[time-nuts] Clock project request from IEEE
Lady Heather has a feature designed just for this application. The TS keyboard command (and the /ts? command line options) allow setting the system clock from the time message sent by a GPS receiver (assuming the program has permission to set the clock). This typically gets the system time set to under 50-100 msecs. There are several issues that had to be overcome to make this work properly... the main one was characterizing and compensating for the delay / offset between when the GPS time message arrives at the computer and the actual time encoded in the message. I characterized the "time sync offset" for all the receivers that Heather supports and the program applies those default values. You can also set the value manually (/tsx=) if your receiver / configuration / system / serial port does not match the default value. The TS keyboard command sets the clock on demand. The various /ts? command line options let you set the clock on a scheduled basis or whenever the system clock and GPS time diverge by a specified amount. The big disadvantage of Heather's clock setting algorithm is that the time set is a rather dumb "jamsync:" of the time... there is none of the smooth, monotonic clock adjustment that things like NTP do. Jamming the time in can screw up file system time stamps, etc (hey! new file write looks like it occurred before an older file write, etc). But, if you in a place without internet access it works quite well. I develop Heather on a Windows XP box that is NEVER connected to the internet... the system clock drifts around a second per day. - > This does have an application that I've recently experienced, manually setting the time on a PC that's used for amateur radio digital (FT8) communications which require the computer's clock to be accurate within 1 second. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Clock project request from IEEE
I've looked at automatically determining the local time zone offset from UTC a few times... and always considered jumping off a cliff to be a better option. Huge, unreliable, always changing boundary data bases... local anomalies due to political reasons... lotsa really boring testing and verification, etc. So, Heather just lets the user tell it what the local time zone and daylight savings time rule is. Ahhh, the sweet, sweet bliss of shuffling off a complex, error prone something onto the user... I did consider (if the user did not specify the time zone) to default it to assume every 15 degrees longitude was a 1 hour time zone. Sort of like Heather's algorithmic guess of the current leap second count (GPS-UTC time offset value) if the receiver / input device does not send a UTC offset value... it's not always right but is better than nothing. If it's not right the user can specify the correct value. Guessed values are shown on the screen in red, user specified values are shown in yellow, device supplied values are shown in white. Speaking of which, aren't we getting close to needing a new leapsecond... it's been a while since the last one? > Maybe Lady Heather could use that to find local time (if she doesn't already do it). ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Venus timing receiver PPS output
I recently add the ability to Lady Heather to monitor a PPS output and apply sawtooth correction sto the measured PPS and log the results. The Venus timing receivers tout a PPS output with +/- 6 nsec PPS jitter and sawtooth corrections. Alas, the PPS output does not appear to meet this claim. The latest receivers that I tested were the Venus/Navspark/Sayer timing receivers that use the Venus GPS timing receiver chip. I was measuring PPS jitter on the order of -26/+32 nsec, which a +/-6 nsec sawtooth correction message has little useful effect on. Plotting a histogram of the measured PPS values shows several humps in the histogram that are spaced 12 nsec apart. It seems that their PPS generator has some issues deciding just which clock cycle to trigger on.___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Correcting measured PPS values with receiver sawtooth correction values
The F9 has a totally new internal architecture / processor, so it's best to make no assumptions about how it works compared to older models. For the LEA-6T the correction strategy is clearly "add previous sawtooth value". That does not work for the F9P. The two candidates for the F9P are "add current sawtooth" or "subtract previous sawtooth". I had been favoring "subtract previous" but some more detailed analysis seems to favor "add current". The difference between the results of the two strategies is rather subtle and it is very hard to determine which is the correct one. > I don't think that uBlox changed the defaults over their previous generation, so whatever worked for the M8 series should be applicable here. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Correcting measured PPS values with receiver sawtooth correction values
I am adding the ability to Lady Heather to apply receiver sawtooth correction
values to measured PPS values... this requires having a receiver that outputs
sawtooth values as the main input device and connecting a TICC/counter
measuring the receiver PPS output as an auxiliary input device.
There are six different ways of calculating the corrected PPS value:
add/subtract the previous/current/next sawtooth value from the measured PPS
value. The combination that works properly depends upon the receiver and
counter. It is easy to find the correct combination by trying each one and
seeing which one produces the "best" results ("best" being determined by which
one had the lowest corrected PPS span, average, sdev, variance, etc).
For all the receivers that I have tested there is only one combination that
jumps out as being the correct one. However, for the new Ublox F9P, there are
two combinations that produce virtually identical measurements and statistics
(add current sawtooth or subtract previous sawtooth). Any ideas on how to
determine which combination is the "correct" one?
___
time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe, go to
http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
and follow the instructions there.
