tirsdag den 24. marts 2020

Replacing Meinberg NTP with Network Time

I purchased a new PC last month with Windows 10 preinstalled. The Windows specs are shown in figure 1.


Figure 1. My new Windows 10.

I had problems after I installed Meinberg NTP. Whenever I booted the PC, the system clock was set by Meinberg, but then time discipline was lost. After some hours, the system clock could deviate as much as 1 sec. It seemed like Meinberg could not control the system time. I worked with this problem for a while, and then I decided to uninstall Meinberg NTP and try another piece of software for time control.

I need accurate time keeping because I'm using weak signal digital protocols in amateur radio. A time deviation of less than 100 ms is required with JT65. I use JT65 when I'm bouncing radio signals off the Moon and back to Earth (distance 800,000 km).


Figure 2. Network Time.

Network Time was easy to install, and it worked right away. Under "Settings" I set "Update Interval" to 20 minutes because I wanted frequent updates. Remaining options were left at the factory settings.

Before installing Network Time I opened UDP port 123 (inbound/outbound) in Windows Defender Firewall. This port is used by the NTP (Network Time Protocol). I named the rule "UDP-port-123-time1", see figure 3.



Figure 3 Windows Defender Firewall (Windows 10).

I changed "Set the time automatically" from On to Off as shown in figure 4. This tells Windows not to use W32time.


Figure 4. Date and Time (Windows 10).

You can check the accuracy of your computer clock by visiting this page.

Vy 73 from OZ1BXM Lars
Webpage: oz1bxm.dk