Re: [time-nuts] homebrew counter new board test result
2) Does any one have the test data of 12 digit/s counter when DUT=REF? I want to know the gap between mine and a commercial counter. Thanks Li Ang I did a lot of testing of 53132A counters a while back to research how well the interpolators worked and to measure the interference when CH1 gets too close to CH2. There was some discussion on the list about this at the time. For the context, see: https://www.febo.com/pipermail/time-nuts/2014-April/084670.html For the plots, see: http://leapsecond.com/pages/53132/ A good paper to read about the trouble when DUT is close (or equal to REF) is: http://literature.cdn.keysight.com/litweb/pdf/5990-9189EN.pdf Isolating Frequency Measurement Error and Sourcing Frequency Error near the Reference Frequency Harmonics See also: https://www.febo.com/pipermail/time-nuts/2012-October/070737.html /tvb ___ 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.
Re: [time-nuts] patek phillipe digital clock, sold as curio/antique
On 2/27/15 3:23 AM, Flemming Larsen wrote: Check the price here: Patek Philippe Digital Display Clock | | | | | | | | | | | Patek Philippe Digital Display ClockVintage digital display clock by Patek Philippe of Geneva. Made for Abou Watfa of Damascus, circa 1970. Rare Patek Philippe digital clocks for sale at M.S. Rau Anti... | | | | View on www.rauantiques.com | Preview by Yahoo | | | | | wow.. $50k. I hope it has an interesting provenance.. This clock was used to countdown to the first French nuclear test or This clock was used to time Formula 1 races in Monte Carlo. Lots of other clocks in their stock, probably using the same movement that tvb was describing.. In yesterday's Wall Street Journal (or maybe USA Today, I can't remember..) Nice Nixie displays... I wonder if it normally displays the same time on all, or if it is a multi-time zone/elapsed time kind of thing. It looks a lot like clock display stacks used for displaying Mission Elapsed Time, Local Time, UTC, etc. ___ 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.
Re: [time-nuts] time-nuts Digest, Vol 127, Issue 33
I have an XL-DC and it has an internal GPS receiver in it. It supplies and monitors 5 volts to a BNC antenna jack for an external amplified GPS antenna. I don't know what the internal GPS engine is but doubt if it is anything special. The manual describes the down converter system as an option. Al, k9si Boy I ran out to mr google and did a search and now I am wondering if some versions of the xl-dc just used a plain old GPS antenna. It sure looks like that could be the case. The manual does say down converter. Maybe it changed over time. Regards Paul WB8TSL ___ 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] Using NIST ACTS with Datum/Symmetricom TS2100
Hi all, I was wondering if anyone has ever had any success with the TS2100 and getting the ACTS system to work correctly and adjust the clock. As most of you know there is a bug in the 4.1 firmware version that was putting everything off a second with GPS. So my company purchased another one (before we knew it was firmware) to try and fix the GPS. What I have currently going on is I reverted the firmware, one of them is on 2.84 and the other 3.1, and am testing them to see if these setups work. On the v2.84 machine I have a GPS signal going into it and timecode coming out and it actually appears to be working. What we are trying to do is get the other, v3.1, to sync with NIST so that we have 2 time sources. We are using a U.S. Robotics 56K V.92 fax modem and since it's the same one as the example in the manual the init string is the same ATH2N6. I set the time initially just based on my computer then based on the other TS2100 that is on gps so right now they are about a half of a second off. My problem is that even when a NIST call works it is not adjusting the time. It is outputting ACTS recorded 0 offset ACTS adjusted clocks but the time is not adjusting at all. It is in Freerun mode and I disabled decode even though that shouldn't have mattered since it is solely using ACTS and pulled out the GPS card, again this shouldn't matter. -- Respectfully, Sean Gallagher Malware Analyst 571-340-3475 ___ 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.
