GPSDO – Courty Designs

Been having issues with the GPSDO project where I couldn’t get the thing to become stable.

Tried a number of things including putting the OXCO in insulation and putting coax in for all the signal traces.

After looking at the diagram again, I saw the oxco is tuned by a PWM signal and this is sent through a slow Low Pass filter giving a stable voltage out, the main part in this filter is a 100uf electrolytic capacitor.

Decided that it wouldn’t do any harm to change it so swapped it out for a nice quality SMT Tantalum one, mounted on the bottom of the board. 1000% better instantly. the stability is almost rock solid now and its run throuhg the setup phases in one or two goes. its up to PH5 in under 1.5 hrs whereas before it took 2 days to get to PH4.

I am constructing the GPSDO by Yannick99

GPSDO means: GPS disciplined oscillator. All GPS satellites are equipped with synchronized atomic clock, the GPS module receives these signals from several satellites and by triangulation, it knows his location. What interests us is the pulse per second and Data out that is found on the GPS module.

With this precise pulse (from atomic clock), we can make a very very accurate oscillator. This frequency generator is 10.000000000 Mhz +- 0.000000001 Mhz or 1 part per billion on 10Mhz

What for ? For reference, for calibration of frequency counter or just for fun to have one in his lab.

https://www.instructables.com/id/GPSDO-YT-10-Mhz-Lcd-2×16-With-LED/

Category: GPSDO

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GPSDO-YT