[time-nuts] Affordable PoE 6-digit time displays?
You could also run Lady Heather on a PI with NTP and select one of the zoomed full screen clock displays (analog watch or digital clock). ___ 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] where can I purchase 794.7 nm VCSEL for building CPT rubidium clock?
Well, no. Green laser pointers convert a rather high power 800 nm laser to 1600 nm in one crystal then divide it to 533 nm in another one. The physics and manufacturing of them is best described as black magic. They are cheap because China developed the process to grow the crystals in bulk and crank out zillions of them for consumer products. I suspect that a 1600-ish nm to 800-ish nm converter is not a stock consumer-quantity device and will cost a pretty penny or two... like a red/IR laser diode can be had for 50 cents and a telecom VCSEL diode can be $500. -- > It cannot be too much, given the fact that these are used in green laser pointers. ___ 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] Cheap-ish PRS-10 rubidiums on Ebay
There is a guy selling some (5) PRS-10's on Ebay for $170. Says pulled from decommissioned systems, but sold for parts. No telling if they are any good... They are listed as being "used" and not "for parts"... which I think means Ebay says you can return them. https://www.ebay.com/itm/Stanford-Research-Systems-PRS10-10MHz-Rubidium-Frequency-Standard/183248949887?epid=1627032553=item2aaa7d127f:g:dUgAAOSw0LhbDWQR There is another guy (in Allen, Texas) that usually keeps one listed for $250... if it sells, another one pops up fairly soon. I've bought a few from him and they were all good. You do have to move 2 or 3 resistors to enable the serial port and one of the more useful signals (PPS IN?). ___ 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] Question about Lady Heather millisecond display
That is exactly what it should be doing... it shows the time of arrival of the receiver time message is varying by around a millisecond. --- > However, when entering this command the three millisecond digits do appear but only alternate back and forth every several seconds between "052" and "053". ___ 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] nuts about position
The typical receiver default self-surveys of 30 minutes to 2 hours are not ideal. They will not include a lot of satellites or the effects of multi-path over time. A survey of at least 12 hours is needed to include all the sats. 24-48 hours is even better. The effects of things like antenna position changing a couple of cm due to expansion and humidity effects are swamped by the receiver accuracy and noise. - > That said, there are certainly a lot of issues with how the self-survey position should be calculated *and* maintained, because it really needs to change over time for optimal performance. ___ 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] nuts about position
The tripod is a survey grade tripod on a limestone terrace (in a horrible location for an antenna). Heather's precision survey uses the receiver's reported position data. It does not take advantage of carrier phase/pseduorange/doppler data and post-processing. Unlike the simple averaging self-surveys that most receivers do it processes the average of medians over 1 minute/1 hour/24 hour intervals. It typically produces results 1-2m better than the simple self-surveys. The next thing I want to try is a receiver self-survey vs the post processed results... I may be able to kludge up a test that does a self-survey / precision survey / post processed survey and compare the results of the methods on the same data set. ___ 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] nuts about position
I did Lady Heather's 48-hour precision survey on an NVS-08 receiver and collected RINEX data at the same time. The NVS was tracking GPS and SBAS satellites. The RINEX result had lat/lon/alt error estimates of .175/.153/.396 meters. The difference between Heather's precision survey results and the RINEX position were: lat/lon/alt: -.638m/1.190m/1.526m ___ 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] nuts about position
As far as I'm concerned anything that you can do to improve the position accuracy, environmental changes, noise environment, etc is a good thing. Minimizing errors and disturbances can't hurt and may even improve things. How much any improvement provides ... ??? But time nuts tend to be a bit nutty about minimizing our therbligs ;-) Most receiver self-surveys seem to get your lat/lon to the 2-3 meter range. Heather's median survey is in the 1-2 meter range. PPP data is in the < 0.25 meter range... seems like something worthwhile. (altitude errors are usually around twice the lat/lon error). There is always the possibility that some receiver model's computation of lat/lon/alt could have some intrinsic bias in it. If so, a position calculated by an external source could possibly degrade performance... > Is this applicable to a Thunderbolt, and would this improved position accuracy be expected to improve the time accuracy from a Thunderbolt compared to using the older Lady Heather 24 hour self survey method? ___ 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] nuts about position
I did a test on a 1 second vs a stripped out 10 second rate from the same 24 hour run. The differences were down in the noise. Some people have actually reported slightly better results with 30 second vs 1 second data... but I doubt that... I suspect they used different data sets and the differences were just due to different data. --- If you are doing a longer run into one of the data analysis services - it does not seem to matter much what the spacing on the readings is ___ 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] nuts about position
I haven't done any extensive testing of how accurate the results are, but comparing them to the position produced by a L1/L2 (error ellipses < 50mm) they seem to be correct. One issue to be aware of is that some receivers want altitude in othometric height (MSL) and others use geoid (GPS) height. If you are transferring the PPP results to a receiver you need to watch out for what the receiver wants. Also MSL based receivers may be using different orthometric models, so knowing how to convert GPS height to what the receiver uses can be problematic. - > Does the position agree with other chip sets? ___ 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] nuts about position
Well, with a little prodding and help from Magnus, I now have the Trimble devices outputting RINEX files. They have pseudorange, doppler, and signal strength observations. A 5 hour 1Hz run was sent to CSRS-PPP and the lat/lon/alt error ellipses were in the 250/250/700 mm range... that should improve with a longer run. Firmware issues in the original Resolution-T limit those to a 3 second observation rate. ___ 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] nuts about position
I repeated the two-receiver test, this time comparing 10 hours of 1 Hz measurements from an LEA-4T with NVS-08C measurments. The NVS has higher resolution RAW data measurements. But, again, the differences in the error ellipses were in the 2-4 mm range. ___ 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] nuts about position
I did another test to see if the M8T offered any positioning advantage over the old (and cheap) LEA-4T and LEA-5T devices. I drove the M8T and LEA-4T with the same antenna, collected data for 12 hours, beamed the RINEX files to Canada. The results matched to within 3mm... so, again, the M8T doesn't offer much benefit for getting precise positions. ___ 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] nuts about position
Ok, I did the experiment. I took an 8 hour M8T RINEX file with
GPS,SBAS,GLONASS,GALILEO data in it. I then used to TEQC to extract GPS only
and GLONASS only data (CSRS-PPP ignores SBAS and GALILEO data). The 95%
confidence error ellipse estimates ("rapid" orbits) were:
GPS+GLONASS:lat 0.245mlon 0.219malt 0.582m
GPS ONLY: lat 0.269mlon 0.239malt 0.616m
GLONASS ONLY: lat 0.610mlon 0.755malt 1.835m
Conclusion... if you are just interested in an accurate antenna position, a
$25 LEA-5T should do just fine. GLONASS brings very little benefit (call it an
inch) to the party. 24 hours of observations can reduce those numbers by
around 50% I used one of those $70 Chinese L1/L2/GLONASS/BEIDOU antennas from
Ebay. Note that my antenna location/environment is HORRIBLE...
Things might change if you get into expensive L1+L2(or L5) receivers.
