Embedded NTP server ideas and feature requests
Greetings time-nuts,
I've finally gotten the software for my NTP server project to the point
where I'm comfortable shipping the boards I have now, so it's about time
to spin the next revision. If you could take a minute to look over the
feature list and let me know on- or off-list what you'd like to see,
hardware or software, I'd really appreciate it.
Here's the current product. I have 3 built and tested, so if you like
what you see and you have a GPS to hook it up to I'd be happy to send
one your way.
https://www.tindie.com/shops/gxti/laureline-gps-ntp-server/
http://partiallystapled.com/2013/01/laureline-gps-ntp-server/
There are a few things that I will definitely be changing. For one,
instead of a "bring your own GPS" I will be integrating a u-blox NEO-6M
receiver. It's not a timing receiver, but from what I've been able to
find on this list it is quite suitable for NTP. Should add about $10 to
the cost but compared to a $30 used Resolution T or similar that's a
good tradeoff. There will be a header where you can connect your own
favorite receiver. Alternately, the NEO-6T timing receiver uses the same
footprint and be soldered down instead, but is much harder to source.
The 5V antenna power will also be removed so there is one less power
supply to deal with, but if you have an antenna that requires more than
3.3V then you can use a header to supply any voltage that it might need.
I will also be beefing up supply filtering. It performs well now but I
want to make absolutely sure that EMI is a non-issue.
I've heard some people say they'd like a 10MHz output from the server. I
can break out the (digital) 10MHz clock from the VCXO, and/or provide a
way to connect your own OCXO if people are interested. The latter will
require some kind of adapter though as most OCXOs need more than the
3.3V VFC used here - a simple op-amp gain will work fine - and a limiter
might also be needed to digitize the sine-wave coming in from the OCXO.
These can be dealt with separately, though.Simply adding an ovenized
oscillator and timing GPS one can turn Laureline into a pretty good GPSDO.
On a semi-related note, I have two PPS Piggies in stock in my Tindie
store as well, so anyone with a Trimble Resolution T or SMT who needs a
way to hook them up should take a look.
Happy ticking,
-- m. tharp
Features?
-
Power the thing with "power over Ethernet" then you can remove the
coaxial power input. Also this would make it real easy to place the
server right at the antenna location. You would simply run cat-5 up
to the roof. The mount the antenna on top of a water proof box with
the server inside the box. If power has to come in via the coaxel
power connection to a wall-wort then it wil be hard to mount this
server outdoors, near the antenna. -
You really should make provision for a 5V antenna. All it will
cost is a tiny little 78L05 to provide a few milliamps. Put a jumper
on the board to select the antenna voltage.
With the GPS on the server using power over Ethernet makes even more
sense because peoplewill want to place the seaver very near the
antenna to make the wiring simpler. Wha not go all the way and put a
patch antenna on the board?
On Sat, Feb 9, 2013 at 2:27 PM, Michael Tharp gxti@partiallystapled.com wrote:
Greetings time-nuts,
I've finally gotten the software for my NTP server project to the point
where I'm comfortable shipping the boards I have now, so it's about time to
spin the next revision. If you could take a minute to look over the feature
list and let me know on- or off-list what you'd like to see, hardware or
software, I'd really appreciate it.
Here's the current product. I have 3 built and tested, so if you like what
you see and you have a GPS to hook it up to I'd be happy to send one your
way.
https://www.tindie.com/shops/gxti/laureline-gps-ntp-server/
http://partiallystapled.com/2013/01/laureline-gps-ntp-server/
There are a few things that I will definitely be changing. For one, instead
of a "bring your own GPS" I will be integrating a u-blox NEO-6M receiver.
It's not a timing receiver, but from what I've been able to find on this
list it is quite suitable for NTP. Should add about $10 to the cost but
compared to a $30 used Resolution T or similar that's a good tradeoff. There
will be a header where you can connect your own favorite receiver.
Alternately, the NEO-6T timing receiver uses the same footprint and be
soldered down instead, but is much harder to source.
The 5V antenna power will also be removed so there is one less power supply
to deal with, but if you have an antenna that requires more than 3.3V then
you can use a header to supply any voltage that it might need. I will also
be beefing up supply filtering. It performs well now but I want to make
absolutely sure that EMI is a non-issue.
