Hi Sounds like you are up and running. TimeLab can be set for any length run you wish. Three to five minutes is a common one. I have a 30 day run going at the moment. Even while the run is going, you can switch between displays to see what's happening.
Unless you have some very unusual OCXO's in your 3805's fiddling with the oven temperature isn't going to help things much. If they are SC based, there may not be a turn over temperature. Often the set point is derived either from crystal data or from wide range temp run performance. Like any piece of surplus, you can indeed have something broken somewhere. In that case, repair is a good idea. Unless you blew the thermistor in the OCXO, it's an unlikely repair though. Bob On May 3, 2013, at 12:48 PM, "Mark C. Stephens" <ma...@non-stop.com.au> wrote: > > > Am on the way to doing my first 'phase difference' with timelab - takes an > hour :) > > This is good stuff, everything went so smoothly, from installing the OS to > using Timelab. > > Now I have to figure out how to measure and set the xtal turning temperature > for this bunch of Z3805A's I have here. > > I have a Z3816A that is super stable. SYST:STAT? usually reports 0.0us for > PU, sometimes it will go out as far as 0.2us, but very rarely :p > > So I am planning on using that guy as my reference to tune the Z3805A's. > > How does that sound? > > > Many thanks, > mark > > > -----Original Message----- > From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On > Behalf Of Bob Camp > Sent: Saturday, 4 May 2013 1:09 AM > To: 'Discussion of precise time and frequency measurement' > Subject: Re: [time-nuts] Measuring Phase difference between different GPSDO > > Hi > > Grab an old garage sale category PC, blow the dust out of it and fire up the > GPIB. Once it's all working next steps: > > Check out TimeLab and EZGpib. Both are pretty good at talking to "stuff". > TimeLab does support the 5370, not sure about the other programs. > > If you have two GPSDO's with pps outputs, feed one into each channel on the > 5370. Put it in start / stop mode and you should see the difference between > the two. Since they can be either ahead or behind each other things can get a > little messy. > > Next, go to the software that runs your GPSDO and look for the "cable delay" > setting. Adjust it on one GPSDO so it's always early (or late) by a couple > hundred nanoseconds. Now fiddle the cables to the counter so it reads a > couple hundred nanoseconds and not almost a full second :). > > At this point you are reading frequency to a very high resolution. The > GPSDO's likely are only good to a couple of nanoseconds at 1 second. The > counter should be good to ~0.02 ns. > > Run like this for a few minutes and see what you get. > > ----------- > > Now that you have conquered that approach it's time to tear it all apart and > try something new. > > Feed the 1 pps into one input of the counter (just like before). Hit the > other input with 10 MHz. You now will get a reading in the 0 to 100 ns range. > Each time a cycle slips past the 1 pps the reading will skip from 99.xxx to > 0.xxx ns. That's called a phase wrap around. Click the appropriate boxes on > which ever software you are running and it should take care of the wrap. > > -------- > > Either way the software should show you frequency, and frequency stability. > > Bob > > > -----Original Message----- > From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On > Behalf Of Mark C. Stephens > Sent: Friday, May 03, 2013 10:07 AM > To: Discussion of precise time and frequency measurement > Subject: Re: [time-nuts] Measuring Phase diference between different GPSDO > > Hey Bob, I was thinking the exact same thought, and I found a NI PCI-GPIB > card in a PC with a dead HDD. > These appear to be 5V PCI cards so I can't stick it in a nice rack mount > server with raid as they all seem to be 3.3v PCI. > So I put a new HDD in the PC and I have stuck WinXP on it. > Now I am awaiting further orders! ;) > > mark > > -----Original Message----- > From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On > Behalf Of Bob Camp > Sent: Friday, 3 May 2013 9:21 PM > To: Discussion of precise time and frequency measurement > Subject: Re: [time-nuts] Measuring Phase diference between different GPSDO > > Hi > > If you have a pile of GPIB cables, you may also have a GPIB card on a PC. > You will have a lot more luck finding free software to read and log the data > from the 5370 than from the 3575. As mentioned before, the 5370 will be much > more accurate / higher resolution in this application. > > Bob > > On May 3, 2013, at 12:28 AM, Mark C. Stephens <ma...@non-stop.com.au> wrote: > >> According to http://www.realhamradio.com/z3801a-turning-point.htm they >> use > a HP 3575A phase meter to perform the measurement. >> Or perhaps I have misinterpreted the whole thing? >> >> >> I do have a temperature controlled workshop that is always 24 degrees >> so > hopefully thermal drift won't be too much of an issue. >> >> >> mark >> >> -----Original Message----- >> From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] >> On Behalf Of li...@lazygranch.com >> Sent: Friday, 3 May 2013 12:12 PM >> To: Discussion of precise time and frequency measurement >> Subject: Re: [time-nuts] Measuring Phase diference between different >> GPSDO >> >> Meditating on this a bit, I assume in a strict sense, you can only > consider GPSDOs phase locked if they are disciplined from the same GPS. >> >> Or is this being pedantic? >> >> _______________________________________________ >> 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. > > > _______________________________________________ > 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. _______________________________________________ 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.
