Build a 10MHz GPS Disciplined Oscillator
I have recently built a 10MHz GPS disciplined oscillator from the design by Andy G4JNT on his web site: http://www.g4jnt.com/SimpleGPSDO.pdf
So the project could also easily be built by radio amateurs in the local club I obtained some ex-equipment Jupiter GPS receivers and made a simple single-sided PCB. The GPS receivers are Conexant model TU30-D145. Firmware is version 2.3 dated 1999. They are similar to the picture above.
To download the ExpressPCB file click here and select save. The PCB is laid out on the top copper layer in ExpressPCB. Print the top layer onto LaserStar or similar PCB film and you will have a mirror image to place in contact with the photo PCB. The 74HC04 on the left is just to give me a few extra gates and is not included on the G4JNT circuit.
Note that you may need to change the value of the tuning voltage from the PLL to suit the VCXO you use. Mine requires 2.5V for 10.000MHz.
I also built a 16 x 2 LCD display board by G4JNT which decodes the NMEA data from the GPS.
http://www.g4jnt.com/pics.htm download the file GPSLOCDIS.ZIP at the bottom of the page.
Apart from indicating that the GPS receiver is working,this board also gives QTH locator to 8 places, Lat, Long, GPS time etc. It piggy backs onto a 16x2 display board. You can edit Andy's assembler and put your own callsign in the display. If you are unable to program the 16F628 PIC yourself email me (email correct at qrz.com) and I'll do it for you.
Pictures not to scale!
To download the display ExpressPCB file click here and select save. The PCB is laid out on the top copper layer in ExpressPCB. Print the top layer onto LaserStar or similar PCB film and you will have a mirror image to place in contact with the photo PCB.
ExpressPCB can be downloaded from here.
Data on the Jupiter boards is available from:
http://www.gpskit.nl/documents/rockwell/jupiter-gps-board.pdf
http://www.gpskit.nl/gps-readme.html
Please note that these data refer to the Model TU30-D140 but the functions and pin out for the TU30-D145 I used here are the same.
Also see G3RUH's web site:
http://www.jrmiller.demon.co.uk/projects/ministd/frqstd.htm
http://www.jrmiller.demon.co.uk/projects/ministd/frqstd0.htm
The next stage of this project is to lock my IC-746 up to the GPSDO. I bought the DFS30 kit by Dave G4HUP and when I have built it I intend to use the simple locking method described by G4YTL.
73 Paul G4DCV (email me at the address at qrz.com)