[time-nuts] Reverse Engineering FTS/Datum/Symmetricom 1050A or 1150A
Hi Jim; This may be best to go back to Time-Nuts for this. A properly working 1050A is still one of the best Quartz Standards/Clean-Up Oscillators ever made and most likely will be for the foreseeable future making it well worth the effort of building extensive documentation - I for one would really enjoy contributing to that effort. Actually I think this logic could apply to a number of products. Now may be a good time if other Time-Nuts are interest in the same thing. A group of Time-Nuts could create a schematic of the basic design and the various revisions/options. Add photos, voltages, and signals at various test points, and how problems were resolved. I have found that most instruments have "The Usual Suspects" a few areas where in the unlikely event they have an issue it will often be the same part. On the short term problem you are seeing I would test the 1000B out of circuit first and follow the signal path from there. Which options and what are the approximate build dates of yours. My main point is years ago there were third party companies like Sam Photo Fax offering tech and repair data on a wide range of electronics, and in this era where more and more companies are unwilling to share schematics and repair info we are seeing communities like the Time-Nuts, Volt-Nuts, and XDevs doing just that. Perhaps it is time to bring a more systemic and structured approach to that end. I would really enjoy being a part of such an effort. Cheers; Tom Knox SR Test and Measurement Engineer Ascent Concepts and Technology 4475 Whitney Place Boulder Colorado 80305 303-554-0307 act...@hotmail.com "Peace is not the absence of violence, but the presence of Justice" Both MLK and Albert Einstein From: AC0XU (Jim) Sent: Monday, November 25, 2019 4:26 PM To: Tom Knox Subject: Re: [time-nuts] Service manuial for FTS 1050A or 1150A Tom- Thanks for that. There is normal power in to the controller board and no power out. Shouldn't be too hard to track down, but the power board suprises me in its complexity. Was hoping to find a schematic... BTW, I also have a few of these units. One works really well. Another has very poor short time stability. I am guessing that there is something wrong with it, but do you have any ideas what could cause the behavior? Jim At 01:22 PM 11/25/2019, you wrote: Hi Jim; Let me know if you have any luck on the 1050A manual and I will do the same, I think the 1050A and 5071A are the holy Grail of service manuals. I have a couple 1050A's with issues. These are great cleanup oscillators, they often far exceed PN specs, I one better then 128dB @ 1Hz which puts them up there with BVA's. The power board should not be to much trouble, If you need me to measure any voltages on a working 1050A let me know. Cheers; Tom Knox SR Test and Measurement Engineer NIST/Ascent Concepts and Technology 4475 Whitney Place Boulder Colorado 80305 303-554-0307 act...@hotmail.com "Peace is not the absence of violence, but the presence of Justice" Both MLK and Albert Einstein From: time-nuts on behalf of AC0XU (Jim) Sent: Sunday, November 24, 2019 9:55 AM To: time-nuts@lists.febo.com Subject: [time-nuts] Service manuial for FTS 1050A or 1150A Does anyone have a service manual for either FTS 1050A or 1150A (they are almost identical)? I have an 1150A with a bad power board Thanks! Jim ___ 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] Spark timer.