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[time-nuts] nuts about position
I finally got in the Ublox M8T and have been testing its RAW data measurements (carrier phase / pseudorange / dopper) data by having Lady Heather write a RINEX file and sending it to CSRS-PPP. Collecting GPS, SBAS, GLONAS, and GALILEO data (CSRS-PPP ignores GALILEO and BEIDOU data) for 2 hours and having it processed with the "ultra rapid" orbits gives a position with around 350 mm lat/lon and 800 mm alt uncertainty ellipse diameter. Using 24 hours of data and the "rapid" (24 hour delayed) orbits gives around 125 mm lat/lon and 300 mm alt uncertainty... the 24 hour file was around 100 MB long, .ZIPed to 25 MB. Not enabling GALILEO would have reduced the file sizes around 25%. I need to see if I can find a program that will split out the GPS/SBAS and GLONAS data into separate RINEX files and see how the two systems compare. ___ 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] Ublox M8T question
I have it working now.The problem was the way I was interpreting the satellite system gnssid:svid values in the RAWX message. Basically the data for all the sat systems were being mapped to GPS prns. Heather has a command for configuring which GNSS constellations that you want to use. Ublox devices have some limits on which constellations that you can enable at the same time. Heather's RINEX writer now supports RINEX v2.11 and v3.03 (needs a couple of tweaks).But none of the processing services support v3.xx so no way to test it. I'm currently writing a 2.11 file with GPS/SBAS/GLONASS/GALILEO data... hopefully that will work. I've done GPS/GLONASS/SBAS files from a NVS-08C. --- I think you need to look at the CFG-GNSS message to enable the constellations that you want. ___ 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] Ublox M8T question
I recently got in a Ublox M8T board in from CSGSHOP. The M8T supposedly outputs raw measurements (carrier phase, pseudorange, doppler) for all the sat systems it supports, but I am only getting raw measurements for GPS and SBAS... no Glonass or Galaileo.Any ideas why? Has anybody gotten raw data for GLONASS or Galileo out of a M8T: This is the receiver id info from the M8T: # Device: Ublox timing receiver # Unit type: Ublox GPS receiver # SW:EXT CORE 3.01 (41 # HW:0008 # ROM 1: ROM BASE 2.01 (75331) # ROM 2: FWVER=TIM 1.10 # ROM 3: PROTVER=22.00 # ROM 4: MOD=NEO-M8T-0 # ROM 5: FIS=0xEF4015 (100111) # ROM 6: GPS;GLO;GAL;BDS # ROM 7: SBAS;IMES;QZSS ___ 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] Antenna cable delay compensation
A related question is: Do you use positive or negative numbers to set the antenna cable delay value? Again, most GPS receiver documentation does not say.I think that I've only seen it explicitly mentioned in the Trimble documentation and the Oscilloquartz Star-4 documentation. Also there is the question of does the receiver time message come out before or after the 1PPS and what is the message offset time from the 1PPS? Again, rarely documented by the receiver manufacturer. Lady Heather can measure those (if the operating system clock is accurately set) Heather uses the message time offset to adjust the displayed time or get the audible "tick clock" aligned to true time. Heather has a table of typical message offsets for the supported receivers, but measuring and setting the value for your receiver/computer/serial port can improve things. ___ 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] NEO-M8N vs. NEO-M8T
One thing to look out for when messing with sawtooth messages is the question of does the message come out before or after the PPS pulse... good look finding the answer in the receiver documentation... "After" seems to be the most common answer. That makes hardware/delay line compensation rather tricky. Sometimes you can use the antenna cable delay / pps offset commands to shift the pulse before the true position (assuming that they support negative offsets) and use a longer delay line to add the tweak back in. ___ 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] NEO-M8N vs. NEO-M8T
Yes, the Ublox sends ps... whatever software that is processing the message is scaling it wrong. And labeling it wrong... qErr:-0.00105210 ps... that aint' right... no way... no how.. ___ 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] NEO-M8N vs. NEO-M8T
It looks like you have slipped a decimal point somewhere (also that "ps" label is wrong). I have an M8N running here and the report sawtooth errors are all within a +/- 10 ns span. (and LEA-5T is +/- 5ns). --- > Class: TIM(0xd) ID: TP(0x1), len: 0x10 tow:1519310.0 qErr:-0.00048400 ps, week:2002 flags:0xa refInfo:0x0 is GPS, UTC available Which says the next PPS is going to be -48.4 nano seconds out. Similar to the 52 nano seconds quantization error of a RasPi 3B.___ 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] ✘NEO-M8N vs. NEO-M8T
Lady Heather can configure the various time pulse / PPS outputs on the Ublox receivers. (P keyboard menu) If the receiver supports sawtooth data, the current sawtooth value will be shown at the top of the screen (second column). It can also be shown in the plot area (GD will toggle the sawtooth graph... it is off by default since it tends to be noisy looking mess). Ublox receivers may power up speaking NMEA. If you start Heather up with the /rxu command, it will put it into Ublox binary mode. The Thunderbolt has no sawtooth error since the GPS RF chain is locked to the OCXO. If the OCXO is too far off freq the Thunderbolt will not be able to track satellites. ___ 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] ✘NEO-M8N vs. NEO-M8T
I think what Gary really wants is a GPS receiver with the most stable PPS output available. That is probably the Furuno GT-8736... 1.7 nsec sawtooth error. Typical PPS span is +/- 4 nsec. Also, the Trimble Thunderbolt has 0 sawtooth error. ___ 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] ✘NEO-M8N vs. NEO-M8T
The sawtooth value is in the 0x0D-0x01 (TIM-TP) message. Third value, called qErr. 32-bit dword. In picoseconds. ___ 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] ✘NEO-M8N vs. NEO-M8T
Most of the post-processing services use reference stations that are surveyed and verified to mm level accuracy. The 13 reference stations used by AUSPOS were uncertainties all less than 4/4/8 mm. Unfortuenatly some of the baselines were rather long. My antenna is swimming in multi-path and other signal killers. A two story house < 25 feet to the west, tall trees, antenna on a terrace surrounded by low-ish walls with 10 foot columns in the corners, stainless steel gates, etc. Heather suggests an elevation mask of around 40 degrees. ___ 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] ✘NEO-M8N vs. NEO-M8T
