Last Updated on April 17, 2026 by g6nhu
Introduction
At the time of writing, there are two viable replacement backends for HamClock.
Open-hamclock-backend (OHB) – For full details see here. This is an open-source backend being worked on by a group of radio amateurs. You can either run an instance yourself, or if you’d rather, you can simply connect to their server.
Hamclock.com (HCDC) – For full details see here. This is a closed-source backed being worked on by a single person. You can’t run this yourself but you can simply connect to his server.
This page is to show you how to switch your devices between backends. At some point in the future I will make a post comparing the two options but for the moment, all I’m doing is providing instructions on switching your HamClock to one or the other.
If you’re using an Inovato Quadra or equivalent
If you have an Inovato Quadra, either the original or the 4K version, or another box running the Quadra build such as the N0LSR HK1RBOX I recommend you use the built in utility. The instructions are here or you can download them as a pdf by clicking here. The scripts below should work, but I’ve not tested them on every model.
If you’re using a Raspberry Pi or another Linux system
This has been tested on multiple Raspberry Pis and computers running Ubuntu Linux. The scripts all use basic Linux commands so this should be very portable.
You don’t need to understand Linux to use these scripts, just follow the instructions to the letter. Commands are case sensitive, make sure you enter them exactly as shown or ideally, copy and paste if possible.
Before you start, Exit HamClock via the padlock. Click the padlock, select Exit HamClock, click Ok and then Ok again.
Open a terminal on your computer. If you’re using a Pi, it’s the 4th icon from left in the top left corner, or you can SSH into the Pi in the normal way.
Enter the following command which will download the scripts you’re going to use.
curl -fsSL https://hamclock.co.uk/tools | sudo bashIf you can’t find the | symbol on your keyboard, it’s often with the backslash and will look like one of these. The version on the left is most common but it could be either.
If you’re using Raspberry Pi OS Trixie (or newer), enter the following command. If you don’t know what version operating system you’re using, enter it anyway. It won’t run on an older operating system and if nothing needs changing on Trixie, it won’t do anything. Without this, /etc/hosts will reset itself after a reboot if you’re using Trixie. It will also resolve the same issue on Ubuntu 25 and onwards.
sudo fix-hostsYou will get one of three responses:
If you were prompted to reboot, do it now.
sudo reboot nowOnce your computer has restarted, you must close HamClock before proceeding.
Click the padlock, select Exit HamClock, click Ok and then Ok again.
Now you need to select a backend for HamClock.
Log back into your Pi and open a terminal as described earlier, or SSH in.
Switching backends is very easy using the scripts I’ve provided.
To select the Open HamClock Backend, type the following:
sudo ohb
To select the Hamclock.com Backend, type the following:
sudo hcdc
You can only have one backend active, the scripts will take care of that. If you want to find out which backend you have selected, use the following command:
what
Then reboot for the changes to take effect.
sudo reboot nowConclusion
That’s it. Whichever backend you have selected will be used by HamClock. The process of switching from one to another will automatically clear the cache so the different backend should come into play immediately.
If you want to switch between them, close HamClock, open a terminal and issue the command for whichever one you want.
sudo ohbsudo hcdcOr if you want to switch back to the original backend:
sudo csiAnd then reboot.
sudo reboot now