SWS GRAFEX HF FREQUENCY PREDICTIONS ADDRESS NO. 1234 =============================================================================== Circuit: Broome Perth Date: 18 September, 2025 T-index: 100 Bearings: 201 24 Distance: 1680 km First Mode |--------F r e q u e n c y (MHz)---------| Second Mode 1F 12-17 1E 2 1 5 10 15 20 25 30 35 40 2F 29-35 2E 10 UT OWF EMUF ALF |...|....| ....|....| ....|....| ....|....| OWF EMUF ALF UT 00 19.5 14.6 8.6 SSSXM MMMBFFFFF% %%... 11.8 9.5 5.1 00 01 20.4 16.3 9.5 ASSSX MMMMBBFFFF %%%... 12.1 10.7 5.6 01 02 20.5 17.4 10.0 ASSSX XMMMBBBFFF %%%... 12.2 11.5 5.8 02 03 20.7 18.0 10.3 ASSSS XMMMBBBBFF %%%... 12.3 11.9 6.0 03 04 20.7 18.2 10.4 SSSS XXMMBBBBFF %%%... 12.4 12.1 6.1 04 05 20.3 18.1 10.3 ASSSS XMMMBBBBFF %%... 12.4 12.0 6.0 05 06 19.1 17.5 10.0 ASSSX XMMMBBBFF% %.... 11.8 11.7 5.8 06 07 18.4 16.5 9.5 ASSSX MMMBBBFF%% %... 11.4 11.0 5.5 07 08 18.4 14.8 8.7 SSSXM MMMBFFFF%% %.... 11.4 10.0 5.1 08 09 18.1 12.2 7.4 SSSMMM MMMFFFFF%% %... 11.2 8.0 4.3 09 10 16.3 2.5 0.0 MMMMMMMMMM MMFFFF%%%% ..... 10.5 0.0 2.3 10 11 13.2 2.5 0.0 XMMMMMMMMM MFF%%%%... ... 9.0 1.6 0.0 11 12 11.8 2.5 0.0 XMMMMMMMMM F%%%%..... 8.1 1.6 0.0 12 13 11.1 2.5 0.0 XMMMMMMMMF F%%%..... 7.5 1.6 0.0 13 14 10.6 2.5 0.0 XMMMMMMMFF %%%..... 7.1 1.6 0.0 14 15 10.5 2.5 0.0 XMMMMMMMFF %%%..... 6.7 1.6 0.0 15 16 9.9 2.5 0.0 XMMMMMMMF% %%..... 6.4 1.6 0.0 16 17 9.1 2.5 0.0 XMMMMMMFF% %..... 6.2 1.6 0.0 17 18 8.0 2.5 0.0 XMMMMMM%%% .... 5.9 1.6 0.0 18 19 7.3 2.5 0.0 XMMMMMF%%. ... 5.3 1.6 0.0 19 20 6.7 2.5 0.0 XMMMMM%%%. .. 4.9 1.6 0.0 20 21 6.7 2.5 0.0 XMMMMM%%%. .. 5.1 1.6 0.0 21 22 9.9 2.5 0.0 XMMMMMMMF% %%... 6.6 1.6 1.0 22 23 16.1 11.8 7.2 SSSMMM MFFFFF%%.. . 9.9 7.5 4.3 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