SWS GRAFEX HF FREQUENCY PREDICTIONS ADDRESS NO. 1234 =============================================================================== Circuit: Karratha Perth Date: 21 June, 2026 T-index: 75 Bearings: 184 5 Distance: 1251 km First Mode |--------F r e q u e n c y (MHz)---------| Second Mode 1F 18-21 1E 5 1 5 10 15 20 25 30 35 40 2F 36-40 2E 14 UT OWF EMUF ALF |...|....| ....|....| ....|....| ....|....| OWF EMUF ALF UT 00 12.4 9.9 5.3 SSMMMMF FF%%... 8.2 5.9 3.3 00 01 14.3 12.1 6.3 ASSXMMM MBFF%%... 9.5 7.4 3.9 01 02 15.0 13.3 6.8 SSXXMM MBBF%%%... . 10.0 8.2 4.2 02 03 14.9 14.1 7.1 SSSXMM MBBB%%%... . 10.0 8.7 4.3 03 04 14.5 14.3 7.2 SSSXMM MBBB%%%... 9.7 8.8 4.4 04 05 14.2 14.2 7.2 SSSXMM MBBB%%.... 9.4 8.8 4.4 05 06 14.2 13.7 7.0 SSXXMM MBBF%%.... 9.4 8.5 4.3 06 07 14.4 12.8 6.5 ASSXMMM MBFF%%%... 9.4 7.9 4.0 07 08 14.2 11.1 5.8 ASXMMMM MFFF%%.... 9.2 6.8 3.6 08 09 13.1 7.8 4.3 ASMMMMMM FFF%%... 8.6 4.5 2.8 09 10 10.3 2.0 0.0 XMMMMMMMFF %%.... 7.0 1.2 0.0 10 11 7.5 2.0 0.0 XMMMMMF%%. ... 5.3 1.2 0.0 11 12 6.2 2.0 0.0 XMMMMF%%.. . 4.5 1.2 0.0 12 13 5.7 2.0 0.0 XMMMM%%... 4.2 1.2 0.0 13 14 5.5 2.0 0.0 XMMMM%%.. 4.1 1.2 0.0 14 15 5.2 2.0 0.0 XMMMM%... 4.0 1.2 0.0 15 16 5.2 2.0 0.0 XMMMM%... 3.9 1.2 0.0 16 17 5.3 2.0 0.0 XMMMM%... 3.9 1.2 0.0 17 18 5.2 2.0 0.0 XMMMM%%.. 3.8 1.2 0.0 18 19 5.2 2.0 0.0 XMMMM%%.. 3.7 1.2 0.0 19 20 5.1 2.0 0.0 XMMMF%... 3.5 1.2 0.0 20 21 4.8 2.0 0.0 XMMM%%... 3.4 1.2 0.0 21 22 5.1 2.0 0.0 XMMMF%.. 3.9 1.2 0.0 22 23 8.5 2.0 0.0 MMMMMMFF%% .. 5.7 0.0 1.5 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) 21-Jun-2026 BoM Space Weather Services, Sydney Australia +61-2-9213-8000