Re: [time-nuts] A man with two clocks...
http://www.satsignal.eu/raspberry-pi/DigitalClock.html third paragraph: I've provided the source and binary files in this Zip archive, so you can either run the program as-is, or modify it to suit your own preferences. On 10/3/2013 6:43 PM, Phil Genera wrote: Is your code posted anywhere? I've been meaning to do roughly the same. -- Phil On Oct 3, 2013 12:07 PM, Collins, Graham coll...@navcanada.ca wrote: David, Your raspberry-pi NTP clock is very cool. I have put together something along the same line but is in reality just a network connected NTP disciplined clock display using an Arduino and a typical 16x2 LCD housed in a small project box. The Arduino has a network shield and get's it power from a USB port although it could be powered by a battery or wall wart type of supply. When it starts, the device attempts to get an IP address using DHCP. Once that is sorted it attempts to sync to my local GPS disciplined NTP server, then sets and displays it's time. It resyncs every some value between 15 and 30 minutes with the NTP server. If ever my local NTP server can't be found, it will attempt to sync to an outside NTP server on the internet. It keeps pretty good time, not time nuts level but is always within a few tenths of a second which is suitable for it's intended purpose. Basic time keeping of the Arduino uses it's 16MHz crystal clock and there is some provision for adjusting in code which I have done to improve it's time keeping. I am toying with the idea of adding a 1 PPS input but just haven't gotten round to it yet. All the bits and pieces of the code was copied from existing projects and libraries it being just a matter of finding the appropriate bits and pieces, putting them together and making changes in a few places to improve it's time keeping. It was a fun project to put together and has proven so useful in my lab that I will probably put together a couple more. Cheers, Graham ve3gtc === Max, I see similar things here. I've always put it down to relatively poor circuitry in the radio clock, which is why I built my NTP-controlled wall clock! http://www.satsignal.eu/raspberry-pi/DigitalClock.html One radio clock is below. That particular MSF clock is actually not too bad - visibly it's in sync with the NTP clock (which itself is within a few microseconds of GPS time). 73, David GM8ARV -- SatSignal Software - Quality software written to your requirements Web: http://www.satsignal.eu Email: david-tay...@blueyonder.co.uk . ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] A Time-Nut's Worst Nightmare
On 5/10/2013 9:52 PM, Ed Palmer wrote: Part of me thinks it's cute, part of me wants to kill it. :-) https://www.tindie.com/products/akafugu/vetinari-clock Ed Agreed... I'm just thinking: Ah noo. Oww oww oww oww ma brainz!!! Just the thought of being off by 250ms is upsetting for me... I can't imagine anyone wanting a clock which will be inaccurate by something like a second or two or perhaps more than that. WTF!? Why?! --Sarah ___ 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] gpsd 1pps pulse?
On 5/7/2013 2:00 PM, Sarah White wrote: If you have problems with PPS, just set the serial port to a higher baud rate... This is the reason I recommend against using the DCD line on the same serial port you're using for TSIP ((snip)) On 5/8/2013 6:53 AM, mike cook wrote: Sara, I'd be interested to know if you ran into the problem and changing baud rate fixed it. I ask that as my understanding of the most common UART indicates that the DCD signal line is not managed with the baud rate clock. At least for the most common 16550x variety, the DCD level changes are signaled in the MSR and then if interrupts are enabled an interrupt is queued. However t there is an anti-metastability filter of 2 CLK cycles before pin level changes are reflected in the MSR. So.. if your UART is on a slow clock, it could be that a 10us transition will be too fast to pass the filter. However, I do agree that trying is the easiest test. --- begin reply --- [CITATION] -- http://www.ntp.org/ntpfaq/NTP-s-config-adv.htm (section) 6.2.4.6.1. What is the shortest Width for a Pulse connected to the DCD Pin of an RS-232 Interface? That depends. The higher the quality your serial port is, the longer pulses will be needed. This is because of the ESD protection of the chip. 26 usec should be about the bit time for a 38400 serial line, so you could connect it to the RxD line instead and see if you receive characters that way when the port is set for 38400 or faster. Another thing to try is to configure the serial port for 115200, some of the chips base their deglitching on the baud rate, often requiring a full symbol before they react. [END CITATION] Mike, I think that's basically what you were saying: (quote of mike cook) ... there is an anti-metastability filter of 2 CLK cycles before pin level changes are reflected in the MSR. So.. if your UART is on a slow clock, it could be that a 10us transition will be too fast to pass the filter. (end of last quote) Or did I misunderstand what you said? Yes. On principle, for some but not 100% of serial ports, the baud rate clock won't matter at all, and the hardware interrupts will still happen with low latency, regardless of the baud rate setting. What will change however, is filtering which MIGHT be related to the baud rate setting. (as per the citation I included in this post) --Sarah P.S. I had trouble understanding the quote reply style / layout... ... refactored the layout by band to look cleaner (my own tastes) ... basically made it easier for me to proofread everything, etc. Also, seems the person who started this topic is currently silent... ... I think it was: Chuck Forsberg WA7KGX N2469R c...@omen.com ___ 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] gpsd 1pps pulse?
On 5/6/2013 9:38 AM, Chuck Forsberg WA7KGX N2469R wrote: I would like to set up a NTP server on a machine running Linux (currently Korora 18). What are the requirements for the 1 PPS signal fed to the carrier detect pin? I presume the 10 us 1pps from the Thunderbolt is too narrow. I assume the rising edge of CD is the one gpsd triggers on. Chuck, 10 microseconds? That sounds fine actually... You could simply try it? Really, I mean it. Just try and it might work with your serial port. I don't recommend any clever hardware hacks which will somehow piggyback the 1 PPS output onto the DCD line on the same serial port you're using for the TSIP protocol. If you have problems with PPS, just set the serial port to a higher baud rate... This is the reason I recommend against using the DCD line on the same serial port you're using for TSIP. Trimble tends to use 9600 baud on the TSIP port, and the signaling on that is too narrow. For PPS, you'll be fine with 115200 BAUD (bit/s) ... This speed comes out to 8680.55 nanoseconds, more than a full microsecond narrower than the 10 microsecond wide PPS. I had trouble getting the right headers to connect to the onboard serial port on the motherboard (not installed by default) ... So I tried a USB-serial, and ultimately switched to a PCI Express to Serial Port version. This is from the product description on my current setup: (quote) Based on a native single chip design (no bridge chip), this 2-port serial adapter card allows you to harness the full capability offered by PCI Express (PCIe), and reducing the load applied to the CPU by as much as 48% over conventional serial cards. ^ I'm really not sure if this helps the latency for hardware interrupts, or makes them worse, but it DEFINITELY works better than the USB-serial adapter I was trying to use before. At less than $100, the price is right though (And now my PPS hardware interrupts are via native PCIe so it only makes sense that it would work better than USB) Hope this helps --Sarah P.S. If anyone needs a good serial port and not sure where to look, I got mine from newegg, they have tons: http://goo.gl/CEzZA ... Mine was specifically, this model, made by startech: http://goo.gl/S9EHx ___ 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] GPS position survey
On 5/5/2013 6:35 AM, Miguel Barbosa Gonçalves wrote: Hi fellow time nuts! I've recently bought a Trimble Acutime gold that will be used as a reference clock for a NTP server. This receiver has the possibility of averaging it's position before entering what Trimble calls the overdetermined clock state. The default is to average the position with 2000 fixes. What do you believe is a good number of fixes for the survey in this case? Cheers, Miguel Accurate position might be important. Light travels a distance of something like 29.9792 centimeters per nanosecond You might find the results of this study to be helpful: http://www.syz.com/gps/gpsaveraging.html I myself did a sampling over a period of 1 million samples (actually, it was a value of 2^20, not exactly 1 million) quickest it could have completed such a survey is 12+ days ... However, I had masks set for elevation, signal, etc. (resulted in occasional periods when there was no lock) I'm quite satisfied / happy with the results :) hope this helps? --Sarah ___ 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] GPS position survey
On 5/6/2013 12:29 AM, Mark Sims wrote: The 48-hour precision survey in Lady Heather uses a statistical weighted median filter to arrive at its final location instead of a simple average of fixes. It processes data of one minute, hour, and overlapping 24 hour intervals to calculate the final position. It can produce a location that is 3-10 times better than simple averaging of the fixes. A further complication is storing the precise location into the receiver. The Tbolt firmware only lets one write the location using single precision floating point numbers (24 bit mantissa). This is well below the desired resolution of the position. Lady Heather gets around this by limitation by doing a royal kludge. Once the precise position has been calculated, it issues single point survey commands to the receiver until one just happens to lie within one foot of the calculated position. Wow, thanks. I didn't realize that. This approach you described from lady heather sounds really cool from my time-nut perspective. I used the trimble provided utility for the survery. Really not sure if the internal firmware did the calculation and/or filtering, or what method was used. --Sarah ___ 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] Atomic Watch.
On 5/1/2013 8:43 AM, Stephen Tompsett (G8LYB) wrote: http://www.theregister.co.uk/2013/05/01/hoptroff_shows_first_atomic_watch_movement/ Stephen, fellow time nuts, [DISCLAIMER] I should really know better than to attempt internet discussions or comments first thing after waking up. Didn't stop me today though (oops) So... Did I just make a fool of myself? Was I mistaken? I tweeted the author of this article, trying to point out that (as I understand) radioactive decay is not relevant in any way for cesium frequency standard/reference thingies: https://twitter.com/kuzetsa/status/329618223916011520 If someone more authoritative and/or experienced (or at least more awake) wanted, please let me know if I was confused and such --Sarah ___ 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] Atomic Watch.
On 5/1/2013 11:40 AM, Sarah White wrote: On 5/1/2013 8:43 AM, Stephen Tompsett (G8LYB) wrote: http://www.theregister.co.uk/2013/05/01/hoptroff_shows_first_atomic_watch_movement/ Stephen, fellow time nuts, [DISCLAIMER] I should really know better than to attempt internet discussions or comments first thing after waking up. Didn't stop me today though (oops) So... Did I just make a fool of myself? Was I mistaken? I tweeted the author of this article, trying to point out that (as I understand) radioactive decay is not relevant in any way for cesium frequency standard/reference thingies: https://twitter.com/kuzetsa/status/329618223916011520 If someone more authoritative and/or experienced (or at least more awake) wanted, please let me know if I was confused and such --Sarah Oh... apparently the article has since been altered in a subtle way. The current wording no longer has any mention of radioactive decay As you were / carry on :) --Sarah P.S. Guess I'll delete my tweet. (unintended rhyme) ___ 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] Atomic Watch.
On 5/1/2013 1:48 PM, Michael Tharp wrote: ((...snip...)) As for the article, The Register is not an outlet known for precise reporting. Take it as a journalistic liberty. NB: Your tweet is not visible to me, so it's somewhat difficult to fact-check :-) -- m. tharp I deleted the tweet once I realized the article had been fixed: http://www.febo.com/pipermail/time-nuts/2013-May/076127.html you meant me, right? what does NB mean? --Sarah ___ 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] Atomic Watch.
On 5/1/2013 4:02 PM, Poul-Henning Kamp wrote: In message 51815556.4050...@partiallystapled.com, Michael Tharp writes: On 5/1/2013 11:40, Sarah White wrote: Symmetricom doesn't go out of their way to say how the damn thing actually works, [...] NIST has documented that in a LOT of detail, they're the ones who came up with it. PHK, Sorry to chew you out on this but like... This poorly formatted reply ERRONEOUSLY implies that I posted a question or comment about Symmetricom. ZERO text in this quote / reply was actually from me. --Sarah ___ 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] Common-View GPS Network
On 4/16/2013 9:53 AM, Achim Vollhardt wrote: Count me in as well, if you need another participating station. I have my Thunderbolt running 24/7 with a solid stationary antenna.. I'm not sure what all I'll need to participate, but I'd like to volunteer my thunderbolt to this sort of network as well. I'm wondering though, is there something inherently different about this proposed network than a network of continually operating reference stations? or are CORS stations for something else? --Sarah ___ 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] antennas was Re: Common-View GPS Network
On 4/16/2013 1:55 AM, Jim Lux wrote: On 4/15/13 10:22 PM, Jim Lux wrote: On 4/15/13 9:27 PM, Tom Van Baak wrote: NIST SIM GPS common view pinwheel described in one of the NIST reports as an aperture coupled slot fed array that is better than a patch, but not as large and heavy as a choke ring. W. Kunysz, 2000, “High Performance GPS Pinwheel Antenna,” in Proceedings of the 2000 International Technical Meeting of the Satellite Division of the Institute of Navigation (ION GPS 2000), 19-22 September 2000, Salt Lake City, Utah, USA (ION, Alexandria, Virginia), pp. 2506-251 http://www.novatel.com/assets/Documents/Papers/GPS-704xWhitePaper.pdf Patented by Novatel Pinwheel is a trademark Performance is almost as good as a choke ring but a heck of a lot smaller and lighter. of course, cake pans with 2-2.5 inch high walls are readily available. There's a Wilton cakepan set with 6,8 and 10 diameter pans with 3 walls.. hmm, an inch between fins.. Oddly, the package shipping size is 12x12x2... I wonder how they fit a 3 high pan in a 2 thick box.. a real restaurant/pastry supply has a mindboggling variety of pans http://www.fantes.com/cake-pans-round.html every integer inch diameter from 4 to 18 and ditto for heights from 2 to 4... People like those machined or cast choke rings because they're easier to fabricate: Slap a block of aluminum in the lathe or milling machine, push GO on the CNC, and stand back. Or for those with a taste for hot metal.. you could cast it with scrap aluminum you've melted in the forge in your time nuts lab.. Turn those empty beer cans into something useful. If you have a fancy multiaxis mill, you could probably do one of those porcupine looking things. Or, if you have a swimming pool or pond, and some sheet aluminum, and some suitable high explosives.. hydroforming is your friend. If you want true timenuts.. do the explosive hydroforming without a mold/buck, and instead use precision timing of shaped charges. Finally, a use for those krytron switches you found at the surplus place. Thanks for that. The last bit of your post was really cute. I needed a good laugh :) I haven't posted much in a while, partly because I've been kinda bummed out by this list since I got the news about shera... There have been so many constant reminders of his passing and whatnot (multiple thread titles mentioning his legacy) I just have to ask though... cake pans? really? I can't imagine it would even be possible to modify a cake pan with enough accuracy to get a usable antenna. -- Sarah ___ 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] Network jitter with NTP
David, Thanks for posting that. I'm currently doing some testing over wifi links myself, and found that page very useful. You do a really good job documenting your experiences with GPS-based NTP refclocks, and I appreciate all the hard work. I just wanted to ask though, are you compiling your own NTP now or what? http://www.davehart.net/ntp/win/x86.please.see.http.support.ntp.org-people-hart-win-x86/ but then under http://support.ntp.org/people/hart/win/x86/ ... most recent seems to be ntp-4.2.7p310 ^Basically, you were previously documenting use of dave hart's builds (overlaid over a meinberg ntp install or otherwise) Sorry rob, I don't have any experience with powerline adapters, but I'm treating your experiences (which don't seem to be promising) as a data point showing that they're no better for timing than using wifi... I'm getting high unpredictable jitter with NTP over wifi as well (compared to cat 6 RJ-45 crossover cable directly between NTP servers) 1-20ms jitter for 5ghz band, 802.11n connection running with bitrate manually limited to 6mbit/s 5-70ms jitter for the 2.4ghz band, 802.11g connection running with bitrate auto-negotiation (up to 54mbit/s) ... My best case scenario for NTP jitter is about 0-5ms between a stratum 1 and a stratum 2 server directly connected via gigabit ethernet crossover (and the stratum 1 itself with a connected refclock seems to be at a baseline of 0-1ms most of the time, and rarely higher than 2ms) Those are just rough estimates based on casual observation, and I haven't done any long-term measurements yet like David Taylor's work... I'm getting there though it's coming slowly because of my trouble with learning curve in this area. --Sarah P.S. I renamed this post. The title Possibly off topic - Jitter on Ethernet over poweradapters seemed silly. Rob, It's not quite clear which direction you are measuring. I take it your Meinberg servers are perfect in NTP terms, and you are monitoring from the house? Or vice-versa? Anyway, my first guess is that jitter might be not dissimilar to Wi-Fi, in which case my lightly-loaded Wi-Fi results might be a starting point: http://www.satsignal.eu/mrtg/performance_ntp_wifi.php Note the improvement with Windows-8 and the latest NTP (top graph, PC Bergen), and the others are somewhat variable. Cheers, David ___ 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] Low noise power supplies?
