.0 16 17 5.6 1.7 0.0 MMMMM%%.. 4.2 1.0 0.0 17 18 5.2 1.7 0.0 MMMMM%.. 4.0 1.0 0.0 18 19 4.9 1.7 0.0 MMMM%%.. 3.6 1.0 0.0 19 20 4.5 1.7 0.0 MMMM%.. 3.4 1.0 0.0 20 21 4.7 1.7 0.0 MMMM%%. 3.5 1.0 0.0 21 22 6.8 1.7 1.2 MMMMM%%.. 4.9 0.0 1.1 22 23 9.1 9.6 5.0 ASXMMBB% %.. 6.2 6.0 3.0 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) 12-Oct-2026 BoM Space Weather Services, Sydney Australia +61-2-9213-8000