felix@cybertrains.org wrote: >Anybody uses SatTrack and can help me? I have problem with some tle >sets there - with some tles it says "check sum error in TLE set" even >after "fixchecksum" and nothing can fix it. For example, I can't view >this tle: > >Iridium 20A >1 25578U 98074B 99197.17911374 +.00001155 +00000-0 +24674-3 0 00853 >2 25578 086.5347 110.6935 0019633 320.0622 039.9143 14.57923427030426 The last digit in line 1 should be a 7 (instead of a 3). The rest of the TLE checks OK against one I have for that spacecraft and that epoch. Somehow the check digit became corrupt. If you have many of them then you may have downloaded a corrupt file. Check digits will equal the sum of all the digits in a line in columns 1 through 68, modulo 10. Spaces, letters, and plus signs (+) equal zero. Minus signs (-) equal 1. Ralph McConahy 34.8829N 117.0064W 670m