Re: [time-nuts] Using HP5071A with dead tube along with GPS
Hi Since the devices may sit for a *long* time on the shelf, humidity can soak into parts. Adsorption / desorption rates normally are very different so a brief soak in may mean a *long* soak out. Bob > On Dec 23, 2019, at 4:01 PM, Hal Murray wrote: > > > kb...@n1k.org said: >> Like all “normal” 10811’s they are an open construction and move a bit from >> humidity and barometric pressure. > > How significant is humidity given that most of the interesting stuff is kept > warm? > > > Could I measure that using a typical bench as an environmental chamber? Or > would it be lost in the noise of temperature and aging? > > > -- > These are my opinions. I hate spam. > > > > > ___ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Using HP5071A with dead tube along with GPS
kb...@n1k.org said: > Like all ânormalâ 10811âs they are an open construction and move a bit > from > humidity and barometric pressure. How significant is humidity given that most of the interesting stuff is kept warm? Could I measure that using a typical bench as an environmental chamber? Or would it be lost in the noise of temperature and aging? -- These are my opinions. I hate spam. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Using HP5071A with dead tube along with GPS
I have done this with an older 5061A that still has a good Cs tube but I don't want to use it too much. I used a Brooks Shera kit and a Trimble Lassen IQ receiver and fitted it all into the empty battery compartment. With a bit of modification it was possible to retain the Cs function but run it as a GPSDO when the Cs is switched off. I had to determine the VXO characteristics as described in the original Shera article and fitted a separate opamp to set the loop gain. Once there's a GPS receiver in there it's a shame to waste the time output so I also fitted a microcontroller to translate the output code to IRIG-B for an external time display. It has worked very well for several years now. The Shera kits are probably not available any more but there are many others that could be used. Good luck! Morris --- Subject: [time-nuts] Using HP5071A with dead tube along with GPS I can't quite remember who gave me this idea...? but I'm pretty sure he was a member of this mailing list. I have an HP5071A high performance version with a dead tube.? But rest of the unit, as far as I know, works just fine.? I know it has a PPS INPUT on it.? I also know it has a very good OCXO in that, too.? Would it be possible to steer this OCXO using GPS when Cs tube is completely dead and unlocked?? I do not want to take this apart, just in case nice usable tube lands in my hand in future. The reason I ask...? I can just do it and see, but I have no way to verify the performance.? I have an old Cs with no characterization, and rest are Rbs and T-bolts.? Seems like what I propose would result in OCXO pulled by two different servos.? (and even if the results were awful, I wouldn't know it) Happy holidays! --- (Mr.) Taka Kamiya KB4EMF / ex JF2DKG ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Using HP5071A with dead tube along with GPS
Hi The PPS input on the 5071 does *not* set the frequency of the device. To do so would “break” the Cs ( = you use the beam to get frequency). The *only* thing the PPS input gets used for is to reset the *time* to sync with UTC. Bob > On Dec 19, 2019, at 5:56 PM, Taka Kamiya via time-nuts > wrote: > > My experiment is not going well so far. I have NOT done any tuning. Just > connected 1 pps out from GPS to 1 pps IN on 5071A. Frequency keeps > increasing, which I think is weird. I thought it might just be unstable > without proper parameters, but no. Over last 24 hours, it kept going up. I > was about to start reading the 5071A manual. Likely as TVB says, it will > likely be needing quite a bit of refining loop parameters. One unknown is, > in this current state (fault), if OCXO is even steerable. 1 pps WAS detected > and menu option did tell me so. > > I didn't know you can put 5071A in (Cs tube only) STAND-BY mode... Mine is > dead so it's in permanent stand-by. It's initial boot sequence detects this > and shuts it down. > > On a slightly different topic, my PRS10 + GPS experiment is working rather > well. I haven't done any tuning and using default for everything. I'm going > to wait about a month before doing so. Loop constant is 1 day, so it may > take quite some time to completely stabilize. > --- > (Mr.) Taka Kamiya > KB4EMF / ex JF2DKG > > >On Thursday, December 19, 2019, 5:34:55 PM EST, Mark Sims > wrote: > > I've actually done this... Lady Heather has built in "alternate > disciplining" algorithm for the Thunderbolt. I tricked up some code to use > this along with a TAPR-TICC to make a GPSDO. The first (rather crude) hack > worked pretty well. I haven't had a chance to do it properly... yet. > > The idea was to allow the 5071A to run with the CBT in standby for > applications that do not require the cesium goodness. > > - > >> A fun (and actually very useful) project would be to turn it into a > GPSDO > ___ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. > > ___ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Using HP5071A with dead tube along with GPS