Re: [time-nuts] No GPS satellites
Hi All of these older rack mount “GPSDO” products had a fairly long lifespan compared to the advances in GPS receivers. When some / most of them first came out, the only practical /proven way to do timing off GPS was with a downconverter. Without things like serial numbers / date codes it’s tough to figure out if this sample of box A has anything at all to do with another sample of the same box. On top of that, these are very low volume products compared to normal HP or Fluke test gear. It’s unlikely that anybody has a database that tells what is what simply from the serial numbers or date codes. I’d bet that many of them were built to order and rarely in groups larger than a few dozen. Bob On Feb 26, 2015, at 8:19 PM, paul swed paulsw...@gmail.com wrote: Boy I ran out to mr google and did a search and now I am wondering if some versions of the xl-dc just used a plain old GPS antenna. It sure looks like that could be the case. The manual does say down converter. Maybe it changed over time. Regards Paul WB8TSL On Thu, Feb 26, 2015 at 8:15 PM, paul swed paulsw...@gmail.com wrote: A fellow time-nut shared the manual for the xl-dc and I downloaded it. It clearly states that it has a down converter. That was very typical of these generation receivers. As examples the Odetics and Austrons. It allowed for very short antenna runs or virtually 0 length antenna runs and losses. The DC468 goes used the same trick. Almost always the receivers show up without the dowconverter because those stay on the roof. Without the down converter the units useless. I have been lucky in some exploits to use odetics down converters with the austron and the another approach using older styles semi-integrated receivers to fake it. So if you want to experiment there is hope. Though it seems each receivers a bit different.The older Truetime manuals were pretty good with schematics and explanations. Unfortunately it looks like the new manual has little to go on. Regards Paul WB8TSL On Thu, Feb 26, 2015 at 4:46 PM, Bill Hawkins b...@iaxs.net wrote: Doesn't the DC in the model number mean down conversion or something like that? Seems to me it did in the obsolete 468-DC GOES time receivers, which had to down convert to about 1.8 MHz. Also, the down conversion was more than a simple local oscillator and mixer. You had to have their antenna to make it work, as the mixer was in the base of the antenna. Bill Hawkins -Original Message- From: Tim Shoppa Sent: Wednesday, February 25, 2015 7:56 PM To: Discussion of precise time and frequency measurement Subject: [time-nuts] No GPS satellites Yes, the XL-DC and other Truetime models had as an option for long cable runs, a downconverter in the antenna. I don't know how to tell the difference from part number, but I know the truetimes my employer uses all have the downconverter option and the option is very common. Tim N3QE ___ 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.
Re: [time-nuts] XL-DC was Re: time-nuts Digest, Vol 127, Issue 33
I can confirm there are at least two common varieties of the XL-DC GPS RX board. One uses a normal GPS antenna (no down-converter, provides DC on the antenna line for an amp in the antenna, the typical antenna provided seems to be an AeroAntenna AT575 variety, but I suspect other antennas that are similar should be fine). The specific antenna part I have is: AT575-142TTW-TNCF-000-RG-41-NM It's been a while since I last decoded that part number but it's a very easily re-useable general use GPS antenna with an integrated RF amp. Works over a fairly wide range of DC supply voltages and claims a slightly higher gain than some other standard timing GPS ice cream cones. There are also versions of the GPS module for the XL-DC that use a GPS antenna with an integrated down converter that is actually physically part of the antenna provided. The down converter antenna is normally a single integrated unit. The part numbers I see on one I have handy are 140-614 (TrueTime) or Model 142-6150 on the Symmetricom label. I don't have any details for the voltages or whether there is a reference frequency provided for the down converter style receiver. I have seen some suggestions that they also had a dedicated down converter module that could be used with normal GPS antennas, but I don't have any details on that option. If you have a RX module that needs the converter antenna there should be a clearly visible little label indicating this on the module itself near the antenna connector. If you don't have that label the RX should work with most GPS antenna systems (and also with most antenna splitter systems too). -- Russell Al Wolfe wrote: I have an XL-DC and it has an internal GPS receiver in it. It supplies and monitors 5 volts to a BNC antenna jack for an external amplified GPS antenna. I don't know what the internal GPS engine is but doubt if it is anything special. The manual describes the down converter system as an option. Al, k9si Boy I ran out to mr google and did a search and now I am wondering if some versions of the xl-dc just used a plain old GPS antenna. It sure looks like that could be the case. The manual does say down converter. Maybe it changed over time. Regards Paul WB8TSL ___ 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] FS -- Thunderbolt temp sensor chips DS1620S Rev C
Hello, all. I have a reel of the good Rev C DS1620S chips as used in the T-bolt. $1 each + shipping. Pic of the chip is at the link below. Please contact me off list if interested. Not sure if anybody needs them anymore, and wanted to check with the list before I get rid of them. Thanks. http://standingwave.org/webdav/maximdsst-1264178984-1808.jpg -Pete ___ 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.
