Device works well, very handy when connecting to MCUs and crossing voltage domains.
Very handy for car related stuff and non-isolated mains powered stuff.
Worth the money, very handy device !

Jeff | Sept. 30, 2014

Almost as simple as plugging it in

For Laureline GPS NTP Server

Unlike some reviewers, I don't have the sophisticated equipment and knowledge to validate or refute claims like "locked to UTC ±200ns". Nor do I actually need to have the accurate time to within 200ns. But I do love the idea of precision timekeeping, so I bought a Laureline.

I started by plugging it into my laptop via USB and attaching a terminal program. As promised, within 3 minutes it was synchronized to GPS time and busy tuning its on-board TXCO. I gave the device a static IP address via my DHCP server (the laureline's hardware address is shown by the "info" command over USB), and plunked it on the network. I also gave it the hostname "ntp" in my DNS (you could use a hosts file too).

In my ntp.conf, I used the configuration line:
server ntp iburst minpoll 2 maxpoll 2

these settings allow ntpd to query the laureline more frequently. With just a handfull of machines querying the laureline over the local network, it can't do any harm, and it seems to give better performance in terms of ntpdc kerninfo's "estimated error" figure.

(I also retained the lines for pool.ntp.org, so in case of an "outage" of the laureline I'll still get network time)

Over the last few weeks I've been informally monitoring my main home computer's NTP performance. It reports an "estimated error" of under 25µs typically (2.5e-5s), and often under 10µs (1e-5s). During that time, the frequency offset for computer's own uncompensated oscillator has varied by about ±1ppm. (which actually seems pretty good)

A final note: I ordered the suggested sparkfun.com antenna. sparkfun.com's page on the antenna specifies it as 3.3V, but the linked datasheet specifies it as 3-5V. I did *not* move the laureline's solder jumper, and so far the antenna seems to work properly with the 5V supply. I've asked sparkfun to clarify their specifications for the antenna, but they hadn't updated the description the last time I looked.

James | Sept. 28, 2014

so far, works perfectly

For Laureline GPS NTP Server

It installed easily, took a few minutes to stabilze. It's been running for several weeks, consistently giving substantially better performance than internet sources. (Right now, I'm showing that I'm within about 11 microseconds; my internet sources are still configures, and are running around 2 to 5 milliseconds off. That is fairly typical.)

Peter | Sept. 8, 2014

What the previous reviewer said

For Laureline GPS NTP Server

My comments and positive experience with the Laureline pretty match what the previous reviewer (that's jrichert) said, delivery took a long time, but eventually it arrived. The use of FTDI rather than the widely-used Prolific USB/serial was great, it just worked out of the box rather than having to go to some Russian site to find patched Windows binaries that may or may not work on your system. Configuration via USB serial was a breeze, plugged it in, a few minutes later I had a lock, and then NTP output, from something that's a tenth the price of a Symmetricom or equivalent.

One for the wishlist, it'd be nice to have the indicator LEDs on the "front" (antenna) side rather than the "back" (power/network cable side). Most SOHO gear (non-rack mount) has the cabling coming out the back and indicator LEDs on the front, with the Laureline you've got to either loop all of the cabling round the back or stick your head around the side to see the status LEDs.

Update: For those using it under Windows, some notes: There's no easy way via the GUI to point to the Laureline, you need to go into the registry and change HKLM\SYSTEM\CurrentControlSet\Services\W32Time\Parameters\NtpServer to "<Laureline-IP>,0x1", then open a command shell as Administrator and restart the Windows time service with "net stop w32time" and "net start w32time", then finally force a resync with "w32tm /resync". To check that this worked, go into Control Panel | Date and Time | Internet Time which will still display the time server as one of the small number of choices that Microsoft provide (none of which are pool.ntp.org or anything similar, sigh), however if all worked out OK you'll see the message "The clock was successfully synchronized with <Laureline-IP> on ... at ...".

Peter | Sept. 8, 2014

Completey satisfied

For Laureline GPS NTP Server

Just got my Laureline yesterday, connected it to my local network, and from that moment I enjoy a highly accurate time base on all my little computers!

Paul | Sept. 7, 2014

The new Laureline is much better than the old Laureline.

For Laureline GPS NTP Server

The new version is on a par with my best NTP servers.
It would be nice if the build/ship status updates had happened a bit more often.
Highly recommended.

By the way, the time specs for a Laureline (200 nanoseconds) are derived from the GPS+local oscillator. They are unrelated to NTP time transfer resolution, which is limited by a number of factors that start at the source network interface and end in the kernel of the receiving device, and NTP timestamp resolution which is ~200 picoseconds.

Alan | Sept. 7, 2014

It has worked perfectly since connecting

For Laureline GPS NTP Server

I unpacked it, plugged it in, connected an unamplified GPS antenna stuck to the glass of my office window and it synced up quickly and has provided time without a hitch since then.

It makes claims about its accuracy which seem to be beyond the NTP spec, and no explanation of how its accuracy was measured. Nevertheless, it seems to work quite well, and I'm sure the designer has made it as accurate as possible.

Everything should be so simple to set up!

Note that it comes jumpered for 5v amplified antennas, but the Tindie site recommends a 3v amplified antenna. Not sure that combination would work.

Jochen | Sept. 7, 2014

Worked perfect out of the box - some whishes for future rel.

For Laureline GPS NTP Server

I was a bit disappointed for the delay of delivery but can understand, you don't have hundreds of them on stock.
But now, since the device is here, I am very happy with it. All is working fine. Configuration via PC and USB worked also perfect. What I most like is the possibility to feed my GPS antenna with 3.3 or 5 Volts. This makes it possible to drive my GPS splitter and use only one antenna.
What I like to have in a future release is the possibility to acces the NTP Server over the network, because my NTP Pi and the Laureline NTP are fed by a USB Power Supply. So there is no way to check the status or alter the configuration without connecting it to a PC or have a look a the LED's.
With that step it would probably also be possible, to add a another timesource from the LAN, like I am doing it with my Raspberry Pi.
My Raspberry is now grabbing time from my "www.blitzortung.org" lightning detection system, the Laureline NTP and from the Swiss Time Source.

So congrats to you, for the nice hard- and software developement and thanks for sharing it with us..

Best wishes from Switzerland, Joe, HB9DRT