[time-nuts] 1pps signal presence with no GPS signal.

David Kirkby david.kirkby at onetel.net
Thu Jul 7 05:36:45 EDT 2005

I have a Synergy GPS unit, which is fitted with a Motorola M12+ 
receiver. Even if there is no signal (even no antenna connected) the 
1pps light flashes on the front and there is a 1pps signal at the output 

It would seem to me that if you lock a crystal/rubidium or whatever to a 
GPS system, the last thing you want to do is to steer your source from a 
1pps signal that must be pretty inaccurate. I assume this gets derived 
from the uncompensated crystal oscillator on the Motorola board, and so 
is far less accurate than the source you are phase locking to it.

I would have thought it more sensible to cease the 1pps signal as soon 
as a GPS is not locked to at least one satellite.

David Kirkby,

Please check out http://www.g8wrb.org/
of if you live in Essex http://www.southminster-branch-line.org.uk/

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