Re: [time-nuts] Affordable PoE 6-digit time displays?
From: Bob kb8tq Hi I think this is one of those really small market items. You can probably cobble one together from bits and pieces for less than you can buy a good one. Bob === For example: http://www.satsignal.eu/raspberry-pi/DigitalClock.html 73, David GM8ARV -- SatSignal Software - Quality software written to your requirements Web: http://www.satsignal.eu Email: david-tay...@blueyonder.co.uk Twitter: @gm8arv ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Bodnar "Precision Frequency Reference (GPS Clock)" AND LeoNTP Networked Time NTP Server Questions
Anyone who is using one (or both) of these, and/or folks who have a logical opinion: [] There's more... but this is a good start. Just want to try and get parts on the way. Have to build a separate outboard regulator for the timing GPS antenna, too. Thanks! Clay Autery = Clay, I have all three of these units, all powered off USB. I don't see any reason why you shouldn't use a USB cable with just the DC part connected, so that there's no issue about radiation. A standard USB port would only supply 0.5A so that's an upper limit on the power consumption. If it's a very long USB cable (you mention mast-head) check the resistance. As a crude guide... - The (larger box) NTP server feels cold to the touch. - The smaller, single output frequency source feels very slightly warm to the touch (feeding an Icom IC-R8600) - The larger, dual-output frequency source feels slightly warm to the touch. There's an e-mail address where you could ask: supp...@leobodnar.com Cheers, David -- SatSignal Software - Quality software written to your requirements Web: http://www.satsignal.eu Email: david-tay...@blueyonder.co.uk Twitter: @gm8arv ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] TCVCXO Adjustment
Hi NTP will give you “millisecond" level accuracy / stability. If you want to set an oscillator to 0.1 ppm, you will need to run for over 10,000 seconds. It is not uncommon to have things out in the 10 ms range. That would put you at 100,000 seconds. In more common units, a couple of hours to > 1 day would be needed. Keep in mind, this is for a single observation. If you need to make three or four tweaks to get things set, the numbers would go up a bit. The earlier mentioned GPS approach with a $10 USB dongle would do it a *lot* faster. More or less, you could expect a bit better than a 1000:1 speed improvement. Bob == With respect, NTP using a GPS/PPS clock can give tens of microseconds or better, even on a Raspberry Pi. For example: http://www.satsignal.eu/mrtg/raspi1_ntp.html (The slight downward slope back over time is an artefact of MRTG with small integers.) Cheers, Davis -- SatSignal Software - Quality software written to your requirements Web: http://www.satsignal.eu Email: david-tay...@blueyonder.co.uk Twitter: @gm8arv ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Cheap jitter measurements
Hi, Yes, but isn't generating pulses OUT of a PC with low latency/jitter one of the difficult issues? If we (somebody smarter than me...) flip this around and modify a copy NTP to grab the QueryPerformanceCounter value when it gets a PPS pulse and log that count, don't we now have a way to compare the high resolution uncorrected counter to NTP and the external PPS? Agreed, not trivial. But maybe fun anyway! Dan Dan, Take a look at Dave Hart's patches to the Microsoft serial port driver, that does something similar. The source may be in the NTP distribution, or Meinberg may have a copy. At one time using the QueryPerfomanceCounter call was an option (look for "QPC"). With Windows-8 and later there is a much more precise GetSystemTime call which NTP uses. I played a little with those calls (in a non-serious way) and wrote some code: http://www.satsignal.eu/ntp/TSCtime.html based on: http://www.lochan.org/2005/keith-cl/useful/win32time.html and just messing around! Perhaps it's of interest or use? Cheers, David -- SatSignal Software - Quality software written to your requirements Web: http://www.satsignal.eu Email: david-tay...@blueyonder.co.uk Twitter: @gm8arv ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Cheap jitter measurements
There is a program for the RPi which handles the PPS input for NTP and can produce an output on a GPIO pin here: https://vanheusden.com/time/rpi_gpio_ntp/ but it's user-mode so of limited use. Perhaps the OP could adapt it? Cheers, David -- SatSignal Software - Quality software written to your requirements Web: http://www.satsignal.eu Email: david-tay...@blueyonder.co.uk Twitter: @gm8arv ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Lady Heather v6.0 Beta for Windows .EXE file
From: Mark Sims [] I've put a copy of the Windows .exe and documentation comments on EEVBLOG: http://www.eevblog.com/forum/metrology/lady-heather-v6-beta-for-windows-exe/msg1434005/#msg1434005 [] Thanks! David -- SatSignal Software - Quality software written to your requirements Web: http://www.satsignal.eu Email: david-tay...@blueyonder.co.uk Twitter: @gm8arv ___ 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] UK government study on: Satellite-derived Time and Position - Critical Dependencies
UK government study on: Satellite-derived Time and Position - Critical Dependencies https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/676675/satellite-derived-time-and-position-blackett-review.pdf Seems quite comprehensive, and may be of interest to GNSS users. 1.6 MB and 86 pages. Cheers, David -- SatSignal Software - Quality software written to your requirements Web: http://www.satsignal.eu Email: david-tay...@blueyonder.co.uk Twitter: @gm8arv ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Suggestion for a timing GPS receiver (Trimble / Ublox /other?)
