there is the tested trimble gps do and bg7tbl mod gps do (made based on mv89a)
All we know the gps do and rubidium oscillator, gps do is with better low phase noise and the long time stable is better than rubidium oscillator... but,after the test,we can seen that,bg7tbl GPSDO is not really good..and ever without a really locked to 10mhz.(none seller take test video,) as most buyers don't have 12 digi counter..so you were think,it is locked.