[time-nuts] Spectrum Instruments TM4 GPSDO
I have a TM4 manual, but don't have a TM4. Heather now has some hooks in it for the TM4. I'd need a TM4 (at least for a couple of weeks) to properly implement the TM4 support (one is on Ebay for $4000+ ... no thanks). Or if somebody with a TM4 can capture around 5 minutes of data from the device, I can use that as a starting point. - > If so, they can do either their custum binary protocoll or NMEA. I have been meaning to suggest for Mark Sims that it would be a apreciated addition to Lady Heather to add the binary protocoll. I should have a manual around, if the TM-4 manual can't be found on the internet. ___ 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] Need info: Spectrum Instruments brand GPSDO
That looks like a re-packaged Spectrum TM-4M: https://i.imgur.com/VKZtQzr.jpg With the internal lead battery and routing to different front connectors removed, it looks quite alike. If so, they can do either their custum binary protocoll or NMEA. I have been meaning to suggest for Mark Sims that it would be a apreciated addition to Lady Heather to add the binary protocoll. I should have a manual around, if the TM-4 manual can't be found on the internet. BR. Thomas. Den fre. 27. jul. 2018 kl. 20:25 skrev ed breya : > > I recently picked up some old cell base station units, and retrieved two > of what appear to be this unit, from Spectrum Instruments: > > http://www.spectruminstruments.net/products/custom2/custom2.html > > I have asked them if any info is available, but no response yet. If > anyone knows anything about this unit, I'd appreciate hearing about it. > > Speaking of redundant references, I can picture two identical units > operating in the "exact" same environment and GPS view, but redundancy > is not my purpose here. I have tested both units separately, and they > seem to work and provide GPS and ref lock indications. I've got them > both mounted in one chassis, with a common PS (15-24 VDC). The plan is > to feed them both with the same input from one GPS active antenna, and > then experiment to see how they behave separately and versus each other. > > I assume I can eventually at least talk to the the Motorola GPS RX > modules, but I don't know about the rest of the custom GPSDO brains. > There are two DB-9 RS-232 (probably) ports on each unit - apparently one > for the GPS, and one for the rest. > > One thing I'm wondering is how much interaction/interference may occur > between the front-ends. I'll be building a module with DC to feed the > antenna, a preamp stage to boost the signal a little and split it > between the RXs, and provision to fool them both into thinking their > usual antenna DC load is present. The post-split RF path lengths will be > closely matched. I can add extra isolation if needed, but I'd like to > see what happens. > > I'd expect that their 1 PPS and 10 MHz should ultimately be in phase. I > don't know if these units do any kind of sawtooth correction, but I > guess I'll find out eventually. The 1 PPS signals are not available on > the panels, but I know they're in there. > > As-are, the GPS modules' internal clocks (19.095 MHz marked on XTLs) are > independent. Other experiments could involve forcing them to be the same. > > Ed > > > > ___ > 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. -- With Best regards, Thomas S. Knutsen. Please avoid sending me Word or PowerPoint attachments. ___ 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] Need info: Spectrum Instruments brand GPSDO
I recently picked up some old cell base station units, and retrieved two of what appear to be this unit, from Spectrum Instruments: http://www.spectruminstruments.net/products/custom2/custom2.html I have asked them if any info is available, but no response yet. If anyone knows anything about this unit, I'd appreciate hearing about it. Speaking of redundant references, I can picture two identical units operating in the "exact" same environment and GPS view, but redundancy is not my purpose here. I have tested both units separately, and they seem to work and provide GPS and ref lock indications. I've got them both mounted in one chassis, with a common PS (15-24 VDC). The plan is to feed them both with the same input from one GPS active antenna, and then experiment to see how they behave separately and versus each other. I assume I can eventually at least talk to the the Motorola GPS RX modules, but I don't know about the rest of the custom GPSDO brains. There are two DB-9 RS-232 (probably) ports on each unit - apparently one for the GPS, and one for the rest. One thing I'm wondering is how much interaction/interference may occur between the front-ends. I'll be building a module with DC to feed the antenna, a preamp stage to boost the signal a little and split it between the RXs, and provision to fool them both into thinking their usual antenna DC load is present. The post-split RF path lengths will be closely matched. I can add extra isolation if needed, but I'd like to see what happens. I'd expect that their 1 PPS and 10 MHz should ultimately be in phase. I don't know if these units do any kind of sawtooth correction, but I guess I'll find out eventually. The 1 PPS signals are not available on the panels, but I know they're in there. As-are, the GPS modules' internal clocks (19.095 MHz marked on XTLs) are independent. Other experiments could involve forcing them to be the same. Ed ___ 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] 10 MHz 'failover' switch?