Dear fellow nuts, I plan to build a decent GPS/GNSS-based Stratum 1 NTP server, and I'm looking for a good and possibly affordable timing GPS receiver. [] Am I overlooking something or missing interesting options? Cheers, Paride IZ3SUS Paride, As Mark notes, you don't need a timing precision GPS receiver for NTP, a standard position GPS receiver is quite good enough providing it has a PPS output. If you're thinking Raspberry Pi, there are some ready-made modules such as: https://store.uputronics.com/index.php?route=product/product&product_id=81 Stephen mentioned the newer series-8 ublox modules. These are indeed excellent (and can receiver Galileo too), but a number of vendors advertising series-8 modules (on both eBay and Amazon) are using remarked series 5 or 6 chips without the series-8 functions. Use the ublox u-center program to check anything you buy. From Amazon, at least, I got an immediate refund. 73, David GM8ARV -- SatSignal Software - Quality software written to your requirements Web: http://www.satsignal.eu Email: david-tay...@blueyonder.co.uk Twitter: @gm8arv ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Time stamp degradation being added in javascript
From: David Possibly not of immediate concern to time-nuts but an article had some trigger words for them in the initial fixes to the much publicised problems with Intel/AMD/ARM etc : "After these changes, the time stamp returned by |performance.now| will be less precise due to lower resolution. Some browsers are going a step further and degrade the accuracy by adding a random jitter." https://hackaday.com/2018/01/06/lowering-javascript-timer-resolution-thwarts-meltdown-and-spectre/ meltdown/spectre background https://www.theregister.co.uk/2018/01/04/intel_amd_arm_cpu_vulnerability/ David, This API appears only to affect browsers. On my Windows systems most have been patched, and I see no visible difference on either PPS-synced, LAN-synched or Wi-Fi devices as recorded by NTP. One PC showed an increase in CPU usage, but other PCs performing similar tasks have not. That same PC showed a doubling of jitter from less than 2 microseconds to less than 4 microseconds. It's an i5-4460 Haswell processor. http://www.satsignal.eu/mrtg/harstad-cpu-week.png Cheers, David -- SatSignal Software - Quality software written to your requirements Web: http://www.satsignal.eu Email: david-tay...@blueyonder.co.uk Twitter: @gm8arv ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Holdover, RTC for Pi as NTP GPS source
From: David C. Partridge ? RasPi-4? Not released until 2019 AFAIK ... I have RasPi-3 === My Raspberry Pi #1 and Raspberry Pi #4. See: http://www.satsignal.eu/mrtg/performance_ntp.php Cheers, David -- SatSignal Software - Quality software written to your requirements Web: http://www.satsignal.eu Email: david-tay...@blueyonder.co.uk Twitter: @gm8arv ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Holdover, RTC for Pi as NTP GPS source
From: Mark Sims I have an analytical balance that reads down to micrograms. The weigh chamber is surrounded by three layers of IR absorbing glass so that radiated body heat does not induce convection currents in the air. I worked on a balance that had nanogram resolution (mostly wishful thinking in that spec). It operated in a vacuum. 30 bit mass-to-digital converters are rather finicky beasties. It does not take all that good of a temperature sensor to detect changes in room temperature due to body heat (or fetching a beer from the fridge in the next room). You are basically a 100 watt space heater... even larger for the more corpulent folks. == Temperature is indeed the killer. My best Raspberry Pis for time-keeping are RasPi-1 and RasPi-4, both of which are in an unheated cupboard not exposed to sunlight, on the north side of the house with indoor patch GPS antennas. http://www.satsignal.eu/mrtg/performance_ntp.php Cheers, David -- SatSignal Software - Quality software written to your requirements Web: http://www.satsignal.eu Email: david-tay...@blueyonder.co.uk Twitter: @gm8arv ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] current crop of GPS receivers for Rpi/Beaglebone forNTP server/etc
I have beagles, but others have pis. There seem to be dozens of GPS receivers out there in a variety of form factors. What's the current "best" inexpensive choice for run of the mill time-setting/1pps that's a "catalog" item Plenty of online "how-to" from 2013 and 2014, but we here on the list know that the "cheap GPS" receiver business is a very moving target - 4 years is a long time. Jim, One example - Uputronics use the latest GPS devices from u-blox which incorporate Galileo support. Available from US and UK sources: https://v3.airspy.us/product/upu-rpigps/ https://store.uputronics.com/index.php?route=product/product&product_id=81 Cheers, David -- SatSignal Software - Quality software written to your requirements Web: http://www.satsignal.eu Email: david-tay...@blueyonder.co.uk Twitter: @gm8arv ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] How well does GPS work in the Arcitic?
