[ntp:questions] Shared PPS source/Multiple PPS sources

walter.preuninger at gmail.com walter.preuninger at gmail.com
Fri Feb 6 23:37:28 UTC 2015


On Friday, February 6, 2015 at 3:38:14 PM UTC-6, William Unruh wrote:

> > Is there any reason why I could not share the PPS output of say, my u-blox 7 GPS module on multiple computers? Would it be good or bad to peer these 2 systems with each other?
> 
> By share you mean run the PPS output to each of the computers? The main
> thing you would need to do is make sure that the gps is able to handle
> the current load, and that the signals had the appropriate level at each
> of the computers. 

Yes, exactly what I mean.
> 
> 
> >
> > On the opposite end of the spectrum, would it be reasonable to have a PPS output from said module on a computer, with a second PPS (from another GPS module) on that same computer?
> 
> Sure. you need to have two differnt interrupt lines available (GPIO,
> serial ports, parallel ports)
> 

Awesome!

> >
> > The Chronodot/DS323X chips have 1 Hz sqaure wave output and they have +/- 2ppm. It seems that the ATOM clock driver could be used, but would it be better to write a driver specifically for this chip?
> 
> 2PPM is not that great. That is one second out per 6 day. A minute out
> per year. 
> What is that chip. 
> 

I was thinking more as a worst case, offline for hours situation. Perhaps a new driver could 'sync' the Dallas Semiconductor/Maxim DS3231 OXCO Real Time Chip periodically.

What is the ppm error of the RTC in a pc or my MacBook?

> > Does someone know the admin of tick.uh.edu? I am not getting a response from them or the server.
> 
> What reponse do you want? Why should they respond to you?

I would like to use tick.uh.edu as one of my 'local' Stratum 1's. I have 1 from Oklahoma, but I'm in Texas... and the server is either down, or the name has changed on Pulic Strat 1's list hasnt been updated.



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