Public NTP/NTS Time Server
time.web-clock.ca
This is a community time server that responds to Network Time Protocol (NTP) v4 requests and supports Network Time Security (NTS). You are encouraged to use NTS where possible.
Stratum: 1
Reference clock: GPS
PPS: Yes, aligned to UTC(USNO)
Location: Ottawa, Ontario, Canada
Service area: Intended for use by clients in North America
Restrictions: Server hostname or IP address(es) may not be hard-coded in any hardware or software without advance explicit written permission from the time server operator
Contact email: admin at the above domain (without “time” subdomain)
The server runs on a Raspberry Pi 5 with 8GB of RAM. A Garmin 18x LVC GPS receiver is connected to the Raspberry Pi GPIO pins, with additional hardware between them for electrical compatibility. The Raspberry Pi uses TTL at 3.3v while the Garmin 18x LVC GPS receiver uses RS-232 at +5v, which are incompatible. To interface these devices, the RS-232 signal from the Garmin 18x LVC GPS receiver must be inverted and shifted from 5v to 3.3v. To invert the signal, a Texas Instruments SN74AHCT14N logic level inverter is used. To shift the voltage level a Texas Instruments SN74LVC245AN logic level shifter is used. Note that the data signal must be both inverted and shifted, while the PPS signal only needs to be shifted, but not inverted.
The Garmin 18x LVC GPS receiver provides 1 pulse per second (PPS) signal accurate to within 1μs of UTC(USNO). The receiver is in a stationary position with a nearly unobstructed view of the sky, behind a thin non-metallic roof for protection.
NTP/NTS service is provided by chrony. GPS facilities are provided by gpsd. SSL certificates are provided by Let’s Encrypt Certificate Authority.
To use the server, add the following line in your configuration file for either NTPsec or chrony (or may be adapted to your environment):
server time.web-clock.ca iburst nts
The iburst option makes the first update of the clock sooner by sending a burst of 4-8 requests.
The nts option enables authentication using the NTS mechanism.
All of the above flags are optional.
Every effort was made to ensure that the server operates as intended and serves the correct time every time, however its use comes with absolutely no warranty of any kind. Its use is solely at your own risk. By using the server, you agree to accept all risks associated with its use.
This page was last updated on: May 30, 2025