Not sure if we are talking about the same thing or not, but in high school physics we had an apparatus that allowed for metal pucks to slide on a metal table. Bumpers could be added or removed from the pucks to model different types of collisions. Metal chains inside surgical tubing allowed pulsed HV to flow from the pucks, thru a piece of paper and into the metal table. The pulses of HV periodically marked the paper and by measuring the distances between the marks one could compute the velocity of the pucks.I have a vague recollection of using Lotus 1-2-3 to process the data collected during multiple repetitions of the same experiment. It never occurred to me to question the stability of the time base for the pulsed HV source when I submitted my findings (: Mark Spencer m...@alignedsolutions.com 604 762 4099 > On Nov 24, 2019, at 12:27 PM, Gary Woods wrote: > >> On Fri, 22 Nov 2019 12:54:32 -0500, you wrote: >> >> I picked up a CENCO Oscillating Spark Timer at the MIT flea market. >> I would have liked to get an old tuning fork frequency standard but >> this old mechanical oscillator peaked my interest and at $5 I could >> not resist taking it home. > > I remember using one of these to time "frictionless" pucks colliding > on a sheet of waxed paper in freshman physics lab in beautiful Troy, > NY. I thought at the time "hey, an electric Vibroplex!" > It pulsed a Model T spark coil, IIRC. > > ___ > 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] John Fluke test equipment tutorial
Perry kindly shared it with me a week or so ago. Its a really good read. Enjoy and thanks Perry. Regards Paul On Mon, Nov 25, 2019 at 6:00 PM Perry Sandeen via time-nuts < time-nuts@lists.febo.com> wrote: > Yo Bubba Dudes!, > I've re-published the John Fluketutorial *Calibration Philosophy and > Practice* Circa 1980. > > It describes how all the basicelectrical standards are derived and > measured. It is a 14 MbytePDF. If anyone is interested in a copy please > send me an *original* emailoff list for a copy > > Regards, > Perrier > ___ > 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] Spark timer.
On Sat, Nov 23, 2019 at 2:01 AM Peter Reilley wrote: > > It works fine, what could actually go wrong with something so simple? > > I remember using one of these in a physics lab acceleration experiment. One thing that could go wrong was that if the paper tape jammed or moved too slowly, it would catch on fire! -- --Jim Harman ___ 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] gpsdo 10MHz steering resolution
Bob This based in Germany, 50Hz mains, hence my thoughts. John ___ 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] John Fluke test equipment tutorial
Yo Bubba Dudes!, I've re-published the John Fluketutorial *Calibration Philosophy and Practice* Circa 1980. It describes how all the basicelectrical standards are derived and measured. It is a 14 MbytePDF. If anyone is interested in a copy please send me an *original* emailoff list for a copy Regards, Perrier ___ 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] gpsdo 10MHz steering resolution
Hi everyone, Thanks for your reply's. The device is indeed in 50hz land (germany). I suspect you are right that it is 50 hz mains pickup. A little surprising since it is a "factory," as opposed to homemade unit. But it is almost 20years old, so the caps may be dry, or it is just a bad design. I measured my DDS based signal generator output, and it was spur free, so my spectrum analyzer and cabling is an unlikely culprit. I had been thinking along the lines of working from an OCXO, and fitting the PPS to the stamped intervals, and assuming that the average interval is exactly one second. The issue then will be OCXO changes vs number of averages from the PPS. I am on vacation till next week, but I will change out the PSU on the truetime (temporarily to my bench linear PSU) and move the internal cabling around to see if the spur amplitudes change. --mike On Mon, Nov 25, 2019 at 5:34 PM Bob kb8tq wrote: > Hi > > I caught the 1KHz and took it to be per division…. oopss … (sorry about > that) > > If the device is indeed in 50 Hz power main land, the 100 Hz spurs might > make some sense > as line related. If it’s in 60 Hz power land, they are coming from > something else. No idea > (yet) what part of the world the device is in. > > Bob > > > On Nov 25, 2019, at 3:55 AM, John Moran, Scawby Design < > j...@scawbydesign.co.uk> wrote: > > > > I may be completely wrong here but if the span of that spectrum is 1kHz, > then the spurs look like 100Hz mains hum frequency modulation of the > 10MHz. > > > > > > ___ > > 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] gpsdo 10MHz steering resolution