Re: [time-nuts] XL-DC was Re: time-nuts Digest, Vol 127, Issue 33
Hi One important caution on antennas: The 575 is quite happy with anything from 5 to 18V as a feed voltage and only pulls 35 ma. There are antennas out there that don’t like voltages over 6V. There also are antennas on the market that pull well over 50 ma. If the “original” box sourced 12V to the antenna and triggers as “overload” around 50 ma, the 575 will work great with the box. If you plug a modern timing antenna (= 5V version) into the box the antenna may be damaged and / or the over current may trigger. There also are 3.3 V antennas out there, but they are rarely seen in timing applications (yet). Simply put - the 575 is a great antenna and it will work on a lot of stuff. The problem is not at all with the antenna. It’s with the stuff specified to work with it. You have no way of knowing if it’s a 12V gizmo or a 5V feed. The same issue can come up with downconverter feeds. They often put +12 on the feed to run the downconverter. It’s best to put a DVM on the feed before attaching a nice new $1,500 antenna to it …(or even a $20 one) Bob On Feb 27, 2015, at 1:11 PM, Russell Rezaian r.reza...@earthlink.net wrote: I can confirm there are at least two common varieties of the XL-DC GPS RX board. One uses a normal GPS antenna (no down-converter, provides DC on the antenna line for an amp in the antenna, the typical antenna provided seems to be an AeroAntenna AT575 variety, but I suspect other antennas that are similar should be fine). The specific antenna part I have is: AT575-142TTW-TNCF-000-RG-41-NM It's been a while since I last decoded that part number but it's a very easily re-useable general use GPS antenna with an integrated RF amp. Works over a fairly wide range of DC supply voltages and claims a slightly higher gain than some other standard timing GPS ice cream cones. There are also versions of the GPS module for the XL-DC that use a GPS antenna with an integrated down converter that is actually physically part of the antenna provided. The down converter antenna is normally a single integrated unit. The part numbers I see on one I have handy are 140-614 (TrueTime) or Model 142-6150 on the Symmetricom label. I don't have any details for the voltages or whether there is a reference frequency provided for the down converter style receiver. I have seen some suggestions that they also had a dedicated down converter module that could be used with normal GPS antennas, but I don't have any details on that option. If you have a RX module that needs the converter antenna there should be a clearly visible little label indicating this on the module itself near the antenna connector. If you don't have that label the RX should work with most GPS antenna systems (and also with most antenna splitter systems too). -- Russell Al Wolfe wrote: I have an XL-DC and it has an internal GPS receiver in it. It supplies and monitors 5 volts to a BNC antenna jack for an external amplified GPS antenna. I don't know what the internal GPS engine is but doubt if it is anything special. The manual describes the down converter system as an option. Al, k9si Boy I ran out to mr google and did a search and now I am wondering if some versions of the xl-dc just used a plain old GPS antenna. It sure looks like that could be the case. The manual does say down converter. Maybe it changed over time. Regards Paul WB8TSL ___ 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.
Re: [time-nuts] Recording mains frequency/phase [WAS: No GPSsatellites]
If we all did this, then I realize that we could identify the different power grids. However, I wonder if there is any interesting variation *within* a grid. As the electricity flows vary throughout the day, it seems possible that the phase difference between two people on the same grid would actually change (a bit). Has anybody done this experiment? Philip Yes, it's really quite interesting and very easy to do. Check the time nuts archives -- over the years there are by now hundreds of postings about measuring mains phase and frequency. See also: http://leapsecond.com/pages/mains/ http://leapsecond.com/pages/mains/mains-picpet-23.gif http://leapsecond.com/pages/ac-detect/ There are many wonderful web sites that deal with power line frequency; some with live plots. Just google for words like: mains frequency detect accuracy stability measurement Also, make sure to read the growing literature about ENF: http://en.wikipedia.org/wiki/Electrical_network_frequency_analysis /tvb ___ 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.
Re: [time-nuts] Trimble Thunderbolt NMEA ?
Hi Tim, probably not the answer you are looking for, because it's a piece of software and not a device, and it doesn't output NMEA, but maybe it can still be of some help https://github.com/mpbraendli/trimble-thunderbold Matthias HB9EGM On 26. 02. 15 05:11, Tim wrote: Hi all, Is there a way to get NMEA instead of TSIP out of a Thunderbolt ? Failing that, is there some translating device that I can insert between the Thunderbolt and another device that is expecting NMEA ? thanks Tim ___ 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.
