SWS GRAFEX HF FREQUENCY PREDICTIONS ADDRESS NO. 1234 =============================================================================== Circuit: Karratha Perth Date: 13 March, 2026 T-index: 100 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 13.5 12.7 6.8 SSXMMM BBF%%%.. 9.1 7.9 4.1 00 01 14.6 14.3 7.4 ASSXMM MBBB%%%... 9.8 8.8 4.5 01 02 14.9 15.2 7.9 ASSXXM MMBBP%%... 10.1 9.5 4.8 02 03 15.3 15.8 8.1 ASSSXM MMBBB%%%.. 10.6 9.8 4.9 03 04 15.4 16.1 8.2 ASSSXM MMBBBP%%.. 10.8 10.0 5.0 04 05 15.6 16.0 8.2 ASSSXM MMBBBP%%.. . 10.9 9.9 5.0 05 06 15.4 15.6 8.0 ASSXXM MMMBB%%%.. . 10.8 9.7 4.9 06 07 14.9 14.8 7.7 ASSXXM MMBB%%%%.. 10.4 9.2 4.6 07 08 14.8 13.5 7.1 SSSXMM MMBF%%%%.. 10.2 8.4 4.3 08 09 14.7 11.6 6.3 ASSXMMM MMFF%%%%.. 10.0 7.2 3.8 09 10 13.3 7.7 4.4 ASMMMMMM MFF%%%... 9.2 4.7 2.7 10 11 12.0 2.1 0.0 XMMMMMMMMM F%%%%... 8.4 1.3 0.0 11 12 10.4 2.1 0.0 XMMMMMMMMF %%%... 7.5 1.3 0.0 12 13 9.6 2.1 0.0 XMMMMMMMF% %%.. 6.8 1.3 0.0 13 14 8.7 2.1 0.0 XMMMMMMM%% %.. 6.3 1.3 0.0 14 15 8.4 2.1 0.0 XMMMMMMF%% ... 6.1 1.3 0.0 15 16 8.2 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 7.7 2.1 0.0 XMMMMMM%%. .. 5.6 1.3 0.0 18 19 7.3 2.1 0.0 XMMMMMF%%. . 5.4 1.3 0.0 19 20 6.4 2.1 0.0 XMMMMM%%.. 4.8 1.3 0.0 20 21 5.9 2.1 0.0 XMMMM%%.. 4.5 1.3 0.0 21 22 7.4 2.1 0.0 XMMMMMF%%. . 5.4 1.3 0.0 22 23 11.4 10.2 5.6 SSXMMMB F%%.. 7.6 6.3 3.4 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) 13-Mar-2026 BoM Space Weather Services, Sydney Australia +61-2-9213-8000