In classic amateur radio operations, the need of a good time synchronization has always been a requirement, for contact logging purposes, or for example in APRS and packet radio systems.

Nowadays, in the weak-signals digital modes era, with time synchronized protocols like FT8 FT4 JT65 and JT9, an accurate time synchronization of your PC clock with an atomic time service has become mandatory.

Time sync has become a so important factor, that makes the difference between being able to make contacts and not to be able.

Synchronizing your computer time it may be very easy task, and sometimes a challenge.

How to know if your computer is perfectly syncronized.

A very simple way to know if your PC Clock is synchronized, is to visit the Time.is web site and check the difference with your PC clock.

The ham radio way

In case you have no internet access, and want to know if your PC is in time sync, try starting from your PC a weak signal software, for instance, WSJT-X or JTDX session and tune into a FT8 Frequency. If you will be able to decode signals, it will mean that you are almost in time sync, and therefore, you don’t really need an additional synchronization.

If you pay attention to the graph, and you see green lines overlapping descending most of the signals, it will mean that your clock is not in sync, and no signals will be therefore decoded.

Fast modes like FT4 where data is exchanges in 8 seconds, having an accurate time synchronization is even more important.

How to sync computer time with internet

Time synchronization in modern operative systems is often built-in, but some times, difference of even half a second may be the cause of problems on decoding signals.

However, under modern Microsoft and Apple operative systems like Windows 10 or MacOSX 10.x you can use a simple commands from Command Prompt or Terminal. These commands will time sync your PC with internet NTP time servers.

NTP Servers

Time services are provided in Internet by Network Time Protocol Servers.
NTP servers are internet services whose job is to provide the current time. They are often very accurate ther are hundreds of them in the net. Said that, we suggest you to choose the closest to you.
You can find a list of NTP servers on these web sites.

• NIST
• NtpPool

Once you have selected one, you can then execute the sync command as in the examples below, just changing the time.nist.gov address we use in the examples below.

Windows time sync command

net time \\time.nist.gov /set /y

Mac OSX time sync command

sudo sntp -sS time.nist.gov

Linux time sync command

ntpdate -u time.nist.gov

Computer Time Sync Software

In addition to sync commands, that will need to be manually executed, we selected for you some of the most popular programs used by hams, that you can easily install on your PC in order to accurately and continuously sync your computer clock with internet NTP servers.

Dimension 4
Freeware software that synchronize your PC's clock. Dimension 4 monitor your Internet connection and automatically adjust your PC's clock when you're online at an interval you specify.

BktTimeSync
IZ2BKT
BktTimeSync synchronizes the PC time using an internet time server (NTP server) or a GPS receiver connected to USB, serial port or Bluetooth. Great for use with digital modes like FT8, JT65, JT9, JS8Call and others. For the operation of this program requires an active internet connection or a GPS receiver. This program works on all versions of Windows 32 or 64 bit

JTSync
UU0JC
JTSync is a simple utility that provides the ability to synchronize your computer clock over a network with world-wide NTP servers. When the Internet connection is not available, JTSync allows you to make time adjustments based on decoded QSOs within the WSJT-X application.

Meinberg NTP for Windows
Meinberg
Meinberg NTP software to sync your computer clock. NTP client package with IPv4 IPv6 support for Windows XP and newer.

NetTime for Windows
timesynctool
NetTime is a simple and free software to sync your computer clock via internet. Very useful tool for FT8 FT4 operating modes.

How to sync your PC time without Internet

In the era before internet, time synchronization was already a need, and sync methods were mostly based on GPS data reception.
Even today, this technique can be very useful for amateur radio portable operations, especially for those who operate in remote locations, where mobile data connection is not available, but where GPS system still works.

For this method to work, you will need an external GPS receiver attached or integrated in your PC.

An interesting article by W0JD explains how to sync clock of your PC with a GPS receiver.

GPS Time Sync Software

GPS2Time
VK4ADC
A means of sync-ing your computer clock using a GPS Receiver. GPS2Time is another GPS network time synchronization software application for Window 7 and higher. Freeware.

GPS time
COAA
GPSTime is a small freeware applet that corrects your PC clock using GPS. GPSTime reads the serial data coming out of your GPS receiver and decodes the $GPRMC messages to determine the precise UTC time. Works on Windows Vista/7/8/10 with PC with serial ports.

Time Sync with FT8

If you are into amateur radio, another cool method to sync you pc time, is to download and use JTSync program. This nice piece of software will reverse the scope. I will not sync your PC time in order to receive FT8 signals, instead, it will use the received FT8 signals to determine the correct time and to accurately sync your clock. Genius!

In conclusion, nowadays to sync a computer clock with or without internet is not really a great problem. If you need you may find additional interesting Internet and GPS time synchronization programs in our links directory