Re: [time-nuts] NEO-M8N vs. NEO-M8T
Yo Mark! On Mon, 21 May 2018 19:21:25 + Mark Sims <hol...@hotmail.com> wrote: > It looks like you have slipped a decimal point somewhere (also that > "ps" label is wrong). Yes, seemed 10x too high to me too. But the doc for UBX-TIM-TP clearly says 'ps'. UBX-TIM-TP: qErr ps Quantization error of time pulse (not supported for the FTS product variant). Here is another data point, with the raw data so you can check the decode: Class: TIM(0xd) ID: TP(0x1), len: 0x10 payload: f0fb5509e7d6d2070a00 tow:1566300.0 qErr:-0.00105210 ps, week:2002 flags:0xa refInfo:0x0 is GPS, UTC available Sure looks like 105 nano seconds to me. If I'm wrong I'd love to know where. > I have an M8N running here and the report > sawtooth errors are all within a +/- 10 ns span. (and LEA-5T is +/- > 5ns). Many things could explain the difference. We seem to only differ by 5x or 10x. Also, my ADEV plot clearly showed the NEO-M8N adev was better than the NEO-M8T adev at tau=0, so your observations match mine. Right now I'm doing a survey-in. Then I'll grab a days worth of TICC data. After that I'll go back and get long term standard deviations for qErr in Stationary and Survey-in modes. That, of course, will take days. RGDS GARY --- Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703 g...@rellim.com Tel:+1 541 382 8588 Veritas liberabit vos. -- Quid est veritas? "If you can’t measure it, you can’t improve it." - Lord Kelvin pgpy6EpQTaJpb.pgp Description: OpenPGP digital 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] NEO-M8N vs. NEO-M8T
Yo Chris! On Mon, 21 May 2018 13:55:23 -0500 "Chris Caudle" <ch...@chriscaudle.org> wrote: > On Mon, May 21, 2018 1:52 pm, Chris Caudle wrote: > > On Mon, May 21, 2018 1:19 pm, Gary E. Miller wrote: > >> Now, how to I tell the Linux kernel to apply that correction? > > > > Have the PPS driver accept the correction before logging the PPS > > timestamp. > > Or just have the PPS driver log the raw timestamp, then have the PLL > engine in ntpd incorporate the corrections into the math of the > control loop. Presumably ntpd will be getting the information passed > in from gpsd, so the clock control daemon should have the correction > information in plenty of time before the next PPS pulse gets logged. I look forward to your patch! RGDS GARY --- Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703 g...@rellim.com Tel:+1 541 382 8588 Veritas liberabit vos. -- Quid est veritas? "If you can’t measure it, you can’t improve it." - Lord Kelvin pgpiFYVgSKpnB.pgp Description: OpenPGP digital 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] ✘NEO-M8N vs. NEO-M8T
Gregory! On Mon, 21 May 2018 19:06:17 + Gregory Maxwell <g...@xiph.org> wrote: > My best guess is that the magnitude of sawtooth error is just not > large enough to matter for typical applications of linux PPS. No need to guess. I recently posted that the RasPi 3B granularity is 52 nano Seconds and the PPS offset reported by UBX-TP is double that! So, clearly it matters. I'll do more data logging to get harder numbers. RGDS GARY --- Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703 g...@rellim.com Tel:+1 541 382 8588 Veritas liberabit vos. -- Quid est veritas? "If you can’t measure it, you can’t improve it." - Lord Kelvin pgpRzSV8XavdG.pgp Description: OpenPGP digital 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] NEO-M8N vs. NEO-M8T
Yo Scott! On Mon, 21 May 2018 13:08:06 -0500 Scott Newell <newell+timen...@n5tnl.com> wrote: > >The NEO-M8T is an FTS product. > > Are you sure about that? I thought the M8T was timing, and the M8F > was FTS. Please check your firmware version string against the table > on page 8. I stand corrected. I do see UBX-TIM-TP: Class: TIM(0xd) ID: TP(0x1), len: 0x10 tow:1519310.0 qErr:-0.00048400 ps, week:2002 flags:0xa refInfo:0x0 is GPS, UTC available Which says the next PPS is going to be -48.4 nano seconds out. Similar to the 52 nano seconds quantization error of a RasPi 3B. Here is another one, -101 nano seconds out: Class: TIM(0xd) ID: TP(0x1), len: 0x10 tow:1522360.0 qErr:-0.00101900 ps, week:2002 flags:0xa refInfo:0x0 is GPS, UTC available That is more than double my quantizaation error! Now, how to I tell the Linux kernel to apply that correction? RGDS GARY --- Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703 g...@rellim.com Tel:+1 541 382 8588 Veritas liberabit vos. -- Quid est veritas? "If you can’t measure it, you can’t improve it." - Lord Kelvin pgpKCL0vRvDzZ.pgp Description: OpenPGP digital 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] ✘NEO-M8N vs. NEO-M8T
Yo Bob! On Mon, 21 May 2018 14:00:41 -0400 Bob kb8tq <kb...@n1k.org> wrote: > >> Ok, are you trying to hold close to UTC or simply have a second > >> that is as close to 1 second as possible? > > > > Yes. One follows the other. > > Not really, you can have a source of seconds that are all within 0.1 > ns of the right length but are offset from UTC by 200 ns. ( stable > but not accurate) > > You can have a series of seconds that are all within 10 ns of UTC, > but one may be 20 ns to short and the next is 20 ns to long. > ( accurate but not stable ) > > So, which of the two is more important? UTC is most important (to me), but if one has perfect UTC, then one also has perfect seconds. RGDS GARY --- Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703 g...@rellim.com Tel:+1 541 382 8588 Veritas liberabit vos. -- Quid est veritas? "If you can’t measure it, you can’t improve it." - Lord Kelvin pgp8XPhkHfA2F.pgp Description: OpenPGP digital 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] NEO-M8N vs. NEO-M8T
Yo Scott! On Sun, 20 May 2018 22:03:49 -0500 Scott Newell <newell+timen...@n5tnl.com> wrote: > At 09:23 PM 5/20/2018, Gary E. Miller wrote: > > >I do not see the keyword 'sawtooth' in the u-blox 8 doc. Can I buy > >a clue? > > UBX-TIM-TP, "Time Pulse Timedata". Look for "Quantization error of > time pulse". I'm seeing this on page 359 of the ublox 8 receiver > description/protocol spec book. As the manual says: "Quantization error of time pulse (not supported for the FTS product variant)." The NEO-M8T is an FTS product. So not on the NEO-M8T. RGDS GARY --- Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703 g...@rellim.com Tel:+1 541 382 8588 Veritas liberabit vos. -- Quid est veritas? "If you can’t measure it, you can’t improve it." - Lord Kelvin pgpGk1JeWvazK.pgp Description: OpenPGP digital 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] ✘NEO-M8N vs. NEO-M8T
Yo Hal! On Sun, 20 May 2018 20:22:46 -0700 Hal Murray <hmur...@megapathdsl.net> wrote: > g...@rellim.com said: > > Yeah, which does me zero good real time. I'm putting the PPS into > > a TICC. My TICC has not way to accept real time corrections. So > > that does me no good, except as a post processing step. > > Yes, but that post processing step can be done in real time. > Assuming you are writing the TICC data to a log file: > Read the TICC data. > Read the sawtooth info. > Apply the sawtooth correction. > Write out the updated TICC data. Your concept of 'real time' does not match mine. Also, how does that get me to the gola of a good PPS to feed into the Linux PPS kernel module? I doubt Linux would accept a patch to put gpsd, and more, into the kernel to read GPS and adjust the PPS. RGDS GARY --- Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703 g...@rellim.com Tel:+1 541 382 8588 Veritas liberabit vos. -- Quid est veritas? "If you can’t measure it, you can’t improve it." - Lord Kelvin pgpYPohJ7hec_.pgp Description: OpenPGP digital 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] ✘NEO-M8N vs. NEO-M8T
Yo Bob! On Mon, 21 May 2018 13:41:08 -0400 Bob kb8tq <kb...@n1k.org> wrote: > Ok, are you trying to hold close to UTC or simply have a second that > is as close to 1 second as possible? Yes. One follows the other. RGDS GARY --- Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703 g...@rellim.com Tel:+1 541 382 8588 Veritas liberabit vos. -- Quid est veritas? "If you can’t measure it, you can’t improve it." - Lord Kelvin pgpczGhZvqeLC.pgp Description: OpenPGP digital 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] ✘NEO-M8N vs. NEO-M8T
Yo Bob! On Mon, 21 May 2018 10:39:33 -0400 Bob kb8tq <kb...@n1k.org> wrote: > > Yeah, which does me zero good real time. I'm putting the PPS into a > > TICC. My TICC has not way to accept real time corrections. So that > > does me no good, except as a post processing step. > > > > You have a *something* to read the TICC output it does not just do it > all on it’s own. Yes, but by then it is not real time. My real goal is to improve Linux time. I'm not holding my breath for a kernel module that takes the corrections. Someday. RGDS GARY --- Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703 g...@rellim.com Tel:+1 541 382 8588 Veritas liberabit vos. -- Quid est veritas? "If you can’t measure it, you can’t improve it." - Lord Kelvin pgplB8NWTwgfN.pgp Description: OpenPGP digital 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] ✘NEO-M8N vs. NEO-M8T
Yo Oleg! On Mon, 21 May 2018 18:05:08 +0300 Oleg Skydan <olegsky...@gmail.com> wrote: > You can use uBlox u-center software to enable and disable messages > you need, the configuration can be saved. I have not done Windows since the year 2000. Not restarting now. RGDS GARY --- Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703 g...@rellim.com Tel:+1 541 382 8588 Veritas liberabit vos. -- Quid est veritas? "If you can’t measure it, you can’t improve it." - Lord Kelvin pgpSX7YICfJKI.pgp Description: OpenPGP digital 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] â NEO-M8N vs. NEO-M8T
Yo Chris! On Mon, 21 May 2018 08:23:27 -0500 "Chris Caudle" <ch...@chriscaudle.org> wrote: > The UBX-TIM-TP message is described in: > 32.21.8.1 Time Pulse Timedata > byte offset 8, name: qErr unit: ps > Quantization error of time pulse (not supported for the FTS product > variant). Notice the: not supported for the FTS product So, not on the NEO-M8T RGDS GARY --- Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703 g...@rellim.com Tel:+1 541 382 8588 Veritas liberabit vos. -- Quid est veritas? "If you can’t measure it, you can’t improve it." - Lord Kelvin pgpVdk9FAD2pc.pgp Description: OpenPGP digital 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] ✘NEO-M8N vs. NEO-M8T
Yo Mark! On Mon, 21 May 2018 03:04:23 + Mark Sims <hol...@hotmail.com> wrote: > The sawtooth value is in the 0x0D-0x01 (TIM-TP) message. Third > value, called qErr. 32-bit dword. In picoseconds. How do I feed that into my TICC in real time? RGDS GARY --- Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703 g...@rellim.com Tel:+1 541 382 8588 Veritas liberabit vos. -- Quid est veritas? "If you can’t measure it, you can’t improve it." - Lord Kelvin pgpqJWMKvIZOe.pgp Description: OpenPGP digital 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] ✘NEO-M8N vs. NEO-M8T
Yo Bob! On Sun, 20 May 2018 22:53:37 -0400 Bob kb8tq <kb...@n1k.org> wrote: > If you look at the section under “timing (page 79)” in the uBlox > manual you will find all the fun stuff that makes the T different. > One of the timing messages includes the time offset between the pps > output and the real GPS time solution. Page 351 and after are the > time related commands. The stuff back around page 358 looks like it’s > got the sawtooth data in it. Yeah, which does me zero good real time. I'm putting the PPS into a TICC. My TICC has not way to accept real time corrections. So that does me no good, except as a post processing step. > Bottom line is that with the sawtooth correction applied, you can get > down to below 1x10^-9 at one second on your plot. Yeah, which does me no good real time. > The T version will > automatically output the magic message with the data in it. Not seeing it by default. RGDS GARY --- Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703 g...@rellim.com Tel:+1 541 382 8588 Veritas liberabit vos. -- Quid est veritas? "If you can’t measure it, you can’t improve it." - Lord Kelvin ___ 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] â NEO-M8N vs. NEO-M8T
Yo Chris! On Sun, 20 May 2018 21:18:02 -0500 "Chris Caudle" <ch...@chriscaudle.org> wrote: > On Sun, May 20, 2018 9:06 pm, Gary E. Miller wrote: > >> Cranking sawtooth correction into your data will move > >> the line down most of the way to the "JLâ" line. > > > > Except that requires a post process step, so not useful for real > > time. > > No, it can be used for real time, that is how GPSDO control loops > back out the effects of sawtooth error so it does not add additional > unnecessary noise into the control loops for the clean up oscillator. I do not see the keyword 'sawtooth' in the u-blox 8 doc. Can I buy a clue? RGDS GARY --- Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703 g...@rellim.com Tel:+1 541 382 8588 Veritas liberabit vos. -- Quid est veritas? "If you can’t measure it, you can’t improve it." - Lord Kelvin pgpVm2ZBI0WG8.pgp Description: OpenPGP digital 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] ✘NEO-M8N vs. NEO-M8T
