SWS GRAFEX HF FREQUENCY PREDICTIONS ADDRESS NO. 1234 =============================================================================== Circuit: Perth district Date: 12 December, 2025 T-index: 110 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 5.9 3.1 2.7 AFF%%.. 00 01 6.3 3.4 2.9 AFFF%.. 01 02 6.7 3.6 3.1 FFF%%.. 02 03 7.0 3.7 3.1 FFF%%.. 03 04 7.2 3.8 3.2 FFFF%.. 04 05 7.2 3.8 3.2 FFFF%%. 05 06 7.1 3.7 3.1 FFFF%.. 06 07 6.9 3.5 3.0 AFFF%%.. 07 08 6.9 3.3 2.8 AFFF%%.. 08 09 6.7 3.0 2.6 AFFF%%.. 09 10 6.7 2.5 2.3 FFFF%%.. 10 11 6.6 1.6 1.5 AFFFF%%. 11 12 6.3 0.5 0.0 FFFFFF%.. 12 13 6.0 0.5 0.0 FFFFF%%. 13 14 5.9 0.5 0.0 FFFFF%%. 14 15 5.7 0.5 0.0 FFFFF%%. 15 16 5.5 0.5 0.0 FFFFF%.. 16 17 5.2 0.5 0.0 FFFFF%. 17 18 4.9 0.5 0.0 FFFF%%. 18 19 4.5 0.5 0.0 FFFF%.. 19 20 4.3 0.5 0.0 FFFF%. 20 21 4.4 0.5 0.0 FFFF%. 21 22 5.0 2.1 2.0 AFF%%. 22 23 5.5 2.8 2.4 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) 12-Dec-2025 BoM Space Weather Services, Sydney Australia +61-2-9213-8000