Re: [time-nuts] XL-DC was Re: time-nuts Digest, Vol 127, Issue 33
In my XL-DC's case, there must have been a downconverter built into the antenna (which I don't have), but there was an upconverter in the chassis which took the IF signal from the cable, and heterodyned it back up to L-Band. I haven't fiddled-around with the upconverter, but I suspect the IF was in the HF band. Overnight my XL-DC says the GPS is unlocked, but is tracking 6 satellites, so my troubles still persist... -Doug -Original Message- From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Russell Rezaian Sent: Friday, February 27, 2015 10:12 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] XL-DC was Re: time-nuts Digest, Vol 127, Issue 33 I can confirm there are at least two common varieties of the XL-DC GPS RX board. One uses a normal GPS antenna (no down-converter, provides DC on the antenna line for an amp in the antenna, the typical antenna provided seems to be an AeroAntenna AT575 variety, but I suspect other antennas that are similar should be fine). The specific antenna part I have is: AT575-142TTW-TNCF-000-RG-41-NM It's been a while since I last decoded that part number but it's a very easily re-useable general use GPS antenna with an integrated RF amp. Works over a fairly wide range of DC supply voltages and claims a slightly higher gain than some other standard timing GPS ice cream cones. There are also versions of the GPS module for the XL-DC that use a GPS antenna with an integrated down converter that is actually physically part of the antenna provided. The down converter antenna is normally a single integrated unit. The part numbers I see on one I have handy are 140-614 (TrueTime) or Model 142-6150 on the Symmetricom label. I don't have any details for the voltages or whether there is a reference frequency provided for the down converter style receiver. I have seen some suggestions that they also had a dedicated down converter module that could be used with normal GPS antennas, but I don't have any details on that option. If you have a RX module that needs the converter antenna there should be a clearly visible little label indicating this on the module itself near the antenna connector. If you don't have that label the RX should work with most GPS antenna systems (and also with most antenna splitter systems too). -- Russell Al Wolfe wrote: I have an XL-DC and it has an internal GPS receiver in it. It supplies and monitors 5 volts to a BNC antenna jack for an external amplified GPS antenna. I don't know what the internal GPS engine is but doubt if it is anything special. The manual describes the down converter system as an option. Al, k9si Boy I ran out to mr google and did a search and now I am wondering if some versions of the xl-dc just used a plain old GPS antenna. It sure looks like that could be the case. The manual does say down converter. Maybe it changed over time. Regards Paul WB8TSL ___ 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.
Re: [time-nuts] Recording mains frequency/phase [WAS: No GPS satellites]
HI On Feb 27, 2015, at 10:46 AM, Philip Gladstone pjsg-timen...@nospam.gladstonefamily.net wrote: On 2/26/15 20:39, Charles Steinmetz wrote: ben wrote: I'm going to have to build one of these. Assume you have some sort of circuit that converts low-voltage AC from a transformer secondary to a pulse train, start a timer, and count x amount of pulses? Here is a zero-cross detector designed for this purpose: http://www.ko4bb.com/manuals/download.php?file=02_GPS_Timing/Simple_AC_Mains_Zero_Crossing_Detector.pdf Most mains-nuts feed the ZCD pulse to the DCD line of a PC's RS232 port and use the computer to time-stamp the crossings and append them to a file of such time stamps. If we all did this, then I realize that we could identify the different power grids. However, I wonder if there is any interesting variation *within* a grid. As the electricity flows vary throughout the day, it seems possible that the phase difference between two people on the same grid would actually change (a bit). Has anybody done this experiment? It’s done by utilities to monitor power flow and balance electric grids. The first data on this (grid vs GPS) date to the 1980’s. I think the paper I recall was done by Quebec Hydro. Since then it’s become a pretty standard monitoring tool. Bob Philip ___ 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.
