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Hans Summers
Andy: When GPS is ON, the U2 relies on the 1pps as it's one second tick. The U1 behaved exactly the same way. If you have a GPS module which stops sending the 1pps signal when it loses satellite lock, then the U2 time would stop too.
Tony: Some GPS modules stop the 1pps signal when the satellites lose lock. If you have that kind, the U2 would stop then too. The U1 behaved the same. If your GPS module lost lock then I think it must be the kind which still sends a 1pps signal regardless (from the GPS module's internal timing).
Andy:? If your U2 jumps 1's and 2's seconds when not in GPS mode then I think you have some other problem, RF pickup, ground loops, I have no idea... but that definitely isn't normal! The U2 should be able to operate correctly with no GPS module and should be accurate enough once you calibrate the system clock, for many days of WSPR operation.
All: You are all correct though: I should make the software so that if the 1pps signal stops for any reason, the system keeps time with its own internal oscillator, the same way as when GPS is off. One more enhancement for the list :-/
73 Hans G0UPL On Mon, Jul 1, 2013 at 2:32 PM, Andy Cutland <gj7rwt@...> wrote:
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