SWS GRAFEX HF FREQUENCY PREDICTIONS ADDRESS NO. 1234 =============================================================================== Circuit: Perth district Date: 8 August, 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 5.5 2.3 1.9 AFFF%. 00 01 6.1 2.8 2.3 FFFF%. 01 02 6.4 3.0 2.5 AFFF%.. 02 03 6.7 3.2 2.6 AFFF%.. 03 04 6.8 3.3 2.6 AFFF%%. 04 05 6.8 3.2 2.6 AFFF%%. 05 06 6.8 3.1 2.5 AFFF%%. 06 07 6.9 2.9 2.4 FFFF%%. 07 08 6.6 2.6 2.2 FFFF%.. 08 09 6.1 1.9 1.7 AFFFF%. 09 10 5.1 0.4 0.0 FFFFF%. 10 11 4.1 0.4 0.0 FFFF%. 11 12 3.5 0.4 0.0 FFF%. 12 13 3.3 0.4 0.0 FFF%. 13 14 3.2 0.4 0.0 FFF%. 14 15 3.1 0.4 0.0 FFF.. 15 16 3.1 0.4 0.0 FFF.. 16 17 3.1 0.4 0.0 FFF.. 17 18 3.0 0.4 0.0 FF%.. 18 19 2.9 0.4 0.0 FF%.. 19 20 2.8 0.4 0.0 FF%.. 20 21 2.7 0.4 0.0 FF%. 21 22 2.8 0.4 0.0 FF%. 22 23 4.1 0.0 0.8 AFFF. 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) 8-Aug-2026 BoM Space Weather Services, Sydney Australia +61-2-9213-8000