Satgen226 Where you are determines What you get Pt2 by GM4IHJ 24 July 93 BID of this msg is SGEN226 Please use this BID if you retransmit the msg The following tables shown typical daily acquisition times for the Shuttle and RS12 at stations at various latitudes. Considering the Shuttle first. Stations at 51N or S and stations further poleward see no orbits at all. Even though this unusually high Shuttle flight went to an altitude of 482 kms it could only see and be seen at 28.5 + 22 degrees maximum latitud north or south. A station at 47N or S sees just 3 orbits very low on his horizon, whereas a station at 20N or S sees a succession of 8 orbits, but a station on the Equator sees 2 blocks each of 4 orbits because it cannot see orbits crossing its meridian of longitude at latitudes above 22 degs. Shuttle 28 degs inclination 482 kms altitude 51N and above See Nothing 47N 0040 2051 2229 20N 0038 0217 0359 1551 1728 1907 2047 2228 0N 0221 0359 0540 0723 1406 1545 1725 1908 20S 0406 0543 0722 0902 1043 1223 1402 1543 47S 0906 1044 1225 51S Sees Nothing RadioSport 12 82 degs inclination 1000kms altitude 70N 0049 0236 0424 0611 0758 0944 1129 1314 1458 1641 1822 2004 2147 2331 56N 0046 0236 0428 0616 0802 0947 1134 1321 2002 2143 2328 40N 0043 0808 0952 1139 2138 2323 20N 0040 0816 0958 1146 2132 2317 0N 0825 1004 1152 2126 2312 20S 0831 1010 1158 2120 2306 40S 0019 0835 1016 1202 1930 2114 2300 56S 0013 0838 1021 1207 1356 1547 1737 1923 2109 2255 70S 0008 0153 0337 0519 0659 0841 1025 1210 1357 1545 1732 1919 2105 2251 By contrast RadioSport 12 with its 82 deg inclination and 1000km altitude has a footprint of 30 degrees . So at its orbit high point it can see 82 + 30 -90 = 22 degrees over the other side of the pole down to latitude 68 . Stations around 56N or S see every orbit except those which pass the other side of the pole from them. By contrast stations at 40N or S cannot see orbits on the far side or the near side of the pole , so they are restricted to just 2 separate blocks each of 3 or 4 orbits, these blocks being centred roughly 12 hours apart. Nearer the Equator stations simply see these two blocks each of 3 orbits , with the blocks centred 12 hours apart ie one of ascending orbits crossing the Equator south to north , with the other featuring descending orbits crossing the Equator north to south. At first sight RS12 appears to have a much more useful orbit. But another way of looking at the situation suggests that RS12 wastes a lot of time over empty polar areas , where none of the polar bears or penguins are licensed and there is no one else to talk to. There is however a third view whereby the fact that most of Northern Europe is out of range of this type of Shuttle orbit makes it useless for most Europeans. Fortunately a small number of Shuttle flights do follow a 57 deg inc track as described in Satgen 224 , so GMs LAs etc cannot complain. 73 de GM4IHJ @ GB7SAN