Hal! On Sun, 20 May 2018 18:42:36 -0700 Hal Murray <hmur...@megapathdsl.net> wrote: > g...@rellim.com said: > > The results were disappointing. See attached. For 8x the price > > all I see is a slightly flatter ADEV curve. > > What were you expecting? I was expecting better, not almost the same. 8x price difference for almost nothing. I woulda hped for 5x better. > How good is your antenna? Very good, roof mounts. And the JL GPSDO I coompared it to was using the same antenna on a splitter. > Can you insert an attenuator and compare them again? Yeah, on my long term TODO list. For now low 50's to high 40s' SNR should be good. I have a good skyview, mostly down to the horizon. > It would also be interesting to see the NEO-M8N with good vs bad antenna. So many experiments, so little time. > It would be interesting to see how well the RINEX location compares > with the surveyed location and/or if using the RINEX location > improves the timing output. I'm working on using the NEO-M8T Survey-In mode now. RINEX later. RGDS GARY --- Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703 g...@rellim.com Tel:+1 541 382 8588 Veritas liberabit vos. -- Quid est veritas? "If you can’t measure it, you can’t improve it." - Lord Kelvin pgpnvfTWaDCTt.pgp Description: OpenPGP digital 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] ✘NEO-M8N vs. NEO-M8T
Mark! On Mon, 21 May 2018 00:22:17 + Mark Sims <hol...@hotmail.com> wrote: > The main significant difference between the M8N and M8T is the fact > that the M8T can output raw data (and sawtooth). The hardware is > the same so there should not be much difference PPS wise between the > two. Yes, the raw data is nice, but I see nothing about 'sawtooth' in the 'U-blox 8 Receiver Description'. Do they use a different term? The hardware difference is replacing the XO with a TCXO. > I have Lady Heather's RINEX writer working pretty well. I look forward to trying that! > GLONASS and GALILEO have not yet been tested with the M8T... gpsd works with those fine. GLONASS is no help. GALILEO can help a bit. RGDS GARY --- Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703 g...@rellim.com Tel:+1 541 382 8588 Veritas liberabit vos. -- Quid est veritas? "If you can’t measure it, you can’t improve it." - Lord Kelvin pgpVEU7i9K1Xg.pgp Description: OpenPGP digital 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] ✘NEO-M8N vs. NEO-M8T
Yo Bob! On Sun, 20 May 2018 19:26:33 -0400 Bob kb8tq <kb...@n1k.org> wrote: > The “big deal” features on the T series are the ability to do single > satellite timing Which I always thought was pointless, that only works for a fixed antenna. Any GPS in a fixed position lab will have a good rooftop antenna with clear skyview. > and the auto output of the sawtooth correction > information. Cranking sawtooth correction into your data will move > the line down most of the way to the “JL” line. Except that requires a post process step, so not useful for real time. I just looked at the 'U-blox 8 Receiver Description' and it makes no mention of sawtooh anything. Is that in a different doc? I'll also test Surevey-In mode to see how much that helps. RGDS GARY --- Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703 g...@rellim.com Tel:+1 541 382 8588 Veritas liberabit vos. -- Quid est veritas? "If you can’t measure it, you can’t improve it." - Lord Kelvin pgpvM3yOyehTU.pgp Description: OpenPGP digital 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.
[time-nuts] ✘NEO-M8N vs. NEO-M8T
Time-nuts! I have heard for a long time to use the u-blox Time Sync products, instead of the basic GPS products, for precisin time. So I ordered a NEO-M8T and compared it against a plain NEO-M8N. Tests done using a TAPR-TICC and a JL GPSDO for reference. All tests using the same antenna and 12 hours of data. The results were disappointing. See attached. For 8x the price all I see is a slightly flatter ADEV curve. The M8T also support raw data, so I can try to use it for RINEX files. RGDS GARY --- Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703 g...@rellim.com Tel:+1 541 382 8588 Veritas liberabit vos. -- Quid est veritas? "If you can’t measure it, you can’t improve it." - Lord Kelvin ___ 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] WTB: HP/Agilent/Symmetricom 58517A Distribution Amplifier
Ole! On Fri, 18 May 2018 20:31:22 +0200 Ole Petter Rønningen <opronnin...@gmail.com> wrote: > Just a heads up, in case you’re not concious of the fact; at least my > HP splitter (can’t recall model# off hand) is strictly L1 - many > others are wide band and will allow L2 and whatever else you might > later want. I have had good luck with cheap chinese wide-band splitters. No problems with L1, L2, GLONASS and more. Like this one for $23: https://www.ebay.com/itm/RF-coaxial-Power-Splitter-Divider-Combiner-SMA-2-way-800-2500MHz-signal-booster/282970977753 Also, mostly good luck with cheap Chinese DC injectors. Some have had bad solder joints, easily fixed. These have been good, for $9: https://www.aliexpress.com/item/RF-Isolator-Bias-Feeder-Bias-Tee-10MHz-3GHz/32848444588.html What I have not had luck with yet is finding a cheap LNA so I can recover the gain lost in the splitters. The ones I have tested so far have all seriously degraded my SNRs. Anyone know of a cheap and good L1/L2/etc. LNA? RGDS GARY --- Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703 g...@rellim.com Tel:+1 541 382 8588 Veritas liberabit vos. -- Quid est veritas? "If you can’t measure it, you can’t improve it." - Lord Kelvin ___ 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] TruePosition GPSDO Holdover Issues
Hal! On Tue, 15 May 2018 12:52:58 -0700 Hal Murray <hmur...@megapathdsl.net> wrote: > Neat. Thanks. That raises several questions. > How high do satellites get if you are at a pole? 44.6 degrees. RGDS GARY --- Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703 g...@rellim.com Tel:+1 541 382 8588 Veritas liberabit vos. -- Quid est veritas? "If you can’t measure it, you can’t improve it." - Lord Kelvin ___ 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] Ublox Galileo/Beidou PRNs
Mark! On Fri, 11 May 2018 21:02:59 + Mark Sims <hol...@hotmail.com> wrote: > Does anybody know how Ublox maps their reported PRNs for Galileo and > Beidou satellites to the true satellite PRNs. What little there is > on the web appears on the web is rather incorrect. Depends a LOT on your u-blox firmware version, and how it is configured. For example, the NMEA versions are inconsistent on PRNs. Check out this document: https://www.u-blox.com/sites/default/files/products/documents/u-blox8-M8_ReceiverDescrProtSpec_%28UBX-13003221%29_Public.pdf 'u-blox8-M8_ReceiverDescrProtSpec_(UBX-13003221).pdf' Appendix A. It's ugly. Have a stiff drink first for courage. The future is gnsid:svid. Someday... RGDS GARY --- Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703 g...@rellim.com Tel:+1 541 382 8588 Veritas liberabit vos. -- Quid est veritas? "If you can’t measure it, you can’t improve it." - Lord Kelvin ___ 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] Help Identifying this surplus Timing Module
A little Googling found a two page datasheet. It doesn't tell you much more than what you already found out, but does have specifications. I can't figure out the correct link to include here, but a Google search with the string "ATiMe-s 38.88" (don't include the quotes) should bring up the link in the first couple of hits. It is a PDF at the www.sbtron.co.kr website. gc On 05/11/2018 07:16 PM, CubeCentral wrote: Hello All! I would like to enlist your help in identifying this "surplus Timing Module": https://imgur.com/a/Psw8gP7 All the hints I've been given are: - Purchased about a decade ago - Might use a Motorola DSP as the processor A quick google search lead me to a possible description: "High speed, hitless, ultra low jitter timing module for OC-N line interfaces: The TF Systems / ATiMe-LC is a timing reference source for OC-N and STM-N interfaces. It complements TeraSync's central timing modules to provide a complete and redundant timing solution at the system level." ...but I'm unsure if that is 100% the same module. If you would like to get some different photos, please let me know and I will see what I can do. Any thoughts or ideas would be greatly appreciated! Thanks! -Randal (at CubeCentral) ___ 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] nuts about position
Yo Mark! On Tue, 1 May 2018 02:48:17 + Mark Sims <hol...@hotmail.com> wrote: > A LEA-6T seems to be able to cope with the data stream at it's > default 9600 baud. I just tried a NEO-8N and it drops packets, I think heather is parsing the UBX_RAW_RATE messages for the raw GPS meansurements. The LEA-6T allows UBX_RAW_RATE, but the NEO-M8N does not. RGDS GARY --- Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703 g...@rellim.com Tel:+1 541 382 8588 Veritas liberabit vos. -- Quid est veritas? "If you can’t measure it, you can’t improve it." - Lord Kelvin pgpX8JFrYGSwt.pgp Description: OpenPGP digital 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] nuts about position
Scott! On Thu, 26 Apr 2018 10:04:54 -0700 Scott McGrath <scmcgr...@gmail.com> wrote: > Swiftnav has a centimeter accurate multi band receiver RTK-585. Its > about 600 bucks minus antenna. Link? With RTK in the name it prolly needs a base and rover? Or post processing? RGDS GARY --- Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703 g...@rellim.com Tel:+1 541 382 8588 Veritas liberabit vos. -- Quid est veritas? "If you can’t measure it, you can’t improve it." - Lord Kelvin ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Cheap jitter measurements
Tom! On Wed, 25 Apr 2018 04:01:10 -0700 "Tom Van Baak" <t...@leapsecond.com> wrote: > Hi Gary, > > > A little coding later and there are nice plots. They were compared > > to the output of tvb's adev.c program. Results are similar. > > Whoa there cowboy. That doesn't mean it's right. Comments: It would not be time nuts if I did not get my head handed back to me on a platter right away. :-) Much to ponder. Thanks much for the feedback. As requested, here is my raw data: http://pi5.rellim.com/1d.log.gz chA is the JL. chB is the u-blox. 24 hours of data. > I strongly, pretty please, strongly advise you to use TimeLab for a > while before you roll your own tools and plots. I'd love to use TimeLab, or Stable32. But they seem to be closed source, and only run on Windows. I have not done Windows since 2000. Any suggestions for something open source and POSIX compatible? Ideally something that runs well on a RasPi. RGDS GARY --- Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703 g...@rellim.com Tel:+1 541 382 8588 Veritas liberabit vos. -- Quid est veritas? "If you can’t measure it, you can’t improve it." - Lord Kelvin ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Cheap jitter measurements
Time-nuts! I went ahead and bought the TAPR-TICC, it is a very impressive instrument. For this setup it is combined with a Jackson Labs GPSTLXO as the 10MHz reference. The JL is a GPS disciplined temperature compensated crystal oscillator. The first setup uses the TAPR-TICC in Period mode, outputting the PPS period individually for channel A and channel B. Channel A is the PPS of a plain u-blox NEO-M8N. Channel B is the PPS of the JL GPSTLXO. Simple to get the cycle times from the USB serial port. Then I grabbed a copy of the easy to use Python Allantools. https://github.com/aewallin/allantools A little coding later and there are nice plots. They were compared to the output of tvb's adev.c program. Results are similar. Results are attached. gps.png is the plain NEO-M8N. GPSTLXO is the JL part. gps.png looks as expected. GPSTLXO.png shows the quality of the JL part, but does have some odd divots in the plot. Maybe artifacts of using the PPS derived from the reference 10MHz? Or an artifact of the 10e6 divider? There are adev's of Rb standards here: http://www.ke5fx.com/rb.htm My guess is that the oadev at 1s would be about 50x better with a Rubidium? But similar at 10k seconds? Comments? RGDS GARY --- Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703 g...@rellim.com Tel:+1 541 382 8588 Veritas liberabit vos. -- Quid est veritas? "If you can’t measure it, you can’t improve it." - Lord Kelvin ___ 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] Weird Stuff Warehouse shutting down
I was at Weird Stuffabout a month ago. Picked up a heavy microscope base. Those are the things you really don't want to buy on ebay. To be honest, I wasn't finding much there. My dentist is nearby, and that was when I would check them out. How old is the stuff on their racks? Remember Bay Networks? Excess Solutions is still around for now, but the pickings have been slim. I buy NEMA or NEMA type cases there for cheap. But the place is so deep into San Jose that it isn't worth the trip. http://www.excesssolutions.com/ I noticed the Electronics Fleamarket has moved again: https://www.electronicsfleamarket.com/ This is a shadow of the Foothill days. As far as I'm concerned, when the Livermore Ham swapmeet left Las Positas College, the show was over. ___ 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] Chinese GPS Survey Antenna