Bob Camp, Thursday, January 31 11:36 AM (Local NY time): ((...snip...)) With a good enough voltmeter you could carry the analogy one step further and compute an ADEV like number on the output voltage. I suspect that's carrying things a bit far. No, I disagree. That's not carrying things nearly far enough. I really think we should figure out a reliable methodology for this sort of thing. This is time nuts after all, so perhaps some time/frequency applications might end up needing sub-nanovolt regulation (and there are those whom might simply need it because they're nuts) Tom Van Baak, Thursday, January 31, 2013 9:43 AM (Local NY time): ((...snip...)) I was never quite satisfied with the outcome of comparing a half dozen power supplies this way: http://www.leapsecond.com/pages/tbolt/noise.htm We have rigorous ways to compare and report oscillator performance; both as numbers and as plots. Is there something equivalent for power supplies? Thanks Tom. I found that writeup about various power supplies rather useful. I'm doing some research and development for power supplies right now, and hope to come up with something completely nuts by the time I'm ready to go from learning how to work with thunderbolts / GPS Disciplined OCXO to something exotic which, today, might be far over my head. --Sarah ___ 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] Serial port / Mouse issue (was mentioned inThunderbolt Monitor)
On 1/25/2013 1:43 AM, David J Taylor wrote: From: Sarah White [complex instructions snipped] --Sarah P.S. sorry to double-post like this. === Sara, It's far simpler to go into the Device Manger and disable the spurious device, as described here: http://www.gpsmap.net/GarminHints.html#GPSR_ComputerMouse No need to edit boot.ini (obsolete in any case), no need to edit the registry. By the way, on a test Windows-8 system the GPS wasn't detected as a serial mouse, so possibly Microsoft have improved the mouse detection code! Cheers, David Beg your pardon? 1) Your comment seems to suggest a misunderstanding. I wasn't advocating any editing of boot.ini in the first place. ...Boot.ini doesn't even exist anymore, so I wasn't suggesting that, as it's s an outdated practice, and the official workaround is the one I was trying to share... 2) At the bottom of the section you just linked, it says: See also the Microsoft Knowledge Base Article # 283063, Serial Device May Be Detected as a Serial Mouse in Windows 2000. The referenced knowledge base article, 283063: http://support.microsoft.com/kb/283063 Title: Serial Device May Be Detected as a Serial Mouse in Windows 2000 ^That workaround is for EVEN OLDER version of windows. --snip-- APPLIES TO Microsoft Windows 2000 Service Pack 1 Microsoft Windows 2000 Service Pack 2 Microsoft Windows 2000 Advanced Server Microsoft Windows 2000 Advanced Server Microsoft Windows 2000 Service Pack 1 Microsoft Windows 2000 Service Pack 2 --snip-- If you disable the offending device in device manager, the automatic plug play can, and often DOES just re-install a second version of this mouse after running windows update. Second opinion about the approach I was recommending: http://answers.microsoft.com/en-us/windows/forum/windows_7-hardware/windows-7-recognized-usb-gps-as-a-serial-mouse-in/0c3f0d94-6181-4a43-9e90-bcea8a21415d Shortened URL: http://goo.gl/xFcSc Note the similarity of official instructions, written by: Samhrutha G S - Microsoft Support. --snip-- i. Click on start ii.In the search box, type in regedit iii. Registry editor windows opens iv. Navigate to the location: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\sermouse --snip-- Whatever works for you though I guess. I was just explaining the officially supported method *shrugs* ___ 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] Serial port / Mouse issue (was mentioned in Thunderbolt Monitor)
On 1/24/2013 11:07 PM, Sarah White wrote: (quotes) NOTE: If you boot Windows with your ThunderBolt connected to the Com port, Windows will think it is a serial mouse and grab the port. It can lead to some interesting Windows behavior as the T-Bolt outputs data. Easy fix. Add the following to your Boot.ini file. Obviously, the x stands for the COM port you are using. NoSerialMice:COMx (end quotes) I'm not sure who typed the above text, the quote style was hard to understand... Might've been some combination of Joe Gray, John Lofgren, and/or someone who signs as mike? Anyway... Here's my $0.02: Windows Vista / 7 doesn't use boot.ini ... do this instead: Click on start -- In the search box, type in regedit Registry editor windows opens... Navigate to the location: HKEY_LOCAL_MACHINE -- SYSTEM -- CurrentControlSet -- Services -- sermouse In the right hand, you'll see stuff like: (default) DisplayName etc. etc. etc. There should be a dword (32bit) value titled: start Set the value of this to: 0004 If you do not see start use the following steps: Right click on the (white) blank space (below the default, displayname, etc.) After right click to get context menu, click New ... a sub-menu will expand: Select the option for: dword 32-bit value Now, give this value the name start Right click to select modify It should have the value: 0004 Restart the computer You're done :) The mouse will no longer freak out, and your GPS (timing mode, TSIP, NMEA, or otherwise) or other RS-232 device will now work normally and not be detected as mouse, make cursor jump strangely, etc. Hope someone finds this useful, Sarah This info applies to windows XP as well: http://goo.gl/IqmDB Post number 6 they said: ---snip--- REGEDIT4 [HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Servic es\sermouse] Start=dword:0004 there should be no blank between Servic and es ---snip--- but uh... I never tested making a .reg file and merge with registry or whatever. I'm pretty sure some antivirus software gets cranky when it sees a .reg file, plus there's often a complication when people use notepad to create a file and the file ends up something.reg.txt or ... oh whatever, the same thing applies. winxp doesn't really use boot.ini either for this --Sarah P.S. sorry to double-post like this. ___ 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] Serial port / Mouse issue (was mentioned in Thunderbolt Monitor)
(quotes) NOTE: If you boot Windows with your ThunderBolt connected to the Com port, Windows will think it is a serial mouse and grab the port. It can lead to some interesting Windows behavior as the T-Bolt outputs data. Easy fix. Add the following to your Boot.ini file. Obviously, the x stands for the COM port you are using. NoSerialMice:COMx (end quotes) I'm not sure who typed the above text, the quote style was hard to understand... Might've been some combination of Joe Gray, John Lofgren, and/or someone who signs as mike? Anyway... Here's my $0.02: Windows Vista / 7 doesn't use boot.ini ... do this instead: Click on start -- In the search box, type in regedit Registry editor windows opens... Navigate to the location: HKEY_LOCAL_MACHINE -- SYSTEM -- CurrentControlSet -- Services -- sermouse In the right hand, you'll see stuff like: (default) DisplayName etc. etc. etc. There should be a dword (32bit) value titled: start Set the value of this to: 0004 If you do not see start use the following steps: Right click on the (white) blank space (below the default, displayname, etc.) After right click to get context menu, click New ... a sub-menu will expand: Select the option for: dword 32-bit value Now, give this value the name start Right click to select modify It should have the value: 0004 Restart the computer You're done :) The mouse will no longer freak out, and your GPS (timing mode, TSIP, NMEA, or otherwise) or other RS-232 device will now work normally and not be detected as mouse, make cursor jump strangely, etc. Hope someone finds this useful, Sarah ___ 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] tbolt temperature coefficient RMS values (as calculated in LH)
On 12/11/2012 10:33 PM, Charles P. Steinmetz wrote: ((...snip...)) I initially thought the third unit's oven controller was broken (low gain). Then I noticed that the great majority of posted Lady Heather plots appear to be from units similar to that one, with the much higher tempco and reversed tempco sign compared to my two low-tempco units. But I have seen a few other plots that appear to be from units similar to my first two. The two with the low tempcos do not appear to be inferior to other Tbolts with respect to stability, PN, or aging. ((...snip...)) I'm pretty sure LH estimates the temperature coefficient in a rather inelegant way: Seems based on the graph / display window, and affected by filtering (RMS is affected by display filtering too) I've been doing measurements this past week, and posted the first set of results here: http://spaceclock.tumblr.com/post/38439854001/ As you can see, with minimal, or filtering completely disabled, LH has a significant jitter problem in the tempco, and sometimes even shows a reversed sign. In my testing, a high or low time constant seemingly has no effect on LH ability or inability to mangle its calculation of the temperature coefficient... The time constant just happens to be 4096 in this case because I'm doing long-term measurements on the effects of using a value other than 100, and ultimately employing a binary search algorithm to determine the most optimal time constant for the crystal in this particular thunderbolt. --Sarah ___ 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] Comparing PPS from 2 GPS units
On 12/21/2012 1:52 AM, Said Jackson wrote: Can you create an executable for windows? Thanks, Said python is a script-type language which runs on top of the python engine (almost similar to how java programs run on a java engine) ... to answer your question: yep, you can download here: http://sourceforge.net/projects/pywin32/files/pywin32/Build%20218/ Most software written for python is usually targeted for 2.7 and/or 3.2, but you can try some other version if you're wanting to risk it. hope this helps, Sarah ___ 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] Synergy SSR-6TR
Sorry, this is off-topic: Wondering I'm if anyone else had part of this particular conversation / thread (Synergy SSR-6TR) sent to their spam folder or otherwise filtered? From what I suspect, it was just a false-positive, as the conversation didn't appear to be spam, wondering if the word synergy mixed with one or more unexpected grammar quirks (shorthand, time frequency related vocabulary or otherwise) could've been the cause. Part of the reason for my posting this message is to help train gmail's spam-filter not to flag this thread / mailing list (for both myself and any other gmail users) ___ 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] Thunderbolt oven / non-stable operating temperature
On 12/11/2012 10:33 PM, Charles P. Steinmetz wrote: All three have Trimble 37265 OCXOs (( sorry to single out that one line )) Just a curiosity. Is there any way to check that via software? Did you just physically look under the cover, or how did you figure out which type of oscillator your thunderbolt has? Thanks, Sarah ___ 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 oven / non-stable operating temperature
Ended up with a gently used trimble thunderbolt a few months ago, and been trying to figure out the best settings to use (time constant, damping, etc.) for best performance. I got distracted though. There is something which I find rather annoying, and I'm spending more time messing with this factor than actually observing the performance at different damping / time constant / etc... The temperature seems to be aprox 20C above ambient temperature rather than a steady 40C. I thought the purpose of the oven was to keep the temperature stable. When I adjust the thermostat because I'm chilly, the thunderbolt gets warmer too (but not by as much) I've tried (seemingly, to me) everything: light insulation putting the unit in a spot away from drafts putting the unit in a place away from drafts in a shoebox with light insulation with a fan blowing in it (currently in a cupboard in this state, and the temp seems to fluctuate the least, but still by more than 1-2 degrees centigrade) I feel like shouldn't need to fuss with ambient conditions this heavily for an OCXO, and find myself researching construction / design for a DIY outer-oven to wrap the thunderbolt in. Anyone have experience with non-stable temperature on a trimble thunderbolt? I've also noticed (monitoring with Lady Heather's Disciplined Oscillator Control Program v3.10 by John Miles aka KE5FX) the thunderbolt unit sometimes flags an alarm briefly (and I rarely ever manage to write it down before the screen updates or the alarm goes away) and the last one I was able to catch before it went away was related to temperature. Should I be getting a steady / non-flucturating 40C or something if the oven is working normally? Thanks in advance, Sarah ___ 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] Thunderbolt oven / non-stable operating temperature
On 12/10/2012 5:22 PM, Bob Camp wrote: Hi The oven in the OCXO keeps the crystal at a constant temperature. It is normal for the TBolt it's self to idle 10 to 20C above ambient. The temperature sensor is located near the 9 pin D connector. It shows a temperature somewhere in between the ambient and the OCXO case temperature. Some have mounted speed controlled fans to keep the TBolt case at a constant temperature. Bob Bob, others: Ah, so then it's probably fine. Thanks, the other posts which followed seem to be in agreement with yours. ... Now then. Suppose I'll likely return my efforts to finding a time constant that makes sense for my particular tbolt / usage needs. ___ 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] Thunderbolt oven / non-stable operating temperature
On 12/10/2012 6:10 PM, Arthur Dent wrote: I believe that the high temperature alarm you see is triggered at 50 degrees C. If that is what you're seeing without artificially raising the temperature of the Thunderbolt by insulating it so it can't radiate the heat, what I said about replacing the chip is correct but if it is staying within a few degrees over the course of the day and is in the 40 degree C range without being insulated, the DS1620 thermometer chip is o.k.. My particular thunderbolt seems to be from 2004, so I guess that manual is at or around checked: ThunderBolt[tm] GPS Disciplined Clock User Guide Version 5.0 5.0 is a version of the manual published in 2003 Table C.2.2 Environmental Specifications: Operating Temp: -0°C to +60°C Storage Temp: -40°C to +85°C ... so I guess I shouldn't worry about a few degrees of difference in the reported temp, especially considering that the sensor in question isn't on the OCXO itself. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] Using a frequency synthesizer replacement for motherboard oscillator
Has anyone ever used a TAPR clock block or other frequency synthesizer to sort the clock drift / timing problems on a regular computer? I'll probably end up with a used dell or IBM workstation for this purpose. Recently, I came across a low-cost frequency synthesizer capable of using a 10mhz frequency reference (planning on using the thunderbolt GPSDO I'm working with once I manage to sort out the temperature issues) http://www.tapr.org/~n8ur/Clock-Block_Manual.pdf ^ TAPR Clock Block has an installation example for how to do what I'm planning with a Soekris net4501 low-cost / low-power embedded device... What I'm hoping to figure out is how to do the same, except on a proper computer such as the local used ones I'm able to get for less than $200 with 2ghz with 30GB hard disk, 512mb or more ram, etc. So I figure this should be fine for what I'm planning. Example of what I'm trying to do, though based on the low-power embedded Soekris net4501 system from the TAPR manual's example section: http://www.febo.com/time-freq/ntp/soekris/index.html ^Aren't those the photos from clock block frequency synthesizer manual? Again, I'm wondering if anyone has opinions or experience about doing such things with NOT an embedded system (as I said, can get a nice 2ghz or so machine for less than $200 locally at a brick and mortar shop within walking distance) Thanks in advance, Sarah ___ 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] Using a frequency synthesizer replacement for motherboard oscillator
