SWS GRAFEX HF FREQUENCY PREDICTIONS ADDRESS NO. 1234 =============================================================================== Circuit: Karratha Perth Date: 22 March, 2026 T-index: 65 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 12.3 12.0 6.3 ASSXMMM BB%%%.. 8.3 7.4 3.8 00 01 13.4 13.6 6.9 SSXXMM BBB%%%... 9.0 8.4 4.2 01 02 13.9 14.5 7.3 ASSXMM MBBP%%%... 9.2 9.0 4.5 02 03 14.0 15.1 7.6 ASSXXM MBBPP%%... 9.4 9.4 4.6 03 04 14.1 15.4 7.7 ASSXXM MBBBP%%... 9.7 9.5 4.7 04 05 14.2 15.3 7.6 ASSXXM MMBBP%%... 9.9 9.5 4.6 05 06 14.0 14.9 7.5 ASSXXM MMBP%%%... 9.7 9.2 4.5 06 07 13.7 14.1 7.1 SSSXMM MBBP%%%... 9.4 8.7 4.3 07 08 13.6 12.8 6.6 ASSXMMM MBF%%%%... 9.1 8.0 4.0 08 09 13.5 10.9 5.7 ASXMMMM MFF%%%%.. 9.0 6.8 3.5 09 10 11.6 6.5 3.8 SMMMMMMM F%%%%.... 7.8 4.0 2.3 10 11 9.5 1.9 0.0 XMMMMMMMM% %%%.... 6.6 1.2 0.0 11 12 8.0 1.9 0.0 XMMMMMMM%% %... 5.8 1.2 0.0 12 13 7.1 1.9 0.0 XMMMMMM%%% .. 5.2 1.2 0.0 13 14 6.8 1.9 0.0 XMMMMM%%%. . 5.0 1.2 0.0 14 15 6.9 1.9 0.0 XMMMMM%%%. . 5.1 1.2 0.0 15 16 6.8 1.9 0.0 XMMMMM%%.. . 5.0 1.2 0.0 16 17 6.8 1.9 0.0 XMMMMM%%.. . 4.9 1.2 0.0 17 18 6.5 1.9 0.0 XMMMMM%%.. 4.8 1.2 0.0 18 19 6.2 1.9 0.0 XMMMMM%%.. 4.6 1.2 0.0 19 20 5.5 1.9 0.0 XMMMM%%.. 4.1 1.2 0.0 20 21 5.0 1.9 0.0 XMMMM%.. 3.7 1.2 0.0 21 22 6.2 1.9 0.0 XMMMMF%%. 4.7 1.2 0.0 22 23 10.0 9.4 5.1 SSMMMB% %%.. 6.8 5.8 3.1 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) 22-Mar-2026 BoM Space Weather Services, Sydney Australia +61-2-9213-8000