I have a 9390-53120. The 16.368 reference for the GPS is coming from a 4 pin (14 pin size ) oscillator on the GPS interface board. The other internal oscillator board mount a 1 MHz TCXO I never had seen locked to GPS. Normally I use it only for UTC time display. This GPS use an antenna with 50dB gain, so I have added a preamplifier to normalize its sensitivity. I had two fault in 10 year of life on the power supply board.
Luciano www.timeok.it 2013/4/14 David I. Emery <d...@dieconsulting.com> > > On Fri, Apr 12, 2013 at 11:48:47AM -0700, Burt I. Weiner wrote: > > Sorry for the delay in posting this update. Things have been hectic, > > and then there was NAB. > > > > Here's what I've discovered: The receiver started working after > > about 6 hours of just sitting. However, the 9390's internal Vectron > > oscillator was quite a ways off frequency and did not want to lock > > after trying to stabilize all night. I had to tweak the adjustment > > screw quite a ways and then, after a while, it locked. Prior to this > > episode the oscillator had been sitting at only a few E-12. I > > suspect that this oscillator has had an intermittent problem for a > > long time, and I should not have had to tweak it as far as it wanted > > to go. The receiver portion has not failed in the few weeks since it > > decided to start seeing satellites again. Maybe because I had > > tweaked the oscillator? > > I have an ancient 9390 that has an ancient Trimble GPS board in > it that takes a 16.368 reference synthesized from the 10 MHz standard in > a PLL loop with a VXCO. This is used in the L band downconversion... > and for timing generally and given that is PLL derived from the 10 MHz > quite likely if the 10 MHz is significantly wrong the receiver won't > find satellites. I remember I had to fix this PLL in my box before the > receiver in that box would lock up... initially the PLL wasn't locked, > but the 16.368 VCXO output WAS present - so for that receiver it has to > be pretty close to right on to work. > > > -- > Dave Emery N1PRE/AE, d...@dieconsulting.com DIE Consulting, Weston, Mass > 02493 > "An empty zombie mind with a forlorn barely readable weatherbeaten > 'For Rent' sign still vainly flapping outside on the weed encrusted pole - in > celebration of what could have been, but wasn't and is not to be now either." > > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.