The MK.4 G.P.S.CLOCK is the latest generation in the line of time-sources for the Arcom Controllers RC210. The whole range was born from the desire for accuracy.


The new MK.4 G.P.S.CLOCK was launched in 2020 after being totally re-designed from the ground up using a more powerful ARM based micro at its heart. The change of processor has allowed improvements to be made to the main program and the introduction of software menu configuration. So, no need to disassemble the case to get to the solder pads for configuration!

The new micro allows the customer to flash upgrade the G.P.S.CLOCK as and when new firmware and features are released.


Also improved is the GPS receiver itself, giving more accuracy and a faster “Time to first Fix”. Finally, the unit is housed in a new-designed laser cut case.

To purchase* the G.P.S.CLOCK or if you have any questions, please use our contact us page. One of the team will be more than 

willing to help you.

*To purchase please supply a delivery address in your request to enable us to find the best shipping solution for you.

Product key features


  • Connects to the RC210’s serial programming port.

  • Injects both time and date twice an hour to maintain the highest level of accuracy without overloading the already busy RC210 processor.

  • The injection process even works if the controller ports are serving repeater traffic.

  • Delayed start-up allows the G.P.S.CLOCK to be powered on at the same time as the RC210 giving the controller to boot and stabilise before time/date injections start.

  • Once the G.P.S.CLOCK finishes its delayed start default time and date data is injected to start the RC210 Scheduler system while satellites are being acquired.

  • Immediate Time/Date injections the moment a reliable G.P.S Signal is acquired.

  • Currently supports D.L.S. Start/stop dates for Europe and the United States

  • Handles leap years so no need to make additional adjustments.

  • Simple to use software setup menu system.

  • Current settings are displayed as part of the boot up process.

  • Supports both 9600 baud and 57600 baud processors.

  • Easy to use “Transparent mode” allows a computer to be connected in series with the G.P.S.CLOCK permanently so no more connecting and disconnecting cables.

  • Current time and date is injected into the RC210 on exit of “Transparent mode”.

  • Powered from either a standard 12V-15V supply or via USB 5V supply.

  • Low power consumption for sites where low power usage is essential.

  • Most important feature.  It fixes the R210 time drift without the need to open the controllers case.

Standard serial connectors are used

Easy to use configuration menu

No need to swap cables around



A brief history, where it all started


Unfortunately the RC210 if left to ‘free run’ drifts. Only few seconds a day but it quickly mounts up. So if your trying to schedule events at set times, this soon becomes a problem.


The Bristol 70cms Repeater Group found this out shortly after upgrading their repeater GB3BS to an RC210 repeater controller. They turned to us to look for a solution.

There was one caveat. The solution could not modify or be added internally to the RC210 as the unit was under warranty.

The first (MK1) G.P.S.CLOCK went into service at the start of 2008 and fulfilled the design requirements by connecting externally via the RS232 programming port. As the G.P.S.CLOCK’s name suggested, time was derived from G.P.S. signals making a highly accurate time source, meeting the first design criteria. Because time data is “injected” into the RC210 via the programming interface there was no need to open the RC210 case, or modify the internal electronics in any way thus protecting the warranty of the RC210.


Not long after the anniversary of the GB3BS G.P.S.CLOCK solution going live we were referred to another repeater group who were also interested in the G.P.S.CLOCK solution. They to had their own design requirements of wanting local time and not the currently supplied U.T.C. It turned out that the Bristol 70cms Repeater Group were also interesting in providing local time as U.T.C. apparently was upsetting the local users of the box.

The MK2 G.P.S.CLOCK was the result. Through dip-switch’s you were able to time zones and set up daylight saving (D.L.S.) time that tracked the European start and end times of D.L.S.  Later software updates introduced D.L.S. for the U.S.A. and the ability to cope with leap years.  Both repeater groups were very happy with this new solution.

The MK3 G.P.S.CLOCK saw a mechanical design change, moving from through-hole technology to surface mount also the dip-switches were removed and replaced by solder pads that set the configuration. The result allowed us to shrink the design and mount it into a smart custom laser cut case. 


Production of the MK3 G.P.S.CLOCK came to an end in early 2018 due to the ever increasing costs and difficulty sourcing the micro controller at the heart of the G.P.S.CLOCK.

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