Re: [time-nuts] Simple AC mains zero-cross detector
csteinm...@yandex.com said: That one is not ideal for this task, because (i) its output pulse is symmetrical about the mains zero cross, and (ii) the hysteresis zone is not well characterized and will drift with temperature and input voltage. So, there is no edge that is well characterized in relation to the AC mains zero cross. What are you going to do with data from the line accurate to 1 microsecond? -- These are my opinions. I hate spam. ___ 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] Time Nuts Overload
Hi everyone, The past couple of weeks or month it seems we've had a lot more traffic than usual. This is a reminder that there are 1300 of us and we look forward to rich content on this list. Postings that have little technical content, or are based on guessing, or are just one-liners, or are off-topic, or even rants are fine once in a while -- but when the list gets too busy, like it has recently, this sort of chatter drives good people away. Worse yet, it sets a really bad precedent for newcomers to the list, who might think this sort of casual content is normal, and then they mimic it. That's an exponential disaster in the making. We want to keep old-timers who value their time and we want to welcome new-comers to the wealth of experience, community, and deep information archives that this list offers. But because it's a mailing list and not a web forum, there must be restraint and focus on postings, and especially replies. So please do your part to keep the S/N really high. If you have questions on recent threads that I stopped, or postings that I rejected, or all the off-list emails that I sent this past week, please contact me directly. Also, if you have any suggestions on how else to solve this overload situation I'm all ears! Do not reply to this posting. Reply to me off-list. I'm at t...@leapsecond.com Thanks, /tvb http://www.leapsecond.com/time-nuts.htm ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Simple AC mains zero-cross detector
Hal wrote: What are you going to do with data from the line accurate to 1 microsecond? Me? Nothing. I don't find the meanderings of the mains frequency all that interesting, aside from observing them from time to time via the sweep second hand of a synchronous wall clock. But lots of other folks do (including our fearless leader, tvb), and they like being able to correlate grid events to single-digit uS (lightning strikes, sections of the grid going out, etc.). That said, I didn't slave away trying to get the ZCD jitter below 1uS -- I anticipated that it would be, just because there's nothing in the design to prevent it, so I wasn't surprised when it worked out that way. Best regards, Charles = Everything works if you let it. Corpus C. Redfish = ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Simple AC mains zero-cross detector
Hi On Dec 16, 2014, at 11:03 PM, Charles Steinmetz csteinm...@yandex.com wrote: Bob wrote: The Collins paper on hard limiters does indeed apply here. You *could* make a 60 Hz chain that got down into 1 us sort of resolution. I don't know how much less than 1uS you mean by , but I was seeing less than 1uS jitter with the circuit described. … as in sub ns if you wish to put in enough stages in the chain. The number of stages is a limit on how good you get. 12 or more stages seems a bit over the limit for this sort of thing. Thus the indeterminate units. Bob Best regards, Charles ___ 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] Choke Rings and Points North
HI On Dec 17, 2014, at 1:07 AM, Chuck Harris cfhar...@erols.com wrote: I would venture that the extent of the magic was to note the physical center of the array, and call that the phase center. As long as you always orient the antenna in the same direction, any errors that might exist in the real phase center will be consistent, and could be corrected for by noting the offset from a benchmark. I’m afraid that’s what they do as well. Just spin it and see what a dial indicator reads sort of thing. I think that I’d want something that actually did some microwave tests …. Bob -Chuck Harris Bob Camp wrote: Inquiring minds surely are in high gear!! And to think, all I wanted to know was how close I needed to to point to north!! The need to point north is a legitimate question. There is a chance that they designed some magic into it to deliberately shape the response. Based on the analysis done so far, you have to wonder just how they set up to check these things for phase center. Given the money you pay for them, I would hope they have a definitive test. Getting back an answer like “some guy named Bob did some math” in response to a request for traceability would be a major downer …. Bob LMAO!! Dave M ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Simple AC mains zero-cross detector
Hi On Dec 17, 2014, at 3:27 AM, Hal Murray hmur...@megapathdsl.net wrote: csteinm...@yandex.com said: That one is not ideal for this task, because (i) its output pulse is symmetrical about the mains zero cross, and (ii) the hysteresis zone is not well characterized and will drift with temperature and input voltage. So, there is no edge that is well characterized in relation to the AC mains zero cross. What are you going to do with data from the line accurate to 1 microsecond? or a nanosecond … Obviously it would depend on just what your system needed to do and the signal to noise on the 60 Hz input. Bob -- These are my opinions. I hate spam. ___ 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] Fwd: CGSIC: FW: New NANU 2014090
