SWS GRAFEX HF FREQUENCY PREDICTIONS ADDRESS NO. 1234 =============================================================================== Circuit: Karratha Perth Date: 19 July, 2026 T-index: 60 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 10.1 5.3 SSXMMMB F%%.. 7.6 6.1 3.3 00 01 13.0 12.1 6.2 ASSXMMM BB%%%... 8.6 7.4 3.8 01 02 13.2 13.3 6.7 SSXXMM BBB%%... 8.9 8.2 4.1 02 03 13.4 14.0 7.0 SSXXMM BBBP%%... 9.0 8.6 4.3 03 04 12.9 14.3 7.1 SSSXMM BBPP%... 8.6 8.8 4.3 04 05 12.7 14.2 7.1 SSSXMM BBPP%... 8.4 8.7 4.3 05 06 12.4 13.7 6.9 SSXXMM BBP%... 8.3 8.4 4.2 06 07 12.4 12.8 6.5 ASSXMMM BB%%... 8.1 7.9 4.0 07 08 12.4 11.2 5.8 ASXMMMB BF%%... 8.1 6.9 3.6 08 09 12.1 8.2 4.5 ASMMMMMF FF%%... 8.0 4.9 2.8 09 10 9.3 1.9 0.0 XMMMMMMFF% %... 6.4 1.2 0.0 10 11 7.1 1.9 0.0 XMMMMMF%%. .. 5.1 1.2 0.0 11 12 6.0 1.9 0.0 XMMMM%%... 4.4 1.2 0.0 12 13 5.5 1.9 0.0 XMMMM%%.. 4.1 1.2 0.0 13 14 5.2 1.9 0.0 XMMMM%... 3.9 1.2 0.0 14 15 5.1 1.9 0.0 XMMMM%.. 3.9 1.2 0.0 15 16 5.2 1.9 0.0 XMMMM%... 3.9 1.2 0.0 16 17 5.0 1.9 0.0 XMMMM%.. 3.8 1.2 0.0 17 18 4.8 1.9 0.0 XMMM%%.. 3.5 1.2 0.0 18 19 4.7 1.9 0.0 XMMM%%.. 3.3 1.2 0.0 19 20 4.5 1.9 0.0 XMMM%%.. 3.1 1.2 0.0 20 21 4.4 1.9 0.0 XMMM%%.. 3.1 1.2 0.0 21 22 4.7 1.9 0.0 XMMM%%. 3.6 1.2 0.0 22 23 7.9 3.5 2.2 AMMMMF%%. . 5.4 0.0 1.9 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) 19-Jul-2026 BoM Space Weather Services, Sydney Australia +61-2-9213-8000