The satellite orbits only go so far north? If you are far enough north for that to be a problem, can you pick up the satellites across the pole? I have several days of NMEA log files from 68 N. I think it will be simple after I have done it, but it may be a while before I get time to plot them. Does anybody have (non-Windows) code to that? === Hal, GPS worked fine for me on a cruise including 80 degrees north. Cheers, David -- SatSignal Software - Quality software written to your requirements Web: http://www.satsignal.eu Email: david-tay...@blueyonder.co.uk Twitter: @gm8arv ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Can Lady Heather set PC time directly from aTrimbleThunderbolt?
Thanks to everyone for the replies, so basically would you say that with a permanent internet connection I should forget using GPS time to set the PC clock and just use Meinberg or NTP (which is what I am currently using and seems to work just fine)? Best Regards, Chris Wilson. = Chris, That would be fine, but if you are interested make yourself a stratum-1 server based on, for example, a Raspberry Pi card. Then if the Internet /does/ go down, you'll still keep time. BTW: you refer to "GPS time". Not my area of expertise, but GPS time and UTC aren't the same - GPS time doesn't use leap-seconds, for example, so it's many seconds off from NTP. Cheers, David -- SatSignal Software - Quality software written to your requirements Web: http://www.satsignal.eu Email: david-tay...@blueyonder.co.uk Twitter: @gm8arv ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Can Lady Heather set PC time directly from a TrimbleThunderbolt?
From: Clay Autery I use Meinberg's NTP for Windows... and their Monitor program. https://www.meinbergglobal.com/english/sw/ntp.htm 73, === Clay, That's a Windows compile of the source I mentioned: https://www.eecis.udel.edu/~ntp/ntp_spool/ntp4/ntp-4.2/ntp-4.2.8p10.tar.gz made into a rather nice installable package. I also offer a guide to installing the software: http://www.satsignal.eu/ntp/setup.html and some recent binaries if all you need are updates (although the Meinberg installer also offers an update only mode): http://www.satsignal.eu/ntp/x86/index.html I have a PPS/GPS attached to several Windows-10 PCs for better timekeeping - down to the hundred-microsecond level: http://www.satsignal.eu/mrtg/performance_ntp.php#windows-stratum-1 73, David GM8ARV -- SatSignal Software - Quality software written to your requirements Web: http://www.satsignal.eu Email: david-tay...@blueyonder.co.uk Twitter: @gm8arv ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Can Lady Heather set PC time directly from a TrimbleThunderbolt?
Apologies for the off list reply. The site www.davehart.net does not appear to be online any more. Would you know of an alternative source for the Dave Hart Windows port of NTP ? Cheers Arne Arne, The official distribution contains a Windows port which compiles under a variety of MS Visual Studio versions. https://www.eecis.udel.edu/~ntp/ntp_spool/ntp4/ntp-4.2/ntp-4.2.8p10.tar.gz https://www.eecis.udel.edu/~ntp/ntp_spool/ntp4/ntp-dev/ntp-dev-4.3.93.tar.gz Many people have contributed to this port, including Dave Hart, of course. Whatever became of Dave? Cheers, David -- SatSignal Software - Quality software written to your requirements Web: http://www.satsignal.eu Email: david-tay...@blueyonder.co.uk Twitter: @gm8arv ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Can Lady Heather set PC time directly from a TrimbleThunderbolt?
I use an NTP client to set my Windows 7 64 bit PC time for digital mode amateur radio activities, but I was wondering if my Trimble Thunderbolt and Lady Heather can do the same job? If it can, how do I do it please, and can the PC show GMT and not UTC, and finally does the date glitch affect this? Lady Heather communicates with the GPS via a true serial port. Thanks! Best Regards, Chris Wilson. 2E0ILY = Chris, If you have a PPS source you can use that directly with your Windows-7 PC. I have some notes here: http://www.satsignal.eu/ntp/Sure-GPS.htm Windows works internally in UTC, just choose your time zone from the Control Panel. I'm guessing that you mean UK local time, as GMT and UTC are the same (at least as far as wall-clock time is concerned). 73, David GM8ARV -- SatSignal Software - Quality software written to your requirements Web: http://www.satsignal.eu Email: david-tay...@blueyonder.co.uk Twitter: @gm8arv ___ 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] Problem behind failing Galileo clocks identified
"Investigators have uncovered the problems behind the failure of atomic clocks onboard Galileo satellites, the European Commission said." See: http://galileognss.eu/problem-behind-failing-clocks-identified/ May be of some interest. Cheers, David -- SatSignal Software - Quality software written to your requirements Web: http://www.satsignal.eu Email: david-tay...@blueyonder.co.uk Twitter: @gm8arv ___ 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.