On 11/30/2012 6:30 PM, Eric Garner wrote: the actual RTC on modern (Intel based) PC's is driven from a standard 32,768 Hz crystal attached to the PCH. some of them are in incredibly small packages now instead of the old tuning fork-in-a-can ones. peeling off the load caps and crystal from the board would allow you plenty of spaces to tack down a lead from an external synthesizer. Yeah, the one on the (Soekis) example was pretty small. So far none of of the replies have indicated that anyone on here has experience beyond an embedded system. Mostly I started this thread because there have been a few with people discussing implementing NTP on embedded microcontrollers, arduino, etc. and I was thinking of doing it from the other side (turning a nice-ish server into a rock-solid timekeeper) Thanks so far everyone. Really impressed that I already managed to get 4x replies so quickly :) ___ 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] Using a frequency synthesizer replacement for motherboard oscillator
On 11/30/2012 7:54 PM, John Ackermann N8UR wrote: On Nov 30, 2012, at 7:10 PM, Sarah White kuze...@gmail.com wrote: On 11/30/2012 6:30 PM, Eric Garner wrote: the actual RTC on modern (Intel based) PC's is driven from a standard 32,768 Hz crystal attached to the PCH. some of them are in incredibly small packages now instead of the old tuning fork-in-a-can ones. peeling off the load caps and crystal from the board would allow you plenty of spaces to tack down a lead from an external synthesizer. Yeah, the one on the (Soekis) example was pretty small. So far none of of the replies have indicated that anyone on here has experience beyond an embedded system. Sarah, when I was designing and protoyping the ClockBlock, I did interface it with a standard mobo (don't recall the specifics). As someone else pointed out, the process is basically: 1. Find and remove the oscillator that drives the CPU, likely something between 33 and 100 Mhz in modern systems. It's *not* the 32.768 kHz crystal (if there still is one; I think it's actually built into thr RTC chip these days). 2. Figure out which pin is the output of the oscillator module. 3. Figure out the proper drive voltage (most easily based on the supply voltage of the oscillator). 4. Hook the ClockBlock output to the signal pad where the oscillator used to be via small-diameter coax cable such as RG-174, connecting the coax shield to ground on the board and using a series resistor if you need to drop the signal voltage below the 3.3V minimum that the ClockBlock can provide via its voltage-select jumper. Some math and/or experimentation may be involved; the goal is to get enough signal to drive the board, without exceeding the safe Vin rsting of whatever devices the clock is driving. 5. Set the ClockBlock jumpers for the proper clock frequency. Have fun! John John :) Ok, wow, thanks! I couldn't have asked for a better answer to my specific question than one from the designer of the module itself (and more or less saying, and confirming yes, I've done this in testing) Slightly unrelated but... Any chance you could recommend a minimalist set of tools that would be helpful for poking around so I could make sure things are wired up right / signaling as desired, etc? Please don't say logic analyzer or oscilloscope because if that sort of thing is mandatory, I'll just give up now. I took a basic electrical engineering course nearly 20 years ago, and have worked on a few simple controllers and even modified a computer motherboard or two, so this won't be my first venture into such things. ... I'm just currently without ANY tools. (Not counting the dremmel rotory tool for doing acrylic fingernails, and/or various repair tooling, cutting, and sanding of things that would take too long by hand) ... Well mostly none. The only decent tool I have on hand is a soldering iron with a variable control / stand to adjust power and to have somewhere to sit it while it warms up (also, there's a position on the stand which is handy for holding the iron stationary so I can tin wires) Guess that's all for now. Thanks everyone :) P.S. Probably not doing anything like this for at least a month anyway. Still need to sock away enough budget for cheap computer to modify and the clock block itself (or some other appropriate frequency synthesizer) P.P.S This might be my last post of the night. Friend's birthday is today / have a party to finish getting things ready for. ___ 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] [off-list] Using a frequency synthesizer replacement for motherboard oscillator
On 11/30/2012 7:58 PM, John Ackermann N8UR wrote: On Nov 30, 2012, at 7:42 PM, John Ackermann N8UR j...@febo.com wrote: In this case, you're not looking for the RTC but rather the clock that drives the COU Read CPU. Stupid iPad keyboard. I use MessageEase on my android smartphone. The standard keyboard, the errors I frequently got, and some of the REALLY BAD / embarrasing auto-correct problems that resulted were causing me much grief. Works on: Android / iPhone / Windows / Pocket PC / Palm OS They even tested it with project glass typing in mid-air too. (google's wearable, headmounted mobile computer platform) Explanation video... http://youtu.be/26ayS-Ita6g Free (for android at least) and it supports multiple languages. I've only been using it for a few months (and I rarely text and almost never email from my phone) and I'm currently up to 30 words per minutes last I checked. ___ 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] [off-list] Using a frequency synthesizer replacement for motherboard oscillator
oops sorry that was supposed to be reply to sender not to list. Sorry sorry. ___ 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] UTC + 0 (was Accurate timestamping on computers )
http://inkushi.freeshell.org/screenshot-1351958570177.png ^See? Hence my filing a bug report a few hours ago. On 11/3/2012 8:54 PM, Brent Gordon wrote: Reykjavík, Iceland is UTC+0 without summer time changes. Brent On 11/3/2012 9:55 AM, Sarah White wrote: P.S. Seems strange that the only two options for a UTC+0 timezone are London, Dublin or Casablanca (neither of which are year-round UTC) ... I'll try to remember to point this out to the cyanogenmod team (running an aftermarket version of android, cyanogenmod on my phone) so it can be fixed in the next release. ___ 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] Accurate timestamping on computers (previously: For my whole life timezones have been weird)
On 11/3/2012 5:32 AM, Sarah White wrote: So, at or around 1981 (the year I was born) there was a cool concept. IBM was selling personal computers (IBM-PC compatible later became a thing) and by the time I was old enough to operate a modem, I had one myself. Life was good. Wonder if there is any sensible way to petition microsoft to fix this stupid mistake dating back to the DOS era. Windows 8 / metro is out now, and I can't bloody stand the changes. Would be nice if windows 7 had an update to fix this issue: http://support.microsoft.com/kb/2687252 Article ID: 2687252 - Last Review: March 13, 2012 - Revision: 4.0 APPLIES TO Microsoft Windows XP Home Edition Microsoft Windows XP Professional Microsoft Windows XP Service Pack 3 Windows Vista Business Windows Vista Enterprise Windows Vista Home Premium Windows Vista Ultimate Windows Vista Service Pack 1 Windows Vista Service Pack 2 Windows 7 Enterprise Windows 7 Home Basic Windows 7 Home Premium Windows 7 Professional Windows 7 Ultimate Windows 7 Service Pack 1 Windows Server 2008 Datacenter Windows Server 2008 Enterprise Windows Server 2008 Standard Windows Server 2008 Service Pack 2 Windows Server 2008 R2 Datacenter Windows Server 2008 R2 Enterprise Windows Server 2008 R2 Standard Windows Server 2008 R2 Service Pack 1 Microsoft Windows Server 2003 Service Pack 2 ... Pretty sure that's 100% of all recent versions of windows. The whole thing started because windows 3.1 / 95 / 98 / 2000 / ME / etc. etc. etc. were all targeted with being backward compatible with the previous OS leading all the way back to DOS (first versions of DOS were coming out in 1981 the year I was born) For where I live, this weekend is the change your clocks for the fall... or don't, or do something else... petition microsoft maybe? I'd love for windows 7 to have a fix for this since I'm not upgrading to the horrible looking windows 8 --- windows 7 will be in extended support until 2020 (( reference: http://goo.gl/unxvj )) so I figure let's try to get them to fix it in the next few years. I'm serious about this. Let's fix this timezone problem!!! Pretty much every other operating system vendor out there (various POSIX platforms including more than one version of BSD, linux and even mac OSX since under the hood it is a POSIX based operating system) it is an option to leave the hardeware real-time-clock (bios clock) on UTC. Ok that's all I'm typing on this. Angry at several of my clocks today, Sarah White There are a number of reasons it can be problematic for an OS to change the hardware clock twice a year. Example being that sometimes is if you dual-boot more than one version of windows, both of them will try to adjust the clock. Historically, more than one machine I've run has had a glitch where the clock was set forward more than just a single hour adjustment due to dual-boot or just crash during reboots when summer time was being set/unset. Plenty can go wrong. It's just not anything I want to worry about / shouldn't be necessary (mac, linux, bsd, etc. don't have this flaw because they typically have the hardware clock set to UTC, and use software settings to display the local time by calculating offset) ...Someone contacted me offlist and pointed out that there is no reason I can't tell windows that I'm in a timezone that uses UTC (without summer time / daylight savings time adjustment) The workaround varies by windows version, but for me it looks basically like this: http://inkushi.freeshell.org/Saturday_November_03_2012_555_UTC_Protest.png http://inkushi.freeshell.org/Saturday_November_03_2012_637_UTC_Workaround.png Basically, a side effect is that windows is now reporting UTC as being local time even though that is NOT my desired local clock for display and other purposes. This was the only workaround I knew for certain would keep my hardware clock set to UTC. My emails are now being timestamped with UTC as a result. Shouldn't confuse me too badly, but this is the most optimal way I could come up with. I don't want to have to think about the behavior / performance of my NTP time synchronization twice a year. This is the main reason (for me) it is an issue. So maybe I really am a little bit nuts (about time too) Sarah White P.S. For windows 7, default tray / notification icon settings: All of the relevant settings are available by simply clicking the clock in the corner. Can even add additional clocks to display alternate timezones and name them whatever you like. Unfortunately, most software now reports the local clock wrong, and the only way I seem to be able to view local time is by using the windows clock / calendar applet in the corner of the taskbar (tray area) Whatever. For my purposes it was more important to have the hardware clock not be tampered with twice a year by the OS ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go
Re: [time-nuts] For my whole life timezones have been weird
On 11/3/2012 8:02 AM, Edgardo Molina wrote: Dear Sarah, Good morning. I just returned home from a long and difficult customer data center migration. I thought of sharing that I feel the same way as you do regarding your thread. Things should always behave like a Mac or Linux, in which if there is a glitch, the OS responsible party jumps into scene with a solution. Not the way it happens and builds your frustration with Windows. Food for thought, just an example of someone supporting their OS user base on a similar topic. To err is human, to fix the errors should also be: http://support.apple.com/kb/TA24568?viewlocale=en_US Cheers, Edgardo Molina Dirección IPTEL Microsoft puts out timezone updates too. The difference is, apple's version of the same doesn't adjust the hardware clock. https://wiki.archlinux.org/index.php/Time#Time_standard The localtime standard is what I'm wanting to get away from. Unfortunately, on windows there is no way to do this and still display the local time correctly. --Sarah ___ 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] Accurate timestamping on computers (previously: For mywhole life timezones have been weird)
On 11/3/2012 8:26 AM, WB6BNQ wrote: Sarah, I am having a hard time understanding your problem. Or at least what you see as a problem. I am not sure what you are really complaining about here ? Is it the daylight change ? Or is it a dual boot problem which would suggest you do not have some settings in their rightful place ? The computer is merely displaying a form of time representation on the screen (human device). Internally, it seems to me, the computer's operating system is merely keeping a count of the passing seconds since reading the actual hardware, hardwired clock chip upon boot-up. After the initial boot it no longer reads the hardware clock chip to my understanding. If that is the case, it would suggest that a flag is recorded as to the daylight savings time change either in firmware or perhaps on the mass storage device that has the operating system. It is possible that the hardwired clock chip may keep track of the daylight savings function. If that is the case, perhaps the way to deal with it is to write a a small program that will make sure that hardwired chip stays in the NON daylight mode as part of a boot-up routine. As for the microsoft reference, it suggests not using a particular registry entry and if it is there to delete it. On my computer it is not present in the registry. While that only fixes some kind of system unresponsiveness issue, it does not seem to keep the daylight function from changing. With all the clock Synching available via the internet, it seems to me your clock should not be an issue in of itself. However, I am retired, as such, do not have a watch and pay little attention to the wall clock. BillWB6BNQ begin reply 1 @ Bill / WB6BNQ wb6...@cox.net The hardware chip does not do any such tracking of the daylight savings time Here is a reference better explaining the problem: http://www.cl.cam.ac.uk/~mgk25/mswish/ut-rtc.html begin reply 2 On 11/3/2012 8:38 AM, li...@lazygranch.com wrote: Microsoft also does updates regarding the day daylight savings time changes, similar to that Apple message. I suspect I'm not following this thread correctly. What I got from the orignal thread is Microsoft will thunk the RTC during the switchover. I'm going to make it a point to insure NTP is logging correctly, and then look for a time error at the switch over. (2AM I think.) @ li...@lazygranch.com Correct. This is the primary concern. Tweaking the clock twice a year to match up with local time is not desired. Seeing as I'm in the process of installing a hardware refclock (trimble thunderbolt connected via serial port) for my NTP, it is highly problematic and potentially error-prone for microsoft's OS to touch the bios hardware clock AT ALL. I'm entertaining the notion of writing a kernel-mode hardware timestamp / PPSAPI driver to pull the signal off the 1 PPS port on the tbolt one way or another. I plan to do this on windows. This is something I want to attempt even though the NT kernel doesn't have the best reputation for realtime hardware / interrupt handling. Plan is to put in a non-zero amount of work, up to and including steps where I go through the driver signing run-around with microsoft to actually have it fully recognized by the OS without modification. (unless budget issues are a limiting factor) ... Possibly, this project could even using a board which physically goes on in a PCI express bus slot in order to do hardware timestamping. ___ 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] Accurate timestamping on computers (previously: For mywhole life timezones have been weird)