[time-nuts] Lucent RFTGm-II-XO / Lucent RFTGm-II-Rb / NT BW50AA
On some GPSDOs (like those made by Trimble that speak TSIP) you can disable disciplining. Doing this usually reduces phase noise on the outputs, but in this mode the frequency will drift over time. A lot of hams normally keep disciplining on and turn it off when they are driving a radio. The oscillator in the "gold box" Thunderbolts (like those bought from TAPR) have oscillators that tend to have rather good phase noise characteristics. -- >None of the GPSDO’s out there are great for multiplying direct to microwaves. >It’s not so much the phase noise as all the spurs (though phase noise does vary a bit). ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] F9T, was Re: Ublox F9P PPS output
Hopefully if Sparkfun does a F9T, they will bring out a pad for TIMEPULSE 2. On the F9P, I have been unable to change the settings for TIMEPULSE2... maybe the F9P does not actually support it even though is is mentioned in the docs. Sparkfun has their SPARKX division that does short runs of boards that are experimental or not mass-market devices... they might do an F9T that way. Maybe some time-nut suggestions will influence them to do a F9T. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Ublox F9P PPS output
I got in a Ublox F9P multi-band receiver from Sparkfun. Lately I've been testing the 1PPS output. This data is from the F9P tracking GPS and GLONASS L1 and L2. The PPS was measured by a TAPR TICC clocked by an HP-5071A. BTW, processing the raw F9P measurement data with CSRS-PPP produces lat/lon/alt location error ellipses in the 5/10/20mm range with my horrible antenna location. Bob got 3/6/12 mm. The GREEN plot is the PPS output from the F9P. The ORANGE plot is that value adjusted by the sawtooth correction. The BLUE line is the PPS ADEV plot. It is interesting that the reported F9P sawtooth values don't average to 0.000 nsec. # # Device: Ublox F9P receiver # # Unit type: TAPR TICC # Serial number: # Firmware ver: # Board ver: # EEPROM ver:0 # Mode: Timestamp # Ref clock: HP-5071A # # # Unit type: Ublox F9 receiver # SW:EXT CORE 1.00 (eba0dc # HW:0019 # ROM 1: ROM BASE 0x118B2060 # ROM 2: FWVER=HPG 1.10 # ROM 3: PROTVER=27.10 # ROM 4: MOD=ZED-F9P # ROM 5: GPS;GLO;GAL;BDS # ROM 6: QZSS # # # PPS ADEV for 84955 points - sample period=1.000 secs - bin count:14 # 1.000 tau 3.4621e-009 (n=43197) # 2.000 tau 1.7355e-009 (n=43195) # 5.000 tau 6.8783e-010 (n=43189) # 10.000 tau 3.4520e-010 (n=43179) # 20.000 tau 1.7183e-010 (n=43159) # 50.000 tau 7.0574e-011 (n=43099) #100.000 tau 3.6007e-011 (n=42999) #200.000 tau 1.8072e-011 (n=42799) #500.000 tau 7.2585e-012 (n=42199) # 1000.000 tau 3.6834e-012 (n=41199) # 2000.000 tau 1.8453e-012 (n=39199) # 5000.000 tau 7.4818e-013 (n=33199) # 1.000 tau 3.5851e-013 (n=23199) # 2.000 tau 1.6814e-013 (n=3199) # # PPS HDEV for 84955 points - sample period=1.000 secs - bin count:13 # 1.000 tau 3.6499e-009 (n=43196) # 2.000 tau 1.8313e-009 (n=43193) # 5.000 tau 7.2455e-010 (n=43184) # 10.000 tau 3.6413e-010 (n=43169) # 20.000 tau 1.8064e-010 (n=43139) # 50.000 tau 7.4202e-011 (n=43049) #100.000 tau 3.7939e-011 (n=42899) #200.000 tau 1.9034e-011 (n=42599) #500.000 tau 7.6306e-012 (n=41699) # 1000.000 tau 3.8724e-012 (n=40199) # 2000.000 tau 1.9281e-012 (n=37199) # 5000.000 tau 7.8140e-013 (n=28199) # 1.000 tau 3.5864e-013 (n=13199) # # PPS MDEV for 84955 points - sample period=1.000 secs - bin count:13 # 1.000 tau 3.4621e-009 (n=43197) # 2.000 tau 1.2295e-009 (n=43194) # 5.000 tau 3.0416e-010 (n=43185) # 10.000 tau 1.0540e-010 (n=43170) # 20.000 tau 3.8724e-011 (n=43140) # 50.000 tau 1.5815e-011 (n=43050) #100.000 tau 7.9180e-012 (n=42900) #200.000 tau 3.5732e-012 (n=42600) #500.000 tau 1.1746e-012 (n=41700) # 1000.000 tau 5.9070e-013 (n=40200) # 2000.000 tau 3.3584e-013 (n=37200) # 5000.000 tau 1.4796e-013 (n=28200) # 1.000 tau 5.1583e-014 (n=13200) # # PPS TDEV for 84955 points - sample period=1.000 secs - bin count:13 # 1.000 tau 1.9989e-009 (n=43197) # 2.000 tau 1.4197e-009 (n=43194) # 5.000 tau 8.7803e-010 (n=43185) # 10.000 tau 6.0855e-010 (n=43170) # 20.000 tau 4.4715e-010 (n=43140) # 50.000 tau 4.5654e-010 (n=43050) #100.000 tau 4.5714e-010 (n=42900) #200.000 tau 4.1260e-010 (n=42600) #500.000 tau 3.3908e-010 (n=41700) # 1000.000 tau 3.4104e-010 (n=40200) # 2000.000 tau 3.8780e-010 (n=37200) # 5000.000 tau 4.2712e-010 (n=28200) # 1.000 tau 2.9781e-010 (n=13200) # # # PPS MTIE for 32768 points - sample period=1.000 secs - bin count:16 # 1.000 tau 6.5166e+000 (n=32768) (nanoseconds max time interval error) # 2.000 tau 6.5166e+000 (n=32766) # 4.000 tau 6.5166e+000 (n=32764) # 8.000 tau 6.5166e+000 (n=32760) # 16.000 tau 6.5166e+000 (n=32752) # 32.000 tau 6.5166e+000 (n=32736) # 64.000 tau 6.5166e+000 (n=32704) #128.000 