Re: [time-nuts] Systematic noise
Tom, On 02/13/2013 05:04 AM, Tom Van Baak wrote: Magnus, Two things to check. 1) Is the bump you see at all correlated to the relative frequency between the two oscillators? I have seen this when comparing two ULN, for example. You can make the bump move left or right depending on the beat frequency. I can check the oscillator frequencies and trim them if needed. Did you see a triangular shaped signal as result of such error. I'll do some stress-test and see what it does to the oscillator. 2) Some oscillators have separate oven and oscillator circuits that make the following experiment easy: perform a phase noise measurement with the oven power on as usual, and then a second measurement with the oven power off. True, the frequency will start to drift within tens of seconds, but this should not spoil the P/N plot, or even the ADEV plot below tau a few seconds. Nocando. This is a small oscillator with a single power supply pin. Cheers, Magnus ___ 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] Network jitter with NTP
David, [] 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) [] --Sarah Yes, Sarah, with initial help from Dave Hart and later help from more C-fluent friends on the various groups, I have managed to compile NTP from the available source code - details here: http://www.satsignal.eu/ntp/setup.html#build To try and offer something in return, I make my recent builds available here: http://www.satsignal.eu/ntp/x86/ although they won't work on Windows-2000 and earlier due to limitations on the MS Visual Studio 2010 Express I am using. You can overlay my ntp*.exe over a Meinberg install. For Windows-Vista and Windows-7 there have been some significant improvements in the most recent builds, and Windows-8 can provide even more improvements, nearer to Linux and FreeBSD than previous versions of Windows, but still not as good. Dave Hart has been involved in a house move recently, so he has been rather quiet. Cheers, David -- 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.
Re: [time-nuts] Systematic noise
Tom, On 02/13/2013 05:04 AM, Tom Van Baak wrote: Magnus, Two things to check. 1) Is the bump you see at all correlated to the relative frequency between the two oscillators? I have seen this when comparing two ULN, for example. You can make the bump move left or right depending on the beat frequency. Your ULNs exhibited a strong beatnote before we bypassed their power supply pins, as I recall. They will likely still do it if you measure them without double-shielded or equivalent coax connections to the 5120A/TimePod. -- john, KE5FX Miles Design LLC ___ 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] Systematic noise
On 02/13/2013 09:07 AM, Magnus Danielson wrote: Tom, On 02/13/2013 05:04 AM, Tom Van Baak wrote: Magnus, Two things to check. 1) Is the bump you see at all correlated to the relative frequency between the two oscillators? I have seen this when comparing two ULN, for example. You can make the bump move left or right depending on the beat frequency. I can check the oscillator frequencies and trim them if needed. Did you see a triangular shaped signal as result of such error. I'll do some stress-test and see what it does to the oscillator. Toss in another oscillator, and the triangular shaped signal is gone. Cheers, Magnus ___ 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] GPStar Plus: Rubidium, anyone?
