locked Re: Clock Sync #Timesync

Alan B

I too thought minpoll of less than 4 was internally rounded up to 4, but I find that minpoll of 3 works (polls every 8 seconds) on my local NTP servers with the version of Meinberg that I'm using. It's a year or so old and works fine so I haven't bothered updating the several machines running it. It is of course not proper to use polling that often with NTP servers other than your own.

The laptop that I run Meinberg on does sleep when it chooses to, and Meinberg recovers pretty quickly, far faster than a reboot.

There are many configurations for NTP servers that will work, but they often have secondary problems, the main one being they don't work offline, they want to see other servers before they will start serving. Comment out all the other servers from your NTP server config file and see if it will start serving anyway once the PPS and NMEA are stable. That's what we need for offline use, whether it be in the field or at home when the network is down.

I also found some Raspbian things that were interfering with the performance like Wifi power saving mode that need to be turned off, at least for nodes using Wifi, otherwise the jitter rises to crazy values.

I included the NTPsec in the document since Frank N6OI chose and used that, and he wrote that section. I didn't follow that path on my install. Lots of choices.

I just checked time.is on the desktop here. It shows 242 milliseconds off, while 2 PPS servers here and one internet servers show 1-3 mS. Seems like time.is doesn't have good accuracy.

73 de w6akb

On Sat, Jul 24, 2021 at 9:47 AM William Smith <w_smith@...> wrote:
In my experience, the Raspian releases tend to lag software packages like gpsd signficantly.

In order to get numbers for "Seen" and "Used" satellites, I had to install gpsd 3.22

When I did apt-get update/ugrade, suddenly I was "upgraded" to 3.17, which doesn't report Seen/Used.  And that took a while to untangle.

apt-cache policy gpsd still shows gpsd 3.17 as the one it'll install.  And 3.17 has a release date of 2017-09-07

For basic functionality it probably works fine, but I like to add monitoring for stuff like sync and number of satellites and SNR and such, so it can send me an email if something goes wrong.

73, Willie N1JBJ

On Jul 24, 2021, at 12:32 PM, Jim Pennino via groups.io <penninojim@...> wrote:

If you find a write up that says you have to compile something or install something outside of the distro, it is guaranteed to be well out of date.

For a Pi and a USB GPS and either Buster or Linux, it is just point gpsd to the correct device.

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