tau 6.5166e+000 (n=32640) #256.000 tau 6.5166e+000 (n=32512) #512.000 tau 6.5166e+000 (n=32256) # 1024.000 tau 6.5166e+000 (n=31744) # 2048.000 tau 6.5166e+000 (n=30720) # 4096.000 tau 6.5166e+000 (n=28672) # 8192.000 tau 6.5166e+000 (n=24576) # 16384.000 tau 6.5166e+000 (n=16384) # 32768.000 tau 6.5166e+000 (n=1) # # # # Plot statistics: # # Sawtooth: # rms: 2.257634439 ns # avg: -0.109084539 ns # sdv: 2.254997522 ns # var: 5.085013825 ns # min: -4.04700 ns # max: 3.80800 ns # span: 7.85500 ns # # Tpps: (measured PPS deviation form 1. seconds) # rms: 3.255180518 ns # avg: 0.000165522 ns # sdv: 3.255180514 ns # var: 10.596200180 ns # min: -8.712959243 ns # max: 8.774804883 ns # span: 17.487764126 ns # # Tadj: (PPS measurement adjusted for sawtooth error) # rms: 2.305958761 ns # avg: -0.108871574 ns # sdv: 2.303387242 ns # var:
[time-nuts] HP Stories: Battery Chargers, and a fading idolization of HP
Back in the late 70's I worked for a mini-computer company. They were a horrendous paper-work factory... spec after needless/useless/virtually identical documentation requirements. I wrote one document where I put all the timings in units of "ffn"... femto-fortnights. It was over three years later that somebody asked me what a "ffn" is. After 5 years, he and I were the only people to ever request a copy of that document. -- >“Hey, no one will notice that the stamping on the transistor doesn’t match the >parts list. I’ll bet no one will look at this schematic carefully anyway. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Rooftop antenna and splitter
You will need RINEX v3.x format to take advantage of the F9 multi-GNSS data. CSRS-PPP seems to be the only online service that takes v3 data. Also they seem to only handle GPS and GLONASS at the moment. I have an F9P on order, but Fedex seems to be taking their sweet time (says 2 weeks to go from Colorado to Texas). When it gets here it should not take too long to get Heather working with it. > Off to figure out how to get the F9P data into RINEX …. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Rooftop antenna and splitter
I don't know if that Chinese multi-band antenna needs a ground plane/pizza pan. My antenna mount tripod has one handy, so I am using it.My first tests were without the pan and I didn't notice any before/after differences but did not do any extensive testing. The CSRS-PPP position error ellipse results were pretty much the same. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Rooftop antenna and splitter
This is the antenna that I am now using. I do have it mounted over an 18" pizza pan... I don't know if that does any good, it seemed to work fine without it. https://www.ebay.com/itm/CORS-RTK-GNSS-Survey-Antenna-high-gain-measurement-GNSS-GPS-GLONASS-BDS/253786590956?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m2749.l2649 ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Connector help?
Before I got my multi-band splitter/amp I was using a HP-58517A 8 channel unit. It worked reasonably well with GLONASS and BEIDOU L1. GLONASS signal was a bit degraded and you would lose a few satellites. I could even track GPS L2 with an Ashtech Z12, but the L2 carrier phase / pseudorange data was rather iffy and getting a good L1/L2 position solution was rather difficult. --- >Since the HP splitter will knock out everything that is not right on top of >GPS, are you sure you want to go that route? ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Rooftop antenna and splitter
I'm currently using one of those sub-$100 Chinese multi-band antennas. It works quite well. With a L1/L2 survey grade receiver I get position error ellipses in the 6-10 mm range (amazing considering my horrible antenna/multipath environment). Antenna feed is 50 feet of RG6 coax. It feeds a multiband S18-NF 8 channel amplified splitter that I bought off of Ebay for $300. https://www.ebay.com/itm/Brand-New-GPS-Source-p-n-S18-NF-GPS-8-Way-Splitter/323647194793?hash=item4b5ae046a9:g:d~AAAOSw9OFZNNxC:rk:89:pf:0 ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Frequency standard
Most of the UCCM devices don't store the position. They do a survey every time they power on. The Samsung devices also seem to do a survey after extended periods of holdover. Some of the Trimble (or is it Symmetricom) units will save the survey position in EEPROM. I recently did a comparison of 17 different models of GPSDOs. The Samsung UCCM device performed quite well... it's currently my favorite "set it and forget it" GPSDO. Note that my antenna position is rather horrible (antenna 1 m above ground, lots of trees, 2 story house 20 feet west of the antenna) so these comparisons provide a good idea of what is possible in sub-optimal conditions. http://www.eevblog.com/forum/metrology/comparing-the-performance-of-17-different-gpsdos/msg2025283/#msg2025283 TVB did some more processing of the raw data through Timelab and came up with some very nice plots of the results: http://leapsecond.com/u/sims/gpsdo17/ > I recommend the UCCM boxes for you because they are pretty well automated; when first connected they do a self survey, store the position they find and then start to output very accurate 10 MHz and 1 pps signals, all with no outside intervention. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Ublox F9P multi-band GPS receiver
