What do we think of this device to create a Strat 1 NTP Server?


#1

#2

What are you connecting it to? The computer hardware & OS are just as important. Will your antenna have an unobstructed view of the sky?


#3

IMHO buying from major players like Garmin would be better. More compacted in size (can be attached to window easily) and does not need separate DC power line.


#4

sure, the antenna would be on the roof, good to go… it would be connected to a reasonably powerful windows 10 system… I have used linux before, but I really dont want to screw around with that, everything I always wanted to do with linux proved to always be more difficult and provided a steeper learning curve.
This device is Cheap, so I was trying to take that into consideration too, but HOW will I interface it to an NTP time server is the biggest question, which is why I may simply go for this thing for $299 Instead:


Yes this is just a “kicking around” of ideas… obviously more expensive (although significantly cheaper than many other +$1000 solutions out there), but more likely to end in a successful project.


#5

There are Windows builds of NTP out there, I think Meinberg is probably the most popular:

https://www.meinbergglobal.com/english/sw/ntp.htm

However, I have no idea how to setup a PPS input on Windows, or if the Meinberg distribution has the correct GPS refclocks compiled in. I’m sure some googling would yield some how-to guides.

For my GPS based NTP servers I prefer FreeBSD… But it can be done on Linux usually by using GPSD.


#6

Funny, yes…thats exactly what I’m using and then through their program I poll a couple of strat 1 servers near me (relatively near) at Columbia U… I’m not sure if I "need " to use a meinberg GPS hardware product to be able to interface with this software or not, thats something I will need to ask them…also I see that going in through a serial port rs232/db9 is usually preferred over USB even when using a rs232 to USB converter due mainly to wildly unpredictable offsets in data transmission, so luckily there is a header for that on my motherboard to break out from and apparently unbeknownst to me a lot of boards have this!


#7

I found out garmin makes 3 types of that model and the only one with PPS is this on 18xLVC


#8

The TM1000A is only rated for 350 NTP requests per second. If you can afford a little bit more, the LeoNTP can do more than 100,000 in real world conditions.


#9

+1 for the LeoNTP, we run one in a commercial datacentre for this reason: http://www.leobodnar.com/shop/index.php?main_page=product_info&products_id=272


#10

Reading the description, the LEA-5T seems to be an accurate timing device, but the main problem is that you still have to find a way to feed the PPS signal to a computer running NTP software. I have been operating an NTP server based on the Garmin 18x LVC which W2AIQ mentioned above and it has the advantage over the LEA-5T that the power is 5 VDC which can be supplied by an attached computer through the USB port and the PPS signal can be connected to a serial port handshake input.

I have had this running since 2010 on a Xeon based server, and since a few months switched to a Raspberry PI 3B+ with the PPS signal connected through GPIO.

Looking at that past 8 years, my conclusion is that cost wise the hardware investment is not the biggest issue. In that time frame I spent significantly more money on electricity than on hardware. Due to its nature, a stratum 1 server will be running 24/7. So if you are searching for a cost effective solution do not only look at the initial hardware costs, but also at the total cost of ownership. A small complete system may in the end be cheaper than a cheap Chinese NTP clock from eBay connected to an power hungry computer.


#11

I was thinking about a Rasberry Pi too… The 3 B+ is only $35, plus you would need a GPS module but those aren’t that much more. I think I read 4W power consumption? Quad-Core 1.4GHz w/ 1GB RAM… Seems more than powerful enough for a pool NTP server.

The Soekris Net4501 that I built several NTP servers from is only a 133MHz single-core 486-class CPU with 64MB of RAM and it does just fine.


#12

Yes, I guess my Pi including the GPS is using around 5 Watt. If you go this route be sure to use the 3B+ because it has a much faster network controller than the older models. This Pi can easily saturate its 100Mbit up/down connection with the internet.

$35 is the board only price though. You need a power supply, housing and an SD card to let it function properly. I use a Swissbit 8GB micro SD card in it which costs about the same as the Pi itself, but provides industrial grade reliability and extended life. Most failing Pi deployments I have seen crash after some years due to SD card failures, not due to the failures in the computer board.