Time-nuts! A while back there was a discussion of cheap Chinese GPS survey antennas. I purchased a TOPGNSS model GN-GGB0710.. Took about a month to arrive. They claim GPS L1 L2 GLONASS G1 G2 BDS B1 B2 B3 and Galileo. I bought it on aliexpress for $75 inc. shipping. https://www.aliexpress.com/item/NEW-3-3-18V-High-precision-high-gain-measurement-GNSS-GPS-GLONASS-BDS-Cors-rtk-GNSS/32815576155.html Specs are here: http://www.topgnss.com/gnssmodule/showproduct.php?lang=en=59 Antenna connection is a simple TNC connector and mounts on a standard 5/8-11 thread. They say 3.3 to 18V. I'm running it on 5V. Construction quality seems fine. Just as in the picture. After a few hours of use I can say it is a nice little antenna. I seem to be getting good strong L1, L2, L5 and GALILEO signals on all elevations and azimuths. A gross comparison to my Trimble 22020 shows the two as roughly comparable. Except I get stronger GALILEO on the TOPGNSS. I have no way to push either antenna to the limit. Many thanks to the list for some fine product suggestions. Add this one to the list. RGDS GARY --- Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703 g...@rellim.com Tel:+1 541 382 8588 Veritas liberabit vos. -- Quid est veritas? "If you can’t measure it, you can’t improve it." - Lord Kelvin ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Cheap jitter measurements
Yo Hal! On Tue, 10 Apr 2018 15:41:41 -0700 Hal Murray <hmur...@megapathdsl.net> wrote: > > Yeah, but the granularity is much worse. > > Do you have code that demonstrates that? (or tell me how and I'll > try it) Look in gpsd git head. In the contrib directory here is a program: clock_test.c It tests the time to do two back to back clock_gettime(). Output looks like this: # ./clock_test samples 101, delay 1000 ns min 67 ns, max 302 ns, mean 176 ns, median 197 ns, StdDev 52 ns You run it a few times and you will see the granularity in the measurements is 10's of ns, or more, depending on your CPU. Probably better discussed on the gpsd-users@ or NTPsec devel@ mailing list. 67 ns not exactly time-nuts precision. RGDS GARY --- Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703 g...@rellim.com Tel:+1 541 382 8588 Veritas liberabit vos. -- Quid est veritas? "If you can’t measure it, you can’t improve it." - Lord Kelvin pgpqBySAD6eqr.pgp Description: OpenPGP digital 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] Cheap jitter measurements
Yo Hal! On Mon, 09 Apr 2018 13:53:21 -0700 Hal Murray <hmur...@megapathdsl.net> wrote: > The API for the kernel clock can be read to a ns. I don't see ntpd > having much use for finer grain than that. I should look at the > source to see what the internal details look like. Yeah, but the granularity is much worse. RGDS GARY --- Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703 g...@rellim.com Tel:+1 541 382 8588 Veritas liberabit vos. -- Quid est veritas? "If you can’t measure it, you can’t improve it." - Lord Kelvin pgpsOvGE7c621.pgp Description: OpenPGP digital 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] Weird Stuff Warehouse shutting down
Yo Richard! On Sat, 7 Apr 2018 14:17:42 -0700 "Richard (Rick) Karlquist" <rich...@karlquist.com> wrote: > On 4/7/2018 10:54 AM, Gary E. Miller wrote: > > > > Sad news. Weird Stuff, Haltek, and Halted were integral parts of > > the Silicon Valley ecosystem. > > Are you saying Halted is gone? Dunno, sorry to mislead, I don't live there anymore. I just meant they were, as a group, vital to the local culture at that time. There web site is still up: http://halted.com/ RGDS GARY --- Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703 g...@rellim.com Tel:+1 541 382 8588 Veritas liberabit vos. -- Quid est veritas? "If you can’t measure it, you can’t improve it." - Lord Kelvin pgpTpZfVxOzxP.pgp Description: OpenPGP digital 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] Weird Stuff Warehouse shutting down
Bruce! On Fri, 6 Apr 2018 20:24:59 -0700 Bruce Lane <kyr...@bluefeathertech.com> wrote: > I'm sorry to report we're losing another surplus place. Weird > Stuff Warehouse, in Sunnyvale, CA, is closing its doors as of Monday, > 9-Apr-18. Sad news. Weird Stuff, Haltek, and Halted were integral parts of the Silicon Valley ecosystem. RGDS GARY --- Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703 g...@rellim.com Tel:+1 541 382 8588 Veritas liberabit vos. -- Quid est veritas? "If you can’t measure it, you can’t improve it." - Lord Kelvin ___ 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] Environmental sensor recommendations
Mark! On Thu, 5 Apr 2018 07:13:49 + Mark Sims <hol...@hotmail.com> wrote: > I looked at the TEMPer devices, but almost all of them seem to be HID > devices that emulate a digi-monkey typing on a keyboard... NTPsec uses them in a polled mode. Very easy to work with. # temper-poll -c 22.1 Python code to do it all here: https://github.com/padelt/temper-python You can get a TEMPer pretty cheap if you order directly from China. > an emulate a serial port. I find that a negative. > it costs more than the dogtaian USB-PA that also does pressure. You're looking at list prices, they are a lot cheaper on ebay. But yes, pressure is nice to have. Next time I need a sensor I'll try the USB-PA. RGDS GARY --- Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703 g...@rellim.com Tel:+1 541 382 8588 Veritas liberabit vos. -- Quid est veritas? "If you can’t measure it, you can’t improve it." - Lord Kelvin ___ 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] Environmental sensor recommendations
Yo Mark! On Thu, 5 Apr 2018 00:58:50 + Mark Sims <hol...@hotmail.com> wrote: > Are there any recommendations for > other off-the-shelf sensors worth looking at? I use several of the TEMPer series. http://pcsensor.com/usb-thermometer/temper1f.html The TEMPer1F has a local and a remote temperature sensor. The TEMPer1F_H1 has a remote etmperature/humidity sensor. The basic TEMPerGold has one temp sensor, is the size of a thumbdrive and costs under $10. All easy to use. Gotta be careful, a ton of slightly different versions on the market. RGDS GARY --- Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703 g...@rellim.com Tel:+1 541 382 8588 Veritas liberabit vos. -- Quid est veritas? "If you can’t measure it, you can’t improve it." - Lord Kelvin ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Cheap jitter measurements
Time Nuts! TL:DR: I decided to go with the Rb and TAPR-TICC. Long story: Thank you to all that made such good suggestions. I think you pretty much covered the spectrum of options to measuring PPS very nicely. I'm tempted by the used 5370/5371 idea. It has 150 ps resolution and does a ton of fun things. But they are large, power hungry (500W), and only talk over GPIB. I just want a TICC and the rest is overhead. All the cool charts, graphs and histograms on the CRT do me no good. Boxes like the Racal 1992 and hp 5334b are more interesting. Most 1991 on ebay are for parts only, and there are more web pages on how to repair them than how to use them. They only resolve down to 1 nano second. I do not see any of either on ebay with rs-232. Since I'm just working with 5V and 3.3V logic levels, I don't need a fancy front end, and output of logic level and/or USB serial is also nice for using on a RasPi. So I looked at the various hobbyist solutions. There are some 'interpolator' designs, but I'd need to build them myself and they also only get to around 1 nano second. Some maybe a lot better performance, but more than some assembly required. Also I would have to figure out how to measure my measuring tool to see what I got. So, I'm back to the Rb and TAPR-TICC solution. No one will seriously question the Rb accuracy, at least when compared to GPS. The TAPR-TICC comes fully assembled, tested and specified. Easy USB serial interface. Just a tad more expensive than other solutions. 60 picosecond resolution and less than 100 picosecond typical jitter. ADev below 1x10-10. All way better than I need, so few should argue with using it to measure GPS PPS. A few downsides. I'll have to write my own code for pretty graphs, but at least I can do it on UNIX. Not a total solution, I still need to add a GPSDO and cable it all together. Now I just have to wait for the postman. Once again, thanks for all the suggestions. RGDS GARY --- Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703 g...@rellim.com Tel:+1 541 382 8588 Veritas liberabit vos. -- Quid est veritas? "If you can’t measure it, you can’t improve it." - Lord Kelvin ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Cheap jitter measurements
Hal! On Tue, 03 Apr 2018 13:06:43 -0700 Hal Murray <hmur...@megapathdsl.net> wrote: > > What would you guys suggest as the cheapest way to see jitter down > > to around 1 nano second? > > What do you mean by "jitter" and what do you really want to do? I mean jitter as NTP defines jitter. Whatever that is. > Jitter usually needs a reference. Do you have one? I have a GPSDO, but that was why I was looking to add the Rubidium standard to the mix. > Do you have a scope? Yup, still got my trusty Tek 465B, and it still works fine. Cost almost as much as a car when I bought it. > The Rigol DS1102E is/was quite popular and is good for close to a > ns. Nice, but not quite fast enough. I've settled on the Rb+TAPR-TICC solution. RGDS GARY --- Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703 g...@rellim.com Tel:+1 541 382 8588 Veritas liberabit vos. -- Quid est veritas? "If you can’t measure it, you can’t improve it." - Lord Kelvin pgpM_n6RkD_uQ.pgp Description: OpenPGP digital 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.
[time-nuts] Cheap jitter measurements
Time-nuts! With care I can measure GPS jitter on a RasPi to a bit over 300 nano sec resolution. That is the smallest increment of the RasPi 3B clock with a 64-bit kernel. That is clearly not time-nuts accuracy. What would you guys suggest as the cheapest way to see jitter down to around 1 nano second? I'm thinking maybe something like a rubidium standard (FE-5680A) and a TICC-TAPR? But that would put me out around $400. The picPET does not look accurate enough. Maybe a clever way to use it for more accuracy? Is there a picPET like thing cheaper than the TICC-TAPR? Ideas? RGDS GARY --- Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703 g...@rellim.com Tel:+1 541 382 8588 Veritas liberabit vos. -- Quid est veritas? "If you can’t measure it, you can’t improve it." - Lord Kelvin ___ 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] Teardown of Chinese made eBay GPS antenna.
Yo Bob! On Wed, 28 Mar 2018 16:37:07 -0400 Bob kb8tq <kb...@n1k.org> wrote: > So, after only two months in transit my examples of the “Chinese GPS > Antenna” are here to poke at. Cool. I just ordered one. I'm finding some GPS need the 40dB LNA this claims, as opposed to the usual 23dB or so. Then I can stop swapping L1/L2 and L1/GLONASS antennas. RGDS GARY --- Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703 g...@rellim.com Tel:+1 541 382 8588 Veritas liberabit vos. -- Quid est veritas? "If you can’t measure it, you can’t improve it." - Lord Kelvin pgpOHrl8RWkxw.pgp Description: OpenPGP digital 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] eBay GPS antennas
Yo Bob! On Fri, 16 Feb 2018 13:47:24 -0500 Bob kb8tq <kb...@n1k.org> wrote: > Reports to date on Glonass have not been encouraging. I have been testing position accuracy lately on a self contained u-blox 8 with built-in antenna supposedly GLONASS capable. I write a Python script to selectively enable GLONASS and GALILEO over GPS. All figures below are rough averages. Typically, with one particular GPS, in one particular spot, it gives a CEP(50) of 10 feet. Enable GLONASS and that worsens to 24 feet. After about a minute the u-blox rejects all the GLONASS, that have good SNR, and the CEP(50) drops back to normal. Enable GALILEO and CEP(50) improves to 6 feet. And stays that way. So be sure to enable GALILEO in your GPS and disable GLONASS. Also note: the passband of GALILEO is technically the same as GPS, but has more energy at the edges. Some GPS antennas cut it a little close and hurt GALILEO performance. RGDS GARY --- Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703 g...@rellim.com Tel:+1 541 382 8588 Veritas liberabit vos. -- Quid est veritas? "If you can’t measure it, you can’t improve it." - Lord Kelvin pgpknAhi5X3St.pgp Description: OpenPGP digital 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] GPS Jamming
Yo Gary! On Fri, 26 Jan 2018 07:57:02 -0700 Gary Neilson <g...@deepskyridge.com> wrote: > Don't know if this has be posted before or not. Also don't know if > this will affect timing info. I am a commercial pilot in Bend, OR. There is a lot of 'GPS testing' going on in Fallon, NV. About every month I recieve a notice about specific times that 'GPS may be unavailable' near Fallon. RGDS GARY --- Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703 g...@rellim.com Tel:+1 541 382 8588 Veritas liberabit vos. -- Quid est veritas? "If you can’t measure it, you can’t improve it." - Lord Kelvin pgpGemeaWkuFh.pgp Description: OpenPGP digital 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.
