Hi Bob, OK, you got me: time as in about 120 minutes. =) It's mostly "+", with the occasional "-" for about an hour or so. Then, it wavers back and forth between "+" and "-", but the long term trend is still very slowly "+". So, I guess the OCXO needs more time to "settle in"? My OCXO is a Trimble 34310-T.
As soon as I can get the serial port wiring done I'll be able to tell if it's in "position hold" mode. I suspect it's not, as it doesn't have a battery on-board. I did wind up mounting a Lithium 3V backup battery, using a holder from an old motherboard. I'll have to look around to see if anyone has any software to graph the DAC track for this board. Bob - AE6RV >________________________________ > From: Bob Camp <li...@rtty.us> >To: Discussion of precise time and frequency measurement <time-nuts@febo.com> >Sent: Friday, July 12, 2013 8:47 AM >Subject: Re: [time-nuts] GPDSO is working > > >Hi > >On Jul 11, 2013, at 11:59 PM, Bob Stewart <b...@evoria.net> wrote: > >> After ham-fistedly breaking a few things, I've finally got my GPSDO working. >> (does happy dance) Now that it's had some time to warm up > >Time as in minutes, or as in a couple of days? If you look at the plot in the >QEX article, a day or so is the expected "warmup" period. > >> I see that it's started wandering around +/- a couple of counts from sample >> to sample (16 seconds). > >If it's + *and* - then the gizmo is driving down the middle of the road. If >it's always + or always - then it's likely not yet locked. > >> Is this because the UT+ is not set to timing mode? > >The UT needs to be in "position hold" mode with a proper (24 to 48 hour) >survey on it's location for best performance. It should not be +/- 100 ns even >without this. > >Is your VCXO a 10811? Does it have the same sensitivity as a 10811? If not, >you may need (per the article) to make some firmware changes. > >Bob > >> Putting in an RS-232 (or USB) to TTL adapter, switchable between the UT+ and >> the VE2ZAZ board, is pretty much next on my schedule. I've got an adapter I >> made many years ago, but it's not suitable for mounting in the box, and >> there's no simple way to hook it up to the UT+ at the moment. >> >> Bob >> _______________________________________________ >> 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. > > > _______________________________________________ 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.