The main significant difference between the M8N and M8T is the fact that the M8T can output raw data (and sawtooth). The hardware is the same so there should not be much difference PPS wise between the two. I have Lady Heather's RINEX writer working pretty well. Tested with the LEA-4T/5T/6T, the Furuno GT87, the NVS-08, and the Ashtech Z12 (with L1 and L2 data). It supports GPS/SBAS/GLONASS/GALILEO (with hooks for future BEIDOU) observations). GLONASS and GALILEO have not yet been tested with the M8T... I'm still waiting for the M8T to arrive. It currently outputs RINEX 2.11 format with some hooks for future v3.03 support. L1 only results with 24 hours of observations and "ultra rapid" orbits yield error estimates in lat/lon/alt of around 0.15/0.15/0.3 meters pk-pk. With 2 hours of data the errors are around twice that. L1/L2 with the Z12 were 31/40/88 mm (antenna is in a TERRIBLE location). ___ 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] WTB: HP/Agilent/Symmetricom 58517A Distribution Amplifier
Well, not strictly L1. I have a 58517A connected to an Ashtech Z12. It does report good signal levels on the L2 data (same range as the L1 signals)... but the Z12 L2 results are rather noisy and I don't get a very accurate solution. Also the '517A does seem to work OK with Galileo and Glonass... maybe not optimum, but still quite OK. > Just a heads up, in case you’re not concious of the fact; at least my HP > splitter (can’t recall model# off hand) is strictly L1 - many others are wide > band and will allow L2 and whatever else you might later want. ___ 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] Thunderbolt code phase measurement
I was losing messages for up to 4 seconds on some of the receivers (ResT?) so I commented out that message request. I need to go back and do some tests to see which ones are actually affected. --- > By "hosing" do you mean that you lose messages for the next second? That was a problem with the Resolution T too. ___ 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] Thunderbolt code phase measurement
Many thanks Peter for confirming what I suspected. The problem with the Trimble receivers is that requesting the satellite C/A code data can hose up a lot of them. So, I'm stuck with calculating the integer number of milliseconds. How to do that? I do know my position to a few feet. I have Lady Heather generating RINEX files for the Ublox timing receivers, the NVS-08, the Furuno GT-87, and the Ashtech Z12 (with both L1/L2 data). It would be nice to be able to support the Trimble receivers. With L1 only data I am getting results in the < 200 mm range. The Z12 with L1/L2 data gets me to around 40 mm. > If you know your position to within 150 kilometers (0.5 ms), you can dispense with the pseudorange-assembly arithmetic and just use the code phase directly, after adding in the appropriate integer number of milliseconds, only one of which will put you within your known 300-kilometer-diameter (1 ms) sphere. ___ 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] Thunderbolt code phase measurement
The Trimble Thunderbolt has a message (0x5A) that outputs raw receiver measurement data. One value is "code phase" (along with PRN, sample length, sig level, dopple, and time-of-measurement). This is a single precision floating point number in units of 1/16 of a chip. Does anybody know how to massage this value into either a carrier phase (in cycles) or a pseudorange (in meters).The reported code phase values tend to be in the 1000 ... 1 range. ___ 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] TruePosition GPSDO Holdover Issues
Lasy Heather can read a receiver data capture file as a "simulation" file. Use the /rs=filename command line option. You can also specify the /0 command line option (don't use serial port) and /rx= command line option to specify the receiver type. The simulation file reads in at around 20-30 times faster than real time (goes faster when the mouse cursor is kept out of the plot area), -- >First is to collect the data. I have a python script that grabs everything from a NMEA device and logs each line with a time stamp. The GPS orbit period is 12 hours so you need 12 hours of data to see everything. But there are 30 satellites, so a few hours will show the hole. The next step is to extract the data into a useful format. That's another python script. Then, just feed that to gunplot. ___ 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] Ashtech Z12 question.
The "new" Z12 from Ebay came in today. Works fine (except bad memory backup batteries). So antenna, power supply, cables are OK. Replacing the memory backup batteries is fairly easy, except for the gazillion and three screw to open it up. A pair of memory batteries costs around $15. I need to go over the bad one in more detail and see if I can find any bad caps... I had done a quick in-circuit test before replacing the batteries and did not see anything suspicious. It could also be something on the RF side or oscillator has drifted out of range. ___ 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] Ublox Galileo/Beidou PRNs
Does anybody know how Ublox maps their reported PRNs for Galileo and Beidou satellites to the true satellite PRNs. What little there is on the web appears on the web is rather incorrect. For Galileo I have seen Ublox PRNs from 212 to 240. That seems to imply it might be ACTUAL = UBLOX_PRN - 210. ___ 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] Ashtech Z12 question.
Antenna is good... it is feeding an HP amplified splitter which goes to 7 other receivers. And yes, it died in the middle of a run. I have another Z12 coming from Ebay... -- > Rats. Is the antenna known to be good? Is the Z12 providing bias on the antenna cable? Did the Z12 stop tracking right in the middle of the session with no nearby events or configuration changes? ___ 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] nuts about position (cheap receiver)
I have Lady Heather's RINEX writer working fairly well. Handles GPS and GLONASS (should also do Galileo when the M8T comes in from Germany... was "in stock" but it took them over a week to ship it). I just did a run on the Furuno GT-8736. It only outputs pseudoranges. A 2.5 hour run @ 1Hz had error ellipses around 0.4 meters lat/lon 1 meter altitude.. similar to a Ublox-5T with pseudoranges and carrier phase. The LEA-5T with 17 hours of 1Hz data were .17 /.15 /.4 meters... not too shabby for a $25 receiver. The NVS-08 with 3 hours of 1Hz GPS/GLONASS data was 0.63/0.59/1.5m (without GLONASS data being processed). Once CSRS-PPP had GLONASS orbit data available, they automatically re-ran it and the error ellipses improved to .57/.56/1.4m A 19 hour/1Hz run on a NVS-08 receiver was 0.175 meters lat/lon .455 meters altitude. Results from the Z12 in L1/L2 mode were... iffy... then the receiver died. ___ 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] Ashtech Z12 question.
Well, my Z12 stopped tracking sats yesterday. It passes all self-tests. I then replaced the memory backup batteries... it fixed the bootup error problem, but still won't track sats. ___ 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] Ashtech Z12 question.