[time-nuts] GPS Jamming
Don't know if this has be posted before or not. Also don't know if this will affect timing info. GPS Jamming <http://www.thedrive.com/the-war-zone/17987/usaf-is-jamming-gps-in-the-western-u-s-for-largest-ever-red-flag-air-war-exercise> I am on the very edge of their coverage map. Gary ___ 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] Microsemi 3120A sold on eBay
On Sat, 27 Jan 2018 22:10:21 -0500, you wrote: >It is interesting to note that the seller is in Salem, MA, a few miles south >of Microsemi in Beverly, MA. OT, a bit: my ham radio elmer worked for Bomac in Beverly, MA, which became Varian, which I just googled and indeed was bought at least in part by Microsemi! The P2V Neptune aircraft used one of their hydrogen thyratrons to fire the megawatt search radar. We now return you to time/frequency stuff --- This email has been checked for viruses by AVG. http://www.avg.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] Suggestion for a timing GPS receiver (Trimble / Ublox / other?)
Yo Paride! On Mon, 22 Jan 2018 16:38:01 +0100 Paride Legovini via time-nuts <time-nuts@febo.com> wrote: > I plan to build a decent GPS/GNSS-based Stratum 1 NTP server, and I'm > looking for a good and possibly affordable timing GPS receiver. Before you bother looking at any GPS, you need to look at your server. Hardly any Intel CPU can give you time resolution much better than 200 nS on a PPS in. Raspberry Pi's actually have slightly better clock resolution than Intel parts, just under 190 nS. That resolution os worse than what you get out of any good modern GPS. By 'local resolution' I mean the shortest time interval you can read by repeatedly doing clock_systime() calls. clock_system() is is many key ntpd paths. The accuracy of your NTP server will be strongly affected by your server choice, and the cheap RasPi is often one of the best for the job. Fot $70 you can get a RasPi and a u-blox-8 hat. Add a few bits here and there and you have a nifty stratum 1. You'll find its harder than it looks to make a better NTP than that combo. Then, once you have a strong baseline, you can see what tricks you can do to improve on that. RGDS GARY --- Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703 g...@rellim.com Tel:+1 541 382 8588 Veritas liberabit vos. -- Quid est veritas? "If you can’t measure it, you can’t improve it." - Lord Kelvin pgp_0UNQPV09D.pgp Description: OpenPGP digital 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] HP nixie counters, free!
On 01/05/2018 02:41 PM, Bob Albert via time-nuts wrote: Scott, it's a shame to trash those great counters. I gave away two of them a while back; one is missing a decade counter so I'd be interested in replacing that. The oven assembly is a great unit as well. Plug-ins are nice too, especially the one that goes to 500 MHz. Some of the 5245L's used the 10544 oscillator for frequency reference. I don't know if that was a later option or what. But it is probably worth saving if you have it. There is an adapter, the HP-10590A, so the plug-ins can be used with the HP-5345A. Of course, the 500 MHz one isn't useful, but the 3 GHz or video amplifier plugins could be used. Gary [...] ___ 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] Oscilloquartz OSA-4350 GPSDO
On Sun, 31 Dec 2017 20:56:26 +0100, you wrote: > Without a thermal camera I've used a 4-1/2 digit DVM set for 200mV full > scale, or 20mV if you can do that. Often the low uV resolution will allow you > to trace the current path, just start at the power and ground inputs to the > board and follow the voltage drops to the short. Or go old-school with an HP > logic pulser and current probe... OK, I think, made an audible low-ohm probe "Shortsqueak?" That can resolve an inch or less of PC board trace. You can't have mine! --- This email has been checked for viruses by AVG. http://www.avg.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] accurate 60 hz reference chips/ckts
Yo All! Jeremy wrote: > I'm surprised Vlad is seeing as much as six seconds differential > but maybe I don't understand the experiment. I've done measurements > of the line frequency here in California and never seen much > variation. I live in Central Oregon. Next to the Pacific Intertie and the Paccific DC Intertie. Near the Round Butte Dam, Pelton Dam, and other power generating dams. The Interties connect the massive hydropower generation of the Columbia River system with southern California. The hypropower system includes the best technology of the 1930's, 1940's and 1950's. I've had converstations with some of the dam operators about how they keep frequency. Pretty simple really. Huge tonnages of spinning steel and copper being pushed by falling water. The water is regulated by flapper valves. Pretty stable short term. Now imagine when a 300MVA intertie blows over, or is burned by a fire, and instantly disconnects. Or a steel mill shuts down for the day, or... The electrical backpressure to the generators drops, so the generators speed up, increasing the line frequency and voltage. When this happens, the dam operators literally pick up the phone, and talk to the other dams to decide what to do. Usually that involves one or more dams closing down a few flapper vavles. That is how the short term frequency of your local power line is controlled. The control room also has a AC synchronous clock, off the power line, and an accurate digital clock. Once a day they manually get the AC clock to agree with the digital clocl. None of this is rocket science, don't use it for anything you need any accuracy for. RGDS GARY --- Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703 g...@rellim.com Tel:+1 541 382 8588 Veritas liberabit vos. -- Quid est veritas? "If you can’t measure it, you can’t improve it." - Lord Kelvin pgp5568AfFDAl.pgp Description: OpenPGP digital 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] ublox NEO-M8T improved by insulated chamber?
Yo Tom! On Wed, 8 Nov 2017 09:31:01 -0800 "Tom Van Baak" <t...@leapsecond.com> wrote: > > How exactly do you measure offset of your GPS time output to > > absolute UTC time? > > Conceptually it's no different from measuring your favorite resister > or thermometer: you compare your DUT against a standard REF and the > difference is your error, a process called calibration. Yup, I worked in metrology for a while. John Fluke Mfg Co., Inc. > Calibrating your UTC is harder. Yup. > Here are couple examples: > That's enough reading to keep you busy for a few days. Yup, I will, thanks. Now when was the last time you did that absolute calibration of a GPS receiver to UTC? Can we see the results? RGDS GARY --- Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703 g...@rellim.com Tel:+1 541 382 8588 Veritas liberabit vos. -- Quid est veritas? "If you can’t measure it, you can’t improve it." - Lord Kelvin pgpa3TEpW0yBO.pgp Description: OpenPGP digital 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] ublox NEO-M8T improved by insulated chamber?
Yo Chris! On Wed, 8 Nov 2017 11:47:05 -0600 "Chris Caudle" <ch...@chriscaudle.org> wrote: > On Wed, November 8, 2017 10:45 am, Gary E. Miller wrote: > > No one here has yet bothered to address the issues I raise > > in Section 3.3.4. > > Sure they did. Why are you referencing the old version instead of the > newer version that Leo Bodner provided the link to? Because that was sent last night after I stopped reading email. I knew about the errata, I left out that detail to see when someone actually read my citation. Leo actually did, but not got to his email yet, I read email in reverse chrono order. > https://www.gps.gov/technical/icwg/IRN-IS-200H-001+002+003_rollup.pdf What I said is correct, IS-GPS-200H is STILL the latest version of the GPS standard. Leo's link, which I found Monday, is to a copy of IS-GPS-200H with the errata applied. So not technically an update to IS-GPS-200H. > "The NAV data contains the requisite data for relating GPS time to > UTC. The accuracy of this data during the transmission interval shall > be such that it relates GPS time (maintained by the MCS of the CS) to > UTC (USNO) within 20 nanoseconds (one sigma). " So yes, UTC from a GPS is now 20 ns (one sigama). What I said about +/- 13 ns being noise relative to the spec still applies. Do you now see how measured GPS time/location can be very precise, but UTC from a GPS less so? Have you read the entire 3.3.4? RGDS GARY --- Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703 g...@rellim.com Tel:+1 541 382 8588 Veritas liberabit vos. -- Quid est veritas? "If you can’t measure it, you can’t improve it." - Lord Kelvin pgp8629VL0oiQ.pgp Description: OpenPGP digital 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] ublox NEO-M8T improved by insulated chamber?
Yo jimlux! On Wed, 8 Nov 2017 06:33:19 -0800 jimlux <jim...@earthlink.net> wrote: > On 11/7/17 8:39 PM, Gary E. Miller wrote: > > Yo Tom! > > > > On Tue, 7 Nov 2017 20:16:09 -0800 > > "Tom Van Baak" <t...@leapsecond.com> wrote: > > > >>> Which is small compared to the published GPS time resolution > >>> (IS_GPS_200H, page 54) of 90 ns. > >> > >> Correct. GPS performs far better than the original spec. Like the > >> Mars rovers... > > > > Of course, but then you are on a wing and a prayer, not > > engineering. > > Not really - the original spec for GPS was based on being able to > track to a single chip of the PN code at 1 MHz, or about 300m > position error, and 30m for the precise code at 10MHz. I agree with almost all you ssid. And none of it applies to the point I made. I'm talking about the current GPS standard (IS-GPS-200H), nothing dated at all. No one here has yet bothered to address the issues I raise in Section 3.3.4. What I say about 3.3.4 is perfectly compatible with with your arguments. I'll be happy to discuss my interpretation of 3.3.4 and what I think it means, when someone shows they actually read it. RGDS GARY --- Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703 g...@rellim.com Tel:+1 541 382 8588 Veritas liberabit vos. -- Quid est veritas? "If you can’t measure it, you can’t improve it." - Lord Kelvin pgp00RpVxbAAU.pgp Description: OpenPGP digital 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] ublox NEO-M8T improved by insulated chamber?
Yo Tom! On Tue, 7 Nov 2017 20:16:09 -0800 "Tom Van Baak" <t...@leapsecond.com> wrote: > > Which is small compared to the published GPS time resolution > > (IS_GPS_200H, page 54) of 90 ns. > > Correct. GPS performs far better than the original spec. Like the > Mars rovers... Of course, but then you are on a wing and a prayer, not engineering. > As a result we're now all used to ~10 ns level of performance out of > GPS, even in a $5 receiver. I'm sure we are not talking about the same thing here. Your talking about GPS time? I'm talking about UTC as output from a GPS, after it converted from GPS time. I am NOT talking about the 'performance' of GPS. What is performance? We talking about frequency stability, or position accuracy, or we talking about absolute offset from USNO UTC time? I'm talking about the later. I'm talking about the spec about how close the GPS time is to UTC time. Your GPS converts the GPS time to UTC time depending on an ephemeris parameter that the GPS owners say is 90 ns (one sigma). Sure, you may get better, but when you are looking at subtle error sources that is surely one to look at. How exactly do you measure offset of your GPS time output to absolute UTC time? > Closer to ~1 ns is possible when you dig > into the bag-of-timing-tricks like zero-D mode, sawtooth correction, > antenna calibration, multi-path mitigating antennae, dual-frequency > receivers, external frequency references, post-processing, > temperature stabilization of antenna, cables, receiver, etc. Yes, of course, but NONE of that fixes the GPS to UTC offset problem. It makes the GPS time much better, but does not solve the problem that the GPS to UTC offset is only good to 90 ns (one sigma). Is your GPS getting a better offset correction somewhere else? Otherwis it has NO way to compute/calculate/devine that offset. > So the > industry big boys are getting sub-cm levels of positioning and sub-ns > levels of timing. It's all pretty cool. Some time nuts are not far > behind. I have seen cm level precision myself. But that is unrelated to the issue I bring up. The positioning depends on stable GPS time, and I agree GPS time is much more stable than 90 ns. I thought the subject was UTC offsets. > Note also that relative timing, such as needed by a GPSDO frequency > standard is always much better than absolute timing, such as needed > by a UTC time standard. This is because many of the unknown offsets > (antenna, cable, receiver RF and f/w) magically cancel when used as a > GPSDO. This is why some GPSDO can get down to parts in 10^14th > frequency stability over a day. Yes, I 100% agree, and totally unrelated to my point. Frequency stability is only loosely correlated to absolute time accuracy. Stable != accurate. > There's a slide I remember seeing that shows how GPS timing accuracy > has improved since the early days. It's page 9 (attached) of: I agree, GPS accuracy is great, but I am NOT talking about GPS timing, I am talking about UTC timing accuracy. I thought the problem was that the UTC time from the GPS was wandering on a diurnal time frame. The GPS can be perfect to one hundred 9s, the GPS position can be perfect to 100 nines, but if the transmitted GPS time to UTC time offset is said, by the US Military, to be only 90 ns (one sigma), then I'd listen to them when it matters. Time for us all to actually read the standard and argue what that means. RGDS GARY --- Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703 g...@rellim.com Tel:+1 541 382 8588 Veritas liberabit vos. -- Quid est veritas? "If you can’t measure it, you can’t improve it." - Lord Kelvin pgp4jNhr0JKde.pgp Description: OpenPGP digital 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] ublox NEO-M8T improved by insulated chamber?
