SWS GRAFEX HF FREQUENCY PREDICTIONS ADDRESS NO. 1234 =============================================================================== Circuit: Geraldton Perth Date: 9 December, 2025 T-index: 90 Bearings: 162 341 Distance: 373 km First Mode |--------F r e q u e n c y (MHz)---------| Second Mode 1F 53-64 1E 24 1 5 10 15 20 25 30 35 40 UT OWF EMUF ALF |...|....| ....|....| ....|....| ....|....| OWF EMUF ALF UT 00 5.8 5.3 3.3 BB%%.. 00 01 6.3 5.7 3.5 ABF%%.. 01 02 6.8 6.0 3.7 ABB%%.. 02 03 7.3 6.2 3.8 ABBF%%. . 03 04 7.5 6.3 3.8 ABBF%%. . 04 05 7.7 6.3 3.8 ABBF%%. . 05 06 7.5 6.2 3.8 ABBF%%. . 06 07 7.3 5.9 3.6 ABFF%%. . 07 08 7.2 5.6 3.5 ABFF%%. . 08 09 7.0 5.0 3.2 BBF%%%. 09 10 6.8 4.2 2.7 ABFF%%.. 10 11 6.6 2.6 1.8 AFFFF%%.. 11 12 6.3 0.8 0.0 FFFFFF%%. 12 13 5.9 0.8 0.0 FFFFF%%.. 13 14 5.7 0.8 0.0 FFFFF%%. 14 15 5.6 0.8 0.0 FFFFF%%. 15 16 5.5 0.8 0.0 FFFFF%%. 16 17 5.1 0.8 0.0 FFFFF%.. 17 18 5.0 0.8 0.0 FFFF%%. 18 19 4.7 0.8 0.0 FFFF%.. 19 20 4.4 0.8 0.0 FFFF%.. 20 21 4.5 0.8 0.0 FFFF%.. 21 22 5.0 3.4 2.3 BF%%.. 22 23 5.4 4.6 2.9 ABF%%. 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) 9-Dec-2025 BoM Space Weather Services, Sydney Australia +61-2-9213-8000