Here is a list of the signals that the M9P can process: GPS L1C/A GPS L2 CL GPS L2 CM Galileo E1 C Galileo E1 B Galileo E5 bI Galileo E5 bQ BeiDou B1I D1 BeiDou B1I D2 BeiDou B2I D1 BeiDou B2I D2 QZSS L1C/A GLONASS L1 OF GLONASS L2 OF With 2 L2 GPS signals available, the lack of GPS L5 is probably not a big deal... ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Ublox F9P multi-band GPS receiver
All the Ublox timing receivers output carrier phase and pseudorange data, so I suspect the F9T will also. Heather can directly write a RINEX file that can be submitted to CSRS-PPP for a precise (say 100 mm) position using L1 only data. For L1/L2 data you have more online processing options available and should get maybe 10mm precision. I'll probably have to improve the RINEX v3.xx writer in order to better handle L2C and L5 data... also may need some code changes to handle the L2 data from the Ublox messages. -- > I think an important question is if the T version still outputs carrier phase on all the signals. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] TICC question
Heather can run on Windows, macOS, Linux (including the RasPi) and FreeBSD. Check the first post of this thread. There is a link to the X11 version source code (also download the attached heather.txt file that contains the documentation). That .zip file also has a pre-compiled binary for macOS. Check the readme.txt file for installation instructions (you need to set some permissions). You will need to install the XQUARTZ package to run it on a mac. http://www.eevblog.com/forum/metrology/lady-heather-v6-beta-for-windows-exe/ > Ah, but I have a Mac, and Heather apparently isn't fond of that environment, ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] TICC question
You can send it a '#' to get back to the config menu. Or use Lady Heather to control it and log data captures. The 'P' keyboard menu has most of the config commands. Heather (and the '#' command won't work with the original firmware release... you may need to upgrade the firmware. Are you sure you selected PERIOD mode... it works fine here? ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Ublox F9P multi-band GPS receiver
That looks like the antenna that I am currently using. The were mentioned on the list last year, but the cheap ones quickly disappeared and the price went to $250-$300. The seem to work very well. I get 6-10 mm error ellipses using L1/L2 GPS on a Trimble NetRS. They have no problem with Glonass/Galileo/Beidou on a M8T. - > My first though was that something like this: https://www.ebay.com/itm/CORS-RTK-GNSS-Survey-Antenna-high-gain-measurement-GNSS-GPS-GLONASS-BDS/253786590956?hash=item3b16dc0eec:g:p8sAAOSwu7hbNoe0:rk:1:pf:0 ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] GPS satellite orbits (was: Calculating sidereal time)
I also expected that, but when I added the ability of Lady Heather to plot the SNR/az/el/carrier phase/pseudorange of a given satellite, I found that they repeat every 24-ish hours. At 12-ish hours the SNR and time the receiver had usable signal was greatly reduced. >The main reason is the GPS satellites come close to following the same ground >track. So I'd expect the elevation and azimuth to a given SVN to be the same on a 12 sidereal hour basis.___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Ublox F9P multi-band GPS receiver
> It is clearly multi-band for GPS. It is unclear from a quick read if it is > multi-band for the other systems. Here's what they say it supports: 184-channel u-blox F9 engine GPS L1C/A L2C, GLO L1OF L2OF, GAL E1B/C E5b, BDS B1I B2I, QZSS L1C/A L2C Here's the link to the Sparkfun device. I think it uses a u.FL antenna connector. https://www.sparkfun.com/products/15136 ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Ublox F9P multi-band GPS receiver
Sparkfun is now selling the Ublox F9P L1/L2 GPS receiver module on a board ($219). The F9P supports GPS/Galileo/Glonass/Beidou and tracks L1/L2 data. It outputs carrier phase data and has survey-in and fixed position support along with RTK support (10 mm accuracy). Looks like the F9P has 1 time pulse output. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Ublox Neo M8T no output on TP2 question, please?