I've heard some people say they'd like a 10MHz output from the server. I can
break out the (digital) 10MHz clock from the VCXO, and/or provide a way to
connect your own OCXO if people are interested. The latter will require some
kind of adapter though as most OCXOs need more than the 3.3V VFC used here -
a simple op-amp gain will work fine - and a limiter might also be needed to
digitize the sine-wave coming in from the OCXO. These can be dealt with
separately, though.Simply adding an ovenized oscillator and timing GPS one
can turn Laureline into a pretty good GPSDO.
On a semi-related note, I have two PPS Piggies in stock in my Tindie store
as well, so anyone with a Trimble Resolution T or SMT who needs a way to
hook them up should take a look.
Happy ticking,
-- m. tharp
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--
Chris Albertson
Redondo Beach, California
On 10/02/2013 9:27 AM, Michael Tharp wrote:
Greetings time-nuts,
I've finally gotten the software for my NTP server project to the
point where I'm comfortable shipping the boards I have now, so it's
about time to spin the next revision. If you could take a minute to
look over the feature list and let me know on- or off-list what you'd
like to see, hardware or software, I'd really appreciate it.
Here's the current product. I have 3 built and tested, so if you like
what you see and you have a GPS to hook it up to I'd be happy to send
one your way.
Hi Michael,
Just checking that these things are ok with Trimble Thunderbolts.
If so I'll order one.
And what's the cost of postage to Penrith, NSW, 2750, Australia ?
thanks
Tim
--
VK2XTT :: QF56if23PB :: BMARC :: WIA :: AMSAT-VK :: AMSAT
On 02/09/2013 08:35 PM, Chris Albertson wrote:
Features?
- Power the thing with "power over Ethernet" then you can remove the
coaxial power input. Also this would make it real easy to place the
server right at the antenna location. You would simply run cat-5 up
to the roof. The mount the antenna on top of a water proof box with
the server inside the box. If power has to come in via the coaxel
power connection to a wall-wort then it wil be hard to mount this
server outdoors, near the antenna.
PoE is a great idea, but I think this is better served by using a
separate, off-the-shelf splitter. It's hard to compete with economies of
scale. "Real" 802.3af in particular is difficult because of the required
isolation.
- You really should make provision for a 5V antenna. All it will
cost is a tiny little 78L05 to provide a few milliamps. Put a jumper
on the board to select the antenna voltage.
You're right, and I've been in "digital mode" long enough that I hadn't
even considered using a linear regulator for that function. Depending on
the antenna and input voltage the regulator could end up dissipating up
to a watt but that's quite feasible. That will definitely be in the next
revision, then.
With the GPS on the server using power over Ethernet makes even more
sense because peoplewill want to place the seaver very near the
antenna to make the wiring simpler. Wha not go all the way and put a
patch antenna on the board?
Again, this sort of comes down to not being able to serve everyone with
one board. Maybe I can make a "rooftop package" with a patch antenna and
passive power injector/splitter in the box. It looks like most ceramic
patch antennas already have a u.FL (they call it "IPEX") connector which
is what I was already planning on using internally.
Thanks a bunch for your feedback.
-- m. tharp
From: Michael Tharp
Greetings time-nuts,
I've finally gotten the software for my NTP server project to the point
where I'm comfortable shipping the boards I have now, so it's about time
to spin the next revision. If you could take a minute to look over the
feature list and let me know on- or off-list what you'd like to see,
hardware or software, I'd really appreciate it.
[]
Happy ticking,
-- m. tharp
---===========
Michael,
This looks to be a delightful little box, and I hope to be buying one in due
course.
Suggestions and questions:
-
NTP management: can this device be managed with the normal NTP commands?
I would like to see it responding to at least "ntpq -p" and "ntpq -c rv"
commands. The ntpq -p should show whether the device is locked to the GPS
or not. -
ideally, NTP log files should be available over FTP (FTP to allow remote
purging of older files). -
some way of determining the satellite status (number and signal level)
over the 'net would be helpful. -
how well would the device perform during a GPS signal interruption? Is
the 10 MHz lock used to time NTP, and held over for a certain period? -
although I've never used it, I do like Chris's suggestion of power over
Ethernet. I see dozens of choices in Amazon's lists - is there a standard
for the power adapter and level?
A ready to go item with patch antenna would suit my needs - likely it would
be placed in the loft rather than outdoors. Having 10 MHz available would
be very useful as well.
I think that's enough to be getting on with!
Cheers,
David
SatSignal Software - Quality software written to your requirements
Web: http://www.satsignal.eu
Email: david-taylor@blueyonder.co.uk