Yo MLewis! On Tue, 7 Nov 2017 16:44:05 -0500 MLewis <mlewis...@rogers.com> wrote: > With a strictly SSE skyview, I still regularly get signals from sats > to my NW. When they're at the right elevation and heading, their > signals pass over me and reflect back at me from a tall building. > When running my M8T with the position unlocked, and those NW sats are > getting a reflection and reporting in, (although the reflecting > building is further away to the SE) my GPS position drifts up to 300' > to my south (S of SSE). (reported position goes for a walk, > staggering across the parking lot, wanders through a park with an > occasional loop, across a road, then sits down for a while, before > wandering back) Yeah, one of my test locations has similar issues. It leads to some 'interesting' results. > Is it reasonable to use the 9" ~= 1 ns for: > running with a fixed & correct survey position, and NW sats > reflecting a signal to me, that 300' drift would equate to a (300' x > 12") / 9" = 400, for a ballpark 400 ns error? I think it is reasonable as a worst case. Basically a 1D model of a 3D problem. With good sat angles, the 3m location change will be trigonomically smaller for a sat at an angle. But, as I said, given that GPS only resolves to 90 ns, the worst case +/- 13 ns is noise. RGDS GARY --- Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703 g...@rellim.com Tel:+1 541 382 8588 Veritas liberabit vos. -- Quid est veritas? "If you can’t measure it, you can’t improve it." - Lord Kelvin pgpLfoMXp4ofz.pgp Description: OpenPGP digital 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] ublox NEO-M8T improved by insulated chamber?
Yo Lars! On Tue, 7 Nov 2017 20:32:19 + Lars Walenius <lars.walen...@hotmail.com> wrote: > Another question: If You have an error in the surveyed position of > say 3meters and you receive all of the available satellites in all > directions how much will this really affect your timing? I'll oversimply a bit by repeating Adm. Grace Hoppers famous giveaway. When asked, she handed out 9 inch long peieces of wire, and said: that is a nanaosecond. 3m is about 118.11 inches is about 13 ns. So worst case, skipping the 3D math, yoy get about +/13 ns. Which is small compared to the published GPS time resolution (IS_GPS_200H, page 54) of 90 ns. RGDS GARY --- Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703 g...@rellim.com Tel:+1 541 382 8588 Veritas liberabit vos. -- Quid est veritas? "If you can’t measure it, you can’t improve it." - Lord Kelvin pgpNO0agkFwFQ.pgp Description: OpenPGP digital 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] ublox NEO-M8T improved by insulated chamber?
Yo MLewis! On Thu, 2 Nov 2017 21:54:57 -0400 MLewis <mlewis...@rogers.com> wrote: > I have no idea what the temperature is inside the chamber. I use the 'temper' to know what temp is in my GPS chamber: https://www.amazon.com/TEMPer-USB-Thermometer-w-Alerts/dp/B002VA813U I use that, and an incadescent light bulb, to stabilize my GPS and XO temps in my chamber. RGDS GARY --- Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703 g...@rellim.com Tel:+1 541 382 8588 Veritas liberabit vos. -- Quid est veritas? "If you can’t measure it, you can’t improve it." - Lord Kelvin pgp286Z5HJd18.pgp Description: OpenPGP digital 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] Designing an embedded precision GPS time server
Yo Nick! On Wed, 25 Oct 2017 17:53:46 -0700 Nick Sayer via time-nuts <time-nuts@febo.com> wrote: > This may be a fool’s errand, certainly, but looking at it from here, > I would think that such a design might offer accuracy in the > microsecond range, I'm looking at 6 Raspberry Pi's right now, each with a different GPS model. Running NTPec and kernel PPS. Adjacent jitter is from 10 to 35 micro seconds over 100 Base-T. Local PPS jitter, is from 250 ns to up to 3,000 ns. The biggest issue is the 186 ns granularity in the kernel system clock. Then interrupt latency and the usual Linux stuff. > Anybody have any ideas or suggestions along these lines? This may be not time-nutty enough for here. Feel free to contact me off list. RGDS GARY --- Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703 g...@rellim.com Tel:+1 541 382 8588 Veritas liberabit vos. -- Quid est veritas? "If you can’t measure it, you can’t improve it." - Lord Kelvin pgpp8WRtok0ml.pgp Description: OpenPGP digital 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] inexpensive, black box, GPS or NTP based TTL time capture?
Yo Hal! On Wed, 18 Oct 2017 12:26:27 -0700 Hal Murray <hmur...@megapathdsl.net> wrote: > > For under a $100 you could get a Raspberry Pi, a GPS HAT, and > > connect your input to a GPIO pin. Configure ntpd to log the real > > PPS and the input as another 'PPS'. > > Is there an option to log all individual PPS events? # ppswatch /dev/pps0 trying PPS source "/dev/pps0" found PPS source "/dev/pps0" timestamp: 1508356708, sequence: 591837, offset: 1412510 timestamp: 1508356709, sequence: 591838, offset: 1381010 timestamp: 1508356709, sequence: 591838, offset: 1381010 timestamp: 1508356710, sequence: 591839, offset: 1397496 timestamp: 1508356710, sequence: 591839, offset: 1397496 Just redirect to a log file. > The $100 for a Pi might be significantly low. It depends on what you > have in your toy box. Looking at Amazon, quantity one, I see: RasPi3 $35 GPS Hat w/ remote antenna and cord: $30 16BG miscro sd card: $9 RaspI + HAT case: $10 USB charger: $8 USB charge cable: $2 Cat5 ethernet cable: $2 Looks like $96 to me. You can save some if you buy in bulk, Plus labor, which after the first one is small. > For getting started, you also need: > SD card reader/writer > keyboard and mouse (Pi has USB) > display adapter (Pi is HDMI) > display Yeah, just for setup. Shall we include the price of the desk it sits and the building it is in? RGDS GARY --- Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703 g...@rellim.com Tel:+1 541 382 8588 Veritas liberabit vos. -- Quid est veritas? "If you can’t measure it, you can’t improve it." - Lord Kelvin pgpeJdgIkucEc.pgp Description: OpenPGP digital 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] inexpensive, black box, GPS or NTP based TTL time capture?
Yo Rob! On Wed, 18 Oct 2017 11:33:28 -0600 Rob Seaman <sea...@noao.edu> wrote: > That’s why they want a black box. Volume is one to several, but could > imagine a bulk order if savings were significant. Hundreds of dollars > might be the price point. For under a $100 you could get a Raspberry Pi, a GPS HAT, and connect your input to a GPIO pin. Configure ntpd to log the real PPS and the input as another 'PPS'. RGDS GARY --- Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703 g...@rellim.com Tel:+1 541 382 8588 Veritas liberabit vos. -- Quid est veritas? "If you can’t measure it, you can’t improve it." - Lord Kelvin pgpKO126L0MRj.pgp Description: OpenPGP digital 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] Machining some aluminum help!
Yo cdel...@juno.com! On Fri, 28 Jul 2017 12:46:30 -0700 <cdel...@juno.com> wrote: > After mounting the tap in the drill > press and putting a dab of Crisco on the tap I was able to tap each > hole to a depth of 7/16" as fast as I could turn the handwheel! Cool! I suggest you get some real cutting fluid. The threads will be smoother. RGDS GARY --- Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703 g...@rellim.com Tel:+1 541 382 8588 Veritas liberabit vos. -- Quid est veritas? "If you can’t measure it, you can’t improve it." - Lord Kelvin pgpn3ISOcp_1P.pgp Description: OpenPGP digital 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.
[time-nuts] Too many GPSDO's
I have more GPSDO's than I need. I have a Trimble Thunderbolt that I would like to trade for a quality 10mhz Rubidium unit. It also comes with a power supply and a Antenna. Let me know what you have. Thanks Gary Neilson ___ 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] 5370B Input Board Repair [WAS: 5370B Question / help needed]
This is very interesting, I have a 5370B that has the same behavior as yours. I will take the input board out again and give it a good inspection. BTW, what did you use to clean the adhesive from the pads ? Thanks Gary On 7/18/2017 2:41 AM, Thomas Allgeier wrote: Hello All Again, I’ve got my 5370B going now and in the process made a “discovery” which I thought might be worth sharing: The A3 input board is a through-hole PCB with a few SMD capacitors and resistors on the reverse of the “switch area”. It turns out that on my 5370 (2410A00777) these components are not soldered, but fitted with conductive adhesive. I first thought it was solder with a black coating but under a microscope it is clear that it is not solder at all. Most probably it is a mixture of epoxy and silver particles, or a similar compound. So no going over joints with a fine iron… Inspecting all this carefully under the microscope I discovered that the “joints” on 2 resistors (R23 and R56) had cracked. As you know this board gets heat from the hybrid amplifier IC’s and due to the way the board is mounted to the front panel I guess it sees thermal stressing when the instrument warms up and cools down. While this obviously lasts a long time it looks that on my unit the adhesive has eventually cracked in places. (Vigorous switch activation and pressing / pulling on the switch handles also won’t be helpful in this respect…) One of the resistors just fell off at the slightest touch with fine tweezers. Anyhow, after removing the offending components, cleaning the pads of the adhesive, and soldering replacements in place, we have a perfect 99.9x ns with the 10 MHz on the commoned inputs. Happy days! So if any of your 5370’s have the kind of intermittent fault I described (and one or two other people seem to have reported) or instability that seems to originate from the A3 board – check the joints around the SMD’s. I wonder why / how it ended up having the adhesive instead of solder – were earlier / later instruments the same, or was this a build change introduced at a certain period? Hope the above is of help to somebody else, Thomas. Message: 1 Date: Sat, 15 Jul 2017 21:54:47 +0100 From: Thomas Allgeier <th.allge...@gmail.com> To: Discussion of precise time and frequency measurement <time-nuts@febo.com> Subject: Re: [time-nuts] 5370B Question / help needed Message-ID:
Re: [time-nuts] WWVB & Eclipse
Yo Graham! On Sat, 15 Jul 2017 01:04:05 + Graham <planoph...@aei.ca> wrote: > I have a CSI MBX-3 DGPS beacon receiver that I have been playing > around with lately. Is this the programming manual for what you have? http://www.saderet.co.uk/Admin/Manual/m_mbx3.pdf > but so far still trying to > get anything out of the binary RTCM data stream. You no longer need a GPS to get the RTCM data, it is available in real time on the internet. Of course it is more fun to get it off your GPS. You just need an ntrip client: https://en.wikipedia.org/wiki/Networked_Transport_of_RTCM_via_Internet_Protocol > I would like to be able to extract the data within binary data stream > and am slowly working my way the RTKLIB apps in an effort to do so. [...] > If anyone has already gone down this path, please point me in the > right direction. I have worked on the gpsd RTCM and NTRIP code. Feel free to contact me off list if yuo think I can be helpful. RGDS GARY --- Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703 g...@rellim.com Tel:+1 541 382 8588 Veritas liberabit vos. -- Quid est veritas? "If you can’t measure it, you can’t improve it." - Lord Kelvin pgpcarFoCWQxF.pgp Description: OpenPGP digital 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.
