SWS GRAFEX HF FREQUENCY PREDICTIONS ADDRESS NO. 1234 =============================================================================== Circuit: Perth district Date: 26 April, 2026 T-index: 60 Bearings: 0 180 Distance: 0-300 km First Mode |--------F r e q u e n c y (MHz)---------| Second Mode 1F 60-90 1E 40-90 1 5 10 15 20 25 30 35 40 ** NONE ** UT OWF EMUF ALF |...|....| ....|....| ....|....| ....|....| OWF EMUF ALF UT 00 6.2 2.4 2.0 AFFFF%. 00 01 7.0 2.8 2.3 FFFF%%. 01 02 7.3 3.1 2.5 AFFFF%.. 02 03 7.5 3.2 2.6 AFFFF%%. 03 04 7.6 3.3 2.7 AFFFF%%. 04 05 7.8 3.3 2.6 AFFFF%%. . 05 06 7.8 3.2 2.6 AFFFF%%. . 06 07 7.7 3.0 2.4 BFFFF%%. . 07 08 7.5 2.6 2.2 FFFFF%%. 08 09 6.9 2.0 1.8 AFFFF%%. 09 10 5.7 0.4 0.0 FFFFF%%. 10 11 4.4 0.4 0.0 FFFF%.. 11 12 3.9 0.4 0.0 FFF%%. 12 13 3.6 0.4 0.0 FFF%.. 13 14 3.5 0.4 0.0 FFF%. 14 15 3.5 0.4 0.0 FFF%. 15 16 3.5 0.4 0.0 FFF%. 16 17 3.5 0.4 0.0 FFF%. 17 18 3.4 0.4 0.0 FFF%. 18 19 3.4 0.4 0.0 FFF%. 19 20 3.3 0.4 0.0 FFF%. 20 21 3.1 0.4 0.0 FFF.. 21 22 3.1 0.4 0.0 FFF. 22 23 4.6 1.3 1.2 FFF%. 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) 26-Apr-2026 BoM Space Weather Services, Sydney Australia +61-2-9213-8000