SWS GRAFEX HF FREQUENCY PREDICTIONS ADDRESS NO. 1234 =============================================================================== Circuit: Broome Perth Date: 27 April, 2026 T-index: 80 Bearings: 201 24 Distance: 1680 km First Mode |--------F r e q u e n c y (MHz)---------| Second Mode 1F 12-15 1E 2 1 5 10 15 20 25 30 35 40 2F 28-33 2E 10 UT OWF EMUF ALF |...|....| ....|....| ....|....| ....|....| OWF EMUF ALF UT 00 18.1 13.3 7.8 ASSXMM MMMFFFFF%% %... 11.5 8.5 4.7 00 01 20.0 15.2 8.7 SSSXM MMMMBFFFF% %%%.... 12.5 9.9 5.2 01 02 20.9 16.4 9.3 ASSSX MMMMMBFFFF %%%%.... 13.0 10.8 5.5 02 03 21.0 17.0 9.6 ASSSX XMMMMBBFFF %%%%..... 13.0 11.2 5.6 03 04 20.9 17.2 9.7 ASSSX XMMMMBBFFF %%%%.... 12.9 11.4 5.7 04 05 20.5 17.1 9.6 ASSSX XMMMMBBFFF %%%%.... 12.8 11.3 5.6 05 06 19.8 16.5 9.3 SSSSX MMMMMBFFF% %%%..... 12.5 10.9 5.4 06 07 19.6 15.3 8.8 SSSXX MMMMMFFFF% %%%%..... 12.4 10.2 5.1 07 08 19.0 13.5 7.9 ASSXXM MMMMFFFF%% %%%..... 12.1 9.1 4.6 08 09 18.2 10.2 6.3 ASSMMMM MMMMFFFF%% %%..... 11.7 6.8 3.6 09 10 14.5 2.3 0.0 XMMMMMMMMM MMFF%%%%%. ..... 9.7 1.5 0.0 10 11 11.1 2.3 0.0 XMMMMMMMMM F%%%%..... . 7.7 1.5 0.0 11 12 9.6 2.3 0.0 XMMMMMMMF% %%%...... 6.7 1.5 0.0 12 13 8.4 2.3 0.0 XMMMMMMF%% %..... 6.0 1.5 0.0 13 14 8.1 2.3 0.0 XMMMMMMF%% %.... 5.8 1.5 0.0 14 15 7.8 2.3 0.0 XMMMMMM%%% .... 5.6 1.5 0.0 15 16 7.8 2.3 0.0 XMMMMMM%%% .... 5.5 1.5 0.0 16 17 7.5 2.3 0.0 XMMMMMM%%% .... 5.5 1.5 0.0 17 18 7.2 2.3 0.0 XMMMMMF%%% ... 5.2 1.5 0.0 18 19 6.8 2.3 0.0 XMMMMM%%%. ... 4.7 1.5 0.0 19 20 6.3 2.3 0.0 XMMMMM%%%. .. 4.4 1.5 0.0 20 21 5.7 2.3 0.0 XMMMM%%%.. . 4.1 1.5 0.0 21 22 7.2 2.3 0.0 XMMMMMF%%. . 5.2 1.5 0.0 22 23 14.4 9.7 6.0 ASMMMMM FFFF%%%.. 8.8 5.6 3.7 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) 27-Apr-2026 BoM Space Weather Services, Sydney Australia +61-2-9213-8000