Re: [time-nuts] Measuring frequency rather than tuning crystal
I don't think your TTi TF930 has a GPS input to calibrate against, based on a quick perusal of the data sheet. I would guess that the calibration constants are thus fixed from the factory (including temperature coefficients). On Thu, Feb 26, 2015 at 3:36 PM, James via time-nuts time-nuts@febo.com wrote: I presume that this is what my TTi TF930 does. Calibration is closed box so I guess the TCXO is free running and the micro inside just uses calibration constants. James -Original Message- From: Paul Alfille paul.alfi...@gmail.com To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Thu, 26 Feb 2015 19:02 Subject: [time-nuts] Measuring frequency rather than tuning crystal I have a couple of HP 5370s with the beaglebone brain transplant. They come with a nice 10811 that has a little adjustment screw. Testing against a Thunderbolt or KS-24361 the 5370 is off by less than 1Hz. I know the traditional method would be to adjust the crystal slowly and make careful measurements, but since I have a fancy computer in there, I wonder if I could just adjust the frequency in software. 64-bit floating point numbers should have sufficient accuracy. All reported measurments would be corrected for the actual reference frequency. Basically, I'd have a 1000.226 Hz internal reference. In fact, could I connect the beaglebone to a a GPS 1 pps source and make this a GPS-disciplined-software-corrected oscillator. So my question is is this a known technique? The discipline feedback circuit seems a little different, I'd adjusting for drift and offset, but not the gain of control-oscillator linkage. ___ 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.
Re: [time-nuts] Recording mains frequency/phase [WAS: No GPS satellites]
On 2/26/15 20:39, Charles Steinmetz wrote: ben wrote: I'm going to have to build one of these. Assume you have some sort of circuit that converts low-voltage AC from a transformer secondary to a pulse train, start a timer, and count x amount of pulses? Here is a zero-cross detector designed for this purpose: http://www.ko4bb.com/manuals/download.php?file=02_GPS_Timing/Simple_AC_Mains_Zero_Crossing_Detector.pdf Most mains-nuts feed the ZCD pulse to the DCD line of a PC's RS232 port and use the computer to time-stamp the crossings and append them to a file of such time stamps. If we all did this, then I realize that we could identify the different power grids. However, I wonder if there is any interesting variation *within* a grid. As the electricity flows vary throughout the day, it seems possible that the phase difference between two people on the same grid would actually change (a bit). Has anybody done this experiment? Philip ___ 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.
Re: [time-nuts] Measuring frequency rather than tuning crystal
I presume that this is what my TTi TF930 does. Calibration is closed box so I guess the TCXO is free running and the micro inside just uses calibration constants. James -Original Message- From: Paul Alfille paul.alfi...@gmail.com To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Thu, 26 Feb 2015 19:02 Subject: [time-nuts] Measuring frequency rather than tuning crystal I have a couple of HP 5370s with the beaglebone brain transplant. They come with a nice 10811 that has a little adjustment screw. Testing against a Thunderbolt or KS-24361 the 5370 is off by less than 1Hz. I know the traditional method would be to adjust the crystal slowly and make careful measurements, but since I have a fancy computer in there, I wonder if I could just adjust the frequency in software. 64-bit floating point numbers should have sufficient accuracy. All reported measurments would be corrected for the actual reference frequency. Basically, I'd have a 1000.226 Hz internal reference. In fact, could I connect the beaglebone to a a GPS 1 pps source and make this a GPS-disciplined-software-corrected oscillator. So my question is is this a known technique? The discipline feedback circuit seems a little different, I'd adjusting for drift and offset, but not the gain of control-oscillator linkage. ___ 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.
Re: [time-nuts] Measuring frequency rather than tuning crystal
The TF930/960 does have a calibration procedure that is performed from the front panel. Basically, you feed it a stable input from any known source (so both 1 Hz and 10 MHz from a GPSDO should work) and then adjust until the displayed frequency agrees with the known input frequency. The resolution of this setting is quite a bit better than the stability of the TCXO in the box. Now, this process could occur either by actually adjusting the frequency of a VCTCXO in the box using a DAC, or by changing a calibration constant stored in the memory of the device. I suspect it's actually the former, because the instructions say that the adjustment path has a low-pass filter that you need to allow to settle. This wouldn't be necessary if the calibration simply changed a stored number. Dave On 27/02/2015 15:08, Paul Alfille wrote: I don't think your TTi TF930 has a GPS input to calibrate against, based on a quick perusal of the data sheet. I would guess that the calibration constants are thus fixed from the factory (including temperature coefficients). On Thu, Feb 26, 2015 at 3:36 PM, James via time-nuts time-nuts@febo.com wrote: I presume that this is what my TTi TF930 does. Calibration is closed box so I guess the TCXO is free running and the micro inside just uses calibration constants. James -Original Message- From: Paul Alfille paul.alfi...@gmail.com To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Thu, 26 Feb 2015 19:02 Subject: [time-nuts] Measuring frequency rather than tuning crystal I have a couple of HP 5370s with the beaglebone brain transplant. They come with a nice 10811 that has a little adjustment screw. Testing against a Thunderbolt or KS-24361 the 5370 is off by less than 1Hz. I know the traditional method would be to adjust the crystal slowly and make careful measurements, but since I have a fancy computer in there, I wonder if I could just adjust the frequency in software. 64-bit floating point numbers should have sufficient accuracy. All reported measurments would be corrected for the actual reference frequency. Basically, I'd have a 1000.226 Hz internal reference. In fact, could I connect the beaglebone to a a GPS 1 pps source and make this a GPS-disciplined-software-corrected oscillator. So my question is is this a known technique? The discipline feedback circuit seems a little different, I'd adjusting for drift and offset, but not the gain of control-oscillator linkage. ___ 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.