[time-nuts] HP 15265A Test Box
I purchased a HP 8082A pulse generator from Ebay as not working, it works fine, pilot lamp is burned out. Part of the alignment procedure is to use a 15265A Test Box, does anyone have a schematic for this unit ? Thanks Gary ___ 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] Fwd: 5370B Question / help needed
I have a 5370B from ebay, it was missing a couple of boards and had a bad interpolator card. Also a bad input hybrid on the stop channel. My unit acts similar to yours, TI measurement on the 10mhz signal shows 107 ns. Frequency and Period measurement is spot on. I think it needs an alignment performed. I will get to that soon. Good Luck Gary - K5DSR Forwarded Message Subject:[time-nuts] 5370B Question / help needed Date: Sat, 1 Jul 2017 21:12:27 +0100 From: Thomas Allgeier <th.allge...@gmail.com> Reply-To: Discussion of precise time and frequency measurement <time-nuts@febo.com> To: Discussion of precise time and frequency measurement <time-nuts@febo.com> I got hold of a 5370B cheaply but it turns out it may have a fault: Going through the motions of measuring TI with it's own 10MHz ref as input (as described in the manual) I don't get 100 ns, but around 15 ns. So this is with the switch set to START COM. Oddly enough I get the same 15 ns with the switch set to SEP, and going through a 6 ft cable between start and stop. Now I can "tune" the thing to display 100 ns by changing the trigger levels. Start at 0.6 V and stop at -0.1 V will achieve this. Once again this does not change by going from COM to SEP i,e. by adding the 6 ft delay. One other observation, probably related: After powerup it took several vigorous switch activations of the COM/SEP switch before the thing swung into action at all - i.e. the first reaction with COM setting was an Err 02, and with SEP I got the 15 ns as described above. So that switch may be a bit dodgy. Measuring in frequency mode gives the 10 MHz quite accurately, less than 1mHz off with its own ref as stop input. Feeding the 10 MHz in from my GPSDO also ties up OK, it is around 40mHz off with perhaps 5-10mHz jitter. Has anybody come across anything similar? I couldn't find much in that vein in the archive but may have overlooked something. The one thing I was worried about at first was the heat sinks at the rear getting really hot but it seems I'm not the only one with that observation. To some extent it looks like the input levels for triggering are off, but then the fact that the 6 ft cable don't show up as extra delay may mean there is something else wrong. Looks like some "fun with Bill and Dave" lies ahead if somebody can point me in the right direction. Thanks in advance, Thomas. ___ 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] Two pieces of old General Radio Freq. Nuts
On Mon, 22 May 2017 05:59:59 -0700, you wrote: >https://goo.gl/photos/tygN5ZFeFLUhc4zX6 > >Near Portland Oregon Neat stuff...did anybody but GR use those hermaphrodite connectors? I have an adapter for them that came with a wide-band amplifier; "delay line" type, with a whole row of, I think, 6AK5s in it. -- Gary Woods AKA K2AHC- PGP key on request, or at home.earthlink.net/~garygarlic Zone 5/4 in upstate New York, 1420' elevation. NY WO G --- This email has been checked for viruses by AVG. http://www.avg.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.
[time-nuts] HP 55300A
I have a HP 55300A GPSDO that works well except for having the wrong date. It does not decode the date from the GPS correctly. It has firmware 3704-D. This appears to be pre Y2K. Does anybody have newer firmware for one of these. ? Gary ___ 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 Time Foundation
Yo Azelio! On Sat, 13 May 2017 16:10:03 +0200 Azelio Boriani <azelio.bori...@gmail.com> wrote: > Is the Network Time foundation the only one to have the NTP source > code? Is the Meinberg code (for example) a different one? There is a fork of NTP Classic, called NTPsec. It is being more activly worked on than NTP Classic and has many new features like ntpmon and ntpviz. It is readily available over git: https://www.ntpsec.org/ https://github.com/ntpsec/ntpsec RGDS GARY --- Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703 g...@rellim.com Tel:+1 541 382 8588 Veritas liberabit vos. -- Quid est veritas? "If you can’t measure it, you can’t improve it." - Lord Kelvin ___ 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] Last notice for live online class, Phase Noise Fundamentals
For anyone interested in a fundamentals class on phase noise, I'm teaching an online class with live instruction (including video recordings in case you miss a class) titled "Phase Noise Fundamentals." https://www.jitterlabs.com/support/training/phasenoiseclass Register with the coupon code TIMENUTS1704 to receive 10% off (coupon is only valid for the April class). If any questions, please call or message me at https://www.jitterlabs.com/company/contact Best regards, Gary Giust JitterLabs Class syllabus follows -- PART 1: BASIC CONCEPTS Measures of Quality Precision. Stability. Accuracy. Crystal oscillators. Drift. Allan deviation. Time error. Time interval error (TIE). Wander. Phase Noise. Phase Noise and Jitter Digital versus RF. Phase noise versus jitter. Power-law model of phase noise. Stability metrics. Sources of phase noise. PART 2: ANALYSIS Phasor representation. Effect of changing temperature, signal power, and carrier frequency on phase noise. Leeson's equation. Amplifiers. Random versus spurious phase noise. Spur-detection algorithms. Convert from dBc/Hz to seconds RMS, and from dBc to seconds peak-peak. Compute phase jitter from phase noise. Select the right offset-frequency range for integration. Spur analysis. Determine dominant noise sources. PART 3: MEASUREMENT Spectrum analyzers. IF-filter resolution bandwidth. Phase noise analyzers. Eliminating AM. Additive, multiplicative, and residual noise. Phase-detector method. PLL with reference-source method. Cross correlation to reduce instrument noise floor. Delay-line discriminator method. Effect of power supply noise. Measuring differential signals. Balun artifacts and how to minimize them. Measurement tradeoffs and best practices. PART 4: APPLICATIONS Phase-locked Loops (PLLs) Analog PLL operation and model. Transfer functions. Effect of bandwidth on phase noise. Sources of spurious and random phase noise. Impact of frequency division, and integer-N versus fractional-N architectures, on phase noise. SERDES Reference Clocks Anatomy of a serial link. PLL jitter transfer. Receiver observed jitter transfer. Reference-clock analysis. Converting phase noise into jitter at a given BER. RF Transceivers (QAM) Role of LO phase noise in RF up/down conversion. I-Q modulation. Constellation diagrams. I-Q demodulation. Phase errors. Phase noise budgeting. Effect of phase noise on symbol error rate (SER), and error vector magnitude (EVM). Testing. Analog Data Converters (ADCs) Operation. Aperture and phase jitter. Signal-to-noise ratio. Offset-frequency range for integration. Effect of clock spurs. ___ 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] live online phase-noise class; general interest articles
For anyone interested in an introductory class on phase noise, I'm teaching an online class with live instruction (with video recordings in case you miss a class) titled "Phase Noise Fundamentals." https://www.jitterlabs.com/support/training Register with the coupon code TIMENUTS1704 to receive 10% off (which can also be applied to our online jitter course). The coupon expires at the end of April 2017. Aside from that, I thought I'd share some general-interest phase-noise articles I published recently: "Determine the dominant source of phase noise, by inspection: A simple 3-step procedure that anyone can apply when viewing a phase noise plot" https://www.jitterlabs.com/support/publications/note4/note4 "Measuring phase noise with baluns" https://www.signalintegrityjournal.com/articles/207-measuring-phase-noise-with-baluns http://www.microwavejournal.com/articles/27224-measuring-phase-noise-with-baluns If any questions, please contact me off list. Best regards, Gary Giust JitterLabs ___ 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] Four hour cycle in GPS NMEA jitter
Yo Chris! On Mon, 20 Mar 2017 15:19:25 -0700 Chris Albertson <albertson.ch...@gmail.com> wrote: > I've only hear of 1 uS being broken with hardware. A Raspberry Pi can get down to a Standard Deviation of about 350 nano seconds using NTPsec.. https://blog.ntpsec.org/2017/02/01/heat-it-up.html RGDS GARY --- Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703 g...@rellim.com Tel:+1 541 382 8588 Veritas liberabit vos. -- Quid est veritas? "If you can’t measure it, you can’t improve it." - Lord Kelvin ___ 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] Smart Phone time display accuracy...?
On Thu, 16 Mar 2017 20:11:30 -0400, you wrote: >Notice Gary doesn't specify which brand of Android phone, much less >the specific model and carrier Sorry about that, and I should know better (In another group "FlDigi won't work with my radio" and nothing else...). Droid Razr M AKA Motorola XT-107 on Verizon. I understand tenths of a second aren't time nuts worthy, but as a clock, it ain't bad. Unless you're measuring the arrival time of neutrinos. -- Gary Woods AKA K2AHC- PGP key on request, or at home.earthlink.net/~garygarlic Zone 5/4 in upstate New York, 1420' elevation. NY WO G --- This email has been checked for viruses by AVG. http://www.avg.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] Smart Phone time display accuracy...?