Not sure if this is quite the right platform, but for someone wanting to experiment it may be worth a look... https://www.kickstarter.com/projects/swiftnav/piksi-the-rtk-gps-receiver http://www.swiftnav.com/piksi.html Dan Date: Tue, 16 Dec 2014 16:01:28 -0800 From: Jim Luxjim...@earthlink.net To:time-nuts@febo.com Subject: Re: [time-nuts] Fwd: CGSIC: FW: New NANU 2014090 Message-ID:5490c7d8.9060...@earthlink.net Content-Type: text/plain; charset=UTF-8; format=flowed On 12/16/14, 3:36 PM, Magnus Danielson wrote: Paul, That is indeed the question. Considering that the signal is better supported, I hope the light goes on somewhere. The signals is all 1,023 Mchips/s, just a thad different. Should be possible to pull off if people want to do dual frequency without going full bandwidth. Then again, if you are willing to pay good money, you can get it today. what about one of the software receivers? I would think that making L2 and L5 filters isn't that tough, so all you need is the back end. ___ 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] Choke Rings and Points North
On 12/17/14, 4:36 AM, Bob Camp wrote: HI On Dec 17, 2014, at 1:07 AM, Chuck Harris cfhar...@erols.com wrote: I would venture that the extent of the magic was to note the physical center of the array, and call that the phase center. As long as you always orient the antenna in the same direction, any errors that might exist in the real phase center will be consistent, and could be corrected for by noting the offset from a benchmark. I’m afraid that’s what they do as well. Just spin it and see what a dial indicator reads sort of thing. I think that I’d want something that actually did some microwave tests …. B The UNAVCO data is an actual RF test. And from a manufacturing standpoint, I would imagine that typical tolerances are better than 0.001 (25.4 microns). Changes much bigger than that would show up as VSWR changes, which *is* something that they check in manufacturing. The Leica artichoke multiband choke ziggurats (they're not flat, so I have a hard time calling it a ring) are cast and then machined. Casting isn't what I would think is a precision operation, but it probably is real consistent from unit to unit. ___ 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] Fwd: CGSIC: FW: New NANU 2014090
On 12/17/14, 5:20 AM, Dan Kemppainen wrote: Not sure if this is quite the right platform, but for someone wanting to experiment it may be worth a look... https://www.kickstarter.com/projects/swiftnav/piksi-the-rtk-gps-receiver http://www.swiftnav.com/piksi.html from that page: 3-bit, 16.368 MS/s L1 front-end supports $500 It uses the MAX2769, which has a tuning range of 1550-1610. -- We get good results at JPL with direct conversion receivers (versus the MAX 2769 is basically a single conversion superhet).. a chain of amplifiers and BPFs followed by a one bit quantizer like an ECL D flipflop clocked by the reference clock chosen to put the aliases at convenient places in band. I suspect, though, that the wide open LNA in the typical JPL receiver is susceptible to interference. Most survey quality receivers (except from Javad, which are LightSquared Readygrin) have pretty bad interference rejection: they want the least stuff that might introduce a phase shift in the signal path: It's all basic time-nuts stuff.. you get that precise position by knowing what the carrier phase is to a fraction of a gnat's eyelash. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Simple AC mains zero-cross detector
Seems to me CFLs and other loads switching on and off would affect the 60 Hz waveform enough to make microsecond measurements meaningless. On 12/17/2014 01:03 AM, Charles Steinmetz wrote: Hal wrote: What are you going to do with data from the line accurate to 1 microsecond? Me? Nothing. I don't find the meanderings of the mains frequency all that interesting, aside from observing them from time to time via the sweep second hand of a synchronous wall clock. But lots of other folks do (including our fearless leader, tvb), and they like being able to correlate grid events to single-digit uS (lightning strikes, sections of the grid going out, etc.). That said, I didn't slave away trying to get the ZCD jitter below 1uS -- I anticipated that it would be, just because there's nothing in the design to prevent it, so I wasn't surprised when it worked out that way. Best regards, Charles = Everything works if you let it. Corpus C. Redfish = ___ 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. -- Chuck Forsberg WA7KGX c...@omen.com www.omen.com Developer of Industrial ZMODEM(Tm) for Embedded Applications Omen Technology Inc The High Reliability Software 10255 NW Old Cornelius Pass Portland OR 97231 503-614-0430 ___ 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] Z3812A
I have searched to no avail. Has anyone a pointer to a real manual for the Z3812A / KS-x devices? cheers, Graham ve3gtc ___ 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] linux kernel pps support
Did a test for a while: every 5 minutes I would look at the output of
ntpq -c pe -n for jitter of the pps source.
