SWS GRAFEX HF FREQUENCY PREDICTIONS ADDRESS NO. 1234 =============================================================================== Circuit: Perth district Date: 18 September, 2025 T-index: 100 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 7.3 2.8 2.4 FFFFF%. 00 01 7.9 3.1 2.7 AFFFF%%. 01 02 8.3 3.4 2.8 AFFFFF%. . 02 03 8.6 3.5 2.9 AFFFFF%% . 03 04 8.7 3.6 3.0 AFFFFF%% . 04 05 8.7 3.6 3.0 AFFFFF%% . 05 06 8.4 3.5 2.9 AFFFFF%. . 06 07 8.1 3.3 2.8 AFFFFF%. . 07 08 7.9 3.0 2.6 AFFFF%%. 08 09 7.7 2.5 2.2 FFFFF%%. 09 10 7.2 1.5 1.4 FFFFFF%.. 10 11 6.3 0.5 0.0 FFFFFF%.. 11 12 5.6 0.5 0.0 FFFFF%%. 12 13 5.1 0.5 0.0 FFFFF%. 13 14 4.8 0.5 0.0 FFFF%%. 14 15 4.6 0.5 0.0 FFFF%.. 15 16 4.4 0.5 0.0 FFFF%. 16 17 4.2 0.5 0.0 FFFF%. 17 18 4.1 0.5 0.0 FFFF%. 18 19 3.9 0.5 0.0 FFF%. 19 20 3.7 0.5 0.0 FFF%. 20 21 3.6 0.5 0.0 FFF%. 21 22 4.3 0.5 0.0 FFFF%. 22 23 6.1 2.1 1.9 AFFFF%. 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) 18-Sep-2025 BoM Space Weather Services, Sydney Australia +61-2-9213-8000