On 11/3/2012 9:18 AM, David J Taylor wrote: -Original Message- From: Sarah White [] Seeing as I'm in the process of installing a hardware refclock (trimble thunderbolt connected via serial port) for my NTP, it is highly problematic and potentially error-prone for microsoft's OS to touch the bios hardware clock AT ALL. I'm entertaining the notion of writing a kernel-mode hardware timestamp / PPSAPI driver to pull the signal off the 1 PPS port on the tbolt one way or another. I plan to do this on windows. This is something I want to attempt even though the NT kernel doesn't have the best reputation for realtime hardware / interrupt handling. Plan is to put in a non-zero amount of work, up to and including steps where I go through the driver signing run-around with microsoft to actually have it fully recognized by the OS without modification. (unless budget issues are a limiting factor) [] Sarah, I don't know which version of Windows you are proposing to use, but I have NTP stratum-1 servers based on GPS devices with a PPS signal on the DCD line of the COM port, and Windows altering, or not altering, the hardware clock has /no effect/ at all. I'm using Dave Hart's serialPPS.sys device driver on Windows-2000 up to Windows-7/64 (including telling Win-7/64 to ignore the signed 64-bit driver requirement). GPS hardware: http://www.satsignal.eu/ntp/FreeBSD-GPS-PPS.htm http://www.satsignal.eu/ntp/Sure-GPS.htm Windows stratum-1 notes: http://www.satsignal.eu/ntp/NTP-on-Windows-serial-port.html I would note that for the best performance on a stratum-1 server you may want to try FreeBSD or even Linux on a Raspberry Pi. http://www.satsignal.eu/ntp/FreeBSD-GPS-PPS.htm http://www.satsignal.eu/ntp/Raspberry-Pi-NTP.html If Dave Hart's driver suits your needs, I'm sure he would be interested in getting it signed for Microsoft use (if he hasn't already done so). Cheers, David Thanks so much David... Really. Thanks. I feel alot better now. Regardless of documented issues on: http://www.cl.cam.ac.uk/~mgk25/mswish/ut-rtc.html (quote) The numerous past malfunctions of Microsoft operating systems caused by keeping local time in the RTC and trying to cleverly perform the RTC adjustment semi-automatically have been repeatedly the subject of concerned public discussion: RISKS 16.54.1 RISKS 18.96.3 RISKS 19.11.16, RISKS 19.12.14 RISKS 19.43.13, RISKS 19.43.14, RISKS 22.34.3... (multiple links) Not sure what timezone you're in... ... So I don't know which day your summer time ends this year. I'd love to see the your loopstats file for as many of your windows boxes as possible (with refclock, or without. Either is fine.) for the day of the DST update this fall (and maybe any other loopstats data from when the realtime clock got updated due to summer time / DST updates) According to: http://www.satsignal.eu/mrtg/daily_ntp.html (section: Hardware and OS configuration) I'm assuming the relevant list is: feenix, stamsund, bacchus, narvik, alta, molde, ystad, puffin, and any other NT-5.x / NT 6.x based kernel (windows machines) I missed. Wow that's a wonderfully diverse list :) I actually thought about it a bit, and in hindsight I'm realizing that internally, NTP uses a synthetic timebase anyway. Perhaps I was being paranoid after all. Thanks for the reply, Sarah White P.S. Your site has always had great documentation about NTP configurations with a GPS-type reflock since I first saw it a couple years ago. I've found it very useful. ___ 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] Accurate timestamping on computers (previously: For mywhole life timezones have been weird)
On 11/3/2012 11:31 AM, David J Taylor wrote: -Original Message- From: Sarah White Sent: Saturday, November 03, 2012 9:49 AM Thanks so much David... Really. Thanks. I feel alot better now. Regardless of documented issues on: http://www.cl.cam.ac.uk/~mgk25/mswish/ut-rtc.html (quote) The numerous past malfunctions of Microsoft operating systems caused by keeping local time in the RTC and trying to cleverly perform the RTC adjustment semi-automatically have been repeatedly the subject of concerned public discussion: RISKS 16.54.1 RISKS 18.96.3 RISKS 19.11.16, RISKS 19.12.14 RISKS 19.43.13, RISKS 19.43.14, RISKS 22.34.3... (multiple links) Not sure what timezone you're in... ... So I don't know which day your summer time ends this year. I'd love to see the your loopstats file for as many of your windows boxes as possible (with refclock, or without. Either is fine.) for the day of the DST update this fall (and maybe any other loopstats data from when the realtime clock got updated due to summer time / DST updates) According to: http://www.satsignal.eu/mrtg/daily_ntp.html (section: Hardware and OS configuration) I'm assuming the relevant list is: feenix, stamsund, bacchus, narvik, alta, molde, ystad, puffin, and any other NT-5.x / NT 6.x based kernel (windows machines) I missed. Wow that's a wonderfully diverse list :) I actually thought about it a bit, and in hindsight I'm realizing that internally, NTP uses a synthetic timebase anyway. Perhaps I was being paranoid after all. Thanks for the reply, Sarah White P.S. Your site has always had great documentation about NTP configurations with a GPS-type reflock since I first saw it a couple years ago. I've found it very useful. Sarah, There's really no issue over the hour change as NTP and Windows work in UTC internally, nevertheless, for your interest some loopstats are here: http://www.satsignal.eu/ntp/2012-10-28-loopstats.zip I'm in UTC here, colloquially GMT/BST and we swap on the last Sunday of October. My PCs all run with wall clock time displayed, and UTC internally (just the normal Windows default). The RTC is only consulted at system boot time, so with systems running 24 x 7 there's no issue. None of my systems multi-boot normally, just possibly the odd test PC may have Win-7 and Win-8 installed. I'm delighted that you find the site useful! Cheers, David Great, thanks for the loopstats. For the included loopstats, I believe Alta was among the ones on which you were running windows 7 + NTP... Would you mind confirming which setting you have for your timezone? (since I'm reasonably certain I know what the timezone menus would look like) http://inkushi.freeshell.org/bst.png http://inkushi.freeshell.org/utc.png Windows has more than one entry for most UTC offsets (DST schedule varies by hemisphere, country, some don't have summer time at all, etc.) ... so the timezone I personally have selected is the UTC option without a summer time adjustment (never set to UTC+01 / BST) ... Also, curious what you mean when you say you have wall clock time displayed (UTC internally) ... ? --Sarah ___ 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] Accurate timestamping on computers (previously: For mywhole life timezones have been weird)
On 11/3/2012 3:12 PM, David J Taylor wrote: -Original Message- From: Sarah White Great, thanks for the loopstats. For the included loopstats, I believe Alta was among the ones on which you were running windows 7 + NTP... Would you mind confirming which setting you have for your timezone? (since I'm reasonably certain I know what the timezone menus would look like) http://inkushi.freeshell.org/bst.png http://inkushi.freeshell.org/utc.png Windows has more than one entry for most UTC offsets (DST schedule varies by hemisphere, country, some don't have summer time at all, etc.) ... so the timezone I personally have selected is the UTC option without a summer time adjustment (never set to UTC+01 / BST) ... Also, curious what you mean when you say you have wall clock time displayed (UTC internally) ... ? --Sarah = Sarah, PC Alta is Win-7/64, with a GPS/PPS ref-clock using Dave Hart's serialPPS.sys device driver. The time-zone on all my PCs is London, Edinburgh, Dublin, which implies GMT (i.e. UTC) in the Winter and BST - British Summer Time - (UTC+1) in the Summer. I.e. http://inkushi.freeshell.org/bst.png What I mean by wall-clock time is that I have the standard settings in the control panel, i.e. telling Windows that I am located in Edinburgh so that the time displayed by normal applications alters with the season, and that the time agrees with normal wall-clock time. This is nothing special, and how almost all PCs in the UK would be set. I mean that I have /not/ set Casablanca where there both Summer and Winter are UTC. I did have one PC set to UTC only and NTP ran equally well on it. As I mentioned, internally Windows runs on UTC, and a program can interrogate that time. Windows also provides offsets so that UTC can be converted to local (wall-clock) time for display within applications. NTP uses the internal UTC time and is unaffected by time-zone or seasonal changes. Cheers, David Ah. Ok, cool. I guess the synthetic timebase used by NTP is probably doing what it was meant to do (ignore inconsistency in the RTC under various circumstances) By the way, I suspect that you didn't know that morocco (casablanca) has observed a summer time adjustment since the year 2008. I sure didn't. http://www.timeanddate.com/news/time/morocco-dst-2012.html Apparently there is now even a special case during the muslim month of ramadan: -(quote: timeanddate.com)- According to the new law, the DST period will be interrupted during the Muslim month of Ramadan (July 20 – August 20, 2012 in the Gregorian calendar) -(end quote)- Earlier I was looking for a UTC timezone to use on my android phone, and nearly set it to casablaca without fact-checking first... Oops! For now I suppose that can be one of my clocks set to local time (NY) since it's a well-known timezone I shouldn't have to worry about too much. --Sarah P.S. Seems strange that the only two options for a UTC+0 timezone are London, Dublin or Casablanca (neither of which are year-round UTC) ... I'll try to remember to point this out to the cyanogenmod team (running an aftermarket version of android, cyanogenmod on my phone) so it can be fixed in the next release. ___ 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] For my whole life timezones have been weird
So, at or around 1981 (the year I was born) there was a cool concept. IBM was selling personal computers (IBM-PC compatible later became a thing) and by the time I was old enough to operate a modem, I had one myself. Life was good. Wonder if there is any sensible way to petition microsoft to fix this stupid mistake dating back to the DOS era. Windows 8 / metro is out now, and I can't bloody stand the changes. Would be nice if windows 7 had an update to fix this issue: http://support.microsoft.com/kb/2687252 Article ID: 2687252 - Last Review: March 13, 2012 - Revision: 4.0 APPLIES TO Microsoft Windows XP Home Edition Microsoft Windows XP Professional Microsoft Windows XP Service Pack 3 Windows Vista Business Windows Vista Enterprise Windows Vista Home Premium Windows Vista Ultimate Windows Vista Service Pack 1 Windows Vista Service Pack 2 Windows 7 Enterprise Windows 7 Home Basic Windows 7 Home Premium Windows 7 Professional Windows 7 Ultimate Windows 7 Service Pack 1 Windows Server 2008 Datacenter Windows Server 2008 Enterprise Windows Server 2008 Standard Windows Server 2008 Service Pack 2 Windows Server 2008 R2 Datacenter Windows Server 2008 R2 Enterprise Windows Server 2008 R2 Standard Windows Server 2008 R2 Service Pack 1 Microsoft Windows Server 2003 Service Pack 2 ... Pretty sure that's 100% of all recent versions of windows. The whole thing started because windows 3.1 / 95 / 98 / 2000 / ME / etc. etc. etc. were all targeted with being backward compatible with the previous OS leading all the way back to DOS (first versions of DOS were coming out in 1981 the year I was born) For where I live, this weekend is the change your clocks for the fall... or don't, or do something else... petition microsoft maybe? I'd love for windows 7 to have a fix for this since I'm not upgrading to the horrible looking windows 8 --- windows 7 will be in extended support until 2020 (( reference: http://goo.gl/unxvj )) so I figure let's try to get them to fix it in the next few years. I'm serious about this. Let's fix this timezone problem!!! Pretty much every other operating system vendor out there (various POSIX platforms including more than one version of BSD, linux and even mac OSX since under the hood it is a POSIX based operating system) it is an option to leave the hardeware real-time-clock (bios clock) on UTC. Ok that's all I'm typing on this. Angry at several of my clocks today, Sarah White ___ 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] Simple NTP server based on a Raspberry Pi
On 10/29/2012 7:53 PM, Chris Albertson wrote: I'm curious what load average numbers do you get if you type uptime after running NTP for some hours. I'd guess that even on the Pi the CPU is hardly used at all. That would also depend of the number of NTP clients you are supporting. On Mon, Oct 29, 2012 at 12:19 PM, David J Taylor david-tay...@blueyonder.co.uk wrote: I've spent the last few days getting a very simple, low-power NTP server working on a Raspberry Pi. Chris Albertson Redondo Beach, California Basically, I'm thinking this method (raspi + refclock) is a good way to feed a handfull of public stratum 2 servers which by definition don't have their own local refclock. If you made your raspi stratum 1 server publicly available via pool.ntp.org it would almost certainly be overloaded. ... Basically, I'm thinking I might do this myself once I get done replacing my low-quality NMEA only / firmware bug / navigation mode GPS refclock with the timing mode one I'm still working on putting together. (this is my first time setting up an antenna of any kind / had to do some research and make sure I ordered the right parts) http://www.endruntechnologies.com/time_server_clients.htm ^using the example from this: Let's assume a raspi can handle 200 packets per second without loosing performance too badly (limited by cpu load, etc.) Now let's assume that all clients using the raspi time server are NOT malfunctioning, and have settled down to the default maxpoll time of 1024 seconds between updates. Number of Clients = (Number of Packets per Second) multiplied by 1024 That would come out to a capacity of just over 200 thousand clients if the rate at which clients send packets were uniformly distributed ... Not sure if it's reasonable to expect a raspi to handle 200 connections per second without breaking a sweat. I've not talked with many people who tested them, so just a guess based on the example from endrun's website which states the cpu on their hardware runs at 133mhz so it might really be possible to handle 200 connections per second with the 700mhz raspi. hope this helps, Sarah White ___ 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] Timing performance of servers
