SWS GRAFEX HF FREQUENCY PREDICTIONS ADDRESS NO. 1234 =============================================================================== Circuit: Karratha Perth Date: 15 March, 2026 T-index: 85 Bearings: 184 5 Distance: 1251 km First Mode |--------F r e q u e n c y (MHz)---------| Second Mode 1F 19-25 1E 5 1 5 10 15 20 25 30 35 40 2F 37-45 2E 14 UT OWF EMUF ALF |...|....| ....|....| ....|....| ....|....| OWF EMUF ALF UT 00 12.9 12.5 6.6 ASSXMMM BB%%%... 8.7 7.7 4.0 00 01 14.1 14.0 7.2 SSSXMM MBBB%%%.. 9.4 8.7 4.4 01 02 14.4 15.0 7.7 ASSXXM MBBBP%%... 9.7 9.3 4.6 02 03 14.6 15.6 7.9 ASSXXM MMBBP%%... 10.1 9.6 4.8 03 04 14.8 15.8 8.0 ASSXXM MMBBP%%... 10.3 9.8 4.9 04 05 15.0 15.7 8.0 ASSXXM MMBBP%%... . 10.5 9.8 4.8 05 06 14.7 15.3 7.8 ASSXXM MMBBP%%%.. 10.3 9.5 4.7 06 07 14.2 14.5 7.5 ASSXMM MMBB%%%... 9.8 9.0 4.5 07 08 14.1 13.3 6.9 SSXXMM MMBF%%%... 9.6 8.3 4.2 08 09 14.1 11.3 6.1 ASSXMMM MFFF%%%... 9.4 7.1 3.7 09 10 12.5 7.4 4.2 ASMMMMMM MF%%%%... 8.5 4.5 2.6 10 11 10.9 2.1 0.0 XMMMMMMMMM %%%%.... 7.6 1.3 0.0 11 12 9.2 2.1 0.0 XMMMMMMMF% %%... 6.7 1.3 0.0 12 13 8.4 2.1 0.0 XMMMMMMM%% %... 6.1 1.3 0.0 13 14 7.8 2.1 0.0 XMMMMMM%%% ... 5.7 1.3 0.0 14 15 7.8 2.1 0.0 XMMMMMM%%% .. 5.7 1.3 0.0 15 16 7.6 2.1 0.0 XMMMMMM%%. .. 5.6 1.3 0.0 16 17 7.6 2.1 0.0 XMMMMMF%%. .. 5.4 1.3 0.0 17 18 7.1 2.1 0.0 XMMMMMF%%. . 5.2 1.3 0.0 18 19 6.8 2.1 0.0 XMMMMM%%.. . 5.0 1.3 0.0 19 20 5.8 2.1 0.0 XMMMM%%.. 4.5 1.3 0.0 20 21 5.4 2.1 0.0 XMMMM%%. 4.1 1.3 0.0 21 22 7.0 2.1 0.0 XMMMMM%%.. 5.1 1.3 0.0 22 23 10.9 9.9 5.4 SSXMMBF %%%.. 7.3 6.1 3.3 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-Mar-2026 BoM Space Weather Services, Sydney Australia +61-2-9213-8000