I just added support for the Z12 to Lady Heather and fired up my Z12 for the first time in a few years. It powers up in some kind of a weird loopback mode and you have to reset the receiver memory to get it working. Does the Z12 have an internal memory backup battery? Mine is currently doing a long L1/L2 RINEX capture and I can't open it and check right now. ___ 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] WWVB: measuring local 60 KHz noise
Although it does not measure propagation delays, Lady Heather can now estimate propagation delays. You can enter the lat/lon/alt of the station or specify the station name. You can enter the ionosphere height, or Heather will estimate it depending upon the month. --- > I'd also like to measure the propagation delays on WWV so a setup for HF that also works down to 60 KHz would be interesting. ___ 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] nuts about position (cheap receiver)
You could add doppler to the RINEX file. All the receivers with raw messages seem to output that. I am playing with the Furuno GT87 output. It does not output carrier phase data (only pseudorange / doppler / SNR). CSRS-PPP can still process that. On the first run (3 hours of data, after a 20 minute self-survey ) it did reject 81% of the epochs. Sigmas were 3/2/5 meters. The GT87 outputs altitude as MSL, not WGS84. I just submitted a new 14 hour run (with the receiver doing a self-survey... not in position hold mode). - > I submitted 4 days (118-121) of RINEX files from an IGS station to CSRS-PPP, but with only the GPS C1, L1, and S1 observations. ___ 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] nuts about position (cheap receiver)
To give an idea about the possible improvement in antenna location available by post-processing the data, I first did a 2 hour self-survey and that put the receiver into position hold mode. Then I collected RINEX data for 16 hours. The post-processed lat/lon/alt values differed around 1/1/3 meters better than the self-survey values (with estimated error ellipses of 0.17/0.15/0.4 meters). Those results were with the "ultra rapid" orbits. It will be interesting to see what they look like when the final precise orbits are available in a couple of weeks. I also need to see how those values compare to Lady Heather's precision survey results. ___ 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] nuts about position (cheap receiver)
Woohoo! Success!I sent a RINEX 2.10 formatted .obs file generated by Heather from a Ublox 5 to Canada for post-processing. The results matched those from RTKLIB processing to within 1mm. Oh, and on noth cases the post-processing used the "emu" orbit info. I haven't heard back from Australia, but I think the file that I sent down under has some duplicate data block errors. ___ 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] nuts about position (cheap receiver)
The goal is to make it as simple as possible and have Heather do all the receiver configuring, data capture, and RINEX making... with none of that tedious mucking about in RTKLIB Currently all I have to do is fire up Heather and tell it to write a log file with the .obs extension. -- > RTKLIB's RTKCONV can convert between RINEX versions. ___ 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] nuts about position (cheap receiver)
I tried submitting Version 3 files to several services... none support Version 3!Heather now creates the uglier/less readable Version 2.10 RINEX, ___ 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] nuts about position (cheap receiver)
G... Canada lives in the dark ages and does not accept RINEX version 3... I'm now trying Australia... Version 3 is cleaner and easier to write than Version 2... ___ 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] nuts about position (cheap receiver)
For the orbits is says "Precise", so maybe not even the hourly ones. I could not find any mention of emu, emr, or igs. Heather can now spit out Rinex 3.02 files (at least for GPS/SBAS sats).I am currently feeding Heather the .raw capture file I sent to Canada and outputting a RINEX .OBS file. I'll send that off to them and see if there is any difference in the results from the one from RTKCONV. The RTKCONV processed values for pseudo ranges and carrier phase values seems to have been tweaked from what the receiver sent... they differ by a fractional amount. - > Was the solution using the NRCan hourly's or the IGS Rapid products ? (It should say in the email response or the .sum file: the 'Satellite orbits/clocks' lines seem to have 'emu', 'emr' or 'igs' for the NRCan hourly/UltraRapid, Rapid and Final solutions respectively). ___ 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] nuts about position (cheap receiver)
Well, I processed the Lady Heather .raw capture file from the $24 LEA-5T through RTKCONV and submitted it to CSRS-PPP and it worked. Using the less precise instant orbits it says the 95% sigma errors are: lat: 0.169m lon:0.148m alt: 0.399m My antenna is that Chinese L1/L2/Glonass/etc antenna from ebay. I'll re-submit the data next week and see how it changes. Also, I now sort-of have Heather outputting a RINEX 3.02 format .OBS file. Oh, and Bob... Heather can run an external program at a given time or after a specified interval, so could be set up to automatically submit the file... you lazy bastard ;-) ___ 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] nuts about position (cheap receiver)
There are some sellers on Ebay LEA-5T receivers on Ebay for cheap. They are pin and layout compatible with the Trimble Resolution-T devices. I bought a couple from this guy ($24 each) and they do output the RAW and SFRB messages. He also has LEA-4T and Trimble boards. There are also other sellers that are more expensive... search for LEA-5T https://www.ebay.com/itm/Ublox-LEA-5T-GPS-MODULE-BOARD/253584793155?hash=item3b0ad4de43:g:6CEAAOSwEZdZ7Z-7 I have not tried to post-process the data yet. I currently have Heather doing a raw data capture... ___ 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] nuts about position
I added some debug log info that shows how many bytes the receiver sent between time messages. The LEA-6T sends around 500-600 bytes every second. That fits easily into 9600 baud. The M8N tracking all sats and with all the raw messages enabled spews around 4000 bytes. That would require 57,600 baud. It looks like M8N's with standard firmware are not suitable for precise positioning. They do not output the required RAW data messages: https://rtklibexplorer.wordpress.com/2017/06/07/newest-u-blox-m8n-receivers-not-usable-with-rtklib/ Various GPS receivers handle transmit buffer overflows in different ways... including various combinations of dropping messages, garbling data, or crashing. Most receivers seem to have transmit/receiver buffers in the 1000 byte range... some are smaller, some are larger. ___ 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] nuts about position
Heather now requests the RAW and RAWX messages... those output carrier phase, doppler, and pseudo ranges.The M8N does not support either, but the M8T supports RAWX. Heather now requests the SFRB and SFRBX messages... those output the satellite navigation messages. All the M8's output SFRBX. I cranked up the M8N baud rate to 115200 and the receiver can handle all the various raw messages But the bugaboo is requesting the TRK-MEAS and TRK-SFRBX messages. The messages are not officially supported, Ublox forbids talking about them on their forums... they might even dispatch Ninja assassins if you talk about them. If you request those messages on the M8N very bad things seem to happen... you start receiving messages 0x27-0x00 with a length of either 68 bytes or around 1300-1400 bytes. Whatever 0x27-0x00 is, nobody's talking... The 0x27 message group is for security features like chip serial numbers. I have an M8T on the way from Germany... -- > I think heather is parsing the UBX_RAW_RATE messages for the raw GPS meansurements. The LEA-6T allows UBX_RAW_RATE, but the NEO-M8N does not. ___ 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] nuts about position
I once spent way too much time trying to get Heather to spit out a RINEX file from a Thunderbolt. I could never get any of the post-processors to accept it. The Thunderbolt's raw data needs to somehow be tweaked to be compatible and I didn't really know what I was doing. A LEA-6T seems to be able to cope with the data stream at it's default 9600 baud. I just tried a NEO-8N and it drops packets, etc. Even weirder, it does not output any of the requested packets that might be flooding the port, but still drops packets. --- > You mean that LH does not translate the data to the correct format *and* > submit it for post processing ? There *is* a lot of data when you turn all this stuff on. If you can get above 115K baud, it’s well worth it. ___ 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] nuts about position
Coincidentally, yesterday I tweaked up Lady Heather's Ublox code to enable all of the necessary raw data messages. Heather also enables the raw messages from Trimble TSIP speaking receivers, the NVS CSM24 receiver, and the Furuno GT87 receiver (if baud rate is >=115200). Heather can write a raw data capture file (/dr=filename on the command line or WY from the keyboard). You should be able to convert those raw capture files to RINEX and then post-process those. ___ 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] nuts about position
You will probably have a some difficulty finding a surveyor that does geodetic/mm accuracy surveys. Most surveyors that use GPS seem to work down to inches/a few cm. ___ 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] nuts about position
I don't know if you can easily see earth tides with a GPS... the post-processing services usually filter and correct them out. But, Lady Heather v6 can model and plot them (as lat/lon/alt displacements in mm). Also the vertical component of the gravity offset (in ugals) ___ 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] Cheap jitter measurements
Lady Heather v6 supports the TAPR TICC. It has most of the functionality of Timelab (but not as pretty), runs on Linux,etc, and can process both channel s(actually 4 channels if you have two TICCs). You can use it either as the main input device or as an auxiliary input device in conjunction with a GPS/GPSDO as the main input device. It also lets you configure the TICC. It does require the TICC firmware update released after the original batch of TICCs was released. ___ 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] nuts about position
When in was developing Lady Heather's precision survey code I was comparing the calculated positions to those from an Ashtech Z12 dual freq GPS (with the position calculated by OPUS). Using the same survey grade antenna and a Thunderbolt the results were usually within a meter. I have not tried it using a more modern GPS receiver. ___ 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] Better quartz crystals with single isotope ?