(or compiled yourself) see reference: http://www.satsignal.eu/ntp/setup.html 2) For any version of NTP compiled from the ntp.org official source (such as above) there is no distinction between client vs server. Depending on settings in: ntp.conf ... 2a) often, the stratum 1 pool servers are peered with other stratum 1 servers (same for stratum 2) ... If any ntp server detects better time from a peer, it will lower it's own stratum and treat the better peer as a new synchronization source. (such as a failed refclock on stratum 1, etc.) 2b) Synchronization only mode, basically you are the closing off yourself to traffic, will not share time with ntp running on downstream stratum, don't have any peers: In this use case, even a local refclock (stratum 0) is marked using a server line in the ntp.conf 2c) not using the reference implementation built from ntp.org source... things stated in 2a and 2b no longer apply... consumer equipment such as wifi routers, or even commercial standalone time servers often implement ntp protocol ... however well or poorly the manufacturer chooses to do so. Meinberg's ntp really is based on the source from ntp.org --- Sorry to post such a long thing on the subject. Most of the work I do with accurate time involves network synchronization. Really, the NTP / SNTP protocol isn't nearly as high performance as Precision time protocol --- PTP is the latest technology to come out of the network time foundation, and NTP protocol has simply been around longer and as such, it is better known: http://networktimefoundation.org/projects/ regards, Sarah White ___ 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] Followup (still want a GPS-type NTP refclock)
On 10/17/2012 12:31 PM, Chris Albertson wrote: On Wed, Oct 17, 2012 at 12:50 AM, Sarah White kuze...@gmail.com wrote: Hi again everyone :) Originally I was hoping for a thunderbolt. The control / diagnostic software looked cool, but I couldn't afford the pricetag on one. ...Here's my followup now: Determined I'd love to get my hands on an iLotus m12m. That's just a statement. My heart is set on getting this. Would it be possible to find a kit (new, used or otherwise) with: 1) iLotus M12M timing mode GPS (serial port version) 2) Aprox 10 meter antenna cable with apropriate connector(s) 3) active antenna which can handle being 10 meters from the module 4) power supply for above list, and much needed luck, all for under $100 US Just over $100. the M12M is about $60 new. If you call up and say you are a hobbyist and heard about it on this list. Buy a timing antenna on eBay for about $30 You can use 30 meters of cable TV wire and some N to F adaptors You can power it all with a salvaged power cube. Then you'd need a mast for the antenna made with plumbing parts and misc hardware and a box for the electronics. Maybe $130 if you were carful But if you are really worried about cost buy an older Oncore. The new m12m is only slightly better then the older m12+T that sells on eBay for $35. The two are nearly identical. (See item # 290656401551) then see item # 270881742870 for an antenna You'd be just under $100 if you went this route. I ended up with a TAPR thunderbolt kit within my price range instead of an oncore variant, so it looks like I ended up doing everything on-budget: F-Type RG59 75 Ohm Coaxial Cable (random off-the shelf 50-foot cable with 75 Ohm impedence to match the specs recommended in tbolt manual) ARS-0325 (Type F Female to Type N Male Adapter to match cable end to the antenna) Symmetricom 58532A antenna (found a gently used one on ebay for cheap) Thanks everyone for the advice and other help figuring all this out. Regards, Sarah White ___ 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] Timing performance of servers
On 10/24/2012 6:47 PM, Magnus Danielson wrote: Fellow time-nuts, When spending time on a conference last week, I heard one interesting comment that they lost data due to bad timing on their Windows servers. Now, I know that the standard Windows uses SNTP in order to achieve the goal of having the timing of the machines sufficiently aligned to allow Kerberos authentication. SNTP suffice for that, as it needs to be a handful of minutes in line. If you need better performance than that, you should use NTP (and then download and install Meinbergs Windows-client for NTP). Then again, I would point out that for this type of data, it would most probably be better served on a Linux box. What should be a nice wake-up call for them would be a summation of how different strategies would give them clock precision of sufficient grade. So, does anyone know of such measurements presented anywhere? There are bits and pieces, but the ideal for this case would be if they where collected in one page/paper. This is an awareness thing, so that people can do a little more well-informed choices. Cheers, Magnus 1) Thanks magnus. This is something I'm quite interested in: I'm not the only one doing testing for Microsoft NT 5.x and higher against NTP-type synchronization. It's actually high enough quality such that a Windows server running NTP with a refclock provides significantly better time than the public NTP servers. Here are a few writeups I've been using for reference, and I've been testing and duplicating some of the listed configurations, hoping for my own writeups: http://www.satsignal.eu/ntp/NTP-on-Windows-Vista.html (basic timing) http://www.satsignal.eu/ntp/NTP-on-Windows-serial-port.html (connected to refclock, timing was better than 50 microseconds jitter, averaging less than 10 microseconds) Am actively in the process of getting everything to replace my own navigation GPS refclock with a timing mode one. At this point I just need to find a good antenna... 2) ... Changing subject slightly: Regardless of if I run linux vs bsd vs windows (will be testing multiple configurations of each, and doing writeups over the next few years as I test more and learn) I'll need a good external antenna for the new GPS I'm going to run. Anyone think I can get by with anything cheaper than a symmetricom 58532a antenna? I can probably get one (used) for less than $50 on ebay, but I'd really prefer to source something more entry-level for closer to $5 or $10 if possible. Any suggestions? ___ 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] Adjusting HP 5065A frequency
(( replied at beginning to be consistent with this thread )) Thanks, this has done a good job at furthering my understanding about error (one way of describing adev as I understand) vs short and long tau times. I don't have anything to add on that subject, but but I have a question about a page you linked... http://www.leapsecond.com/pages/gpsdo/ section: Trimble Thunderbolt GPSDO (OCXO version) The text This version of the Thunderbolt has an OCXO (unlike the model shown on the Trimble web page). These are also recently available on the surplus market. just before chart image titled Free vs. Locked: GPSDO [#a20] So when I did a quick fact check, I was immediately confused: (re-quote) ...version of the Thunderbolt has an OCXO (unlike the model shown on the Trimble web page)... Fact checking with today's site: http://www.trimble.com/timing/ The TBoltI can even find is the Thunderbolt® E GPS Disciplined Clock Which in turn, if I follow the link: Under Key features section: Ovenized quartz oscillator provides stable 10 MHz and 1 PPS output to maximizes bandwidth Leaves me wondering. Does trimble even offer a non-ovenized TBolt at this point? I can logically infer / assume that at one point, they did, but I don't know what to think now. New and curious, Sarah On 10/22/2012 7:32 AM, Tom Van Baak wrote: Hi Bert, Not sure about the range/resolution. That would depend on how the standard is used and what its frequency drift rate is. The stability doesn't have to be too much better than the standard itself. The Austron 2055 resolution is 1e-14, IIRC. The Symmetricom AOG is 1e-19 (overkill). What I've found in some GPSDO and passive atomic standards (e.g., Rb or Cs) is that as soon as you turn on the DAC and enable the loop, you get more short-term noise, say in the range of 1 to 100 seconds. That's why for best stability you always switch off the loop during a sensitive measurement. Many older Cs had a Cs off switch for this. Not only did it conserve cesium but it also means you're running straight off the high-quality OCXO. This is also true for GPSDO, like the TBolt which allows you to turn off disciplining with a s/w command. In general, when you discipline a OCXO you get that characteristic ADEV hump. This is expected, a natural byproduct of combining two unknowns, one that's assumed to be better at short tau and worse at long tau (e.g., OCXO) and one that's assumed to be better at long tau and worse at short tau (e.g., Rb cell, or Cs beam, or GPS receiver). At some point there is a cross-over and you know/assume that at that point each must be contributing 1/sqrt(2) of the noise. To see the humps in living color, refer to: http://www.leapsecond.com/pages/gpsdo/ To answer your question about short/medium/long, I guess in this case short is tau left of the hump; medium is the hump, and long is tau to the right of the hump. /tvb - Original Message - From: ewkeh...@aol.com To: time-nuts@febo.com Sent: Monday, October 22, 2012 4:04 AM Subject: Re: [time-nuts] Adjusting HP 5065A frequency Tom I have two questions what should the range, resolution and stability of the delay generator be and how much do you think a digital loop driven by a Tbolt would degrade short and medium precision. What is your definition of short and medium? Bert Kehren In a message dated 10/22/2012 12:25:08 A.M. Eastern Daylight Time, t...@leapsecond.com writes: Three companies come to mind for phase microsteppers. A popular one decades ago was made by Austron (model 2055A). I got mine on eBay but they are not as common now as ten years ago. The current models by Symmetricom and Spectra Dynamics are extremely high-end (expensive) and overqualified for use with a vintage rubidium oscillator. If you visit NIST or USNO you will see these impressive units. It would be a very fun project to make your own. I suspect other group members could either help you or would eagerly employ your design for their own use. But -- before you decide on a hardware solution see if you can do it in software. An analogy is what we do with GPS 1PPS sawtooth errors. There are two ways to deal with this. One is to capture the correction message over RS232, measure the DUT vs. GPS 1PPS with a TIC, and then numerically apply the sawtooth correction with one line of code. Several of the popular GPS monitor programs do this automatically for you (TBoltmon and TAC32, for example). The software solution is perfect to the granularity of the sawtooth message, typically 1 ns. The hardware implementation usually involves a PIC and a programmable delay generator. The PIC listens for the correction message over RS232 and then has plenty of time (up to one second) to program the delay chip. When the hardware 1PPS arrives it is delayed to compensate for the aforementioned sawtooth error.
Re: [time-nuts] documentation for beginners
On 10/21/2012 12:39 PM, Attila Kinali wrote: On Sun, 21 Oct 2012 18:02:40 +0200 Magnus Danielson mag...@rubidium.dyndns.org wrote: Ah, but this is Time-Nuts.. are you sure you don't need 1E-13 performance? You may not think you do today, but inevitably, the horrible uncertainty in your time stamps will gnaw at your innermost soul, and pretty soon, you'll be building choke rings, wrapping your $6 receiver in an oven, cobbling together some weird combination of surplus parts. Hear! Hear! As time-nuts, we try to get the best possible performance for least possible cost. Then again, we oldies should recall that new-comers still need to get started. We should give them advice that gives them a good start while not spending too much money on a solution which isn't sufficiently expandable into the future. We should have a wiki for FAQ and references. Yes, definitly. Often it's very simple information one is lacking. Like: where to find such information :-) KO4BB's site is definitly worth a look, even if a bit overwhelming and not clearly structured (especially if you dont know what you are looking for). A list of OCXOs and their benefits/drawbacks, like the list Luciano (aka timeok) send a couple of weeks back is also a great help. Or Vig's presentation on quarz resonators (if you haven't read it, you should!) Then a list of sources for time/frequency refrences and how to aquire them (like GPS - GPSDO, DCF77/WWVB receivers etc). But i don't know of any document that does this... And something that glues all of the above together... The rest is just a mater of asking and finding the right documenation. :-) Attila Kinali I would better appreciate that list of information if I confidently / specifically knew how to access any of it. Any chance you have links to the helpful information-type things you just listed? I feel almost insulted by my ignorance right about now :( ...Like maybe I'm missing something from earlier in the mailing list. I was following the thread with // Followup (still want a GPS-type NTP refclock) // and now I don't know where this thread actually started. Am I responding to the original post? Still waking up / confused by first post I'm responding to today --Sarah ___ 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] documentation for beginners
On 10/21/2012 1:13 PM, Magnus Danielson wrote: Dear Sarah, On 10/21/2012 06:48 PM, Sarah White wrote: I would better appreciate that list of information if I confidently / specifically knew how to access any of it. Any chance you have links to the helpful information-type things you just listed? I feel almost insulted by my ignorance right about now :( ...Like maybe I'm missing something from earlier in the mailing list. I was following the thread with // Followup (still want a GPS-type NTP refclock) // and now I don't know where this thread actually started. Am I responding to the original post? Still waking up / confused by first post I'm responding to today --Sarah There have been so much material passing through the list, that reading up on it would be a large effort. However, the point of a Wiki-based FAQ/BCP is to speed the learning up for folks like you. It would be good if list emails/threads could be linked in as references in articles. This also helps to give credit where credit is due. Cheers, Magnus (quote) It would be good if list emails/threads could be linked (end) Works fine for me: http://www.mail-archive.com/time-nuts@febo.com/msg52589.html ^is it considered meta that I quoted a post, then linked to it? lol ___ 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] Are serial port headers standardized?
I've done enough reading to know that continuing to use this navigation (NOT timing mode) GPS is not an option. Initially, I was pleased to find out that the old RS232 (serial) --- USB adapter I pulled out of storage uses the same prolific 2303 USB-serial driver ... At least at first I was. Supposedly, normal serial ports have less trouble with latency than anything done over USB. I definitely have an annoying 590 (ish) millisecond delay when using the NMEA driver on my NTP daemon, and basically, it shouldn't ever be necessary to use the fudge times if you're doing things right. None of that is a question. I just feel foolish for nearly putting a nicer (timing mode) GPS on a USB -- serial adapter. So I was looking at my motherboard manual, and realized something: (( QUOTE )) COM1 (Optional) The motherboard kit provides an additional serial COM header for your machine. Connect one side of a switching cable to the header and then attach the serial COM device to the other side of the cable. (( END QUOTE )) Do what with my what? err... http://www.evga.com/support/manuals/files/122-ck-nf63.pdf Page 15, there is a yellow 10 (9) pin header, and page 26 was what I quoted. Really wish there was more information... I've had this motherboard for something like 5 years at this point, and am fairly certain I lost or outright tossed the serial port headers. Are they fairly standard? Will this work: http://www.newegg.com/Product/Product.aspx?Item=N82E16815158115 ... That's my only real question. What nonsense were they referring to? Connect one side of a switching cable to the header and then attach the serial COM device to the other side of the cable. switching cable Like I said: Do what with my what? Thanks everyone, Sarah ___ 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] Are serial port headers standardized?