This pps source was measured either in the kernel (this newly added
gpio pps support in the raspberry pi) or in user space using my own
rpi_gpio_ntp.
kernel pps interrupt handling
-
root@detijd:/etc# while true ; do echo `date +%s` `ntpq -c pe -n | grep
127.127.22.0` ; sleep 300 ; done | tee -a /pps.log
root@detijd:/etc# cat /pps.log | awk '{ print $11; }' | awk 'BEGIN { max = -1;
min = 1000; } { if ($1 max) { max=$1; } if ($1 min) { min=$1; } t+=$1; n++;
} END { print min, max, t/n, n; }'
0.001 0.124 0.0131945 797
This is minimum, maximum (yes that's 124!) and average. And I took 797
samples which is almost 3 days.
average temperature of soc: 49.7 with stddev of 1.87
userspace
-
note: I looked at ntpq every 30 seconds(!)
root@hetlicht:/var/log/ntpstats# cat /rpn.log | awk '{ print $11; }' | awk
'BEGIN { max = -1; min = 1000; } { if ($1 max) { max=$1; } if ($1 min) {
min=$1; } t+=$1; n++; } END { print min, max, t/n, n; }'
0.001 0.101 0.00955351 27797
This is over 9,6 days.
average temperature of soc: 51,1 with stddev of 4.01
TL;DR:
- kernel : 13.2us jitter on average
- userspace: 9.6us jitter on average
Folkert van Heusden
--
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www.smartwinning.info
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Re: [time-nuts] linux kernel pps support
On Wed, Dec 17, 2014 at 10:56 AM, folkert folk...@vanheusden.com wrote: Did a test for a while: every 5 minutes I would look at the output of ntpq -c pe -n for jitter of the pps source. I have some interest in various ntp comparisons but it's not really time-nuts material. Would you be interested in moving this thread to ntp-questions? ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Simple AC mains zero-cross detector
On 12/17/14, 6:46 AM, Chuck Forsberg WA7KGX wrote: Seems to me CFLs and other loads switching on and off would affect the 60 Hz waveform enough to make microsecond measurements meaningless. folks measure the frequency to tenths of a Hz (albeit not a single cycle).. 0.1 Hz out of 60 Hz is 27 microseconds. But yes, given the terrible power factor of a lot of consumer loads, I suspect you could see a change in the phase of the voltage just due to the IR drop in the feeder and distribution, since the I isn't in phase with the E. The 15 year old refrigerator I just got rid of was 200W+ and had a PF of 0.50-0.60, which is pretty bad. ___ 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] CGSIC: FW: New NANU 2014090
On Dec 17, 2014, at 1:38 PM, Jim Lux jim...@earthlink.net wrote: but there probably are some software receivers (open source?) out there.. I'll add to the list: Fellow time-nut Peter Monta's GNSS Firehose http://pmonta.com/blog/2014/06/17/new-gnss-firehose-board/ https://github.com/pmonta/GNSS_Firehose The designer of the NSL Primo, Michele Bavaro http://michelebavaro.blogspot.com, sells a better alternative to the US$500, L1-only GN3S, namely the SdrNav00 for EUR 220 http://www.onetalent-gnss.com/ideas/software-defined-radio/sdrnav00 One of these days, yours truly will be selling a cape for the BeagleBone Black SBC containing an L1-only Si 4150L (maybe I should rethink that) plus Xilinx LX45 FPGA www.jks.com/wrx/wrx.html which runs Andrew Holme's homemade software-defined GPS receiver http://www.aholme.co.uk/GPS/Main.htm Plus you get a shortwave SDR for free.. ___ 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] Z3812A
Hi Since the box was only made for Lucent, it’s a good bet that there is no formal manual. There may be a spec sheet or something in a non-manual format. For right now, the best bet is to grab the Z3801 manuals that are out there. The boxes are similar enough that the info in one sort of applies to the other. The Z3801 manuals sub-reference the instrument versions of the manuals for more of the details. Those manuals are also out on the internet. Some of the data on the SCPI stuff in them is also useful. Simple answer - search for Z3801 and Z3805 manuals and info. The odds of turning up with a schematic or parts list for these boxes are essentially zero. They stopped doing that stuff long before they did these boxes. Bob On Dec 17, 2014, at 10:21 AM, planoph...@aei.ca wrote: I have searched to no avail. Has anyone a pointer to a real manual for the Z3812A / KS-x devices? cheers, Graham ve3gtc ___ 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] Choke Rings and Points North
