SWS GRAFEX HF FREQUENCY PREDICTIONS ADDRESS NO. 1234 =============================================================================== Circuit: Karratha Perth Date: 7 December, 2025 T-index: 120 Bearings: 184 5 Distance: 1251 km First Mode |--------F r e q u e n c y (MHz)---------| Second Mode 1F 19-31 1E 5 1 5 10 15 20 25 30 35 40 2F 38-52 2E 14 UT OWF EMUF ALF |...|....| ....|....| ....|....| ....|....| OWF EMUF ALF UT 00 10.7 13.9 7.4 ASSXMB PPP... 7.7 8.7 4.5 00 01 11.3 15.2 8.0 ASSXXM BPPEE.. 8.2 9.5 4.8 01 02 11.9 16.0 8.4 ASSSXM BPPPEE.. 8.6 10.0 5.0 02 03 12.3 16.5 8.6 SSSXX MBPPPE.. 8.9 10.3 5.2 03 04 12.5 16.7 8.7 SSSXX MBPPPE.. 9.2 10.4 5.2 04 05 12.8 16.7 8.7 SSSXX MBPPPE... 9.3 10.4 5.2 05 06 12.5 16.3 8.5 SSSXX MBPPPE.. 9.1 10.2 5.1 06 07 12.2 15.6 8.2 ASSSXM MBPPP... 8.8 9.8 4.9 07 08 11.9 14.6 7.7 ASSXXM MPPP%.. 8.7 9.1 4.7 08 09 11.8 13.0 7.0 SSXXMM BPP%%.. 8.6 8.1 4.3 09 10 11.6 10.7 6.0 ASXMMMM F%%%... 8.6 6.5 3.7 10 11 11.5 3.7 2.5 MMMMMMMM F%%%.. 8.5 0.0 2.2 11 12 10.9 2.3 0.0 XMMMMMMMMM %%%.. 8.2 1.4 0.0 12 13 10.6 2.3 0.0 XMMMMMMMMF %%%.. 7.8 1.4 0.0 13 14 10.2 2.3 0.0 XMMMMMMMMF %%.. 7.5 1.4 0.0 14 15 10.2 2.3 0.0 XMMMMMMMMF %%.. 7.3 1.4 0.0 15 16 10.1 2.3 0.0 XMMMMMMMFF %%.. 7.2 1.4 0.0 16 17 9.4 2.3 0.0 XMMMMMMMF% %.. 6.8 1.4 0.0 17 18 8.5 2.3 0.0 XMMMMMMM%% .. 6.3 1.4 0.0 18 19 7.9 2.3 0.0 XMMMMMM%%% .. 5.8 1.4 0.0 19 20 7.4 2.3 0.0 XMMMMMM%%. . 5.5 1.4 0.0 20 21 7.3 2.3 0.0 XMMMMMM%%. . 5.5 1.4 0.0 21 22 8.8 8.8 5.1 SSMMM%% %.. 6.5 5.3 3.1 22 23 10.3 12.0 6.6 ASSXMMB PP.... 7.3 7.5 4.0 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) 7-Dec-2025 BoM Space Weather Services, Sydney Australia +61-2-9213-8000