3 ms·

If you are running Bind or SSL/x.509 certs, than an RTC is pretty much a requirement on the raspberry pi. Network time leaps over NTP even when working (first

If you are running Bind or SSL/x.509 certs, than an RTC is pretty much a requirement on the raspberry pi. Network time leaps over NTP even when working (first big leap was allowed etc.) can still bork a lot of services. Local stratum 1 GPS time (even with PPS pin) servers based on Pi's can suffer similar issues when they lose satellite lock (weather etc.) Have a great day =)

hcfman 3y ago
Having said that, I've never personally seen my stratum #1 Pi loose sync due to weather and I run about 4 of em here. I also use a cheap 7 euro ublox 7m. So long as you position it or an antennae with a reasonable view of the sky that shouldn't happen I reckon. Why all the complex solutions when it's so easy and cheap now to install a stratum #1 time server, even a Pi 3 will suffice. It works on a Pi Zero, but then you only have a wifi link. The sbts-au project make's it incredibly easy to setup. git lone and then install. One command, it's that simple.
- teruakohatu 3y ago
  Any advice for a cheap USB GPS for a stratum #1 time server? EDIT: Any any advice on how essential PPS is?
  - Joel_Mckay 3y ago
    The PPS can be good (pi kernel support is stable), but one needs to be careful as some modules PPS signal has a great deal of instability. Some U-Blox modules support the additional ground based navigation signal and cellular beacons. This is recommended in addition to the 3 satellite networks classes, but note some modules will not work with some antennas (get the unified hardware with built in antenna/lna if unsure about RF notes). Best regards, =)
    - hcfman 3y ago
      If you have good sky visibility, then I don't need an antenna. Though this often tends to mean putting a Pi outside. I'm also using just the first Antenna I find actually.
  - hcfman 3y ago
    I have good results with cheap ublox 6m's and 7m's from aliexpress. For some reason the 8m's I got were poor in sensitivity. Adafruit ones also work great, but are a lot mor expensive, I do have several though. PPS is criticial to proper timing. However... I was using the time synched systems for sound localization. But as they only cost around 7 euros on aliexpress, why not.

hcfman 3y ago

Having said that, I've never personally seen my stratum #1 Pi loose sync due to weather and I run about 4 of em here. I also use a cheap 7 euro ublox 7m. So long as you position it or an antennae with a reasonable view of the sky that shouldn't happen I reckon. Why all the complex solutions when it's so easy and cheap now to install a stratum #1 time server, even a Pi 3 will suffice. It works on a Pi Zero, but then you only have a wifi link. The sbts-au project make's it incredibly easy to setup. git lone and then install. One command, it's that simple.

teruakohatu 3y ago
Any advice for a cheap USB GPS for a stratum #1 time server? EDIT: Any any advice on how essential PPS is?
- Joel_Mckay 3y ago
  The PPS can be good (pi kernel support is stable), but one needs to be careful as some modules PPS signal has a great deal of instability. Some U-Blox modules support the additional ground based navigation signal and cellular beacons. This is recommended in addition to the 3 satellite networks classes, but note some modules will not work with some antennas (get the unified hardware with built in antenna/lna if unsure about RF notes). Best regards, =)
  - hcfman 3y ago
    If you have good sky visibility, then I don't need an antenna. Though this often tends to mean putting a Pi outside. I'm also using just the first Antenna I find actually.
- hcfman 3y ago
  I have good results with cheap ublox 6m's and 7m's from aliexpress. For some reason the 8m's I got were poor in sensitivity. Adafruit ones also work great, but are a lot mor expensive, I do have several though. PPS is criticial to proper timing. However... I was using the time synched systems for sound localization. But as they only cost around 7 euros on aliexpress, why not.