Hi Anton,
> My question is what good synchronization of a gps clock in Nano seconds?
That's not much to go on; there are so many variables. To start with,
almost any cheap eBay GPS/1PPS receiver these days will give you time to
within a couple 100 ns with no special effort on your part.
If
Does it have to be Wifi ?
What about using 315/433MHz or one of the other LIPD bands on an Arduino ?
e.g.
https://www.instructables.com/id/RF-315433-MHz-Transmitter-receiver-Module-and-Ardu/
regards
Tim
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On 12/2/19 12:01 AM, Anton Strydom wrote:
Good day All
I am new here.
I have been busy with GPS systems for the last couple of years and have
also developed a number of low cost high accuracy L1 units.
I also play around with photography and especially in the field of
photogrammetry and 3D
Hi Everyone,
CBS News ran a brief news story about this.
...Not very much technical info, but it's at least an inside look.
Two related concepts that interest me are system resiliency, redundancy,
and a possible secondary ground-based backup system.
CBS posted it on YouTube, in case you'd like
Bob, I want to revise my previous statement about ESP8266 WiFi times with
some actual measurements. Below are pings to ESP8266 on local Wi-Fi. Most
are 0.7ms to 1.1ms with occasional spikes larger than that.
PING 192.168.1.13 (192.168.1.13) 56(84) bytes of data.
64 bytes from 192.168.1.13:
I have a Trimble Thunderbolt for sale. This unit has the Trimble OCXO inside.
The unit works and includes a MeanWell AC power supply to power the T-bolt.
Asking $225 + shipping to a CONUS address. Please reply off list.
-Brian, WA1ZMS
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Hi
Welcome !
The answer to any good question will always be “that depends” :)
First depends is what sort of module:
Just about any GPS that is doing a reasonable job will sync to under 50 ns.
That’s without correcting for sawtooth error. The sync would be device to
device over a local
Good day All
I am new here.
I have been busy with GPS systems for the last couple of years and have
also developed a number of low cost high accuracy L1 units.
I also play around with photography and especially in the field of
photogrammetry and 3D point cloud situations.
Time being the one
List -- there will be a posting shortly about synchronization. The
author is new to time nuts but has an interesting application and
requirements. Please be as constructive as possible.
Thanks,
/tvb
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Hi
I’m sitting here getting things set up to start digging into the whole wired /
wireless / whatever
side of this. The “real” application will be purely WiFi. More or less, the
“real” budget is an
equal jitter from the server, the client, and the router. If that all comes in
under 10 ms,
Dear colleagues
I was a bit lazy in the past, so it took way too long to finish the schematics
for my new GPSDO.
I am currently making some first trials on the PCB layout; however, I still
would like to show you guys my schematics and ask what you think about it. See
the attachment.
Page 1
Bob,
Will all the devices and the NTP server be connecting to an already existing
Wifi AP - or is there a possibility that the Wifi AP itself provides the NTP
service?
When I did more testing, I discovered that it isn't just ESP32s that do weird
things on WiFi - when pinging from something on
Does it need to be actual NTP, or could it use a custom broadcast protocol
for the 'last yards' ?
I'm imagining something that broadcasts a packet subject to the usual
anticollision strategies, then in the next packet it reports how far off it
actually was (like a GPS sawtooth frame).
Some other
Hi
Wired is out for this particular setup. It needs to be some sort of wireless.
It all would
be *much* more simple with wires.
Bob
> On Dec 2, 2019, at 12:46 PM, Robert LaJeunesse wrote:
>
> If wired Ethernet seems to be the way to go consider the Orange Pi Zero -
> about the cheapest
Hi
Part of the process is going to be validating the various bits and pieces
on the “might use” list against the Meinberg server here at home. Things like
lightweight routers and low power clients may be a “surprise" once I get
around to looking at them.
Bob
> On Dec 2, 2019, at 9:56 AM, Tim
For a lot of IoT applications, 100mS might as well be instantaneous. These
things are used for data logging or remote control where it simply does not
matter.
On Mon, Dec 2, 2019, 7:02 AM Bob kb8tq wrote:
> Hi
>
> Indeed, if you get up into the “many tens” of ms, that rules it out in my
>
If wired Ethernet seems to be the way to go consider the Orange Pi Zero - about
the cheapest wired Ethernet board available that runs Linux. Ethernet is via
on-chip MAC and phy, so no USB path delays.
http://www.orangepi.org/orangepizero/
Plenty of support exists on the web, for example:
Bob, I find that 2.4GHz Wi-Fi UDP latency with ESP8266 will frequently be
tens of milliseconds and is never/rarely consistent.
There are specialized non-WiFi 2.4GHz systems for time distribution that
are far more consistent (possibly even at the tens of microseconds). I
think several years ago on
Hi
Indeed, if you get up into the “many tens” of ms, that rules it out in my
application.
A consistent 90 ms would be ok, you could compensate for that. Random flopping
from 4 to 90 … not so much.
It seems like that sort of jitter would get in the way of a lot of things. I
guess that just
I did some testing against an ESP32 this evening to see how feasible it would
be to use this platform. Unfortunately there is extremely high jitter on the
wifi interface of the ESP32 (between 4ms to 90ms) - even after adjusting some
settings and disabling all power management. This was
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