Single isotope diamond is 50% better thermal conductivity of normal diamond. It has been used in laser optics and thermal transfer applications (semiconductor heatsinks). I think the highest reported thermal transfer rate used isotopically pure diamond etched with micro-fluidic channels fed with coolant. GE makes the diamond material... it was developed as part of Reagan's Star Wars project. Isotopically pure silicon has 60% better thermal conductivity than natural silicon. Isotopically pure platinum has been used in RTD temperature sensors. ___ 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] Introduction & GPSDO Question
I'm not sure if Heather v5 works with all of those those receivers (I think you have what us known as a "UCCM" receiver... these are pulls from telecom equipment). If you are on Windows, you might want to try the v6 Beta code. Install the v5 from ke5fx.com, then download the v6 .exe from here: http://www.eevblog.com/forum/metrology/lady-heather-v6-beta-for-windows-exe/ Next, copy the v6 .exe in the .zip file to the directory you installed v5 in. You might need to start Heather with the /rxc command line option to force the "UCCM" receiver type. - > If so may want to try and connect it to your pc and use the Lady Heather > GPSDO monitoring program. ___ 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] getting accurate timing on RTL-SDR output
Note that on a lot of GPS devices that only one edge of the 1PPS pulse is stable and the other edge can jitter a bit. Also, you might want to try programming the PPS to a 50% duty cycle (but having an asymmetrical PPS pulse might have some advantages for post processing). The receiver with the best 1PPS stability that I have tested is the Furuno GT-8736. Its typical span is under +/- 4ns from nominal. ___ 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] RINEX for Android
Lady Heather will write raw data capture files from any of the devices that it supports. It can also read them in as a simulation file (except for "polled" receivers where you have to explicitly poll the receivers for each piece of data you want... the polling queries are not written to the receiver data capture files). Heather might not config the receiver to send some of the "advanced" messages you might be interested in, but it is easy to modify the code to request those. --- > So now I just need to get some binary files out of my GPS receivers. ___ 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] Holdover: Z3801A vs KS-24361
SS is signal strength. CN is carrier to noise ratio. They basically indicate the same thing, but their scale may be different. You can't compare the absolute magnitude of the values from different types of receivers, only do relative comparisons. Other receivers can report dBc, etc. And Trimble devices can report AMU (amplitude measurement units). Some Trimble devices don't support dBc readings. By switching a Tbolt between AMU and dBc, I worked out a table that Lady Heather uses to convert AMU to dBc to that those devices can display the more common dBc values. On the Trimble devices you set the signal level mask in AMUs. --- > the Satellite Status area has a header of SS on the Z3801A and C/N on the KS ___ 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] Environmental sensor recommendations
By comparing how much the DAC voltage changed with temperature. Heather can calculate the OCXO EFC sensitivity (Hz/volt). Combine that with the DAC setting and you get Hz/degree. --- > How did you measure temperature sensitivity ___ 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] Environmental sensor recommendations
I replaced the OCXO on one of my Thunderbolts with an Oscilloquartz 8663 and the temperature sensitivity went down by about 2/3, so I always assumed the main contributor was the OCXO. I didn't try mod-ing any other Tbolts. I also tried temperature stabilizing the power supply and it seemed to also have an influence. - > I respectfully disagree. The OCXO is not the temperature problem with the > Tbolt. ___ 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] Environmental sensor recommendations
Digital temperature sensors have some advantages (like nice factory calibration), but also so issues. The IIC/SPI ones need to be mounted to a PCB and also have quite a bit of thermal mass. They also need 4-6 wire cables. They are hard to attach directly to a point that you want to monitor. The advantage of thermistors is that they are small, cheap, readily available with leads attached, and only require a two wire cable. You can easily tape them to whatever point you want to monitor. The ADT7420 is $8 a pop + PCB + assembly + cable. Decent thermistors can be had for less than a buck. -- > Check out ADT7420: ___ 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] Environmental sensor recommendations
Long ago I did a board for evaluating high power LEDs and drivers. Iit was called Luxor and if you look through the Lady Heather code, you will see references to it. It has all the functionality (and them some) needed for an environmental sensor and temperature controller. It has 4 dual voltage IIC ports (with support for themocouples and Melixs IR thermometers (also LM75's and thermistors), 8 x 16 bit ADCs (or were they 12 bit?) , a couple of isolated hall effect current sensors, a 50 amp MOSFET 16-bit PWM'd at up to15 kHz, a four channel color sensor, a light PWM sensor, and a few other things. It collects data continuously at the sensor max data rate, averages readings over 1 second intervals, and streams the data at 1 Hz. That is the basic design I will probably use for my environmental sensor. As mentioned, themocouples are not good for this application. I'm leaning towards thermistors since they can be cheap (or expensive) and you can get small ones with low thermal mass. I'd like to do RTDs, but good interface chips can be pricey... plus the RTDs can be pricey and delicate. I think, that in this application, resolution is more important than absolute accuracy. The pressure sensor in the BME280 can detect an altitude change of under 1 foot. ___ 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] Environmental sensor recommendations
I looked at the TEMPer devices, but almost all of them seem to be HID devices that emulate a digi-monkey typing on a keyboard... tis' not something Heather wants to work with. Also, none of them seem to do air pressure. They do have a device that does temperature and humidity and can emulate a serial port. I could not find any info on how to talk to it and it costs more than the dogtaian USB-PA that also does pressure. > I use several of the TEMPer series. ___ 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] Environmental sensor recommendations
Lady Heather has a very nice temperature control PID in it (designed by Warren Sarkisen). It was originally designed to stabilize the temperature of a Thunderbolt GPSDO. The standard Thunderbolt OCXO is rather temperature sensitive. The standard/simple implementation involves sticking the Thunderbolt in a cardboard box with some thermal mass and baffling. Heather then PWMs a fan (at 1 Hz, using the serial port modem control signals and a DC solid state relay) to mix room temperature air into the box. It can control the temperature readings to around 0.01C with long term RMS errors in the low microdegree range (absolute accuracy depends upon the temp sensor). --- > I would suggest that if you are looking at taking temperature sensor data and attempting to control some type of heating/cooling device that you implement a PID loop for stability. ___ 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] Cheap jitter measurements
The TICC is a very nice device. A LOT of bang for the buck.Highly recommended. Lady Heather supports it (you can actually connect two for 4 channel operation) and can run under Linux. It provides most of the basic functionality of Timelab (with less pretty plots). ___ 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] Environmental sensor recommendations
