3 ms·
GPS satellites broadcasting L1 signals are transmitting 25 bit/s at 25.6W and they're only about 12551 miles away and moving at 8700 mph.
by CalChris 7y ago
GPS satellites broadcasting L1 signals are transmitting 25 bit/s at 25.6W and they're only about 12551 miles away and moving at 8700 mph.
- jacquesm 7y agoBut they are line of sight. That's what makes this so special. Stars are many lightyears away, and radiate insane amounts of power the vast majority of which is lost. By the time it reaches here you may need a very long exposure to be able to see them at all. But it is line of sight. These waves were of the line-of-sight variety and somehow they were bent around the planet enough to register. That's a very hard to achieve thing.
- NovemberWhiskey 7y agoVoyager 1 is still in contact using a nominal 23W, despite being over 13 billion miles away and heading further out at over 10 miles per second.
- varenc 7y agoSince it launched in 1979, have software updates improved the error correcting codes in Voyager's radio communications?
- CalChris 7y agoThat was done in 1989 with an update to Reed Solomon Viterbi – Version 2. https://sourceforge.isae.fr/projects/simplified-communications-schemes-of-voyager-i-probe/wiki/History_and_some_definitions_that_you_need_to_know https://sourceforge.isae.fr/projects/simplified-communicatio...