The official RPi touchscreen mounted in a Smartipi case (with the extended back cover) works very well. That's how I have my alarm clock configured. The GPS and a backup battery are mounted in the back cover. I once hacked up a version of Heather that does the singing clock during the day but silences that when the alarm is enabled... I need to resurrect that. I'm thinking about putting a TAPR TICC in one. I tried putting a Samsung UCCM GPSDO in one, but it wouldn't quite fit... looking at 3D printing for that. Also, the latest version of Heather supports Winchester chimes (if you supply your own sound files). For the nautically inclined there is the ship's bell clock. My office clock (and probably 3 or 4 other Heathers running at the same time) does the snippets from the Tallis Scholars Missa Assumpta. --- > have plans for an RPi / uBlox / audio amplifier / speaker installation for > the office with the cuckoo clock enabled. :) ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Tuning a Thunderbolt
Oooh, very nice, the full monty of tuning goodness!After doing all that you can spend countless hours tweaking things in search of maximum time-nut-goodness... I'm not sure that a 96 hour precision survey is measurably better than 48 hours, but what the heck, might as well go for it. -- >After that week, I believe the correct procedure is: - Set the elevation mask angle to 0.0 (fe, 0.0) & signal level mask to 1.0 (fl, 1.0) - Clear and let run for a 6-12 hours (cm) - Run a site precision survey (/sp=96) - Autotune the DAC () - Save to EEPROM (ee) ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Calculating sidereal time
When I was playing with the sidereal time code I found lots of buggy/bogus implementations and also lots of web calculators that were either totally wrong or off by some amount.Same for sunrise/sunset code and equation-of-time code. It's hard to know what code / sites you can trust. Heather could be off... A lot of the web based ones seemed to have their system clocks not all that accurate. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Calculating sidereal time
Check out the sidereal code in Lady Heather (it's in heathmsc.cpp) and see if anything looks usable. Heather uses double precision floating point for all the time functions. To display sidereal times set the time zone to GMST, GMAT, LMST, or LAST. Also, if you are doing integer arithmetic, check very carefully for overflows, etc. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] New Lady Heather Beta release
I have updated first post on the thread on EEVBLOG.COM to version 6.14 Beta. It has the Windows .exe file attached and also a link to download the source code and Linux/MacOS/FreBSD build package. This update includes support for Trimble receivers that speak RT17 (such as the NetRS), the Samsung "UCCM" GPSDOs, an RPN calculator function, support for small (480x320) screens, and a few bug fixes and cosmetic improvements. http://www.eevblog.com/forum/metrology/lady-heather-v6-beta-for-windows-exe/msg1434005/#msg1434005 ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Misuse of word "decimate" (was Re: Short term 10MHz source)
Yes, my use of "decimate" was not a good one. I was going to use "round", but the previous discussion sort of implied to me that the least significant data values were just going to be chopped off and not rounded. "Truncate" would have been better, but the word eluded me at the time. Since it was mentioned to get the data to 10 ps resolution, the word "decimate" sprang from my addled mind to my finger tips. Anyway, I am a great fan of reporting sensor data to the full resolution/values that the device/calculations generate and not massaging it further. You never know if anything useful might be hiding in the "grass". Report the data as collected and let the users process/filter/truncate/modify/smash/bash it as they see fit. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Short term 10MHz source
Lady Heather has a TICC tuning feature ( keyboard command) that sets the channel offset, etc values. You connect a 1PPS input to both channels via matched cables and a "T" adapter. Heather calculates and sets various parameters. And as far as decimating the TICC output values in firmware... please don't. Let the user decimate the values if they want to. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Short term 10MHz source
Lady Heather also supports the TICC. The TICC can be the main input "receiver" device and/or an auxiliary input device. With two TICCs connected you can process four channels of data. Heather lets you configure the main input device TICC parameters and also has the ability to "tune" the TICC channel offsets, etc. - >The TICC talks to a host computer using ASCII on USB. John Miles' TimeLab software can read data directly from it, or you can just save the data as a text file with a terminal program ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Lars Walineus
It is with great sadness that I announce the passing of my friend and fellow time-nut Lars Walenius. Lars was a wonderful person that was always willing to share his knowledge and offer help to anybody that asked. He is probably most famous here for his "Lars GPSDO", a very simple and low cost TIC (with 1 ns resoulution) and GPSDO. He was also famous for his work in temperature compensating voltage references. He will be greatly missed... http://www.eevblog.com/forum/metrology/farewell-to-our-friend-lars/ ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Atomic Clocks: It is important that they keep good time, Part 1
Lady Heather does have an audible "tick" clock mode. It ticks on the second and beeps on the minute. The ticks and beeps are fairly well synchronized to true time. You can also set the clock name displayed on the analog clock display... Mine is usually set to Patek-Philippe. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] FCC OTA pre-emption and restrictions on GPS antennas [was: Short term 10MHz source]
A friend of mine has his GPS antenna disguised as a bird feeder... ground plane is a pizza pan. Antenna mounted at the top of a clear tube filled with bird food... alas, no holes for the birds to get to the food. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] More ES100 WWVB Measurements
Lady Heather has DST code. It has rules for USA, Europe, and Australia or the user can specify a local rule. The code is not very complicated, but getting it right (and testing) can be tricky. >Has anybody looked into how much code it takes to implement DST? ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Trimble NetRS PPS output
I recently got in a Trimble NetRS L1/L2/L2C survey grade receiver (Evil Uncle Bob made me do it ;-) ). It consistently gives position error ellipses in the 6mm range after post-processing 24 hours of data. I had high hopes it would have a decent 1PPS output... nope. The PPS output usually has a 40 nsec span (looks like a 25 MHz clock is in the device), with some occasional 80 nsec or so spans. The internal oscillator looks to be an OCXO... the PPS does not show your typical wobbly PPS sawtooth error plots. It is more like a pulse train with a slowly drifting duty cycle. But the killer is the occasional (2-3 times per hour) "zingers" in the PPS output. These show up as a large negative error spike followed immediately by an equal positive errors. These "zingers" are typically in the 1-100 millisecond range. I can't imagine how/why the circuitry would do this... Lady Heather can now monitor the NetRS (and probably other receivers that can output RT17 and Trimcomm data. The NetRS does not respond to requests for status and configuration commands over the RT17 ports, so a lot of useful/informative stuff is not available. It can write RINEX files.___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Comparing the performance of 17 different GPSDOs