3x corrections: 1) Page 11, there is a yellow pinout header labeled 15 2) I think I tossed the serial port cables (headers are on the MB) 3) clarification... USB-type GPS uses the same driver as an actual USB-serial adapter does: ((...snip...)) http://www.ankaka.com/usb-gps-receiver-for-computers-laptop-worked-as-gps-navigator_p46411.html AGI-G217 USB GPS Receiver ((...snip...)) ^copied from other thread: Followup (still want a GPS-type NTP refclock) Thanks again, Sarah On 10/20/2012 2:05 AM, Sarah White wrote: I've done enough reading to know that continuing to use this navigation (NOT timing mode) GPS is not an option. Initially, I was pleased to find out that the old RS232 (serial) --- USB adapter I pulled out of storage uses the same prolific 2303 USB-serial driver ... At least at first I was. Supposedly, normal serial ports have less trouble with latency than anything done over USB. I definitely have an annoying 590 (ish) millisecond delay when using the NMEA driver on my NTP daemon, and basically, it shouldn't ever be necessary to use the fudge times if you're doing things right. None of that is a question. I just feel foolish for nearly putting a nicer (timing mode) GPS on a USB -- serial adapter. So I was looking at my motherboard manual, and realized something: (( QUOTE )) COM1 (Optional) The motherboard kit provides an additional serial COM header for your machine. Connect one side of a switching cable to the header and then attach the serial COM device to the other side of the cable. (( END QUOTE )) Do what with my what? err... http://www.evga.com/support/manuals/files/122-ck-nf63.pdf Page 15, there is a yellow 10 (9) pin header, and page 26 was what I quoted. Really wish there was more information... I've had this motherboard for something like 5 years at this point, and am fairly certain I lost or outright tossed the serial port headers. Are they fairly standard? Will this work: http://www.newegg.com/Product/Product.aspx?Item=N82E16815158115 ... That's my only real question. What nonsense were they referring to? Connect one side of a switching cable to the header and then attach the serial COM device to the other side of the cable. switching cable Like I said: Do what with my what? Thanks everyone, Sarah ___ 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] Are serial port headers standardized?
On 10/20/2012 7:48 AM, Azelio Boriani wrote: Usually a crimp type DB9 can be wired directly to the crimp type IDC connector, leaving out the pin 10 of the IDC, it is missing in the header. But, yes, better to test as indicated by Peter. ((...snip...)) o - This pin should be ground o o o o - Serial out o o - Serial in o o Regards, Pete ((...snip...)) I'm kinda wanting to try it too. Talking to myself via realterm on an oldschool-ish com port instead of just poking a GPS with a builtin USB--serial sounds fun. Just need to steal a jumper off ... well... I don't have spare hardware lying around or anything, but I think I know someone who might. Oops, forgot what else I was going to post. Landlord had a few contractors fixing something in the building today, and had to let them in and help with a few minor things. Guess I'll eat breakfast now? Still half asleep, Sarah ___ 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] Are serial port headers standardized?
On 10/20/2012 10:06 AM, Bob Camp wrote: Hi The IDC to 9 pin cables are a generic / cheap item on eBay or from Newegg. Less than $3 delivered last time I needed any. Bob ((...snip...)) Motherboard manual said: Connect one side of a switching cable to the header and then attach the serial COM device to the other side of the cable. ... is IDC another way of saying this? what does the acronym represent? Also, pricing... yeah, I had noticed that they're not very expensive, and posted this, trying to figure out if they're mostly all just about the same: http://www.newegg.com/Product/Product.aspx?Item=N82E16815158115 Someone pointed out it was the low-profile version (I wasn't paying attention when I linked it earlier) so I'll look a bit later for the full-slot type. Thanks for answering my original question asked in the topic. generic (standardized?) is what I was hoping for. Regards, Sarah ___ 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] Are serial port headers standardized?
On 10/20/2012 11:56 AM, Dennis Ferguson wrote: On 20 Oct, 2012, at 02:05 , Sarah White kuze...@gmail.com wrote: Page 15, there is a yellow 10 (9) pin header, and page 26 was what I quoted. Really wish there was more information... I've had this motherboard for something like 5 years at this point, and am fairly certain I lost or outright tossed the serial port headers. Are they fairly standard? I think there are two standard variants, this one http://www.pccables.com/07120.htm and this one http://www.pccables.com/07121.htm For Intel motherboards I've only seen the first one used, but I don't know about anything else. Dennis Ferguson Wow! That's perfect. (and cheaper than I had hoped) THANKS!!! -Sarah ___ 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] Followup (still want a GPS-type NTP refclock)
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 On 10/18/2012 3:33 AM, Hal Murray wrote: ((...snip...)) Where did you get one for $6? What make/model/brand? ((...snip...)) Does anybody have a favorite low cost timing mode unit? How about one with minimal soldering required? http://www.ankaka.com/usb-gps-receiver-for-computers-laptop-worked-as-gps-navigator_p46411.html AGI-G217 USB GPS Receiver ... on the USB side of things, it shows up as prolific 2303: PL-2303 USB-to-Serial drivers are a PITA (pain in the backside) to find though / the website for drivers changed. Apparently, the current list price is $40 USD / wholesale for cheaper ... not sure what the deal I got was. Mine might've fallen off a truck or something shady to explain inventory loss. Really not sure. oops ... somehow I ONLY paid for shipping. Really can't explain why or what happened: $6.76 shipped via sendfromchina.com and tracking via hongkongpost.com It's not timing mode though... As for your second question low cost timing mode unit? How about one with minimal soldering required? Basically, motorola oncore variants such as the M12+T / M12M ... or UT or otherwise... The ones I was originally talking about in this thread / earlier post... These can KINDA be found for less than $100 and I'm starting to think that's probably as far down as low cost can get for timing mode. ((digitally signed)) Sarah White -BEGIN PGP SIGNATURE- Version: GnuPG v2.0.17 (MingW32) Comment: Using GnuPG with Mozilla - http://www.enigmail.net/ iQIcBAEBAgAGBQJQgFjqAAoJEL5NTv0FKXxn4nAP/Rb0UoOk/NH9Sedb160gAXYA 1g+zBw6wsJFuE2VbuDmyFGLl1DzW9dm6w4noge0LK2WowQnActXCwtYyStpiguh1 x+9jKGXYXmT6butO/0TzsUQbfo1Uclcuo1lxXMNJ9Wa1a/7+eUMpvB8nwjP3QZdd zer7LzvTN2nwBgTECezyWoFxLfKi8ofo+3Zgw/+4nguh2Ml00xDkwDpxC9YR3SoW uV1rFD5tHBRiaabKHrbHydDe94X5aAZuC4dNKcsMvKbFiQPMRhUWAgwkNAGRZUY5 /CCxJxlkRmpWnPZgDNfBYc/+9NwGJgNQ1uTE1KRa1Kuofqk3kTlmRMf022nWKaLy zBSC34+80XzFCBnpAvzxVYwEXq3hH5eCqARjyoomEevyvFehd96CpB7aCnMim+L+ vqpPNlhdogNpVatnwrH8RIwNLwF89NTg2CIiOgqJ8/s7iG0ZoFx6iqKbFqfCK5Nf uGTx+ieyptGfCAw8VVYe2KgNQD5GHFSXhRnUD7Jp2mvwVeQ4WbnAJ4a++88Vm/iO kgWjHeFf/aNiDRyjMljhoqu8A59sSCC0O5IdP3tPv774V32CD4RULPQ8oLe+cmcb JZPxBlBqfhODXEH5hIPA2HWe5jOC6hPONUgpQ4Sv6J37vjLl8RDuLT2E/kuail2L ZJwuPG59mn8OAcROhNKD =TVnE -END PGP SIGNATURE- ___ 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] Followup (still want a GPS-type NTP refclock)
On 10/18/2012 1:20 PM, saidj...@aol.com wrote: Let the GPS average the antenna position over a very long time. On a good GPSDO one can select the number of averages, and the position variance before the survey is finished, and the (now very precise) position is stored in memory. Indoors this may take a very long time to do (weeks?), but should work too. The problem indoors is multi path, one never knows where the signal is coming from that is seen. Setting up signal squelch in the GPS really helps with that, for example the C/No could be set to a minimum of 35dB, and anything below that is ignored so only the strongest signals are used. We made a customer's urban solution work that way, it effectively deleted all the multipath issues he had from adjacent high-rises, since the multipath signal strengths yielded about 20 to 28dB C/No and were thus all squelched, whereas the direct signals were 35 to 50dB C/No. bye, Said Wow thanks. I've never seen such an insightful explanation for dealing with multipath signal issues. Fortunately, I'm not doing this for any sort of for profit purpose / just learning for now. This list really has a lot of experts :) -- Sarah P.S. Sorry for the earlier PGP signatures... In the past 24 hours someone pointed out to me, to paraphrase: most of the people reading this list aren't using email systems which make any use of the (rather long) message validation blocks ___ 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] Followup (still want a GPS-type NTP refclock)
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 Hi again everyone :) Originally I was hoping for a thunderbolt. The control / diagnostic software looked cool, but I couldn't afford the pricetag on one. ...Here's my followup now: Determined I'd love to get my hands on an iLotus m12m. That's just a statement. My heart is set on getting this. Would it be possible to find a kit (new, used or otherwise) with: 1) iLotus M12M timing mode GPS (serial port version) 2) Aprox 10 meter antenna cable with apropriate connector(s) 3) active antenna which can handle being 10 meters from the module 4) power supply for above list, and much needed luck, all for under $100 USD Discovered something amusing about my sirf III GPS mouse / puck --- uses the same prolific 2303 chip internally (same driver) as the USB --- Serial converter I dug out of my storage area and tested in the past 24 hours... At least I know it works with the various operating systems I'll be trying to time on... Speaking of my ugly little $6 usb gps not-timing-mode module... I've been playing with: setupSiRFDemo.exe ((installer package dated from 2007)) 6.37 MB (6,680,594 bytes) CRC32: 147BF6E1 MD5: 2C1DC21831CC131AFFF3F6AEE6F392FF SHA-1: 6A5F7940922A8360347784BC532CD67F39F387F3 Works fine for my crappy NMEA / sirf-binary GPS thingy... will this also work for the iLotus M12M or is there a new or comparable version of the same? (similar to the thunderbolt or sirf thingy) ... Is the iLotus M12M actually sirf-based? Not quite sure based on a few seemingly conflicting statements I've seen from diferent vendors. Are these iLotus M12M basically aftermarket motorola oncore? That's all I guess. ((digitally signed)) Sarah White - --- Original post quoted below --- Date: Sun, 19 Aug 2012 00:25:51 -0400 From: Sarah White kuze...@gmail.com Subject: re: L1 GPS timing (followup) Hi, this is my first post. First off. Windows 7 USB connection to the GPS (no serial ports / modern computer) and I'm pretty sure that is my main problem. Past few months, I've been trying to figure out my timing issues. Lots of reading trying to figure out how to best configure everything. I'm typically still off (randomly) by 20-100 miliseconds. I'd like to at least get to within 50 microseconds (nanoseconds would be wonderful) 1) I need a computer with a serial port. The curent GPS module I'm using is INTERNALLY RS232 -- USB converter, and recognized by my windows 7 computer as: Prolific USB-to-Serial Comm Port (COM3) ... the latency and jitter is horrible, and both are seemingly random. 2) I need to run my stratum 1 clock (connected to the stratum 0 time source via old-school RS232 serial) on linux or a form of BSD with support for kernel timestamps, and a version of NTP with a driver to supports my reference clock... points 1 and 2 seem fine. 3) I'm clueless about mounting an antenna, running cable, grounding / lightning protection, etc... Really want an easy to install one. For software, I've used 4.2.6 (stable / production) as well as 4.2.7 (dev version) NTP and haven't been able to tell any difference. Just using the generic NMEA driver / this is a no-name cheapo SIRF module. Also, trying to wrap my head around these: http://linuxpps.org/wiki/index.php/LinuxPPS_installation http://linuxpps.org/wiki/index.php/LinuxPPS_NTPD_support And here is where I give up. As the subject line suggests: HELP!!! I'd like to convert L1 GPS timing signal(s) into local time on computer(s) -BEGIN PGP SIGNATURE- Version: GnuPG v2.0.17 (MingW32) Comment: Using GnuPG with Mozilla - http://www.enigmail.net/ iQIcBAEBAgAGBQJQfmNRAAoJEL5NTv0FKXxnfBoP/jB+Z1HrUKJ/bnS/xlm6qvUc nCkIrIkDAMDlct3oPyrFhhgioN9GHU0a+IWnoz4QsN5aMEsebcHHsfBv2sk7oWJo 5Srv2bbtsA3obQmaLB/ozkQDpmaKM3GdySXy5rumHS3bpiYGqGkhuFbOdN+zgywE H2jtj8OVMmf3oS18wyuDTIcmXWKBINifcARPBzpEv3eDYJyCl/QPJFfAC+IMF2ip TPjKouJnuFpyopNo8VXgryR+tz7TPMSJQVyIvMXx23Tga031QELdSxVnNhNdw+z6 i4cMaKv/tHJaSg8YvSWyFaynGdyOH5sZvudgZtfA6CBZujauSIK6rgaBb4z0KE4q vB5ZmBOZGBpCrHDVa1758HXSNtxMGWWPVcsp5xHhueKJSPbs1JXRMbpJC8QIXYGX VO5UfaceMWK61irjnkkuXRJQjDAO/ijr9+8PNE7aWcIWFV9Z6/x4tRgF+Z6upcDd NhqKg3XM/uAf+t3L0tPawFu2XzRCsnn3nffr+rQx84h8QtwvkxhBZ57VISzgKoR1 rdgbM8IbcSkwp+KqnK/qB/QG7k7ne1TK8/EVDmc9CV2fhdc5wZ81srjUUYOtgAED QnJJ9gGFGYuFQF0wGdell6F24iBuBhJOmButE46hOIv5p95eRbANq7YBnNpJ7d0U vfghHDqWvvWkIC6ISErG =Hymt -END PGP SIGNATURE- ___ 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] Followup (still want a GPS-type NTP refclock)
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 Wed, Oct 17, 2012 at 12:50 AM, Sarah White kuze...@gmail.com wrote: ((...snip...)) -- my post was long. Sorry hehe. 1) iLotus M12M timing mode GPS (serial port version) 2) Aprox 10 meter antenna cable with apropriate connector(s) 3) active antenna which can handle being 10 meters from the module 4) power supply for above list, and much needed luck, all for under $100 US (quote block from) Chris Albertson Just over $100. the M12M is about $60 new. If you call up and say you are a hobbyist and heard about it on this list. Buy a timing antenna on eBay for about $30 You can use 30 meters of cable TV wire and some N to F adaptors You can power it all with a salvaged power cube. Then you'd need a mast for the antenna made with plumbing parts and misc hardware and a box for the electronics. Maybe $130 if you were carful But if you are really worried about cost buy an older Oncore. The new m12m is only slightly better then the older m12+T that sells on eBay for $35. The two are nearly identical. (See item # 290656401551) then see item # 270881742870 for an antenna You'd be just under $100 if you went this route. Hmm ok wow. That all sounds pretty good. I'm confused about one or two things though... 1) I'm planning to mount the antenna indoors. Will be pressed up into the skylight here in the living room / den with cable management... Pretty sure the landlord doesn't want an antenna mast mounted on the roof, yard, etc... Would be scared to attempt this anyway because I don't know how to set up a proper array of lightning rods / grounding / surge protection / etc. 2) salvaged power cube ... I don't really know what that means: typically I don't go mucking around with random electronics (salvaged or otherwise) unless it's something I understand and have experience with. Are there ready-made power supplies known to work with M12-type timing GPSes? The most wiring I really want to do is get a tool with which I can crimp some antenna cable and/or install adapters on the ends. ((Digitally Signed)) Sarah White -BEGIN PGP SIGNATURE- Version: GnuPG v2.0.17 (MingW32) Comment: Using GnuPG with Mozilla - http://www.enigmail.net/ iQIcBAEBAgAGBQJQfyDJAAoJEL5NTv0FKXxnUX8P/0N2Jse552siq3B5tit7X2S7 jtNyQIOtuB2C9FPJBMjNAHMcKJkltHsZtWm9FrQcaB4o2E4kXB+M8SNADNBr+8gh Nba5kuzTzt3X5b3SLrhSVk8ccnrrihz7JusLCBi8rgFWlLNP74AiM/y88VnSEaIa sIfSVK2i3R9Ibvamk0ztMoWXQFTmHeJGfquH8G90iolXcV7XWZoW63Lb7WxdUu0g JHXDJP1GvNX+PuZE4B/FLYahxwEJN8GGN+6WVmlcm49w97G8UXK2BfgqgZQYlP03 X0uYLdEm/CNWbWVWQsw54NAe8c46+bMsHrTjvVz8mWrDdbkikTLelTNwCRdDRKsy XVNZCVefzEkZ0iT7/3i9ZSV/Sj1ZoYsb5o7lG/FBnEbF851cHiPEdpbtPB4h3D0A SBkid49aqBVZoMTY0T59moqXkX8dOxBV4vAxyNJxCpFTftP3Ci4cNb3j95hKOOtC S45m8qTG8CAhb53Fz1RyLBYa9m7JuUZEQtJI0X6q2feuor+xAWGuTPcR7bmSxwHu 0J4QaZhU6ZTFlOdqMSRYLBw6WolsujebAEP7M8PQgHZW6VO70uVnLvK/wyvAk414 i+eQvr85WiZqI3rcKfqswdZBCmqMWxkUevNXNpAMYyZv/GQ90bqRpYdi5td5RyVq MoYQB7vkisSDvktN3EB8 =OPiF -END PGP SIGNATURE- ___ 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] Followup (still want a GPS-type NTP refclock)
