SWS GRAFEX HF FREQUENCY PREDICTIONS ADDRESS NO. 1234 =============================================================================== Circuit: Karratha Perth Date: 30 August, 2026 T-index: 95 Bearings: 184 5 Distance: 1251 km First Mode |--------F r e q u e n c y (MHz)---------| Second Mode 1F 18-23 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 14.3 11.8 6.3 ASSXMMM MFFF%%... 9.4 7.2 3.8 00 01 15.6 13.5 7.1 SSSXMM MMBFF%%%.. . 10.2 8.3 4.3 01 02 15.7 14.6 7.5 ASSXMM MMBBF%%%.. . 10.4 9.0 4.6 02 03 15.8 15.3 7.8 ASSXXM MMBBB%%%.. . 10.7 9.4 4.7 03 04 15.5 15.5 7.9 ASSXXM MMBBB%%%.. 10.7 9.6 4.8 04 05 15.3 15.4 7.9 ASSXXM MMBBB%%... 10.6 9.6 4.8 05 06 14.6 15.0 7.7 ASSXXM MMBBP%%.. 10.3 9.3 4.7 06 07 14.1 14.1 7.3 SSSXMM MBBB%%... 10.0 8.7 4.4 07 08 14.0 12.7 6.7 SSXMMM MBF%%%... 9.8 7.9 4.1 08 09 14.0 10.4 5.6 SSXMMMM MFF%%%... 9.5 6.4 3.4 09 10 12.5 2.1 0.0 XMMMMMMMMM FF%%%... 8.6 1.3 0.0 10 11 10.3 2.1 0.0 XMMMMMMMMF %%%... 7.2 1.3 0.0 11 12 8.8 2.1 0.0 XMMMMMMM%% %... 6.3 1.3 0.0 12 13 8.0 2.1 0.0 XMMMMMM%%% .. 5.8 1.3 0.0 13 14 7.6 2.1 0.0 XMMMMMF%%. .. 5.5 1.3 0.0 14 15 7.1 2.1 0.0 XMMMMMF%%. . 5.2 1.3 0.0 15 16 6.8 2.1 0.0 XMMMMM%%.. . 5.0 1.3 0.0 16 17 6.5 2.1 0.0 XMMMMM%%.. 4.9 1.3 0.0 17 18 6.2 2.1 0.0 XMMMMF%%.. 4.7 1.3 0.0 18 19 5.8 2.1 0.0 XMMMM%%... 4.4 1.3 0.0 19 20 5.3 2.1 0.0 XMMMM%%.. 4.0 1.3 0.0 20 21 5.0 2.1 0.0 XMMMM%.. 3.8 1.3 0.0 21 22 6.0 2.1 0.0 XMMMM%%.. 4.6 1.3 0.0 22 23 10.8 8.4 4.7 ASMMMMFF %%.. 7.3 5.0 2.9 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) 30-Aug-2026 BoM Space Weather Services, Sydney Australia +61-2-9213-8000