I recently completed some comparison tests of the PPS and 10 MHz outputs of 17 different GPSDOs. The tests were done with a TAPR TICC time interval counter running in timestamp mode and the data was acquired and processed with Lady Heather. The TICC was clocked by a HP-5071A cesium beam oscillator with the high-performance tube. The TICC has a resolution of around 60 picoseconds. The PPS signal from the GPSDO was connected to channel A of the TICC (for those GPSDOs that have an easily accessible PPS signal). For receivers without a PPS signal available, Heather shows ADEV, HDEV, MDEV, and TDEV data for the 10 MHz signal. For receivers with a PPS, ADEV is shown for the 1PPS and 10 MHz signals. The GPSDO output frequency (10 MHZ) was connected to channel B of the TICC through a TAPR TADD-2 Mini divider to get a 1 Hz output. Note that PPS and 10 MHz plots have a display averaging filter applied. Without this filter the plots mostly show noisy "grass" and not any interesting details. A side effect of the display filter is to reduce the "span" (difference between the max and min values seen) of the plot data. Typically the unfiltered spans are around twice the value shown in the plot header, but for a couple of receivers it is up to a 10x reduction of the raw span. Each GPSDO was allowed to warm up for at least 24 hours, or longer... until the DAC output voltage slope leveled off. The GPSDO antenna was a L1/L2/GPS/GLONASS/BEIDOU antenna from China. With a L1/L2 survey receiver this antenna produces location error ellipse in the 5-10mm range. It is mounted on a 1 meter tripod and fed into an 8-way amplified L1/L2/Glonass/Beidou splitter. The antenna is in a rather horrible location for multi-path and sky view. Lots of tall trees and a 2 story stucco-over-wire mesh house. http://www.eevblog.com/forum/metrology/comparing-the-performance-of-17-different-gpsdos/msg2025295/#msg2025295 ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Project GREAT - Galloping Galileo version
Looks like somebody (sort of) duplicated Tom's experiment (and stole the name): https://www.theregister.co.uk/2018/12/07/galileos_magnifico_measurement_1976_redshift_test_updated/ ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Trueposition Antenna Location
Not all the "holdovers" on the Trueposition are due to signal issues. Many seem to be related to it tuning itself up after a power cycle and they improve or go away after a couple of days of running. But your antenna signal level map is rather awful... lots of red. It could be antenna, cable, or location of the antenna. My antenna is in a horrible location, but still works well. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] PRS10 case temperature
The case temperature derived from the ADC reading does not match actual measured values. The PRS10 data sheet says it is roughly the temperature midway between the baseplate and lamp temps. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] PRS10 case temperature
My case temp runs around 70C with the SRS heatsink installed. If you don't have a heatsink (a rather bad idea) it might run 80C. The latest SRS heatsinks don't seem to be as good as the earlier units which had a lot more metal to them... my heatsink is the later model. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Lady heather on a Raspberry pi
Lady Heather uses the DTR and RTS modem control signals to control the fan. If you are using a USB-Serial converter the code should work as-is. Heather does not have any code specific to a particular type of hardware (such as the PI). If you are using the PI GPIO serial port, you would need to modify the program to manipulate some GPIO pins. This is probably best done in the functions SetDtrLine() and SetRtsLIne() in the heather.cpp file... there are Windows and Linux versions of these routines. The functions apply_heat() and apply_cool() and hold_temp() in heathmsc.cpp could also be modified. There is also some code to use a parallel port to control the fan, but that is rather Windows/DOS specific. It could be modified for Linux. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] HP 58503B PSU replacement
I put a $25 50 watt (?) Meanwell in mine and in mine and it works well. The original power supply was made by PowerOne. They are still made...$300-$400 on Digikey and Mouser. My 58503B had a shorted ceramic cap across the input of one of the 15V regulators. The cap was glowing orange with the new supply. Maybe that killed the original supply. I think the OCXO oven heater is powered across across +/- 15V. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Helium and MEMS oscillators don;t mix well
https://ifixit.org/blog/11986/iphones-are-allergic-to-helium/ ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] OCXO Board
A SMA connector for EFC input would be nice. Also a footprint for the Oscilloquartz 8663 DOCXO... these are rather nice oscillators. They do have a ref voltage output. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] TAPR TICC (Cable run time delay)
The fudge value is generally used to compensate for the channel A vs B internal offsets. Lady Heather works with the TICC and has an "autotune" function () that can calculate and set the FUDGE and TIME2 parameters. You feed a 1PPS signal into a "T" adapter and feed the T outputs to the TICC via matched cables. It calculates the difference between the chA and chB readings and sets the the FUDGE1 to the difference (on mine -315 ps) ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Troubleshooting an HP 58503A
The 58503A needs a null-modem pinout serial cable to connect to a PC. The baud rate defaults to 9600:8:N:1 ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] One of my Thunderbolts is drifting
Try the !h keyboard command to hard reset it back to factory defaults... ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Samsung GPSDO : Chinese surplus
All the UCCM receivers have a EXT option... but most refer to it as LINK. Heather sets it to GPS on startup. I believe LINK/EXT selects an external PPS/PP2S provided by the base station. I think they normally operate it in GPS mode and switch to EXT if the GPS goes down. -- > I'm still intrigued though by the very existence of that EXT/GPS software > switch as a configuration option for the GPSDO itself, and wondering just > what EXT might actually imply in this instance. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Samsung GPSDO : Chinese surplus
I had to make several changes to Lady Heather to work with these... you may have an earlier version. How are you connecting the serial port? In the photo, I did not see the row of four holes that is on the Trimble / Symmetricom versions. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Lars GPSDO on EEVblog
Lady Heather now has some partial support for the Lars GPSDO. It does not directly send any commands to the device (I don't have one yet to implement that), but you can use the !u or !t keyboard commands to do that, Heather treats the Lars GPSDO as a time interval counter. You need to start Heather with /rxi (time interval counter as input device) and /itl (interval counter device is a Lars GPSDO). You can also use the Lars GPSDO as an "extra" input device with the GPS receiver as the main input device (/ei=port /itl). This mode lets Heather calculate true ADEV values while monitoring the GPS receiver. When using the Lars GPSDO, you do want to manually set the DAC gain setting () so that the frequency calculations based on the DAC setting are accurate. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Observations on how "Atomic" WWVB clocks set time
The Arcron Zeit clock does. It also has an RS-232 port. Lady Heather supports it (but calls it an Acron Zeit due to some typos in the original docs that I found and since there are maybe two people in the universe that still use them, I haven't had much motivation to fix that). At one time it was one of the most popular / capable WWVB clocks out there... I'd love to have one. - > BTW, has anyone ever seen a WWVB-based clock that displays the year? ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Lost GPS lock or 1PPS recently?
