Re: [chrony-users] GPS/PSS hardware

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On Tue, 8 May 2018, Nicolas Embriz wrote:

Hi, thanks for all the comments feedback, I am thinking on building something like
this: with an ODROID-C2. 
Regarding the configuration, how do you configure your pool of servers?

You use something like

    server your-ip-2 iburst prefer
    server your-ip-3 iburst prefer

Or how you keep them sync, all the clients will use server my-pool.tld but wondering mainly about the servers it self.

They are presumably kept in sync because they sync themselves with a source of
time which is defined all over the surface of the earth. Ie, if all are in
sync with the same clock, they are also in sync with each other. Note that you
can sync with a gps sattelite far better than you can sync with any earthbound
clock, since the communication with that earthbound clock is subject to a
whole slew of random propagation delays.

Thanks in advance.


On Tue, May 8, 2018 at 7:15 PM, Alan Scott <project.director@xxxxxxxxx> wrote:
      Yes, this is totally possible and the equipment ect. does exist.....but what may I ask is the difference between
      hooking equipment "x" up to your server and having a raspberry PI attached to it......?

      You are still going to have to hook up some equipment regardless, correct...or am I missing something....

      I have the exact build you describe from uptronics below, (although I use the newer much smaller GPS they have
      on offer) and it works very well.....

           remote                                   refid st t when poll reach   delay   offset   jitter
      *SHM(1)                                  .PPS. 0 l    9   64  377   0.0000  -0.0685   0.0399
      xSHM(0)                                  .GPS. 0 l    9   64  377   0.0000 -112.395   1.3963                         .POOL. 16 p    -   64    0   0.0000   0.0000   0.0019             3 u   78  128  377  21.2007  -1.7077   1.8072       2 u   30   64  375  41.9868  -0.2644   1.0297   3 u   63   64  376  40.1422   1.1676   1.1980 2 u    5  128  377  31.1699   2.4556   0.9245           2 u   80  128  377  38.9460   4.6676   0.6918    2 u   37  128  377  61.9936   1.1824   2.1731             2 u   28   64  375  59.9884  -1.8464   1.3485

      If you have any questions about my setup I would be more than happy to answer but for around $100 usd it's hard
      to beat....


      On 05/08/2018 06:06 AM, Bill Unruh wrote:

            On Tue, 8 May 2018, Nicolas Embriz wrote:

                  Hi, I would like to build/test a stratum-1 server, I have found articles about how to do
                  that with a raspberry PI and boards

                  But wondering if there is hardware/devices that could be attached via USB and connect to
                  an existing server.

            USB is possible but not ideal. The interrupts are soft interrrupts (ie done by
            sending signals on the usb in software rather than some hardware line.) Best
            is if your system has some hardware line (eg serial port or parallel port) to
            use. Of course that depends on what kind of accuracy you want. If it is ms
            then a serial to usb converter will certainly work, and even just the GPS
            signal on the usb might be fine. If it is sub-ms you want, then a hardware
            interrupt is needed.
            Or your desktop server might already have a serial port, and you can use that.

                  Any recommendations?

                  Thanks in advance.

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