Hi On Dec 17, 2014, at 8:49 AM, Jim Lux jim...@earthlink.net wrote: On 12/17/14, 4:36 AM, Bob Camp wrote: HI On Dec 17, 2014, at 1:07 AM, Chuck Harris cfhar...@erols.com wrote: I would venture that the extent of the magic was to note the physical center of the array, and call that the phase center. As long as you always orient the antenna in the same direction, any errors that might exist in the real phase center will be consistent, and could be corrected for by noting the offset from a benchmark. I’m afraid that’s what they do as well. Just spin it and see what a dial indicator reads sort of thing. I think that I’d want something that actually did some microwave tests …. B The UNAVCO data is an actual RF test. And from a manufacturing standpoint, I would imagine that typical tolerances are better than 0.001 (25.4 microns). Changes much bigger than that would show up as VSWR changes, which *is* something that they check in manufacturing. The Leica artichoke multiband choke ziggurats (they're not flat, so I have a hard time calling it a ring) are cast and then machined. Casting isn't what I would think is a precision operation, but it probably is real consistent from unit to unit. There are some *very* accurate casting techniques these days. They do an amazing job on multidimensional gizmos like antennas or golf club heads. It’s not a cheap thing to set up or keep under control. It’s probably cheaper than a full blown machining process. It would not surprise me to find that most of the errors are scale errors rather than errors in any one dimension. If you “inflate” the whole structure by 0.1%, I doubt that impacts a receiving antenna a whole lot. Getting back to the phase center question, it should have very little impact on the phase center. Stability wise, a casting is often a good idea. Having the center (where ever it is) stay put is more important than it being “perfect”. There is a sub issue to all of this. You can have an antenna with a good “averaged” phase center. You also can have one that truly has the same center no matter which way the signal comes from. With a timing setup trying to do per satellite data, *that* parameter would indeed matter quite a bit. I doubt that it’s a big design issue on your run of the mill $3 antenna. I believe it would be quite a bit better on one of the fancy antennas. Pathogenic issues in phase center could indeed be part of some of the 12/24/48 hour stuff one sees in GPS plots. Separating them from multipath in a field setting could be a bit difficult. Bob ___ 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] Lady Heather and comm port setup...
I keep a VMware image file with a very old copy on Windows on it just for old programs like this. The image file will boot up on a Mac or Linux machine or even in a Win 7 PC. I keep thinking it would be good to re-write LH so it would run on a more reasonable/modern platform but there are about 1,000 other things ahead in the queue. On Wed, Dec 17, 2014 at 5:31 PM, Mark Sims hol...@hotmail.com wrote: Win 95? Get real! Real men run WIN98. Lady Heather runs fine on WIN98. I use a Compaq Armada 1700 running WIN98 at 230 MHz. I have run it (but not lately) on a steam driven 90 MHz Fujitsu laptop with passive matrix screen. You would be amazed at what you can find laptop wise on Ebay. I wanted a laptop to run Mach3 for a small CNC mill/laser cutter. Laptops can be problematic with Mach3 because they want to drop into sleep modes at the worst possible time. I found a reference that a 2+ GHz Compaq EVO N610C laptop works fine with Mach3 and has hardware serial and parallel ports, wifi, etc. Checking Ebay at the time, I found several in the $75-$150 dollar range. And a listing for 5 of them, loaded with XP and Office for $150 total... shipped. She also tossed in 7 extra battery packs (all good). That's a lot of CPU power for $30 a copy... The screen on my Armada recently died and I had to pay over $50 for a new Armada. ___ 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. -- Chris Albertson Redondo Beach, California ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] STEL-1173/CM Source
Ed, On 11/15/2014 04:38 PM, Ed Palmer wrote: Yes, I'm sure. I did check the cabling. :) If I was somehow measuring the Tbolt or 4065A against itself, there wouldn't be any frequency offset. The Oscilloquartz 3210 (which appears to be an OEM'd 4065A) is spec'ed at 3E-13 @ 100K seconds. The 4065C is even better at 8.5E-14 with a noise floor of 5E-14. My OSA 3210 is not the same core as 4065A. My data run is continuing. The end of the graph is flopping around as usual, but it's now showing Total Deviation of about 1.4E-13 @ 100K seconds with a total of 226 800 readings at 1 second intervals. Frequency offset error is still 6E-13. Autocorrelation of the results shows diurnal spikes at approximately 86 160 and 172 310 seconds (i.e. one and two sidereal days). Most likely thermal sensitivity. Got myself some STEL 1173 in PLCC 44 from that source. Thanks for sharing link! Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