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 On 10/17/2012 4:18 AM, Attila Kinali wrote: Hi Sarah, I've just reread the old thread from august and i don't quite get what you are aiming for. From what i gather, you want to have an ntp startum 1 server for your internal network at home? How accurate does it have to be? Sub-ms? Sub-us? ((...snip...)) Oh, but I'm already managing sub-ms just fine. I have an NTP server in my living room getting time from a stratum 2 NTP server I'm operating in a local-ish datacenter... THAT stratum 2 server currently prefers getting time from a local stratum 1 operated by hurricane electric / CDMA refclock... so basically, I'd just be ever-so-tickled if my stratum 2 server was marking the time from my living room as being acceptable / best source even if only rarely. I'm probably nuts as far as timekeeping goes. There's not really any other reason I'm on this list. Some day I might be good enough with all this tech, such that I could act as a consultant on the subject... For now though, I'm enjoying the learning experience(s) Thanks everyone :) ((Digitally Signed)) Sarah White -BEGIN PGP SIGNATURE- Version: GnuPG v2.0.17 (MingW32) Comment: Using GnuPG with Mozilla - http://www.enigmail.net/ iQIcBAEBAgAGBQJQfyOLAAoJEL5NTv0FKXxnTyYQAIYHgP33Lf7GtjyTro3jQl37 RiPQ2wBKBECRyUREsnk55vCbwDk1N7miAkfuwYILEawCFrwT1v49YsqWi7oqP56K rFcVjXKeZQLy5gNdMNNAP0ze6ojRXvYcCj9ufKTNDPkGIPkk3e/iVVAwcLieA13g cHAD1VAs9eOSnFVlGCGtSD+0oz+6Ft+nBYsU8sp0Eza/UCQfQBfykGHqetZLUA0s 1N8Vng/KVgCbKBGBCSz2S8UsrDjakb2XV4qO64F9wd3QT7+K23ZJYuTxv/nJ7vx8 iy6sTXoA5p1A/Xbi+Fyyu5xbkvPjSniKJALSAH5N6s8YXZx+tqCaYg96VcR2cRqG u6Oopelee8ZB/8QCktQ8WbOb+uLysLbh9zl1FBRL4ZrWTr3Z7N7AJDdv897H79oX 7MNFwHsDmt/7r0dhpQ2PIfxsAXGRqztCzkwNgGvMNGhSycTMA3y9AYNq5vbfjv/E f6Pdd3CUSdb2azF4Lay81Jw+uIB1NZwOgbYKiD740o/xohDVLEQ8Sh7/I6c7TAvm 8f6kxn5EYTCaycfbrEuWn7Q3yj3vDYSKjWxINPProXwYH6YBgHIzEz7zIkxGSC+W DQh6VbeMl+8/KOAhBJ1kEUDPPyg6Z4xf6ZgwEBmwTikKAh+j1pzsto13x/e04osk nJF5h+Si9eERUasOi1pf =kzeq -END PGP SIGNATURE- ___ 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] Followup (still want a GPS-type NTP refclock)
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 On 10/17/2012 6:04 PM, Chris Albertson wrote: ((...snip...)) -- 1 Indoor antennas can work. It depands on the details. Hopefully the skylight looks to the south. BTW that thin sheet of plastic that makes the skylight window will not protect from lightening. It makes little difference. ((...snip...)) -- 2 It means those plug-in power suply boxes that plug into a wall outlet and have a coaxial power plug. They are use to power cell phone charges and notebook computers and you name it. Most people have many of those around the hose. The output voltage will be printed in the cube (part 1) This is a glass skylight window, not plastic. Also, the skylight window in question is not the highest point on the roof, there is a domed metal cover on an exhaust fan vent thingy... Regardless though, landlord won't allow things to go on roof or in the yard so I'm stuck with using the window. ... Basically, this way I won't have to consider any waterproofing for the antenna, and just hope that if lightning strikes it goes for the exhaust vent dome thingy instead... Ah well whatever. My plan remains unchanged in this regard --- it is going to be in one of the south-facing (roof is angled) skylight windows. (part 2) For phone chargers... Not lately, no. Both my phone, and the person I'm living with Have a modern phone. For the past couple years, phone device manufacturers give you a very tiny USB-type AC adapter which you use to plug a USB micro micro directly into the wall. They're cute :) As for notebook computers, both mine and that of the person I live with have the modern style (and they output 12 and 19.5 volt respectively) Basically I'd have to go looking at the local thrift store to find older hardware as you described... But... I don't exactly want to sit around tinkering with my soldering iron (a friend gave it to me. her roommate left a bunch of crap and it would've just gone to the landfill otherwise) and/or a multimeter of some sort (which I don't own) ...Also, most weather conditions, and/or for most hours of the day (subject to position for the GPS constellation period(s) or whatever) I'm still able to get a good signal and clear view for at least 5-6 distinct PRNs out of this south-ish (angled roof) skylight window. And that's with a $6 navigation GPS thingy (USB puck-type NMEA-only) That's navigation... Timing mode only needs 1 satellite lock after all, and I suspect I will at minimum be able to get needed 1 satellite lock with nearly any active GPS antenna. ((digitally signed)) Sarah White -BEGIN PGP SIGNATURE- Version: GnuPG v2.0.17 (MingW32) Comment: Using GnuPG with Mozilla - http://www.enigmail.net/ iQIcBAEBAgAGBQJQf0PFAAoJEL5NTv0FKXxnkVwP/iZEQZPKA43qryTGMLRwh8qR TxBgcjLfOfKeeX6QdFODYci/g5lLbaZ1UMIdhyXLoYjGTepBDnoPzyfOIXpsmuP/ aQ2eXoY+sBag1u3Y2m+Ime7lOjFyaJopW5eRlhHe3rYc1YgMKaDqcwKt7q2XfZd8 6Sd1+fwaw1X9QEx02FaELq/3Kv1obLuS8AjhGWT720sDmzaH90/Cig+YzAsYuAzt BVzY/+vDv/olg9r2fBz+38CTDqIupIiQ7mRgywF1eWQeLTDOivV5Nnf3M7AHpnfR DUirAJ73w1Y9nkMMz3vIZFJIKt+KyztygGD48kD3uMphpL3Ze2x1BZl7YEfjr2bl UeDr5TpGfAHNwBmJe1OMuJBXAup5MRb1seCBkl+rGSIT+D6gdzwgX0oiwIlRh8U2 KfyTVPKM8moriCSBPrCXUy2h2htiG7h606Kopz0QP8841ftylgYzaeh9CDTRNzSl e4ggt4xsyNgRgw700lhvLnlxXshqR+d98McqzFUVkz2KQoHNI1nT8RZjjbBjQlB5 dAaZ0gUJz4RNn6KX7hnmeueESQNY1eXl6dvbGT6abvuRI1wLBYsrdDwXaR6MaPjP q/uRXChjTJ5EF3ivxm3PHcrvIxBUykU3aaT3d6P1HTWd6xDbTuHVB/bZ1b6joSjK CmFWnV4WK0iLLdCd++wi =9KEJ -END PGP SIGNATURE- ___ 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] : L1 GPS timing signal(s) into local time on computer(s)
Thanks Chris. I always appreciate clear explanations. I'm assuming that the fixed location requirement is important to note for purposes of compensating for any dopler shift, as well as the distance the signal must first travel before being decoded. ... I would presume that the fixed location used for above calculations would be relative to the position of the antenna? I read somewhere that even compensating for the length of the antenna cabling is important? This is all so exciting. Thanks everyone. On 8/21/2012 2:01 AM, Chris Albertson wrote: On Mon, Aug 20, 2012 at 3:10 PM, Sarah White kuze...@gmail.com wrote: I really like that the thunderbolt can (assuming the initial location has been uploaded, or the default site survey has been completed) still keep accurate time / discipline based on a single satellite lock (before falling back on the ovenized crystal in pure holdover mode) All timing mode GPSes can keep time with one GPS sat in view. It works becaus ethe GPS knows it is not moving. and it has the exact location f the one satellite. Holding over when there are zero satellites is not standard and required a good local oscillator. You can built one froma cheap $20 timing GPS and a OCXO and some logic chips. The t-bolt is a GPS with a built-in GPSDO. Chris Albertson Redondo Beach, California ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] : L1 GPS timing signal(s) into local time on computer(s)
Wow. Okay. The user manual actual considers this cable delay to be worth mention? I can see why the trimble thunderbolt is a favorite among time nuts 3 I'm sold. On 8/21/2012 12:48 PM, Chris Albertson wrote: On Tue, Aug 21, 2012 at 9:35 AM, Sarah White kuze...@gmail.com wrote: Thanks Chris. I always appreciate clear explanations. I'm assuming that the fixed location requirement is important to note for purposes of compensating for any dopler shift, as well as the distance the signal must first travel before being decoded. ... I would presume that the fixed location used for above calculations would be relative to the position of the antenna? I read somewhere that even compensating for the length of the antenna cabling is important? Yes, the GPS' site survey measure the antenna location. And it will not be exactly right unless you measure the cable length. Yes. the cable length delay is close to the speed of light or aboutone nanosecond per foot. Actually there is a correction called velocity factor that a given cable will have. All this is in the Trimble user manual and I'm sure the UMs for other GPSes. There is delay in the serial cable and in any glue logic chps and in the PPS distibution amp.To push the state of the art you have to carefully model all of this. For normal use you may not have to except if you have really long cables. Chris Albertson Redondo Beach, California ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] : L1 GPS timing signal(s) into local time on computer(s)
CFO: oooh, really. So 10mhz reference is pretty standard for a GPS disciplined frequency standard. Thanks. I really like that the thunderbolt can (assuming the initial location has been uploaded, or the default site survey has been completed) still keep accurate time / discipline based on a single satellite lock (before falling back on the ovenized crystal in pure holdover mode) ... Is that a common feature? Know of any good ones other than the trible thunderbolt? On 8/20/2012 5:07 PM, cfo wrote: On Sun, 19 Aug 2012 15:29:22 -0400, Sarah White wrote: oh wow, thanks. I'll try that. Also, I figured out that typing in trimble thunderbolt instead of thunderbolt gps gives me zero hits for phone... but fewer hits for the GPSDO too :( Try to search on : 10mhz gps You should see most thunderbolts,and especially this one (eB#) 170886463609 US located , and the only decent priced Tbolts left on eB CFO - Denmark ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] L1 GPS timing signal(s) into local time on computer(s)
Ken: From what I've read, most GPS modules which output PPS, the NMEA sentence has the timestamp of the next, upcoming pulse. Regardless of how the NMEA or other time data is, the PPS itself is only a guarantee this is the boundary for a second and NTP documentation typically recommends a second reference clock to number the seconds anyway. Everyone: Thanks everyone. I got many responses which confirm my initial conclusions. I had trouble locating a GPS thunderbolt on ebay because there is an HTC phone with thunderbolt in the name. (I got a few hits for the GPS module, but there is no way to filter out phones or I might just be bad at operating ebay) uhm... yeah. As someone pointed out. It is a total nightmare to figure out which direction my GPS time is wandering, and finding the correct offset. I'm just gonna give up on this USB module, and get a real one with PPS Also, I really hate google's new shopping experience. They started listing less content, and now push content from stores which charge 2-3 times as much. As far as existing hardware goes, I don't have any slots free in my desktop for a serial board... Despite the new google shopping headache, I was able to determine that many older computers from the windows XP era which still have serial ports, and are available refurbished from walmart of all the crazy places. (most of the time, better price than the ones being pushed by google shopping, and even have XP installed and a 1 year warranty) So no problem. I can source a suitable machine to run NTP, and for less than $200, guaranteed. Will probably be using gentoo linux, as the default configuration does NOT expect you to run any specific kernel. I can easily recompile anything I need without breaking unusual, unforeseen dependencies. (doesn't hurt that I've been using gentoo since the stage1 install was preferred, all the way back to the GCC 2.x era) I'm really aiming to run a server which ONLY runs NTP, and at most 1 or two other daemons (light duty on those) Thanks so much everyone. On 8/19/2012 7:11 AM, Ken Duffill wrote: Just one further question. When the pps input triggers, so my linux box knows a second has just ticked; is the time of that second the one the NMEA sentence has just sent, or will send next? Or to put it another way, when I receive an NMEA sentence is this the current time (as was when the sentence was constructed) or the time at the next PPS 'tick'? Thanks in advance. KenD On 19/08/12 11:23, Bill Dailey wrote: I will jump in a bit. I, and many have been right where you are. You are correct...USB is a no go for accurate time. Same on windows. So you need a Linux box with serial port. Anything from a Beaglebone, pandabox...or pc will work. You certainly need a gps with a pulse per second output (most have) and you can wire that up to the appropriate line on the serial cable or send to the target computer via gpio pin. The pps thing is fairly simple really. If you are receiving gps data via serial connection it takes a variable amount of time to get each status report from the gps...list time etc etc in text format and sends it repeatedly. This gets ntp to within a second or some fraction thereof...the pps part refines that..no text or anything... Just a one pulse per second separate from the gps info that acts as a exclamation point to tell ntp right here is the actual start of the second! alone the pps wouldn't be useful for time but with the time info ntp already has from the nmea sentences it is priceless for really precise time. That's about it. Once you have gps and pps configured on Linux you should be in the sub 5 microsecond range. It gets tricky getting better than that and you have to Ntpns and really worry about hardware issues that affect precision (system clock stability etc) but it can be done. Doc KX0O Sent from my iPad On Aug 18, 2012, at 11:25 PM, Sarah White kuze...@gmail.com wrote: Hi, this is my first post. First off. Windows 7 USB connection to the GPS (no serial ports / modern computer) and I'm pretty sure that is my main problem. Past few months, I've been trying to figure out my timing issues. Lots of reading trying to figure out how to best configure everything. I'm typically still off (randomly) by 20-100 miliseconds. I'd like to at least get to within 50 microseconds (nanoseconds would be wonderful) 1) I need a computer with a serial port. The curent GPS module I'm using is INTERNALLY RS232 -- USB converter, and recognized by my windows 7 computer as: Prolific USB-to-Serial Comm Port (COM3) ... the latency and jitter is horrible, and both are seemingly random. 2) I need to run my stratum 1 clock (connected to the stratum 0 time source via old-school RS232 serial) on linux or a form of BSD with support for kernel timestamps, and a version of NTP with a driver to supports my reference clock... points 1 and 2 seem fine. 3) I'm clueless about mounting
Re: [time-nuts] Embedded NTP servers?