Re: [time-nuts] XL-DC was Re: time-nuts Digest, Vol 127, Issue 33
Hi, AT575-142TTW-TNCF-000-RG-41-NM Not all 575 antennas eat the same power. Its the RG in the part number above that specifies 4.2V to 15V DC power for the internal LNA. This is the most common option - but there are others. -- Björn div Originalmeddelande /divdivFrån: Bob Camp kb...@n1k.org /divdivDatum:2015-02-27 20:21 (GMT+01:00) /divdivTill: Discussion of precise time and frequency measurement time-nuts@febo.com /divdivRubrik: Re: [time-nuts] XL-DC was Re: time-nuts Digest, Vol 127, Issue 33 /divdiv /divHi One important caution on antennas: The 575 is quite happy with anything from 5 to 18V as a feed voltage and only pulls 35 ma. There are antennas out there that don’t like voltages over 6V. There also are antennas on the market that pull well over 50 ma. If the “original” box sourced 12V to the antenna and triggers as “overload” around 50 ma, the 575 will work great with the box. If you plug a modern timing antenna (= 5V version) into the box the antenna may be damaged and / or the over current may trigger. There also are 3.3 V antennas out there, but they are rarely seen in timing applications (yet). Simply put - the 575 is a great antenna and it will work on a lot of stuff. The problem is not at all with the antenna. It’s with the stuff specified to work with it. You have no way of knowing if it’s a 12V gizmo or a 5V feed. The same issue can come up with downconverter feeds. They often put +12 on the feed to run the downconverter. It’s best to put a DVM on the feed before attaching a nice new $1,500 antenna to it …(or even a $20 one) Bob On Feb 27, 2015, at 1:11 PM, Russell Rezaian r.reza...@earthlink.net wrote: I can confirm there are at least two common varieties of the XL-DC GPS RX board. One uses a normal GPS antenna (no down-converter, provides DC on the antenna line for an amp in the antenna, the typical antenna provided seems to be an AeroAntenna AT575 variety, but I suspect other antennas that are similar should be fine). The specific antenna part I have is: AT575-142TTW-TNCF-000-RG-41-NM It's been a while since I last decoded that part number but it's a very easily re-useable general use GPS antenna with an integrated RF amp. Works over a fairly wide range of DC supply voltages and claims a slightly higher gain than some other standard timing GPS ice cream cones. There are also versions of the GPS module for the XL-DC that use a GPS antenna with an integrated down converter that is actually physically part of the antenna provided. The down converter antenna is normally a single integrated unit. The part numbers I see on one I have handy are 140-614 (TrueTime) or Model 142-6150 on the Symmetricom label. I don't have any details for the voltages or whether there is a reference frequency provided for the down converter style receiver. I have seen some suggestions that they also had a dedicated down converter module that could be used with normal GPS antennas, but I don't have any details on that option. If you have a RX module that needs the converter antenna there should be a clearly visible little label indicating this on the module itself near the antenna connector. If you don't have that label the RX should work with most GPS antenna systems (and also with most antenna splitter systems too). -- Russell Al Wolfe wrote: I have an XL-DC and it has an internal GPS receiver in it. It supplies and monitors 5 volts to a BNC antenna jack for an external amplified GPS antenna. I don't know what the internal GPS engine is but doubt if it is anything special. The manual describes the down converter system as an option. Al, k9si Boy I ran out to mr google and did a search and now I am wondering if some versions of the xl-dc just used a plain old GPS antenna. It sure looks like that could be the case. The manual does say down converter. Maybe it changed over time. Regards Paul WB8TSL ___ 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] patek phillipe digital clock, sold as curio/antique
In yesterday's Wall Street Journal (or maybe USA Today, I can't remember..) Nice Nixie displays... I wonder if it normally displays the same time on all, or if it is a multi-time zone/elapsed time kind of thing. It looks a lot like clock display stacks used for displaying Mission Elapsed Time, Local Time, UTC, etc. ___ 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.