I read that the latest GPS sats don't even have the ability to implement selective availability... seems a dubious claim to me, though. - > Indeed it might get turned back on again. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Samsung GPSDO : Chinese surplus
These are Samsung's version of the "UCCM" series of GPSDOs. Lady Heather now works with them. I had to tweak the code to handle their funky/erratic end-of-line sequences... various versions of CR/LF, LF, LF/CR. Their STATUS screen and some message responses are also a bit different. They do tell you the antenna current. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] FTDI UT232R-200 USB to Serial Converter (BARGAIN ALERT)
I just bought a couple of Advantech AIMB-214E mini-ITX 1.86 GHz motherboards from a local surplus store for $25 ea (NIB). They have 6 genuine RS-232 ports (two can be configured for RS-422/485). Alas, the store don't do mail order and are currently out of stock (but the boards are around $50 on Ebay). And suitable cases/power supples look like at least $50. They can be run off of 12V@2A from an on-board barrel connector. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] WWVB Signal Generator
If your receiver has it the $GPZDA can be a better message to use. They usually have better seconds resolution and some receivers give them some special love as to when they come out. But, depending upon your code, this may not matter. Also check to see if your chosen time message comes out before or after the 1PPS. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] PLL/GPSDO/etc learning resources for mere mortals
Besides temperature compensation for holdover conditions you should also include drift compensation for OCXO aging. The Trimble GPSDOs, HP 38xx and 53xxx GPSDOs, and Oscilloquartz Star-4 do this. Oscilliquartz calls it ATDC (Automatic Temperature and Drift Compensation). For many OCXOs the magnitude of the temperature and drift values are of similar importance in predicting holdover compensation corrections. Teasing out and modeling the independent effects of temperature and drift can be quite a challenge in operational systems. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Lots of Off Topic discussion
Me too... that's why Lady Heather can calculate and plot solid earth tide displacements. Also the vertical offset in gravity due to solar/lunar tidal effects. - >I'd rather read about Earth tides affecting time measurements. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] NIST
I recently added a feature to Lady Heather that can output the sun and moon positions to a port. This was for use by solar trackers and moon bounce antennas. It would be easy to modify that code to output the position of a satellite (or all satellites) if you wanted to keep an antenna pointed at a specific satellite. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] NIST
A GPS receiver that supports SBAS, etc will tell you where the sats are. Some only report to 1 degree, others 0.1 to 0.01 degrees resolution. The beam with of a small dish at GPS freqs is not all that narrow. Using orbital elements or processing the GNSS ephemeris message will give you a result with quite a bit better resolution. - > There is another problem in that area. How accurately is the location of > the satellite known? published? ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Effects of Simple GPS jamming on GPSDO's ?
Several GPS receivers have a setting for enabling jamming detection and/or mitigation. The datasheets don't tend to talk about what it does. But, if the receiver supports it (Trimble and Venus devices), Lady Heather can configure it. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] NIST
I once bought a pair of low power 315 MHz TX/RX modules and was going to try them in a model rocket + GPS. I tested them with a serial port and they had a range of a couple thousand feet at 1200 BPS. But when the transmitter was connected to the GPS, the GPS lost lock... turns out 315 MHz * 5 is the GPS carrier frequency. They would totally jam GPS over around a mile diameter. Also the maker of the modules stopped selling them and actually disavowed that they ever existed! ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] WWVB Chronverter update progress
The Ublox 7 has two programmable "timepulse" outputs. The default freqs are (I think) 1 PPS and 10 MHz.I don't remember if the Ublox 6 has one or two outputs... also some of the earlier Ublox receivers have limits on the range you can set the output(s) to (like 1 kHz). Lady Heather can program the outputs (start up with /rxu to force Ublox binary mode). The pulse output control commands are in the "P" menu. You may have to bodge a wire onto the Ublox module to get access to timepulse2 on those cheap Ublox7 boards. I bought a couple that brought TP2 out to a pad. -- > Mark I looked at the 7 and the pulse out wasn't obvious ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] WWVB Chronverter update progress
Like I mentioned before, get a $10-ish Ublox Neo7 board/antenna off of Ebay, program one of the Ublox pulse output pins for 60 kHz. Add your favorite microprocessor to talk to the Ublox and drive the modulator. The Ublox 60kHz output should be more than accurate and stable enough to do the job. I don't know how well 77.5 kHz for DCF would work, but I suspect it might work. >If you're going to reference it from a GPSDO anyway, why worry about a TCXO reference (and power too, for that matter). You can easily make the 60 kHz from the 10 MHz. For example, with two 74HC390s and a 74HC86 you can make 50 kHz and 10 kHz and mix them with one EXOR section of the '86 to have 60 kHz available ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] WWVB Signal Generator
If I was going to do it I would take a cheap Ublox 7M board (around $10 with antenna), program one of the time pulse outputs for 60 kHz (it divides evenly into 48 Mhz so no jitter), feed the Ublox serial data / 1PPS to an AVR chip (or $2 Arduino Nano clone), and use that to modulate the 60 KHz output. Total cost less than $20 and should get to to the microsecond level range. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] TNS-BUF update
Also check your red LEDs. I have some that have a Vf of over 3V. They could be a blue LED/phosphor (not likely, blue -> red conversion is rather inefficient) or two red LEDs in series. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Stable32 Input (Multiplier)
Also note that Heather can only get/update the FC value (usually( every two seconds. Occasionally, due to vagaries in the PRS-10 response timing, you can see two consecutive values in the log that are not the same. > 2) Have any of you ever logged the FC values while at the same time taken > precision measurements of PRS10 output phase? I think that Heather can do that if you use a TICC or counter as an auxiliary input device (/ei command). In that mode Heather gets the "PPS" and/or "OSC" values from the counter. Since the FC value is treated as the Heather "OSC" value, the PPS value would come from the counter (chA on a TICC). I'll try to do that next week... my TICC and 5370 are doing something else right now. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] More Galileo satellites available.