Bruce, Just a slight correction on the part number the Odetics GPStar Plus was model 365. When the company changed to Zyfer and they upgraded the unit it became a 565. Rob -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Bruce Lane Sent: 12 February 2013 20:55 To: time-nuts@febo.com Subject: [time-nuts] GPStar Plus: Rubidium, anyone? Fellow Time Trackers, Does anyone happen to have an Odetics GPStar Plus (their model 565, if I recall) with the rubidium option installed? If so, could I bother you for some detailed photos of the innards, particularly the main PC board jumpers, the additional power supply and any extra cabling the rubidium module uses? My goal is to retrofit my own GPStar. Thanks much. Bruce Lane, Owner Head Hardware Heavy, Blue Feather Technologies (http://www.bluefeathertech.com) Assoc. member, AAZK IAATE Salvadore Dali's computer has surreal ports... ___ 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] Network jitter with NTP
Sarah, David, I've changed my Minpoll and Maxpoll settings as suggested by David and now getting much better results (1 - 2 mS) when settled for the Meinberg Stratum 1 units. I'm also using Meinberg's version of NTP (6.2.6). I'm still experimenting with settings, but it looks like my original post regarding the Ethernet over Power adapters might have been a red herring. Rob -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Sarah White Sent: 13 February 2013 01:42 To: Discussion of precise time and frequency measurement Subject: [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-h art-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. ___ 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] Network jitter with NTP
Sarah, David, I've changed my Minpoll and Maxpoll settings as suggested by David and now getting much better results (1 - 2 mS) when settled for the Meinberg Stratum 1 units. I'm also using Meinberg's version of NTP (6.2.6). I'm still experimenting with settings, but it looks like my original post regarding the Ethernet over Power adapters might have been a red herring. Rob == Rob, your previous post is likely quite valid. The power adapters, like Wi-Fi, introduce timing uncertainties as those more expert than me have described. The smaller poll intervals you are now using hide the problem with Windows-7 Vista which was fixed in 4.2.7p348 and later. So with the latest version (4.2.7p354) http://www.satsignal.eu/ntp/x86/ you should find improved results even with the longer poll interval. Of course, once you are using servers on your LAN there's no need to use long poll intervals to access them, so you might want to leave it as is (first rule of networking: if it works, leave it!). If you need even better timekeeping on the non-stratum-1 clients, consider Windows-8. I did say consider, not you must install, BTW! Cheers, David -- 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] GPStar Plus: Rubidium, anyone?
Despite what has been previously posted I’ve found my 565s to be very good frequency references for my counters and they seem to compare well to the Thunderbolts. I haven’t run any long term checks but comparing Tbolts to 565s on my scope from time to time I’ve never seen any jumps or significant frequency drift (at 5ns/cm). The 565s generally report parts in E-12 to E-14 depending on conditions. In regard to replacing the crystal oscillator with a rubidium, I tried that once using an X72 and wasn’t impressed. It worked o.k. but as you can see from the manual specs below the only gain would be during long periods of signal loss or ‘coasting’. As long as you have a signal the average accuracy will be the same and I feel the OCXO could possibly be a little less noisy and perhaps have better short term stability although I never checked it. -Arthur 565 (High Performance Quartz) Accuracy Error Time Locked1 X 10-12 (1 day average) Coasting. 5 X 10-10/day (Rubidium) Accuracy Error Time Locked1 X 10-12 (1 day average) Coasting. 2 X 10-11 /day ___ 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] GPSDO - 8 days of data (and FTS-4060 for sale)
I produced some TimeLab charts from my 8 days of GPSDO (VE2ZAZ) data and put them on my blog page at http://w0ep.us/OM/ Would love to hear any comments you all have. My goal was to confirm that the thing is working right and that the standard deviation calculation which comes from VE2ZAZ's Windows monitoring program was a good handle on general health and accuracy. I'm not into it enough to know the fine benefits of the various measuring possibilities. My intent was just to be able to say something like 10 MHz +/- X Hertz. I am very happy with a number like X=.003 Having done this, I would like to sell the FTS-4060 and use the money to buy a better HF radio, and get back to the part of my hobby activities I enjoy more. No offense, but time-nuts stuff sure takes a long time. Chris Howard W0EP Columbus, Mississippi ___ 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] switchers
lot of 4 16 in 12 out, 251144853198 Don -- Neither the voice of authority nor the weight of reason and argument are as significant as experiment, for thence comes quiet to the mind. De Erroribus Medicorum, R. Bacon, 13th century. If you don't know what it is, don't poke it. Ghost in the Shell Dr. Don Latham AJ7LL Six Mile Systems LLP 17850 Six Mile Road POB 134 Huson, MT, 59846 VOX 406-626-4304 www.lightningforensics.com www.sixmilesystems.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] switchers
No shipment to Europe... Am 13.02.2013 21:51, schrieb Don Latham: lot of 4 16 in 12 out, 251144853198 Don ___ 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.
