[time-nuts] Home Brew GSPDO

[W Private]

Hello all, Thanks for letting me join. I just built a GPSDO from some junk I had lying aroundI used a Navman GPS Jupiter 12 and an Isotemp 118-12 which can be controlled by the NavmanThe Isotemp is controlled by the heater in it which can be controlled by external DC signal.
The Navman puts out a 10 KHz square wave and I compared this to the divided 10 MHz OXCO output thru a XOR. The XOR output is rectified to DC and used to control the Isotemp.
I divided the 10 MHz with three 74LS90 DIPsI think this is pretty old stuff.I believe the thing works, my 10 KHz square waves line up nicely at a stable distance after a while and the output seems stable. It seems stable at 500 MHz harmonic. I cannot see even a one Hz change at 500 MHz on any of my equipment, such as it is.
Is there an easy way to put an indicator on this thing so I know when it is locked, rather than using a computer or hooking up my scope?Any suggestions on how to get more information from the GPS unit without using a computer? Like designing a readout for time or whatever?Just looking for ideas before I button the thing up in it's new case.
Wally KC9INK