On Thu, 16 Mar 2017 13:16:11 -0700, you wrote: >My iPhone seems to be accurate to 5 minutes or so. There are two of them in >my >house and they never agree. My computer is saying 1:15 PM local time, my >iPhone >says 1:20PM Not to gloat, but my Android phone is always spot on. I have a GPS time app that shows the difference between GPS and phone time and it's always in the tenths of a second area. -- Gary Woods O- K2AHC Public keys at home.earthlink.net/~garygarlic, or get 0x1D64A93D via keyserver fingerprint = E2 6F 50 93 7B C7 F3 CA 1F 8B 3C C0 B0 28 68 0B --- This email has been checked for viruses by AVG. http://www.avg.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] Bye-Bye Crystals
On Mon, 13 Mar 2017 15:01:39 +, you wrote: >What minimal equipment would you need to make your own crystals ? There was a WWII era "how they spend your war bonds" film that showed the process pretty well. Diamond saws to cut the raw quartz, X-ray diffraction to find the proper axes prior to cutting out blanks, assorted polishing/lapping stuff, etching with truly nasty stuff. ISTR that if you put a piece of foil under the plate glass you're grinding on, you can hear a noise peak on a receiver at the approximate frequency. I once raised a cheapo surplus crystal 60Kc plus to put it into the 40-meter CW band; worked fine! IOW, not a trivial thing. -- Gary Woods AKA K2AHC- PGP key on request, or at home.earthlink.net/~garygarlic Zone 5/4 in upstate New York, 1420' elevation. NY WO G --- This email has been checked for viruses by AVG. http://www.avg.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] ``direct'' RS-232 vs. RS-232 via USB vs. PPS decoding cards
Yo Chris! On Wed, 15 Feb 2017 23:48:39 -0800 Chris Albertson <albertson.ch...@gmail.com> wrote: > An ntpd that is running as > strum one that has no other ntpd connected to it has VERY little to do That would be a marginal configuration. I have yet to see a GPS that did not lose sat lock, or lep second, or UTC offset now and then. Best practice is to have at least 3 other network chimers configured. RGDS GARY --- Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703 g...@rellim.com Tel:+1 541 382 8588 Veritas liberabit vos. -- Quid est veritas? "If you can’t measure it, you can’t improve it." - Lord Kelvin ___ 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] ``direct'' RS-232 vs. RS-232 via USB vs. PPS decoding cards
Yo Chris! On Wed, 15 Feb 2017 23:55:02 -0800 Chris Albertson <albertson.ch...@gmail.com> wrote: > On Wed, Feb 15, 2017 at 11:48 PM, Chris Albertson > <albertson.ch...@gmail.com> wrote: > > On Wed, Feb 15, 2017 at 10:30 PM, Ruslan Nabioullin > > <rnabioul...@gmail.com> wrote: > >> On 02/15/2017 01:17 PM, Chris Albertson wrote: > >>> > >>> Why set up a dedicated NTP server if you only have two computers > >>> that will use it?Your server will be accurate to a few > >>> microseconds but your two computers will only by good to a few > >>> milliseconds because ethernet is not nearly as good as PPS. > >> > >> > >> Well Ethernet can be *extremely* accurate if PTP is used (a > >> whitepaper specifies <= 100 ns accuracy if the LAN is optimized > >> for it). > > But PTP requires special hardware. You may not have this. No, PTP works optimally with special hardware, it can work with any ethernet port. I will give you that software mode PTP is no more accurate than plain NTPv4. RGDS GARY --- Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703 g...@rellim.com Tel:+1 541 382 8588 Veritas liberabit vos. -- Quid est veritas? "If you can’t measure it, you can’t improve it." - Lord Kelvin ___ 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] ``direct'' RS-232 vs. RS-232 via USB vs. PPS decoding cards
Yo Ruslan! On Mon, 13 Feb 2017 11:07:49 -0500 Ruslan Nabioullin <rnabioul...@gmail.com> wrote: > Hi, generally speaking, what are the performance differences between > the following: 1. direct RS-232 (i.e., what I believe is a standard > PCI card offering RS-232---essentially UARTs interfaced more-or-less > directly to the PCI bus); 2. RS-232 via USB; 3. PPS decoding PCI > cards (which might also have an IRIG input or even an onboard GNSS > receiver). #2 will have a lot higher jitter than #1. On a #2 you can expect 500 micro second best timing. On a #1 you can get to 1 micro second. On a RasPi using GPIO you can get to 500 nano second. Data available on request, but better on the de...@ntpsec.org list. RGDS GARY --- Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703 g...@rellim.com Tel:+1 541 382 8588 Veritas liberabit vos. -- Quid est veritas? "If you can’t measure it, you can’t improve it." - Lord Kelvin ___ 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] Vintage Frequency Measurement
On Sun, 12 Feb 2017 17:16:18 + (UTC), you wrote: >In a word,Wavemeters. Classic US onwas the BC221 with built in 100kHz crystal >calibrator A couple of years ago, I got a BC221 from an estate; had to recap the homebrew power supply the late ham had built for it, but the BC221 worked fine and after all these years I could still zero beat the reference crystal against WWV, using the S-meter when the beats got too slow to hear. Absolutely beautiful dial mechanism on those critters. Totally OT: I once sat radio in a P2V "Neptune" that was being ferried back to Alameda for update; still had the ART-13/BC-348 combo with an LM freq meter. -- Gary Woods AKA K2AHC- PGP key on request, or at home.earthlink.net/~garygarlic Zone 5/4 in upstate New York, 1420' elevation. NY WO G ___ 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] eLoran is up and operating. Looking good
Yo Bob! On Tue, 7 Feb 2017 21:38:52 -0500 Bob Camp <kb...@n1k.org> wrote: > Teaching > the NTP drivers when not to use the data and how to compare data is a > do-able thing. It’s just that nobody has ever bothered to do it. The NTPsec team would love to work with anyone that has a device that could use an improved NTP driver. > Coming up with some simple to use tools to estimate the errors and > config them in is likely the only practical way to do it. NTPsec has done a lot of recent work on tools. We are open to any suggestions or requests that people may make. RGDS GARY --- Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703 g...@rellim.com Tel:+1 541 382 8588 Veritas liberabit vos. -- Quid est veritas? "If you can’t measure it, you can’t improve it." - Lord Kelvin ___ 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] HP 55300A Date Problem
I have a HP 55300A Telecom Primary Reference Standard that I am using as a frequency reference (10 mhz) in my lab. The unit work well and outputs 10mhz, 1pps, IRIG-B, as well as other telecom frequencies all work ok. The unit has a problem with the Date received from the GPS. After it starts acquiring satellites it sets the date as June 6, 1997. The date does increment each day. This seems to me like a firmware bug. My unit has firmware version 3704-D. From the documentation there are later versions of the firmware to fix Y2K bugs which apparently this unit needs. Anyone know of firmware available for this unit ? Thanks Gary - K5DSR ___ 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] hm H Maser
Hydrogen maser in radio astronomy to sync worldwide systems: http://flip.it/rmbdRQ (Lifted from the Albany, NY astronomy group). -- Gary Woods O- K2AHC Public keys at home.earthlink.net/~garygarlic, or get 0x1D64A93D via keyserver fingerprint = E2 6F 50 93 7B C7 F3 CA 1F 8B 3C C0 B0 28 68 0B ___ 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] Datum 9520-1000
I am looking for documentation for a Datum 9520-1000 time code display. Thanks Gary ___ 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] Survey plot as art.
Yo Tom! On Mon, 9 Jan 2017 16:37:27 -0800 "Tom Van Baak" <t...@leapsecond.com> wrote: > Your ADEV plots differ from mine by orders of magnitude. You are right, my ADEV plots are junk. Removed. It was the 24 hour scatter plots that I wanted you to look at. Hard to argue with lat/lon data as reported by the device. You can also checkout the TDOPs which are better on the MAX-M8N > Remember > this is time-nuts, not an NTP or a GPSD forum. The Adafruit GPS board > is fine, even fantastic. But I suspect there are issues with your > measurement techniques. Hard for me to accept your relative opinion of two devices when you have never played with one of them. Whatever my techniques may be, I have side-by-side concurrent data for many GPS. Hopefully any systematic errors cancel out in the comparisons. And anyone can run, maybe even improve, the FOSS programs I'm using for comparison as well. But I agree, moving off topic for time-nuts. RGDS GARY --- Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703 g...@rellim.com Tel:+1 541 382 8588 Veritas liberabit vos. -- Quid est veritas? "If you can’t measure it, you can’t improve it." - Lord Kelvin pgp50DZI7wYyb.pgp Description: OpenPGP digital 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] Survey plot as art.
Yo Tom! On Mon, 9 Jan 2017 14:01:18 -0800 "Tom Van Baak" <t...@leapsecond.com> wrote: > Hi Gary, > > > Clearly the Adafruit is not high accuracy. I have played with some > > short baseline DGPS (cm level data) and not found any issue with > > antenn separation. > > I'm surprised by your claim. My measurements show that the Adafruit > is a wonderful GPS receiver. Yes, I also find the Adafruit wonderful. It was my favorite GPS when I got it. I just find that the Uputronics GPS HAT is even better, for the same price. Compare these two pages, the first the Adafruit, the second an Uputronics Version 2. Sitting right next to each other, both iwth matching GPS antennas.: https://pi2.rellim.com/day/ https://pi4.rellim.com/day/ Especially check out the scatter plots. The number of sats received, and the DOPs, are consistently better on the Uputronics. > Attached are ADEV MDEV TDEV plots of 5 > different GPS/1PPS receivers. The raw data is from: > > http://www.leapsecond.com/pages/gpsdo-sim/ What? No pretty graphs? :-) > The Adafruit "Ultimate GPS" (MTK3339 chipset) does very well. It's > also cheap, has a built-in antenna, has a uFL connector for optional > external antenna, runs in 3D so you can use it mobile or fixed, you > don't have to bother with survey or sawtooth correction. The data you > see above is out-of-the-box; you give it 5V and out comes a 1PPS: I find the Adafruit works better for me indoors with an external antenna. I find the uFL a pain for lab use. The Uputronics have no internal antenna and an SMA connector. Plus it has a u-Blox 8. But, to be fair, both are far beyond any practical needs I have. YMMV. RGDS GARY --- Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703 g...@rellim.com Tel:+1 541 382 8588 Veritas liberabit vos. -- Quid est veritas? "If you can’t measure it, you can’t improve it." - Lord Kelvin pgpDaUHomVCuK.pgp Description: OpenPGP digital 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] Survey plot as art.
Yo Björn! On Mon, 9 Jan 2017 07:45:00 +0100 "Björn Gabrielsson" <b...@lysator.liu.se> wrote: > >> My gut reaction is that "coupling" between the two antennas may > >> have some effect on some of the variation. > > For high accuracy applications, I have been given the advice to keep > GPS antenna separation much higher. 1 meter separation was suggested. Clearly the Adafruit is not high accuracy. I have played with some short baseline DGPS (cm level data) and not found any issue with antenna separation. > For comparing GPS receiver behavior its a cleaner setup to use a GPS > signal splitter (or basic RF splitter with suitable DC-blocks). Care to recommend any that have SMA connectors? I have found that a 3dB difference in antenna can degrade my data quality, it would be interesting to see how the 3dB loss of the splitter affects thins. RGDS GARY --- Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703 g...@rellim.com Tel:+1 541 382 8588 Veritas liberabit vos. -- Quid est veritas? "If you can’t measure it, you can’t improve it." - Lord Kelvin pgpBUF_w0vMDM.pgp Description: OpenPGP digital 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] Survey plot as art.
Yo Hal! On Sun, 08 Jan 2017 20:41:25 -0800 Hal Murray <hmur...@megapathdsl.net> wrote: > g...@rellim.com said: > >> The Adafruit receiver outputs NMEA format data. The lat/lon values > >> are sent as dddmm.mm format (ddd=degrees, mm.mm=minutes) This > >> restricts the resolution of the values. > > > Yes, easy to see the quantization in the Adafruit plot. > > Something doesn't look quite right. If the problem was as simple as > reduced lat/lon resolution, I'd expect the output to be on a grid. > Instead, what I see is more like a grid that was also missing 1 out > of N slots. Where is that coming from? How do I predict N? Yes, the raw data shows that it is not using all the possible precision. It does skip lat/lons that are representable. I'm almost at 45N, so that partlly explains why the lat missing codes are smaller than the lon missing codes. > I expect it's something like roundoff after the conversion from mm.mm > to meters, or something like that. No rounding happening in gpsd. That is in the raw NMEA. > Just to make sure we are on the same wavelength, this is the graph > I'm looking at. > > https://www.febo.com/pipermail/time-nuts/attachments/20170108/051ba89d/attachm > ent-0003.png Yup. RGDS GARY --- Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703 g...@rellim.com Tel:+1 541 382 8588 Veritas liberabit vos. -- Quid est veritas? "If you can’t measure it, you can’t improve it." - Lord Kelvin pgpIKSdqw2umQ.pgp Description: OpenPGP digital 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] Survey plot as art.
Yo Mark! On Mon, 9 Jan 2017 03:41:07 + Mark Sims <hol...@hotmail.com> wrote: > The Adafruit receiver outputs NMEA format data. The lat/lon values > are sent as dddmm.mm format (ddd=degrees, mm.mm=minutes) This > restricts the resolution of the values. Some receivers and newer > NMEA specs support more digits past the decimal point. Receivers > that support native binary formats that report lat/lon as 32-bit > floats show similar quantization. Yes, easy to see the quantization in the Adafruit plot. RGDS GARY --- Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703 g...@rellim.com Tel:+1 541 382 8588 Veritas liberabit vos. -- Quid est veritas? "If you can’t measure it, you can’t improve it." - Lord Kelvin pgphIZvf8Pj9b.pgp Description: OpenPGP digital 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] Survey plot as art.
Yo Artek! On Sun, 8 Jan 2017 17:18:06 -0500 Artek Manuals <manu...@artekmanuals.com> wrote: > Only 1" ? (1" center to center or edge to edge spacing?) One inch edge to edge. > My gut reaction is that "coupling" between the two antennas may have > some effect on some of the variation. I have tried many various combinations over the last 6 months. using 6 diferent GPS. Before that I took some GPS to an open field. Also friends of mine have run gpsprof and gotten similar. All look pretty much like these, modulo the different GPS chips. gpsprof is part of the gpsd package, feel free to do yooou own plots. RGDS GARY --- Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703 g...@rellim.com Tel:+1 541 382 8588 Veritas liberabit vos. -- Quid est veritas? "If you can’t measure it, you can’t improve it." - Lord Kelvin pgpuRav0K7SO1.pgp Description: OpenPGP digital 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] Survey plot as art.
Yo All! I just ran 24 scatter plots on 2 GPS with external antennas one inch apart. pi2-5.png is an Adafruit GPS HAT with an MTK-3301. upuv2.png is an Uputronics GPS HAT version 2, with a uBlox 8. See attached. I'm not sure it sheds any light on this discussion... There does appear to be a bit of correlation between the bigger random walks in the graphs. And a whole lot of other things going on. During that time, the Adafruit saw 6 to 12 sats and a constant TDOP of 0.82. The Uputronics reported seeing 4 to 20 sats and a TDOP from 0.42 to 32.6 and a mean of 0.786 and a SD of 0.668. To bring this back to time-nuttery, when the TDOP hit 32.6 I can see a 2 micro Second spike in NTP jitter. So for that small period in time my Raspberry Pi clock was more stable than my PPS. RGDS GARY --- Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703 g...@rellim.com Tel:+1 541 382 8588 Veritas liberabit vos. -- Quid est veritas? "If you can’t measure it, you can’t improve it." - Lord Kelvin pgpEQi7T8mkHT.pgp Description: OpenPGP digital 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] Survey plot as art.