Three of the four Galileo satellites launched last December have been activated (passive hydrpren maser clocks) bringing the total number of usable sats to 17. The fourth one is still "under comiisioning" .Four more sats were launched last month... hopefully it won't take them 8 months to commission... ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Spectrum Instruments TM4 GPSDO
I have a TM4 manual, but don't have a TM4. Heather now has some hooks in it for the TM4. I'd need a TM4 (at least for a couple of weeks) to properly implement the TM4 support (one is on Ebay for $4000+ ... no thanks). Or if somebody with a TM4 can capture around 5 minutes of data from the device, I can use that as a starting point. - > If so, they can do either their custum binary protocoll or NMEA. I have been meaning to suggest for Mark Sims that it would be a apreciated addition to Lady Heather to add the binary protocoll. I should have a manual around, if the TM-4 manual can't be found on the internet. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Alternatives for Thunderbolts
I've been happy with these: https://www.ebay.com/itm/10Mhz-GPSDO-OSCILLOQUARTZ-OSA-OEM-GPS-GPSDO-10MHz-1PPS-STAR-GPS-Clock/262861459973?hash=item3d33c39205%3Ag%3AsbYAAOSwh2xYAjrp&_sacat=0&_nkw=oscilloquartz+gpsdo&_from=R40=nc&_trksid=m570.l1313 They are not nearly as tweakable as the Thunderbolt, but the GPSDO inside is made by a company that seems to know what they are doing. The 8663 DOCXO used in the ATDC version is thei highest spec'd version. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Better leapseconds and PTP support for Windows 10
https://arstechnica.com/gadgets/2018/07/windows-10-will-get-better-at-telling-the-time-with-new-leap-second-support/ ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Improved CSRS-PPP service coming
I just got an email from CSRS-PPP outlining their upgraded service coming 14 Aug 2018. https://webapp.geod.nrcan.gc.ca/geod/tools-outils/documentation.php The new software supports all GNSS systems and will handle carrier phase observations for L1 only receivers. Currently CSRS-PPP only supports GPS and GLONASS pseduorange data. It will be interesting to see how the new software improves (or breaks) the antenna position results. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Pseudorange and carrier phase data in L1 only RINEX
The main reason is to reduce the file size. RINEX files can be rather long... depending upon what the receiver reports and the satellite systems in use, a 24 hour long 1 Hz file can be over 40 MB. BTW, you can .zip the file for uploading. CSRS-PPP is the only online service that I have found that does L1 only data. For the Trimble receivers, I generate pseudorange data from their code phase data message (quite a pain to calculate... you have to calculate the range from the ephemeris data). Trimble does not output any carrier phase data. For the other receivers I output whatever they output... - > Could another service be of assistance? > Why do you reduce report-rate? ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Lady Heather V6.0 and RINEX files...
Yes, the altitude error estimates are generally around twice the lat/lon values. I'm currently playing with taking the same 16 hour/1 sec interval data set (from a Trimble Acutime GG receiver) and decimating it to 5/10/30 second intervals and also to 2/4/8/16 hour lengths and seeing how the results change. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Lady Heather V6.0 and RINEX files...
Actually it is that simple. The relevant RINEX commands are in the new "M" (mesurement) keyboard menu. The MW command is used to write the file. MR is used to set the measurement rate (defaiult 1 second). The other commands mostly provide various info that can be added to the RINEX file (marker name, number, antenna type, number, etc). The Trimble and Furuno GT87xx receivers are not the best ones for precise positioning since they only have pseudorange data to work with. The Ublox, NVS, and Venus RTK receivers also output carrier phase data. The Ashtech Z12 is the best since it is L1/L2 with carrier phase data.. As far as "a few minutes"... you need at least a couple of hours of data. 12-24 hours can improve the results by 50+%. I am getting reported error ellipses in the 150mm range (< 10mm for the Z12) --- >I presume this may not be a simple as setting up my Trimble Thunderbolt and Lady Heather V6.0 in the field and gathering RINEX files for a few minutes?? ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
