A new clock plus 10MHz reference GPSDO

I built a thing! This is a GPSDO using a PCB and kit of parts supplied by G8CUL and a OXCO from G1OGY. It uses a Jupiter GPS module which provides the PPS signal and a 10kHz output and the completed module provides 2x 10MHz and 1x 1MHz outputs. Although there are a number of such designs this one is nice in that it also has a display and shows the current date and time as UTC.

A GPSDO system based on a GPS module and OXCO module.

This was, I think my third SMD construction and certainly the Mose SMD devices including multi-legged chips. No issues in construction especially given the quality of the PCB that G8CUL had made.

The display on the GPSDO module showing the number of satellites and quality of signal.
The display on the GPSDO module showing the current date and UTC.

The backup battery is a CR2 3.3V type and helps with warm starting. As the regulator gets hot I managed to fit a heatsink between it and the rear of the case and hopefully this will sort out heat transfer, otherwise I may need to bolt another heatsink on the rear. Construction in a die cast box would have been better maybe but the blue/white box fits in with others in the shack, plus I had it already! The bezel is cut down from a 3D printed one from Printables.com designed specifically for the 2×16 LCD displays. The button – which is not the best but I had one etc. – selects the various displays which include date and time, satellites seen, latitude, longitude, altitude and QRA locator.

10MHz OXCO

I recently acquired a 10Ghz / 144MHz transverter which should get me a little closer to the band. I do still have a kit to build but having this means I can eventually test that as well. It needs a 10MHz reference input and I was recommended one from an eBay seller in China. The unit arrived today and having had it sat on a ‘scope and counter for several hours it does seem to produce a solid 10Mhz signal at a nice sine wave (it has TTL output too). Not bad for £12.

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