I recently (mostly) finished adding external environmental sensor support to Lady Heather. You can use the sensor as the primary "receiver" device or in conjunction with any of the "receivers" that Lady Heather supports (except currently the HP-5071A which uses the same plot queue entries as the environmental sensors). Heather supports humidity, pressure, and two temperature values. I am currently using a dogratian.com USB-PA sensor with temperature, humidity, and pressure. I am also designing a Heather specific board (BME280, two thernistors, temperature controller interface, maybe a couple of ADC channels, etc). Are there any recommendations for other off-the-shelf sensors worth looking at? The main requirement is that the sensor should send data over a serial port or virtual serial port or maybe ethernet. Ideally it would stream readings at 1 Hz, but a polled device (like the dogratian.com devices) can be accomodated. Also, it would be very nice if the temperature sensors are small, responsive, and on leads that could be attached to whatever is being monitored. Attached is a screen dump of the USB-PA running. Can you spot the furnace cycling and sunrise? ___ 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] quartz / liquid nitrogen
And you want your semiconductors to be in ceramic/lided packages with the bond wires flapping in free air. Bond wires embedded in epoxy like to break... don't ask how I found this out ;-) ... it brings back bad memories... and makes bad memories... Quantum chips have very elaborate/specialized bonding to survive liquid helium... even with that, thermal cycling still breaks them. ___ 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] TV Signals as a frequency reference
Here's a local guy's take on monitoring time and DST errors on the stations in the Dallas area: http://home.earthlink.net/~schultdw/atsc/ ___ 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] TV Signals as a frequency reference
I read that there is a requirement that the time data in the PSIP data stream has to be within one second. I have an over-the-air DVR that would mess up the time and recordings because it was originally not filtering the times the stations broadcast. They finally modified the DVR firmware to do something like a median filter to throw out the outliers. A local TV guru beat up on all the local stations with a copy of the FCC rules to get the stations to broadcast the correct time. And don't me started on the ways the stations still mess up the daylight savings time transitions. Many are a month, week, or day off. --- > There is no requirement for us to inject time of any prescribed accuracy into the digital stream. ___ 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] New GNSS chipsets
I was measuring the jitter and adevs of the PPS signal from a GT-8736. GPS only seems to be slightly better (1-3 ns more span) than GPS+GLONASS. GLONASS only seems have around 50% more jitter than GPS only. Glonaas only adevs are 3 times as large as GPS only (at tau=1 seconds). - > It is indeed a benefit to use the different constellations. ___ 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] Lady Heather BST command line question
Ooops, that should have been /b=2 to select the European time zone rule! ___ 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] Lady Heather BST command line question
Try: /b=1 (sets European time change rule) /tz=0GMT/BST (sets time zone offset and names... and thats the number 0, not the letter O) It should then automatically switch between the time and time zone names according to the rule. For non-standard places, you can specify a custom rule. Check the comments at the start of heather.cpp for details (search for "daylight") ___ 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] GPS System Message (was: TV Signals as a frequency reference)
Or on the GPS/GNSS signals... I was verifying Lady Heather's support for the old SV6/Palisade/Acutime receivers and came across a mention of the "GPS System Message" command. It is requested by TSIP packet 0x28 and returns packet 0x48. Newer Trimble receivers (like the Resolution-T don't seem to support the 0x28/0x48 messages. It is only mentioned in the SV6 docs. The system message is a 22 character ASCII string embedded in the GPS navigation messages. If you dig into the GPS ICD docs it says it is used like a "bulletin board" for GPS users and can be a plaintext or encrypted message. They currently seem to be encrypted... perhaps a way to distribute P-code keys? I wonder if any of the newer GNSS sats have some hidden goodies in the signals? When sent to the SV6, you get a single response. When sent to a Thunderbolt, you get 31 messages (mostly all the same). I think the different messages are due to delays in the ground control system updating the satellites or the receiver not tracking particular satellites between updates. Here a couple of responses from a Thunderbolt: # GPS system message:X4W-BZXE3/HPU77G49PU1V # GPS system message:X4W-BZXE3/HPU77G49PU1V # GPS system message:X4W-BZXE3/HPU77G49PU1V # GPS system message:X4W-BZXE3/HPU77G49PU1V # GPS system message:X4W-BZXE3/HPU77G49PU1V # GPS system message:Z9Mx69BOC1 Lx+:LR3X2 Q # GPS system message:Z9Mx69BOC1 Lx+:LR3X2 Q # GPS system message:X4W-BZXE3/HPU77G49PU1V # GPS system message:X4W-BZXE3/HPU77G49PU1V # GPS system message:Z9Mx69BOC1 Lx+:LR3X2 Q # GPS system message:X4W-BZXE3/HPU77G49PU1V # GPS system message:X4W-BZXE3/HPU77G49PU1V # GPS system message:X4W-BZXE3/HPU77G49PU1V # GPS system message:X4W-BZXE3/HPU77G49PU1V # GPS system message:X4W-BZXE3/HPU77G49PU1V # GPS system message:X4W-BZXE3/HPU77G49PU1V # GPS system message:X4W-BZXE3/HPU77G49PU1V # GPS system message:X4W-BZXE3/HPU77G49PU1V # GPS system message:X4W-BZXE3/HPU77G49PU1V # GPS system message:X4W-BZXE3/HPU77G49PU1V # GPS system message:X4W-BZXE3/HPU77G49PU1V # GPS system message:X4W-BZXE3/HPU77G49PU1V # GPS system message:X4W-BZXE3/HPU77G49PU1V # GPS system message:X4W-BZXE3/HPU77G49PU1V # GPS system message:X4W-BZXE3/HPU77G49PU1V # GPS system message:X4W-BZXE3/HPU77G49PU1V # GPS system message:X4W-BZXE3/HPU77G49PU1V # GPS system message:X4W-BZXE3/HPU77G49PU1V # GPS system message:X4W-BZXE3/HPU77G49PU1V # GPS system message:X4W-BZXE3/HPU77G49PU1V # GPS system message:X4W-BZXE3/HPU77G49PU1V # GPS system message:E:S4.A2'3'A65/C5M8 UQO # GPS system message:E:S4.A2'3'A65/C5M8 UQO # GPS system message:E:S4.A2'3'A65/C5M8 UQO # GPS system message:E:S4.A2'3'A65/C5M8 UQO # GPS system message:E:S4.A2'3'A65/C5M8 UQO # GPS system message:5FT16X78CN53GVWVF1/8BW # GPS system message:5FT16X78CN53GVWVF1/8BW # GPS system message:E:S4.A2'3'A65/C5M8 UQO # GPS system message:E:S4.A2'3'A65/C5M8 UQO # GPS system message:5FT16X78CN53GVWVF1/8BW # GPS system message:E:S4.A2'3'A65/C5M8 UQO # GPS system message:E:S4.A2'3'A65/C5M8 UQO # GPS system message:E:S4.A2'3'A65/C5M8 UQO # GPS system message:E:S4.A2'3'A65/C5M8 UQO # GPS system message:E:S4.A2'3'A65/C5M8 UQO # GPS system message:E:S4.A2'3'A65/C5M8 UQO # GPS system message:E:S4.A2'3'A65/C5M8 UQO # GPS system message:E:S4.A2'3'A65/C5M8 UQO # GPS system message:E:S4.A2'3'A65/C5M8 UQO # GPS system message:E:S4.A2'3'A65/C5M8 UQO # GPS system message:E:S4.A2'3'A65/C5M8 UQO # GPS system message:E:S4.A2'3'A65/C5M8 UQO # GPS system message:E:S4.A2'3'A65/C5M8 UQO # GPS system message:E:S4.A2'3'A65/C5M8 UQO # GPS system message:E:S4.A2'3'A65/C5M8 UQO # GPS system message:E:S4.A2'3'A65/C5M8 UQO # GPS system message:E:S4.A2'3'A65/C5M8 UQO # GPS system message:E:S4.A2'3'A65/C5M8 UQO # GPS system message:E:S4.A2'3'A65/C5M8 UQO # GPS system message:E:S4.A2'3'A65/C5M8 UQO # GPS system message:E:S4.A2'3'A65/C5M8 UQO > I wonder how many secret services are parasites on the commercial TV transponders ___ 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] Teardown of Chinese made eBay GPS antenna.
