Bob,

I can tell you from years of experience with writing tracking programs for Windows and iOS that one of the biggest problems is decay. Strange things happen to math routines when the altitude of the satellite drops below the surface of the earth. One solution is filtering out these decayed sats from the list. The tracking program is the easy part the hard part is dealing with "bad" tle data. The old saying in the computer biz - "garbage in, garbage" out.

Less you think this stuff is trivial take a look at this fine work by G3RUH. http://www.amsat.org/amsat/articles/g3ruh/111.html

Maintaining lists of satellites and web pages is very time consuming. Some quit because it is a PITA. Fortunately there are some truly dedicated souls who do not give in to the lame PITA excuse.

Dr. T.S. Kelso TS.Kelso@celestrak.com is one. He maintains the most reliable set of sat tle data I know of. http://www.celestrak.com/

Another is Erich Eichmann who puts in countless hours of his time maintaining and improving SatPC32. We all owe a great deal to these two pillars of the hobby.

I suggest using the Celestrak data sets exclusively. There will be the occasional sat that has decayed that may cause a problem but that is the nature of the hobby. All the sat tracking programs are complex - the only thing more complex than trying to figure out a sat tracking program is trying to figure out two of them. I am sure others have a different opinion but IMHO stick with SatPC32.

73 W9KE Tom Doyle

On Tue, Jun 3, 2014 at 10:53 PM, Bob- W7LRD w7lrd@comcast.net wrote:

I can not get it to run (satpc-32). Someone said it is because of a inactive satellite in the list. Which one?? It will just keep happening. Also I am looking for a backup sat program as satpc32 is unreliable. Recommendations?? 73 Bob W7LRD _______________________________________________ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb