SWS GRAFEX HF FREQUENCY PREDICTIONS ADDRESS NO. 1234 =============================================================================== Circuit: Albany Perth Date: 20 April, 2026 T-index: 65 Bearings: 331 152 Distance: 386 km First Mode |--------F r e q u e n c y (MHz)---------| Second Mode 1F 51-54 1E 24 1 5 10 15 20 25 30 35 40 UT OWF EMUF ALF |...|....| ....|....| ....|....| ....|....| OWF EMUF ALF UT 00 7.2 4.7 2.7 ABFFF%.. 00 01 8.0 5.5 3.0 ABBFF%%. . 01 02 8.3 6.0 3.3 BBBFF%% . 02 03 8.6 6.2 3.4 BBBFF%% .. 03 04 8.8 6.3 3.4 BBBFF%% .. 04 05 9.0 6.3 3.4 BBBFF%% .. 05 06 8.8 6.1 3.3 BBBFF%% .. 06 07 8.7 5.7 3.2 BBFFF%% .. 07 08 8.4 5.1 2.9 ABBFFF%% .. 08 09 7.9 3.9 2.3 BFFFF%%. . 09 10 6.4 0.8 0.0 FFFFFF%%.. 10 11 4.9 0.8 0.0 FFFF%%.. 11 12 4.3 0.8 0.0 FFFF%.. 12 13 3.9 0.8 0.0 FFF%%. 13 14 3.8 0.8 0.0 FFF%%. 14 15 3.8 0.8 0.0 FFF%.. 15 16 3.7 0.8 0.0 FFF%.. 16 17 3.7 0.8 0.0 FFF%.. 17 18 3.7 0.8 0.0 FFF%.. 18 19 3.6 0.8 0.0 FFF%.. 19 20 3.5 0.8 0.0 FFF%. 20 21 3.3 0.8 0.0 FFF%. 21 22 3.4 0.8 0.0 FFF%. 22 23 5.4 3.0 1.8 ABFF%. 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) 20-Apr-2026 BoM Space Weather Services, Sydney Australia +61-2-9213-8000