Yo Hal! On Sat, 07 Jan 2017 14:16:16 -0800 Hal Murray <hmur...@megapathdsl.net> wrote: > g...@rellim.com said: > >> In my case (the original post) there can be no multipath > >> difference, same antenna and done at the same time. > > There sure can be. The GPS birds are moving in orbit. At certain > > points in the sky their signal may be bouncing off a nearby steel > > building and into your antenna. > > He didn't say no multipath, but rather no multipath difference. He's > feeding 2 GPS units from the same antenna through a splitter. Ah. Got it. Thank you. Same model GPS? RGDS GARY --- Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703 g...@rellim.com Tel:+1 541 382 8588 Veritas liberabit vos. -- Quid est veritas? "If you can’t measure it, you can’t improve it." - Lord Kelvin pgp3dBeHeOtP4.pgp Description: OpenPGP digital 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] Survey plot as art.
Yo Peter! On Sat, 7 Jan 2017 16:31:25 -0500 Peter Reilley <preilley_...@comcast.net> wrote: > In my case (the original post) there can be no multipath difference, > same antenna and done at the same time. There sure can be. The GPS birds are moving in orbit. At certain points in the sky their signal may be bouncing off a nearby steel building and into your antenna. RGDS GARY --- Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703 g...@rellim.com Tel:+1 541 382 8588 Veritas liberabit vos. -- Quid est veritas? "If you can’t measure it, you can’t improve it." - Lord Kelvin pgpNm5XiRnW1p.pgp Description: OpenPGP digital 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] Survey plot as art.
Yo Bob! On Sat, 7 Jan 2017 16:16:44 -0500 Bob Camp <kb...@n1k.org> wrote: > In terms of multipath at GPS frequencies, a couple of inches is a > *lot*. Also unless you have pretty good antennas (as in much larger > than 1” each) they will have phase issues unique to each antenna. > Phase cancellation and addition is what gives you multipath. I see up to 10x better/worse between GPS brands. Measured by CEP(). A much smaller change between antenna models. I also have interchanged antennas between my GPS to rule them out as the major contributing source to error and discard the worst ones. I just started 24 hour plots of 4 adjacent GPS. I guess tomorrow I'll rotate the antennas between GPS, witout moving the antennas, and repeat. I suspect we may be just seeing different aspects of the same thing. A big difference between GPS models is probably the quality of multipath rejection. And I can easily change my GPS, but chaning my geoplogy is a lot harder. RGDS GARY --- Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703 g...@rellim.com Tel:+1 541 382 8588 Veritas liberabit vos. -- Quid est veritas? "If you can’t measure it, you can’t improve it." - Lord Kelvin pgpYyS_YvRTlC.pgp Description: OpenPGP digital 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] Survey plot as art.
Yo Bob! On Sat, 7 Jan 2017 15:16:34 -0500 Bob Camp <kb...@n1k.org> wrote: > The “simple” answer is that the weird legs going out from the central > blob are the result of multi-path / reflections in the received > signal. With enough data you might be able to correlate them to > observed obstructions. I have lots of data from GPS with the antennas mounted 1 inch apart. They show different weird legs, so I suspect that local geology/architecture is not the whole story. For example, compare the plot I just sent, to the one attached here. Two GPS right next to each other, very differently looking plots. I'll admit to never generating plots over the same time interval, I'll start a 24 hour test of two GPS right now. RGDS GARY --- Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703 g...@rellim.com Tel:+1 541 382 8588 Veritas liberabit vos. -- Quid est veritas? "If you can’t measure it, you can’t improve it." - Lord Kelvin pgpW3hGP3bDIV.pgp Description: OpenPGP digital 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] Survey plot as art.
Yo Peter! On Sat, 7 Jan 2017 12:54:45 -0500 Peter Reilley <preilley_...@comcast.net> wrote: > This is the survey from my Trimble NTBW50AA. It looks like some > bacteria floating around. You can get those from any GPS using the program gpsprof from gpsd. See attached for a 24 plot from a stationary GlobalSat MR-350P I find these plots very useful when comparing GPS models. RGDS GARY --- Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703 g...@rellim.com Tel:+1 541 382 8588 Veritas liberabit vos. -- Quid est veritas? "If you can’t measure it, you can’t improve it." - Lord Kelvin pgpPR55fTeIcf.pgp Description: OpenPGP digital 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] Temperature (environmental) sensors
Yo jimlux! On Thu, 5 Jan 2017 12:21:44 -0800 jimlux <jim...@earthlink.net> wrote: > I'm kind of curious about their "UI".. hold CapsLock? how does this > device manifest itself to the host computer? I saw a mention of HID, > so it is emulating a keyboard? I received serveral off list requests, so I looked into this a bit more. As I said before, I use temper-python on Linux to read my TEMPer's: https://github.com/padelt/temper-python All you need to run that program is Python and the pyusb library: https://pypi.python.org/pypi/pyusb/1.0.0 Python runs on pretty much anything half-way sane. pyusb runs on Linux, Windblows, OS X, and most POSIX systems. The paranoids will want to run Wireshark in USB capture mode to be sure nothing devious is going on. RGDS Veritas liberabit vos GARY Quid est veritas? --- Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703 g...@rellim.com Tel:+1 541 382 8588 pgpPpRdQ_QkQ5.pgp Description: OpenPGP digital 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] Temperature (environmental) sensors
Yo jimlux! On Thu, 5 Jan 2017 12:21:44 -0800 jimlux <jim...@earthlink.net> wrote: > > http://www.pcsensor.com/usb-hygrometer/temperhum.html > > I'm kind of curious about their "UI".. hold CapsLock? how does this > device manifest itself to the host computer? I saw a mention of HID, > so it is emulating a keyboard? It presents to the host OS as an HID/Keyboard,, but sends no data by default. I run it on Linux and use the following FOSS Python program to read it: https://github.com/padelt/temper-python Looking at the Python code, a simple binary packet is sent to the device and it returns a binary packet with the data. I can't speak to how it works on anything but Linux. I've never seen the TEMPer interfere with anything. RGDS Veritas liberabit vos GARY Quid est veritas? --- Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703 g...@rellim.com Tel:+1 541 382 8588 pgppsRagnxsvI.pgp Description: OpenPGP digital 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] Temperature (environmental) sensors
Yo All! I am surprised that the TEMPer and TEMPerHUM have not been mentioned yet. They are cheap reliable USB temperature sensors. The TEMPerHUM adds a humidity sensor. I have several TEMPer's running to log room temp around NTP servers. The basic TEMPer reads to 0.1°F is only $9: http://www.pcsensor.com/usb-thermometers/gold-temper.html I can't speak to its accuracy, but it tracks well with my OXO's frequency shifts. There is the double sensor TEMPER for about $19: http://www.pcsensor.com/usb-thermometer/temper2.html I do NOT recommend this one. The external temp will not match the internal temp. When I put an IR camera on it I found the external temp sensor self heats in free ait by several degrees F. I have not tried the TEMPerHum. It adds a humidity sensor and is $20: http://www.pcsensor.com/usb-hygrometer/temperhum.html From what I can tell, many different Chinese companies make TEMPer's so YMMV. But hard to go wrong for $9. RGDS Veritas liberabit vos GARY Quid est veritas? --- Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703 g...@rellim.com Tel:+1 541 382 8588 pgpOJonJ0uFyp.pgp Description: OpenPGP digital 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] SR620 Failure Code.
On Thu, 22 Dec 2016 16:50:17 -0500, you wrote: >That's just crazy, but that was the problem. It's documented, so it's not a bug. -- Gary Woods AKA K2AHC- PGP key on request, or at home.earthlink.net/~garygarlic Zone 5/4 in upstate New York, 1420' elevation. NY WO G ___ 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] RPi/ beagle bone-like computer without video
There do seem to be a lot of small SBCs out there. I have used boards from Technologic Systems, http://www.embeddedarm.com and EMAC, Inc, http://www.emacinc.com They have numerous models for you to look though. Some various features: - SBC or SoM/CoM on baseboard - Various form factors including PC/104 - Usually with RS-232, USB, GPIO, Ethernet. - Many without video. - ARM processor - Many with industrial temperature range - Linux and development environment provided (may not be latest) - Lower power then BBB. One model runs at 0.5 watts. Many around 1. Prices generally 2 or 3 x BBB prices. Gary On 11/30/2016 03:42 PM, jimlux wrote: I'm looking for a small linux single board - similar to RPi or Beaglebone Black, but don't need the HDMI, or video stuff. Preferably without weird connectors, and available for wide temperature ranges (it's for a data logger/collector in the field) What's out there? There's BBB in industrial flavor (-40 to +85C ) for $60-70 ___ 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] Google public NTP service
Yo Tom! On Wed, 30 Nov 2016 13:06:06 -0800 "Tom Van Baak" <t...@leapsecond.com> wrote: > From Gary Miller: > > You gotta start sometime. Now is a good time. This is not the > > first time Google has done this, and certainly will not be the > > last. It had bad consequences last time and they did not learn > > from that. > > This is not the fault of google. The big players will continue to > innovate and solve timing problems as long as the official scientific > and political world do nothing. This is not innovation, this is anarchy. We have standards that hard working people have build over decades. Ignoring the lessons of the past is a bad thing. Arbitrarily changing standards is the path to madness. > May I request that further discussion of this google / NTP / leap > second issue take place in ntp forums or the LEAPSECS list, and not > here on time-nuts. I'll continue to suggest this move to de...@ntpsec.org. There are many people on the NTP IETF committes there. RGDS GARY --- Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703 g...@rellim.com Tel:+1 541 382 8588 pgpmnn5U7BFEP.pgp Description: OpenPGP digital 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] Google public NTP service
Yo Poul-Henning! On Wed, 30 Nov 2016 21:01:44 + "Poul-Henning Kamp" <p...@phk.freebsd.dk> wrote: > > In message <20161130125857.7229b...@spidey.rellim.com>, "Gary E. > Miller" writes : > > >Not 'odd'. Fully specified in the RFC. Anyone that did not > >implement the spec gets what they deserve. > > Actually, anybody who does implement the spec *precisely* gets a lot > of things nobody should ever be at the receiving end of. If you know of any such thing I suggest you bring it up on de...@ntpsec.org. Several of the authors of the upcoming NTS spec hang out there. If you can document anything specific the NTPsec team would like to get it handled in their code and documentation. Currently they are turning around fixes in days for most issues. They have already changed a bit of their implementation of the RFC for security reasons and would do so for any new issues. Things like symetric mode are now automagically downgraded to a more secure client server mode. RGDS GARY --- Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703 g...@rellim.com Tel:+1 541 382 8588 pgpYmPcH0LY9W.pgp Description: OpenPGP digital 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] Best Chance GPS module
Yo MLewis! On Wed, 30 Nov 2016 16:11:05 -0500 MLewis <mlewis...@rogers.com> wrote: > I'm after a time solution for my personal computer. It looks like I > need: I suggest you take this over to NTPsec: de...@ntpsec.org, or on gpsd: gpsd-us...@nongnu.org They are working on a HOWTO that does exactly what you want. You can download a git copy of it: https://gitlab.com/NTPsec/stratum-1-microserver-howto I have 4 RasPis with various GPS attached, and an Orange Pi to add soon. Works great. RGDS GARY --- Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703 g...@rellim.com Tel:+1 541 382 8588 pgpJJXxdoKcOu.pgp Description: OpenPGP digital 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] Google public NTP service
Yo Bob! On Wed, 30 Nov 2016 15:42:58 -0500 Bob Camp <kb...@n1k.org> wrote: > I believe the point was: If you start tossing around packets that are > odd sized, it is likely to break a lot of existing code. Not 'odd'. Fully specified in the RFC. Anyone that did not implement the spec gets what they deserve. IMHO, better for a packet that can be misinterpreted be dropped, Like the new non-standard Google NTP. Unmarked these new packets can cause havoc. But, to be fair, some assert the spec is a bit ambiguous. So any extention should be a new RFC. Like Autokey. RGDS GARY --- Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703 g...@rellim.com Tel:+1 541 382 8588 pgpMImyMn51mm.pgp Description: OpenPGP digital 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.
