The Raspberry Pi as a Stratum-1 NTP Server

I just built one of these. It&#x27;s fun to have a little computer that can synchronize highly accurate time without an internet connection by listening to things in outer space!<p>I built an auto-install script that anyone here is welcome to use or reference[1]. If you know what you&#x27;re doing, just change the GPIO pin to your PPS input and fire away.<p>Unlike the author I used Chrony instead of NTP. It&#x27;s lighter-weight and much easier to configure with a PPS&#x2F;GPS reference clock.<p>The GPS chip I used was an ATGM336H, which can be had for less than $8 on ebay. I&#x27;m able to lock consistently 11 satellites from my desk[2]<p>Keep in mind the Pi has no hw RTC. If you&#x27;re doing this for fun spend a few more bucks and buy an rtc chip from ebay so you don&#x27;t drift considerably between being powered off.<p>1. <a href="https:&#x2F;&#x2F;github.com&#x2F;stephen-mw&#x2F;raspberrypi&#x2F;blob&#x2F;master&#x2F;roles&#x2F;stratum_1_timeserver&#x2F;install" rel="nofollow">https:&#x2F;&#x2F;github.com&#x2F;stephen-mw&#x2F;raspberrypi&#x2F;blob&#x2F;master&#x2F;roles&#x2F;...</a><p>2. <a href="https:&#x2F;&#x2F;www.ebay.com&#x2F;sch&#x2F;i.html?_from=R40&amp;_nkw=ATGM336H&amp;_sacat=0&amp;LH_TitleDesc=0&amp;LH_BIN=1&amp;_sop=15" rel="nofollow">https:&#x2F;&#x2F;www.ebay.com&#x2F;sch&#x2F;i.html?_from=R40&amp;_nkw=ATGM336H&amp;_sac...</a>

I had one of these running with a 10 meter cable to the window so the receiver could get enough satellites. After 24&#x2F;7 for about a year it just died and I haven&#x27;t had time to figure out what&#x27;s wrong. Lights blink but it&#x27;s not reachable via ping, ssh or scp. HDMI output shows nothing. I had to move on to other projects, so I gave up and assumed I either got hacked or I hit the cheap-SD-card problem of corruption that seems to plague other users running their Pi continuously for longer periods.<p>I&#x27;ve started buying SanDisk&#x27;s &quot;High Endurance&quot; microSD cards hoping it will mitigate any such issues in the future, but I haven&#x27;t had time to get the NTP set up again... I really should have cloned the image.<p>I think the hardest part was finding a case with space for the GPS hat[0] with an open end for the coax connector. The hat sits a bit crooked because of something bulbous on top (condensator?).<p>[0]: <a href="https:&#x2F;&#x2F;store.uputronics.com&#x2F;index.php?route=product&#x2F;product&amp;product_id=81&amp;search=GPS+Expansion+Board+" rel="nofollow">https:&#x2F;&#x2F;store.uputronics.com&#x2F;index.php?route=product&#x2F;product...</a>

Maybe add [2012] to the title, dear mods?

Off topic: I love this couples website. If you click through to the homepage they&#x27;ve got lots of stuff to browse.<p>Yes, it maybe old-style, but it&#x27;s these sort of sites that the internet was originally built on. It&#x27;s a real shame that they are becoming a dying breed.

&gt; Configuring Wi-Fi<p>That alone will negate <i>any</i> benefit of running a stratum 1. You lose the precision and accuracy over wifi. Jitter on intranet with the pi as a timesource would be magnitudes greater than the GPS link.

this is pretty cool. i was looking at your case, could you tell me the exact model case you were using? i couldn&#x27;t find the exact model on modmypi.<p>also, here&#x27;s a writeup i did on my experiences creating something with an rpi 3 model b+:<p><a href="https:&#x2F;&#x2F;github.com&#x2F;stephenhu&#x2F;written&#x2F;blob&#x2F;master&#x2F;raspberrypi.md" rel="nofollow">https:&#x2F;&#x2F;github.com&#x2F;stephenhu&#x2F;written&#x2F;blob&#x2F;master&#x2F;raspberrypi...</a>

What is the use case for microsecond-accurate timekeeping?

I built a nixie tube clock like that with a gps receiver, it works amazingly

They still haven&#x27;t separated the USB&#x2F;Ethernet Bus :&#x2F;

Are there performance differences regarding Pi 1&#x2F;2&#x2F;3?