SWS GRAFEX HF FREQUENCY PREDICTIONS ADDRESS NO. 1234 =============================================================================== Circuit: Karratha Perth Date: 2 August, 2026 T-index: 55 Bearings: 184 5 Distance: 1251 km First Mode |--------F r e q u e n c y (MHz)---------| Second Mode 1F 18-22 1E 5 1 5 10 15 20 25 30 35 40 2F 36-41 2E 14 UT OWF EMUF ALF |...|....| ....|....| ....|....| ....|....| OWF EMUF ALF UT 00 11.4 10.4 5.4 SSXMMMB F%%.. 7.7 6.3 3.4 00 01 12.8 12.3 6.3 ASSXMMM BB%%%.. 8.5 7.5 3.8 01 02 13.1 13.4 6.8 SSXXMM BBB%%... 8.7 8.3 4.1 02 03 13.3 14.1 7.0 SSXXMM BBBP%.... 8.8 8.7 4.3 03 04 12.9 14.4 7.1 SSSXMM BBPP%... 8.5 8.9 4.4 04 05 12.7 14.3 7.1 SSSXMM BBPP%... 8.3 8.8 4.3 05 06 12.4 13.8 6.9 SSXXMM BBP%... 8.1 8.5 4.2 06 07 12.4 12.9 6.5 ASSXMMM BB%%... 8.0 8.0 4.0 07 08 12.2 11.4 5.9 ASXMMMB BF%%... 7.9 7.0 3.6 08 09 11.9 8.7 4.7 ASXMMMMF F%%%.. 7.8 5.2 2.9 09 10 9.6 1.9 0.0 XMMMMMMMF% %%... 6.6 1.2 0.0 10 11 7.4 1.9 0.0 XMMMMMF%%. ... 5.3 1.2 0.0 11 12 6.3 1.9 0.0 XMMMMF%%.. . 4.5 1.2 0.0 12 13 5.7 1.9 0.0 XMMMM%%... 4.2 1.2 0.0 13 14 5.5 1.9 0.0 XMMMM%%.. 4.1 1.2 0.0 14 15 5.4 1.9 0.0 XMMMM%... 4.1 1.2 0.0 15 16 5.3 1.9 0.0 XMMMM%... 4.0 1.2 0.0 16 17 5.2 1.9 0.0 XMMMM%... 4.0 1.2 0.0 17 18 5.0 1.9 0.0 XMMMM%... 3.7 1.2 0.0 18 19 4.9 1.9 0.0 XMMMM%... 3.4 1.2 0.0 19 20 4.6 1.9 0.0 XMMM%%.. 3.2 1.2 0.0 20 21 4.3 1.9 0.0 XMMM%... 3.0 1.2 0.0 21 22 4.6 1.9 0.0 XMMM%.. 3.6 1.2 0.0 22 23 8.2 5.6 3.3 SMMMFF%. . 5.7 2.6 2.2 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) 2-Aug-2026 BoM Space Weather Services, Sydney Australia +61-2-9213-8000