One more thing - this is less likely, but possible. Depending on the physical setup, it's possible to have magnetic coupling from transformers and wiring interfering with sensitive circuitry. This can be internal to a piece of equipment (the way it's built), or external, like if one piece of gear is adjacent another, with unfortunate locations of their various internal items. Magnetic interference from a transformer will tend to be mostly at the fundamental line frequency, while that from wiring loops say, associated with the (full-wave) rectifier and filtering will be at the double frequency. These emanations also contribute to overall ground loop currents in a system. In highly sensitive setups, even having the chassis of one piece electrically contacting (or not) another can make a difference. These kinds of issues are easy to spot by rearranging things. 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] gpsdo 10MHz steering resolution
Hi I caught the 1KHz and took it to be per division…. oopss … (sorry about that) If the device is indeed in 50 Hz power main land, the 100 Hz spurs might make some sense as line related. If it’s in 60 Hz power land, they are coming from something else. No idea (yet) what part of the world the device is in. Bob > On Nov 25, 2019, at 3:55 AM, John Moran, Scawby Design > wrote: > > I may be completely wrong here but if the span of that spectrum is 1kHz, then > the spurs look like 100Hz mains hum frequency modulation of the 10MHz. > > > ___ > 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] gpsdo 10MHz steering resolution
From the picture, I'd guess the spurs are due to excessive line frequency ripple from your 50 Hz mains (full-wave rectified = 100 Hz spurs) - it could be internal to the reference source or other gear in the system, or ground loops. Check the specs for residual line noise on the various equipment (including the SA itself) - it seems it should be much better than what's showing. If the overall setup specs should show much better, then look for internal problems like bad filter capacitors etc in power supplies, or external ground loops and cable shielding failures. If your 1.5 GHz PLL mentioned is home-made, you may want to look at that too, and ensure that its power supply is clean enough. If you find and fix such failures, you may not need to change to a new reference. Good luck. 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] gpsdo 10MHz steering resolution
Hi The quick version: Going straight from 10 MHz to 1.5 GHz with no spurs is a tall order if the 10 MHz comes from some sort of system. The normal answer is to put in a cleanup oscillator (often a OCXO) in the 100 MHz range. That locks through a narrow loop and takes care about as well as you can. A typical GPSDO has a very small LSB. The spurs in the output are far more likely to come from the various digital gizmos associated with the design. The same issue (spurs from the digital side) shows up in several Telecom Rb’s as well. At some point in the 0.1 to 0.001 ppb range you get into the basic issues with GPS. It is very noisy close in and a lot of averaging is done to get a GPSDO to work. The base signal out of a number of GPS modules have jitter in the 1 ppb range, even after correction. The grubby details: One mili-hertz at 10 MHz is 0.1 ppb. Sub-mili-hertz at 10 MHz might be 0.01 ppb. On a peak to peak / 1 sigma basis at a 1 second sample rate, that is doing well for a GPSDO that is OCXO based. Run the measurement for a day and you will find 0.1 ppb peaks. Measured as a 1 second ADEV something around 0.01 ppb to 0.001 ppb is doing quite well. The often mentioned TBolt is one example of a GPSDO that does this sort of performance. Spur wise, you can easily find spurs in the 60 dbc range on some OCXO’s. Finding a device that is clean to 100 dbc would be unusual. A 1 KHz spur at -70 dbc would be unusual but by no means impossible. (20 log N from the -30 on your display). To get things down in the -60 db range, the GPSDO would need to be better than -100. That is the “why” of the cleanup loop / 100 MHz OCXO. One very “simple" solution: Don’t try to use a GPSDO as the input to the device. Run it off of a “free running” OCXO. That will give you the best spurs and reasonable stability. Then compare the LO to a GPSDO via a secondary chain. Feed the data from that chain into the SDR and let it correct the display. There are a *lot* of systems out there that do it this way ….. Bob > On Nov 25, 2019, at 3:34 AM, Mike Ingle wrote: > > Hi all, this is my first post to the the list. I am working on a time > stamped RF receiver system which can stamp at a fraction of a ps > resolution, with a jitter (1 sigma) of about 10ps. I have been using a > truetime XL-AK Irig receiver as my 1pps and 10MHz references. > Unfortunately, the truetime 10MHz has strong spurs which my 1.5GHz PLL is > unhappy with, leading to spurs in my RF. Can anyone recommend a good GPSDO > with sub millihertz steering? For example, I bought a GPSDO from a ham > here in germany, and the 10MHz is pure, but has a step resolution of > 0.2Hz. I have attached the truetime 10MHz output. best regard --mike > > > > > [image: IMG_0269.JPG] > ___ > 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] gpsdo 10MHz steering resolution
I may be completely wrong here but if the span of that spectrum is 1kHz, then the spurs look like 100Hz mains hum frequency modulation of the 10MHz. ___ 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.