I can confirm that they work well on Glonass and Beidou. I have not tried them on my Z12 with L2 signals. Last night a big lightning strike across the street took out a tree. Antenna survived without damage, but my antenna is on a 3 foot tripod on the ground... it was quite a brown-trousers producing, ear-ringing strike. BTW, the HP/Symmeticom 58517A antenna splitter/amplifier seems to work well with Glonass/Beidou. I don't think it does L2, 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] Setting correct date on Trimble Thunderbolt receiver
Thanks, excellent code to do the fixup on Arduinos, etc. Heather already has Julian <-> Gregorian routines that use double precision numbers and allows date/time tweaks to millisecond levels, so I used those. I am modifying the rollover adjustment code to not latch onto a specific rollover compensation value. That was originally done for a couple of old receivers that did things rather bizarrely. Subsequent improvements to the code made that no longer necessary. So now Heather will be able to recover from date/time issues due to bogus dates that occur during receiver startup. > Ah, more complicated math to solve a problem vs. simpler math to avoid a > problem in the first place. ___ 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] Setting correct date on Trimble Thunderbolt receiver
Lady Heather's automatic rollover fixer works by looking at the year in any time message that it sees. If it sees 10 consecutive year values less than 2016, it assumes the receiver has rollover issues and then adds 1024 weeks worth of seconds to the Julian date/time calculated from the receiver time/date message until the resulting year is past 2016. One problem with this is when a receiver is first powered up... most of them send dates in the 1980s to 1990s until they start tracking satellites. Once Heather detects a rollover condition, the code does not currently undo it if the receiver starts sending good dates. Heather keeps all times as a double precision Julian date. Using Heather's code can be a problem on Arduinos since their "double" precision numbers are actually 32 bit single precision, so you would need to do some more complicated math. Heather's rollover compensation value is actually in double precision seconds. You can manually specify a rollover correction to sub-second resolution and tweak the displayed time/date to anything you want... comes in handy for testing calendar/eclipse/sunrise/sunset/etc code. Speaking of rollovers, the GPS system has a 1024 week rollover next year (April 6th-7th). A lot of older receivers had code that could handle the first system rollover in 1999, but might have issues this time. ___ 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] Looking for information on True Position GPSDO.
When I dumped the flash rom from one of the TruePosition units, we found a couple of commands that seem related to OCXO learning. They are discussed a little in the thread on EEVBLOG. > If you *do* go swapping around OCXO’s (or whatever) on a GPSDO board, it’s very nice to be able to change the internal “magic numbers” to get the control loop running properly again. ___ 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] Looking for information on True Position GPSDO.
The magic word is $PROCEED. There is quite a bit of info about these on eevblog.com https://www.eevblog.com/forum/projects/gpsdo-loss-of-satellitesfix-troubleshooting/ Lady Heather v6 Beta supports these. If you have v5 installed from ke5fx.com, you can get the .exe for v6 from here or if you run Linux, macOS, FreeBSD, etc I can email you the source code to compile: http://www.eevblog.com/forum/metrology/lady-heather-v6-beta-for-windows-exe/ ___ 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] Furuno GT-87
The TICC reference is a HP-5071A cesium beam oscillator with high performance tube. The GT-87 is connected to the TICC channel B input. The TICC is running in timestamp mode. The orange plot is the Time Interval Error of the 1PPS signal... the difference between 1 second and the measured 1PPS. The grey plot is the accumulated phase error for channel B. I just finished the measurement of the GT87 running on GLONASS sats only. The PPS span was still in the +/-4 ns range with a couple of points +/- 6 ns. However the ADEV measurements on the 1PPS were 3 (at tau-100 secs) to 5 times higher. (at tau=1 seconds). I am typically tracking 5-8 GLONASS sats. The GT87 sends an "accuracy" value. In GLONASS only mode the GT87 reports an accuracy of 12 ns. With GPS enabled it tends to say 5-6 ns, but I have seen it as low as 2 ns. ___ 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] Furuno GT-87
I re-confgured the GT-87 to just use GPS satellites (the posted data had GPS, SBAS, and GLONASS enabled). The 1PPS span was mostly +/- 2.5 ns, with a few excursions to the +/- 3.5 ns range. I'll try GLONASS only next. I looks like Furuno is not going to add Galileo support to the GT-87 firmware. ___ 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] Power line frequency monitoring using a PICPET
I kludged up a very simple power line interface (3VAC transformer -> 10K resistor -> diode -> PICPET) and fed the (unfiltered) output into a PICPET. The PICPET was clocked using a 10 MHz TTL oscillator. I used Lady Heather to capture and analyze the data. It was measuring the time interval between 60 cycles on the input waveform and calculating the frequency error, phase, and xDEVs. It worked surprisingly well. Overnight the freq varied over a 0.0475 Hz range. Average freq was off by -0.005 Hz___ 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] Recommendations for Mains Power Monitor / Logger
Lady Heather v6 now supports the PICPET. I don't think it would like a 60 Hz input, though. When testing receivers with a high navigation rate (like over 20 Hz) it gets overwhelmed processing the data stream and updating the screen. It might work with the PICPET since the sole message that it sends is rather short. I have been meaning to try it. Or, perhaps I can add some code to skip some messages and get to a friendlier effective data rate. ___ 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] FURUNO GT-80 for Brandywine GPS-4
The GT80 is a family of devices including the 8031 and 8037. Perhaps posting a picture would help. ___ 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] FURUNO GT-80 for Brandywine GPS-4
I don't know which receiver is in the GPS-4. Open yours up and take a peek... I do know the GPS-4 uses $PFEC commands. I have a 8031 and Lady Heather works with it. I have an 8037, but don't know what command set it uses... yet. --- > Would these other modules be compatible with the controller and firmware in the GPS-4? I wasn't sure if they all used the same commands and responses. ___ 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] FURUNO GT-80 for Brandywine GPS-4
There are Furuno GT-8031's and GT-8037's listed on Ebay for cheap-ish. Tge 8031 is a small (around 1x1") module with an antenna pigtail with a H.FL connector on it. The 8037 looks like a Motoroa M12 board with a MMCX connector. ___ 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] Frequency deviations in Europe affect clocks
A more detailed explanation of what is happening: https://arstechnica.com/tech-policy/2018/03/ovens-across-europe-display-the-wrong-time-due-to-a-serbia-kosovo-grid-dispute/ ___ 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] TymServe TS2100 dead power supply
I once looked into adding IRIG generation to Lady Heather. I never came up with a reliable / robust way to do it. It could possibly be done with some of the Windows multi-media support, but that would leave the Linux/macOS/FreeBSD people in the dark. I just added TS2100 support to Lady Heather... but it only reads the time code output string and drives the clock displays. I don't have a TS2100 to properly test it, but it works when fed with a simulation file. > RANDOM QUESTION -- does anybody know of software to *generate* IRIG time > code? Something in C that's adaptable to a modern micro would be good. In > something like a Raspberry Pi 3, IRIG generation would make a nice addition > to Lady Heather... ___ 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] Ultra low power RTC
