[AusNOG] EVERYONE should have a Stratum 1 time server, right?

John Edwards jaedwards at gmail.com
Mon Nov 14 19:22:32 AEDT 2022

FWIW, when I was working with vendor-H design folks on building an LTE/5G
network in 2016, best practice was to move away from using GPS for time
sync on mobile sites and trust Synchronous Ethernet from central sources

This gets around the problems of urban canyons, tunnels, or just clouds. It
also meant there was one less device to fail or need maintenance at
each location.

That particular network did some magic tricks that shared TDD spectrum
between adjacent towers, so sync was very important.


On Mon, 14 Nov 2022 at 16:26, Matthew Moyle-Croft <mmc at mmc.com.au> wrote:

> Mark isn't wrong. Large cloud builds I've been a part of - getting roof
> access for GPS antennas for this was ALWAYS a pain.
> I have a small GPS thing to help with a project to validate the various
> GNSS networks (https://galmon.eu) and unless the antenna is physically
> outside it's pretty much useless. Even windows with some metallic coating
> will almost completely block signals.
> On Mon, Nov 14, 2022 at 4:14 PM Mark Delany <g2x at juliet.emu.st> wrote:
>> On 14Nov22, Chris Barnes allegedly wrote:
>> > Finally a timesource I can feel confident setting my watch to.
>> > On Mon, 14 Nov 2022 at 07:38, Rob Thomas <xrobau at gmail.com> wrote:
>> >
>> > > The good news is, you now can!  After about 6 months of wrangling
>> bits and
>> > > pieces together, "Honest" Rob's Used Car (and VoIP) Emporium has
>> finally
>> > > managed to get a bunch of custom made GPS Shields built and they are
>> > > sitting right next to me here in Australia, suitable for lego-esque
>> > > construction of your own NTP server!
>> While I'm a big fan of all who run their own Stratum 1 time servers and
>> Rob providing a
>> hat/shield to do so is fantastic news, but...
>> ...be aware that the GPS signal is particularly weak and you almost
>> certainly need to
>> connect to an external antenna with specialized cabling to have any hope
>> of getting a
>> reliable signal.
>> I'm happy to be proved wrong, but this is not a device you can install in
>> your office (or
>> home) server rack and expect to get signal. Ultimately it needs to see
>> clear sky.
>> And if you're thinking of installing this in a data-centre,
>> forgeddaboutit. They charge
>> crazy money to run a cable to an antenna on their roof.
>> Don't get me wrong, I absolutely applaud the effort and I might buy one
>> myself but just be
>> aware of the antenna requirements which seem to have been downplayed in
>> the original
>> posts.
>> Mark.
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