Hi Isolation in a carefully managed test setup can be done (with enough money to spend). Isolation it the real world with grounds and cables running here and there is likely to be a challenge. At least that’s been the case on the few dozen of these systems I’ve designed and put into production …. Bob > On Jul 27, 2018, at 11:29 AM, ed breya wrote: > > Getting great isolation at 10 MHz is the easy part, given enough switching > elements and control. One question is whether the switchover needs to be > transparent (glitchless), without adding or losing any clock cycles, and > ideally with no phase shift. This would involve a much more sophisticated > system, with two or more redundant references locked together, at least > short-term. > > Ed > > ___ > 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] 10 MHz 'failover' switch?
Getting great isolation at 10 MHz is the easy part, given enough switching elements and control. One question is whether the switchover needs to be transparent (glitchless), without adding or losing any clock cycles, and ideally with no phase shift. This would involve a much more sophisticated system, with two or more redundant references locked together, at least short-term. Ed ___ 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] Oscilloquartz 3210 Cesium Standard Schematics
Good News. I finally decided to leave it running for a few days, after a bit of inspection (changed some caps here and there, removing '77 vingage NiCs batteries, etc). Everything is fine, no alarms, readings are ok. But, still no Ion Current. At least at the meters, both internal and external. Since HV generation is off a sealed module, and not directly, I'll run a measurement on the bare wire going to the tube. https://www.ebay.it/itm/High-Voltage-PS-from-OSCILLOQUARTZ-3102-CESIUM-FREQUENCY-STANDARD-ATOMIC-CLOCK/253730161665?hash=item3b137f0401:g:djEAAMXQ01tRWP7 Voltage is quite High, around 5Kv, that probably means no load from the tube. Any advice ? Ciao, Giorgio. From: Giorgio Barinetti Sent: giovedì 12 luglio 2018 21:49 To: time-nuts@lists.febo.com Subject: Oscilloquartz 3210 Cesium Standard Schematics Hi Tom, Ok and stable were referred to the general behavior of the unit (PSU voltages, current draw). After a 2 h warmup I've run the following test: Frequency has then been measured with the aid of an HP 5345 clocked to a Efratom MFST GPS+Rb and is stable. Phase noise is just around -135 @ 100 hz, output power is 10 dBm. I did not run a full test since I have to be sure that the clock is "safe" in term of leaky capacitors And so on. Leaving a 44 Year instruments running unattended in the lab after 20 years of sleep Does not sound very safe to me :) During the weekend I'll try to keep it running for 48H so I'll see what will happen. In the meantime, thanks for your help! Ciao, Giorgio. > i have been lucky to found a working Oscilloquartz 3210 Cesium ( warehouse of > a telco operator ) in a good shape. Nice find. The OSA 32xx manual that I scanned is at: http://leapsecond.com/museum/osa3200/ That's 33 pages of "Operating and Instruction Manual". If your unit is working within spec, that's sufficient. I'll check if additional manual pages are around here somewhere, in case you need to repair it. > seems ok and stable Words like "ok" or "stable" are vague; try to give numerical measurements for accuracy and stability. That will help determine if your vintage Cs clock is actually working to spec or not. Also log values over time. The ion pump should not have been zero if the unit was sitting in a warehouse for 20 years. But after some hours or days, yes, it could be near zero and this might be a good sign. For an old, surplus, vintage Cs standard, its best to carefully monitor everything immediately after power up and continuing for several hours or days. The trend lines will tell you a great deal about the condition and prognosis of the instrument. /tvb - Original Message - From: "Giorgio Barinetti" http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com>> To: http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com>> Sent: Wednesday, July 11, 2018 3:17 PM Subject: [time-nuts] Oscilloquartz 3210 Cesium Standard Schematics > Hi Guys, > > i have been lucky to found a working Oscilloquartz 3210 Cesium ( warehouse of > a telco operator ) in a good shape. > > Powers up, seems ok and stable ( capacitors on the unit has 10/1974 date, so > very old unit, serial 83), but the signal > From the preamplifier is a little low and the Ion Pump current is 0. Like the > 3 Kv supply is low ? > > Like to investigate but it will be nice to have a schematic. > > I've found a 2014 message where Tom was willing to scan the remaining part of > the manual, so I'm kindly asking :) > > > Thanks, > Giorgio Barinetti ___ 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.