A friend of mine is a product engineer for one of the largest (the largest?) makers of RTC chips. He groans about the (rather pointless) quest for the lowest power RTC chips. Making robust, stable, accurate oscillators that run at nanowatts is a losing proposition. At those levels external factors can wreak havoc. And he blames crystal makers for a lot of problems... batch X works great, batch Y is wonky, batch Z is utter crap. Pretty much the same for load capacitors. Eventually users come to their senses and go with a robust, slightly higher power device. ___ 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] Ultra low power RTC
Probably 20+ years for a lithium coin cell... basically the shelf life of the cell. I have a card of 24 year old CR-2032's that are still above 3V, and no sign of leakage. BTW, never handle a coin cell (particularly in watch applications) with your fingers... your grubby fingerprints are rather conductive and can discharge a cell surprisingly quickly. Also note the clock chip has 512 bytes of RAM in it. > Assuming you are going to run it off a battery. What’s the self discharge rate on a reasonable battery? ___ 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] Ultra low power RTC
Sparkfun is selling an interesting RTC clock chip board. It draws 22 nA. It has a rather novel clock generator... a tuning fork crystal disciplines an RC oscillator every few minutes. They claim 3 minutes per year drift. https://www.sparkfun.com/products/14642 ___ 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] Z3801A OCXO manual trimming
I'm not sure what the Z3801A uses for EFC range. Heather uses the EFC relative command to report the EFC setting. That command reports values from -100% to 100%. There is a command that reports the DAC input in counts, but nothing documented that shows volts/count. Since the DAC is at -2V with a 99+% DAC setting, it looks like the DAC circuit has issues, or power supply problems. I think the DAC circuit is a 16 bit DAC with 4 more bits of resolution created by dithering the DAC inputs. ___ 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] TymServe TS2100 dead power supply
First check for power / ground shorts on the power supply outputs with an ohm meter. There is a good chance of a shorted tantalum cap somewhere in the system shutting down the supply. If the power supply is connected to the system via a connector, disconnect it from the system and see if the supply puts out anything. ___ 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] Z3801A OCXO manual trimming
Or, it you are sure it's the OCXO, go shopping for a new one.There is a reputable seller with them (the double oven version) for $100 on Ebay. A couple of things to try... monitor the EFC voltage, power up the unit, and see if it is changing as it attempts to lock. If it does not, you may have a DAC problem... I don't think the Z3801 remembers the last DAC voltage to speed up the initial lock, so it should be searching for the lock voltage. Also monitor the OCXO output and see how it changes as it warms up. It should start out several Hz off and converge to 10 MHz as it warms up. > Either tear into the OCXO or go shopping for a new(er) GPSDO. ___ 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] WWV or Net Clock controlled oscillator
I've been known to use the egg timer mode in the kitchen... I get distracted easily and burned food has been known to occur. Due to system vagaries, it is probably only accurate to say 30 milliseconds (better on Linux, of course), so less than perfect eggs are possible. I've thought about letting the alarm set a modem control line so that you can control an automatic egg extractor device. The egg timer can be configured to sound the alarm file once, or repeatedly until you stop it. It can also be set to automatically re-start a new countdown. The alarm clock can be set with a time, a date, or a date/time. When set with just a time, it will trigger every day at that time. If the time you set is less than the current time, it triggers on the next day. Currently you can only set one egg timer and one alarm time... I'm thinking of adding support for multiple timers so you can cook more than one thing at a time. I did add the ability to add an alarm time to the greetings calendar events. I might add the ability of things like the equinox events to automatically fill in the proper alarm time. Heather can also play sounds at sunrise, sun transit, and sunset (or moonrise/moon transit/moonset). The default is a rooster at rise/set and church bells at solar noon. > because doesn't everyone time their soft boiled eggs to the microsecond? ___ 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] WWV or Net Clock controlled oscillator
The university that I hang out at has a clock tower with a full set of bells. Several years ago the tower and bells were restored, at hefty expense. But, alas, some no-goodnik neighbors objected to the sound, so they cut back the use of the clock. I don't know what system they use to get the time and sound the bells. The bells can also be played from a keyboard (used to be done by a professor in the electrical engineering department until he passed away). It's rare to hear the bells played anymore. Lady Heather has support for several audible clocks. The simplest in the v6 Beta code is a tick clock. Ticks on the second and beeps on the minute. This ticks/beeps are compensated for the delays/offsets in the GPS time message. This mode is intended for doing things like setting mechanical clocks. There is a Ships Bells mode that sounds the time in ships bells format. There is a cuckoo clock mode. There is a singing clock that can be configured to play .wav files at various minutes past the hour. The default config plays passages from the Palestrina, Missa Assumpta est Maria. I've been meaning to add a Big Ben mode that allows both playing a file on the hour and then chiming the hour (a cross between the singing clock and the cuckoo clock). The easiest way to do that would be to have 12 separate hour files. Besides those clocks Heather has alarm clock and egg timer alarms. ___ 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] X72 and 1pps
> I can´t find this option - I can toggle the PPS output, but not the input. OK, I remember now... the X72/SA22 with firmware disciplining have a bit in the control reg that reports if a PPS input has been seen. I found some obscure reference that implied you could disable the PPS input, but that did not work, so I removed that option. > BTW, what´s the "set TIC" option? I can enter a number here, but I can´t find something about this command in the manual... The SET TIC command issues the X72 "k" command to set the TIC offset register. It is used to null out offsets in the value of the TIC register. Note that this command takes 6 seconds to complete. > What´s the expected behaviour if I go to d-e: "Enable HW discipline" ? I > can´t see any changes here. First, you need to have the PPS output enabled for disciplining to work. Then you have to pray to the Gods of X72 Crapitude that the hardware disciplining works. You need a good PPS input. It can take a long time (or forever) for the X72 to decide the PPS is good enough to use. I have had a lot of issues getting the firmware discipling to work. ___ 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] Z3801A OCXO manual trimming
Oops... I checked and the Z38xx devices don't have a DAC setting command. It was the UCCM GPSDOs that have a SCPI command for controlling the DAC manually, - > When I press "D" Lady Heather replies: Manual disciplining not supported by this receiverpress ESC ___ 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] Z3801A OCXO manual trimming
Lady Heather has a command that lets you set the DAC voltage. It's in the "D" menu. Depending upon the firmware, you may need to disable disciplining first (also in the "D" menu). If the DAC command works to change the OCXO freq, the osc EFC and DAC are probably OK. If it does not, I'd suspect the DAC or the osc EFC input... or perhaps your firmware does no support the DAC setting command. ___ 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.
