OK! I'm going with the Raspberry PI B+ with a plug in GPS receiver.
So on the http://ava.upuaut.net store it list the GPS receiver then down
below it list the nine related products. So if I understand right I
want the B+ version. The case looks cool and I just need the case and
the 25mm M3 Standoff Kit for Geaux Robot Case. What about Stacking
header kit for Raspberry Pi+ do I need it and do I need this one too,
11mm Stand off kit for Raspberry Pi+? Which of those three GPS antennas
do I need and what's the difference between them.
On 12/16/2015 1:20, Mike Cook wrote:
Hi Nate,
I think you can forget about using your radio as the E1’s lowest
band is from 100KHz and WWVB which is what you want for timing is on
60KHz. I don’t know of any FM station time decoders.
After that cold shower, the options are limitless wth quite a number
entailing gluing small bits.
I have gone the way of gluing bits and I have a lot of them.
Your stats are are bad, due probably to the >2:1 asymmetry in
upload/download rates on 4G plus latency on the WIFI. You might also
be compounding that with power saving on your system though you don’t
say how that is configured.
If you want low budget, and have no better internet access you might
get by with a cheap PCI-E GPS such as Ublox GPS B39 PCI-5S-1-500 at <
$10 delivered from the auction site, coupled to a mini PCI-E to PCI-E
adapter (ex 181622523046 on the same site) for $5 delivered, an
active
SMA antenna with say 5m of cable , another $10 plus
an SMA pigtail to replace the RP-SMA at a couple of $
(ex.281842153844).
Link all that up and you will have an NMEA ref clock (over what will
look like a USB serial port to your OS) that should give you low ms
accuracy and stability for less than $50.
The GPS receiver seems to have a 4Hz update rate which is not useful,
but it can be reconfigured to 1Hz (see
<http://emerythacks.blogspot.fr/2013/01/u-blox-pci-5s-cheap-gps-module-for-your.html>
) with Ublox’s U-Center free software. That runs on windows only, but
should run under wine in linux or maybe you can dual boot your system
or ask a friend.
I prefer to have my time servers independent of application workload
, so I have many minis dedicated to that.
A good cheap one is a Raspberry PI B+ with a plug in GPS receiver
such as
<http://ava.upuaut.net/store/index.php?route=product/product&path=59_60&product_id=117>
which has few bits and only one connector to solder. If you ask
nicely, the seller will probably do it for you. If you add a usb wifi
dongle you won’t need cabling but you get better latency with cable,
so I would use that as you have ethernet on your box. The advantages
here are that you can leave it on all the time, and it will have 1PPS
ref clock, so you have microsecond accuracy and stability. Well I do
with that config. With a case, antenna etc I think you can get a
clean setup for < $150.
Of course you can do cheaper with bits. Take your choice.
Caveat:
As you have a crappy internet connection , even with a really
accurate inboard or external time source, it will be only ONE. This
is
not a good config . You really need a minimum of 3 .
How much would a proper internet connection cost you?
You seem to be between a rock and a hard place.
Regards,
Mike
Le 13 déc. 2015 à 17:06, Nate Homier <n...@universal-mechanism.org> a
écrit :
I am using a system76.com Wild Dog Pro desktop computer running
Ubuntu 15.10, I bought it in December 2015. It has no serial port. I
have a Shortwave radio if that will work to hook up to NTP.
Researching the net reveals many howto for hooking up GPS OEM radios.
This usually involves soldering, cutting and working with little tiny
things, all of which I am terrible at. I have heard of GPS radios
that plug into your PCI-E slot, now that sounds cool, but pricey.
Does anybody have any recommendation as to how I can turn myself
into an accurate stratum 0 or 1 client, I am not interested in being
Stratum 0 is the reference clock, Atomic, GPS, WWVB or whatever . It
is what makes an NTP source Stratum 1, so if you have a ref clock
then
your box will default to stratum 1 while the ref clock is reachable.
You can fudge stratum levels in the config, but it is unusual outside
testing.
a server. In case your wondering why, I don't know why, I do have
an official diagnosis of OCD, that might explain it. Not accurate
time bothers me a lot.
I have an Eton E1 HF receiver that keeps it's clock accurate via the
HF time bands, but not the LF band, strange, on the other hand your
guaranteed to get an HF signal worldwide as opposed to LF. It also
has an audio line out and does anybody have any experience with line
level audio for time keeping. Maybe I should start there before
forking over the cash for some project I can't finish.
Here's what I'm willing to do.
Do the shortwave radio thing first. Free and what I learn from it I
can apply to below.
Buy an PCI-E port serial card, one that you guys tell me to buy,
budget $75
Buy an GPS PCI-E card or external device. I can't give you a figure
for what I'm willing to pay because I have no idea what they cost.
Just doing this for fun. Love NTP.
Currently I am getting Internet through my Verizon Samsung Galaxy S6
Edge WiFi hotspot. -102 dBm and 38 asu signal, poor signal for 4G
LTE. Once I get up in the morning I turn off the Internet at about 11
am and the computer won't see a connection again until 8 or 9 pm. So
NTP is only connected during the night when I'm sleeping. Anybody
know how I can keep track of clock drift when NTP gets woken up at
night, be interesting to see how accurate the motherboard is.
NTP’s drift file will give you that info , though your connection
looks so bad that it may not be that good a figure. You really need
stable sources for to enable NTP to calculate it.
My current NTP stats.
First one is from peer.awk
ident cnt mean rms max delay
dist disp
==========================================================================
208.75.89.4 21 30.724 60.139 161.716 103.967
989.601 149.718
2604:a880:800:10::bc:c00d 19 8.736 16.624 32.476 134.039
499.117 42.186
50.116.38.157 18 19.069 23.196 46.512 141.819
495.233 44.446
2001:67c:1560:8003::c7 17 -2.631 18.085 41.863 204.340
173.570 23.222
104.41.150.68 18 37.286 26.949 50.019 147.775
174.419 39.181
nate@frontier:~$ ntpq -p
remote refid st t when poll reach delay
offset jitter
==============================================================================
+deekayen.net 152.2.133.52 2 u 554 1024 377 135.533
-23.196 82.525
*time.tritn.com 198.60.22.240 2 u 531 1024 377 82.637
-26.905 62.751
+2604:a880:800:1 131.234.137.24 2 u 592 1024 377 149.243
-23.740 63.528
+104.41.150.68 129.6.15.30 2 u 1007 1024 377 109.755
5.461 87.911
+golem.canonical 170.224.124.217 2 u 488 1024 377 182.265
-44.495 158.015
Sincerely Nate.
_______________________________________________
questions mailing list
questions@lists.ntp.org
http://lists.ntp.org/listinfo/questions