My experiment is not going well so far. I have NOT done any tuning. Just connected 1 pps out from GPS to 1 pps IN on 5071A. Frequency keeps increasing, which I think is weird. I thought it might just be unstable without proper parameters, but no. Over last 24 hours, it kept going up. I was about to start reading the 5071A manual. Likely as TVB says, it will likely be needing quite a bit of refining loop parameters. One unknown is, in this current state (fault), if OCXO is even steerable. 1 pps WAS detected and menu option did tell me so. I didn't know you can put 5071A in (Cs tube only) STAND-BY mode... Mine is dead so it's in permanent stand-by. It's initial boot sequence detects this and shuts it down. On a slightly different topic, my PRS10 + GPS experiment is working rather well. I haven't done any tuning and using default for everything. I'm going to wait about a month before doing so. Loop constant is 1 day, so it may take quite some time to completely stabilize. --- (Mr.) Taka Kamiya KB4EMF / ex JF2DKG On Thursday, December 19, 2019, 5:34:55 PM EST, Mark Sims wrote: I've actually done this... Lady Heather has built in "alternate disciplining" algorithm for the Thunderbolt. I tricked up some code to use this along with a TAPR-TICC to make a GPSDO. The first (rather crude) hack worked pretty well. I haven't had a chance to do it properly... yet. The idea was to allow the 5071A to run with the CBT in standby for applications that do not require the cesium goodness. - > A fun (and actually very useful) project would be to turn it into a GPSDO ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Using HP5071A with dead tube along with GPS
I've actually done this... Lady Heather has built in "alternate disciplining" algorithm for the Thunderbolt. I tricked up some code to use this along with a TAPR-TICC to make a GPSDO. The first (rather crude) hack worked pretty well. I haven't had a chance to do it properly... yet. The idea was to allow the 5071A to run with the CBT in standby for applications that do not require the cesium goodness. - > A fun (and actually very useful) project would be to turn it into a GPSDO ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Using HP5071A with dead tube along with GPS
Hi The OCXO in the 5071 is an HP10811 it was selected at the time of manufacture for good performance. As far as anybody knows that testing was for short term stability. How well it retains that performance many years later - who knows? Is the original OCXO in the device - who knows…. Other than a bit better ADEV at 1 second, the performance of the device may be no better / no worse than what you get on eBay. Like all “normal” 10811’s they are an open construction and move a bit from humidity and barometric pressure. How much either issue impacts a GPSDO is open to debate. Bob > On Dec 18, 2019, at 10:13 PM, Taka Kamiya via time-nuts > wrote: > > I can't quite remember who gave me this idea... but I'm pretty sure he was a > member of this mailing list. > I have an HP5071A high performance version with a dead tube. But rest of the > unit, as far as I know, works just fine. I know it has a PPS INPUT on it. I > also know it has a very good OCXO in that, too. Would it be possible to > steer this OCXO using GPS when Cs tube is completely dead and unlocked? I do > not want to take this apart, just in case nice usable tube lands in my hand > in future. > The reason I ask... I can just do it and see, but I have no way to verify > the performance. I have an old Cs with no characterization, and rest are Rbs > and T-bolts. Seems like what I propose would result in OCXO pulled by two > different servos. (and even if the results were awful, I wouldn't know it) > > Happy holidays! > > --- > (Mr.) Taka Kamiya > KB4EMF / ex JF2DKG > ___ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Using HP5071A with dead tube along with GPS
Taka, Check your inbox from 10/2/2019: "A fun (and actually very useful) project would be to turn it into a GPSDO. There are SCPI commands to slew the rate of the internal synthesizer so you wouldn't even need to remove any parts, break any wires, or solder anything". There are copies of the 5071A "Operating and Programming Manual" (p/n 05071-90041) on the web. The SOUR:PTIM:SLEW command lets you set the phase to within 50 ns. And the SOUR:ROSC:STEER command lets you adjust the oscillator with 6.4e-15 resolution. Note that is better resolution than a traditional DAC/EFC-based GPSDO. All you need is a GPS/1PPS board and a TIC. Would make a fun Arduino project. In fact, since your Cs tube is dead, take the tube out and there's plenty of room for the GPS, TIC, and Arduino. /tvb On 12/18/2019 7:13 PM, Taka Kamiya via time-nuts wrote: I can't quite remember who gave me this idea... but I'm pretty sure he was a member of this mailing list. I have an HP5071A high performance version with a dead tube. But rest of the unit, as far as I know, works just fine. I know it has a PPS INPUT on it. I also know it has a very good OCXO in that, too. Would it be possible to steer this OCXO using GPS when Cs tube is completely dead and unlocked? I do not want to take this apart, just in case nice usable tube lands in my hand in future. The reason I ask... I can just do it and see, but I have no way to verify the performance. I have an old Cs with no characterization, and rest are Rbs and T-bolts. Seems like what I propose would result in OCXO pulled by two different servos. (and even if the results were awful, I wouldn't know it) Happy holidays! --- (Mr.) Taka Kamiya KB4EMF / ex JF2DKG ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Using HP5071A with dead tube along with GPS
I can't quite remember who gave me this idea... but I'm pretty sure he was a member of this mailing list. I have an HP5071A high performance version with a dead tube. But rest of the unit, as far as I know, works just fine. I know it has a PPS INPUT on it. I also know it has a very good OCXO in that, too. Would it be possible to steer this OCXO using GPS when Cs tube is completely dead and unlocked? I do not want to take this apart, just in case nice usable tube lands in my hand in future. The reason I ask... I can just do it and see, but I have no way to verify the performance. I have an old Cs with no characterization, and rest are Rbs and T-bolts. Seems like what I propose would result in OCXO pulled by two different servos. (and even if the results were awful, I wouldn't know it) Happy holidays! --- (Mr.) Taka Kamiya KB4EMF / ex JF2DKG ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
