SWS GRAFEX HF FREQUENCY PREDICTIONS ADDRESS NO. 1234 =============================================================================== Circuit: Carnarvon Perth Date: 18 September, 2025 T-index: 100 Bearings: 165 344 Distance: 815 km First Mode |--------F r e q u e n c y (MHz)---------| Second Mode 1F 29-36 1E 10 1 5 10 15 20 25 30 35 40 2F 50-56 2E 22 UT OWF EMUF ALF |...|....| ....|....| ....|....| ....|....| OWF EMUF ALF UT 00 11.0 9.0 4.5 SXMMMMF %%%. 8.3 5.3 3.1 00 01 11.6 10.2 5.1 SSMMMMM F%%.. 8.8 6.0 3.4 01 02 11.8 11.0 5.4 ASXMMMM B%%.. 9.2 6.5 3.7 02 03 11.9 11.5 5.6 ASXMMMM M%%%.. 9.4 6.8 3.8 03 04 12.1 11.7 5.7 ASXMMMM MF%%.. 9.5 6.9 3.9 04 05 12.0 11.7 5.7 ASXMMMM M%%%.. 9.6 6.9 3.9 05 06 11.5 11.4 5.6 ASXMMMM B%%.. 9.2 6.7 3.8 06 07 11.1 10.8 5.3 ASXMMMM F%%.. 8.8 6.4 3.6 07 08 11.0 9.9 4.9 SXMMMMM %%%.. 8.7 5.8 3.4 08 09 10.8 8.4 4.3 ASMMMMMM %%%. 8.5 4.9 3.0 09 10 10.2 5.4 3.0 MMMMMMMF %%.. 8.0 3.0 2.1 10 11 8.8 1.6 0.0 MMMMMMMM%% %.. 6.9 0.9 0.0 11 12 7.7 1.6 0.0 MMMMMMM%%. . 6.2 0.9 0.0 12 13 7.1 1.6 0.0 MMMMMMM%%. 5.7 0.9 0.0 13 14 6.6 1.6 0.0 MMMMMM%%.. 5.4 0.9 0.0 14 15 6.3 1.6 0.0 MMMMMM%%.. 5.1 0.9 0.0 15 16 6.0 1.6 0.0 MMMMMM%.. 4.9 0.9 0.0 16 17 5.7 1.6 0.0 MMMMMM%.. 4.7 0.9 0.0 17 18 5.4 1.6 0.0 MMMMM%.. 4.5 0.9 0.0 18 19 5.1 1.6 0.0 MMMMM%.. 4.3 0.9 0.0 19 20 4.8 1.6 0.0 MMMMM%. 4.1 0.9 0.0 20 21 4.6 1.6 0.0 MMMMM.. 4.0 0.9 0.0 21 22 5.6 1.6 0.0 MMMMM%.. 4.7 0.9 0.0 22 23 8.7 6.7 3.5 SMMMMM%% . 6.8 3.9 2.4 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) 18-Sep-2025 BoM Space Weather Services, Sydney Australia +61-2-9213-8000