If your design gets off the ground, I'd surely try to replicate it from your part list or buy a kit from you or whatever. Sounds great. On 8/19/2012 2:19 PM, Michael Tharp wrote: On 08/19/2012 01:38 PM, Chris Albertson wrote: NTP is not as easy as you think. Just doing the cryptography to handle authentication is more then I would want to write. When a free open source ntpd exists it will be really hard to get people to help work on re-inventing it. But your idea to use a GPSDO to drive the system clock is good. People have done that and it works. You basically unsolder a TTL can oscillator and put a small connector in it's place. This is specifically *not* a full ntp implementation. There's no client, no PLLs or clock correction, nothing but using 10MHz+PPS+NMEA to feed an internal clock and serving it out over ntp to more intelligent clients. I haven't written any code yet but from nosing around in wireshark it seems like the ntp part of the project wouldn't take more than an hour or two to write. The only tricky part is keeping a calendar so it knows when to insert a leap second. I'm not initially interested in authentication, although I do have all my PCs at home running in authenticated broadcast mode. So I might add auth later so it can participate, but I would be satisfied without it. -- m. tharp ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] : L1 GPS timing signal(s) into local time on computer(s)
oh wow, thanks. I'll try that. Also, I figured out that typing in trimble thunderbolt instead of thunderbolt gps gives me zero hits for phone... but fewer hits for the GPSDO too :( On 8/19/2012 3:21 PM, Willy Willemse wrote: Sarah, If you want to filter in ebay, you can use a- for a subject that you don't want to see. It is the same syntax as you can use in a browser. Regards, Willy -Oorspronkelijk bericht- Van: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] Namens time-nuts-requ...@febo.com Verzonden: zondag 19 augustus 2012 19:07 Aan: time-nuts@febo.com Onderwerp: time-nuts Digest, Vol 97, Issue 48 Send time-nuts mailing list submissions to time-nuts@febo.com To subscribe or unsubscribe via the World Wide Web, visit https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts or, via email, send a message with subject or body 'help' to time-nuts-requ...@febo.com You can reach the person managing the list at time-nuts-ow...@febo.com When replying, please edit your Subject line so it is more specific than Re: Contents of time-nuts digest... Today's Topics: 1. Re: L1 GPS timing signal(s) into local time on computer(s) (Sarah White) 2. Modern motherboard with RS232 port (Stan, W1LE) 3. Re: L1 GPS timing signal(s) into local time on computer(s) (KD0GLS) 4. Embedded NTP servers? (Michael Tharp) 5. Re: Modern motherboard with RS232 port (Chris Albertson) -- Message: 1 Date: Sun, 19 Aug 2012 10:41:39 -0400 From: Sarah White kuze...@gmail.com To: time-nuts@febo.com Subject: Re: [time-nuts] L1 GPS timing signal(s) into local time on computer(s) Message-ID: 5030fb23.7040...@gmail.com Content-Type: text/plain; charset=ISO-8859-1 Ken: From what I've read, most GPS modules which output PPS, the NMEA sentence has the timestamp of the next, upcoming pulse. Regardless of how the NMEA or other time data is, the PPS itself is only a guarantee this is the boundary for a second and NTP documentation typically recommends a second reference clock to number the seconds anyway. Everyone: Thanks everyone. I got many responses which confirm my initial conclusions. I had trouble locating a GPS thunderbolt on ebay because there is an HTC phone with thunderbolt in the name. (I got a few hits for the GPS module, but there is no way to filter out phones or I might just be bad at operating ebay) uhm... yeah. As someone pointed out. It is a total nightmare to figure out which direction my GPS time is wandering, and finding the correct offset. I'm just gonna give up on this USB module, and get a real one with PPS Also, I really hate google's new shopping experience. They started listing less content, and now push content from stores which charge 2-3 times as much. As far as existing hardware goes, I don't have any slots free in my desktop for a serial board... Despite the new google shopping headache, I was able to determine that many older computers from the windows XP era which still have serial ports, and are available refurbished from walmart of all the crazy places. (most of the time, better price than the ones being pushed by google shopping, and even have XP installed and a 1 year warranty) So no problem. I can source a suitable machine to run NTP, and for less than $200, guaranteed. Will probably be using gentoo linux, as the default configuration does NOT expect you to run any specific kernel. I can easily recompile anything I need without breaking unusual, unforeseen dependencies. (doesn't hurt that I've been using gentoo since the stage1 install was preferred, all the way back to the GCC 2.x era) I'm really aiming to run a server which ONLY runs NTP, and at most 1 or two other daemons (light duty on those) Thanks so much everyone. On 8/19/2012 7:11 AM, Ken Duffill wrote: Just one further question. When the pps input triggers, so my linux box knows a second has just ticked; is the time of that second the one the NMEA sentence has just sent, or will send next? Or to put it another way, when I receive an NMEA sentence is this the current time (as was when the sentence was constructed) or the time at the next PPS 'tick'? Thanks in advance. KenD On 19/08/12 11:23, Bill Dailey wrote: I will jump in a bit. I, and many have been right where you are. You are correct...USB is a no go for accurate time. Same on windows. So you need a Linux box with serial port. Anything from a Beaglebone, pandabox...or pc will work. You certainly need a gps with a pulse per second output (most have) and you can wire that up to the appropriate line on the serial cable or send to the target computer via gpio pin. The pps thing is fairly simple really. If you are receiving gps data via serial connection it takes a variable amount of time to get each
Re: [time-nuts] Modern motherboard with RS232 port
Ed: you're sorta right, but only on a really basic level of electrical engineering. Induction and capacitance and random transformer magnetic flux nonsense that makes AC currents act in unexpected ways. The difference between volt-amp versus RMS watt versus peak watts, etc, etc. can be off by more than you'd expect. It really comes into play when you're trying to build power supplies (regulated or otherwise) On 8/19/2012 3:19 PM, Tom Knox wrote: Hi Ed; I may not have had enough coffee yet, but if Volt X Amps = Watts why would there be a difference? Best Wishes; Thomas Knox Date: Sun, 19 Aug 2012 12:35:51 -0600 From: ed_pal...@sasktel.net To: time-nuts@febo.com Subject: Re: [time-nuts] Modern motherboard with RS232 port It's important to remember that on a computer, the wattage shown has no relationship to the wattage pulled from the socket. The numbers shown are maximum values. You have to measure the power draw and you have to measure it in volt-amps, not watts because that's how residential power is measured (at least in North America). Buy an energy meter that shows volt-amps. They're relatively cheap - typically less than $50. Ed On 8/19/2012 11:06 AM, Chris Albertson wrote: This sounds like a newer version of the board I use. The thing to check is if the CPU heat sink has a fan or not. Having no fan indicates that the CPU is not using much power. It also removes a common failure point. To reduce power even more. On an NTP server you can unplug the keyboard, mouse and monitor and if you have other servers on the LAN configure one as a boot server and have it run TFTP then your NTP server does not need a disk drive. It can run off a RAM disk. This makes it very fast, even faster than a SSD and it saves some cash. Makes backup easy too as there is nothing to backup if there is no local storage. If you don't have a TFTP server use a small notebook size disk drive. Even a 80GB drive is overkill. You can also boot from a USB thumb drive and run a RAM disk. It is worth it to look at your electric bill to find how much you pay for power. Here I'm at $0.21 per KWH. A full size PC server can use 250W or more. There are 8760 hours in a year so you get $460 per year to run that 250W PC. The little Atom will pay for itself in just a few months. The first time I did that calculation, my power hogs where given away. On Sun, Aug 19, 2012 at 7:42 AM, Stan, W1LE stanw...@verizon.net wrote: Hello The Net, For your consideration: The INTEL model DN2800mt ITX mother board uses a ATOM CPU and draws about 11 watts of AC power when configured as: (I have not measured DC power yet.) 30 GB OCZ Nocti mSATA solid state drive, WIN7 pro, 64 bit, USB keyboard and mouse APEX MI-0008 case. Also has: parallel port available on mother board, you extend to a connector RS232 serial port available on mother board, you extend to a connector a single DC power supply from 11 to 19 V DC. 1 each PCIe expansion port, I will use with a premium 4 channel sound card SATA ports available for HDD/SDD, USB ports are available, Motherboard sound, and Gigalan. I have not played with NTP, (yet), but it sounds like a decent time nut technical challenge. My application is for a remote site with only 13V DC power available from PV/batteries. Then use fiber ethernet to get off site. The INTEL website would have further details. Stan, W1LECape Cod FN41sr z ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] L1 GPS timing signal(s) into local time on computer(s)
Hi, this is my first post. First off. Windows 7 USB connection to the GPS (no serial ports / modern computer) and I'm pretty sure that is my main problem. Past few months, I've been trying to figure out my timing issues. Lots of reading trying to figure out how to best configure everything. I'm typically still off (randomly) by 20-100 miliseconds. I'd like to at least get to within 50 microseconds (nanoseconds would be wonderful) 1) I need a computer with a serial port. The curent GPS module I'm using is INTERNALLY RS232 -- USB converter, and recognized by my windows 7 computer as: Prolific USB-to-Serial Comm Port (COM3) ... the latency and jitter is horrible, and both are seemingly random. 2) I need to run my stratum 1 clock (connected to the stratum 0 time source via old-school RS232 serial) on linux or a form of BSD with support for kernel timestamps, and a version of NTP with a driver to supports my reference clock... points 1 and 2 seem fine. 3) I'm clueless about mounting an antenna, running cable, grounding / lightning protection, etc... Really want an easy to install one. For software, I've used 4.2.6 (stable / production) as well as 4.2.7 (dev version) NTP and haven't been able to tell any difference. Just using the generic NMEA driver / this is a no-name cheapo SIRF module. Also, trying to wrap my head around these: http://linuxpps.org/wiki/index.php/LinuxPPS_installation http://linuxpps.org/wiki/index.php/LinuxPPS_NTPD_support And here is where I give up. As the subject line suggests: HELP!!! I'd like to convert L1 GPS timing signal(s) into local time on computer(s) ___ 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.