Re: [time-nuts] patek phillipe digital clock, sold as curio/antique
Check the price here: Patek Philippe Digital Display Clock | | | | | | | | | | | Patek Philippe Digital Display ClockVintage digital display clock by Patek Philippe of Geneva. Made for Abou Watfa of Damascus, circa 1970. Rare Patek Philippe digital clocks for sale at M.S. Rau Anti... | | | | View on www.rauantiques.com | Preview by Yahoo | | | | | From: Jim Lux jim...@earthlink.net To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Thursday, February 26, 2015 2:22 PM Subject: [time-nuts] patek phillipe digital clock, sold as curio/antique In yesterday's Wall Street Journal (or maybe USA Today, I can't remember..) Nice Nixie displays... I wonder if it normally displays the same time on all, or if it is a multi-time zone/elapsed time kind of thing. It looks a lot like clock display stacks used for displaying Mission Elapsed Time, Local Time, UTC, etc. ___ 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.
Re: [time-nuts] homebrew counter new board test result
Hi Thanks about the explanation on hysteresis and comparator. The PM6685(http://assets.fluke.com/manuals/PM6685__smeng.pdf ) is using 74ALS176 as the frontend for REF channel. So I tried that on the previous board. The performance is better with 74ALS176+74LVC2G14 than MC100LVELT22 at the sin wave input condition. Since the stdev has reached the spec of TDC chip, I need to do some more experiments with these chips next. There are some questions I want to ask: 1) Does the trigger interval need to be very accurate? Now I am using software scheduler to generate the interval, it might vary few ms. 2) Does any one have the test data of 12 digit/s counter when DUT=REF? I want to know the gap between mine and a commercial counter. Thanks Li Ang 2015-02-27 4:30 GMT+08:00 Charles Steinmetz csteinm...@yandex.com: Magnus wrote: A bit of hysteresis can help to avoid flipping back, but considering the type of signal, it passes the mid-point (0 V) at highest slew-rate, so there is very little risk of flipping back and fourth in the first place, so hysteresis may not even be needed. A 1 Vrms, 10MHz sine wave has a zero-cross slew rate of 88v/uS (88mV/nS). One would think that would be enough to avoid indecision in a comparator with 5-10nS of propagation delay. However, the LT1016 (10nS) is prone to jitter problems when operating as a ZCD with such a signal, and external hysteresis does not help much because it is delayed by 10nS. (The problem appears to be that the front end has some indecision at this input slew rate that happens faster than the propagation delay to the output -- but this is just an inference because the internal nodes are not accessible for measurement.) For this application, the small amount of internal hysteresis of the LT1719 and LT1720 is very beneficial. Best regards, Charles ___ 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.
Re: [time-nuts] patek phillipe digital clock, sold as curio/antique
In yesterday's Wall Street Journal (or maybe USA Today, I can't remember..) Nice Nixie displays... I wonder if it normally displays the same time on all, or if it is a multi-time zone/elapsed time kind of thing. It looks a lot like clock display stacks used for displaying Mission Elapsed Time, Local Time, UTC, etc. Jim -- Nice find. Crazy prices. Color images cached at: http://leapsecond.com/museum/patek/ Time Nuts -- Not many of us are interested in high-end mechanical clocks and watches, but the name Patek Philippe catches our eye because many of the early time/frequency standards from Tracor, Austron, and Hewlett Packard used a 1 PPS stepper driven analog dial clock display made by Patek Philippe. After the Nixie tube era, but before the LED, LCD, and VFD era, HP used these wonderful Patek movements in their 5061A and 5065A standards. You can see an example on the early model 5061A/01 at http://www.leapsecond.com/hpclocks/ /tvb ___ 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.
