[time-nuts] radio clocks
Does anyone know of a (WWVB) radio controlled clock that meets all the necessary points and many if not most of the optional points listed in the compliance checklist in section 10 of NIST Special Publication 960-14, available for reference here: http://tf.nist.gov/general/pdf/1976.pdf (compliance checklist begins on pdf page 47/64) Thanks, Eric ___ 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] Z3801A LED display...
That would be neat to get a copy. I've saved a screen shot of a
Thunderbolt at 23:59:60.
Thought I'd show it at the 1/10 NEWS meeting.
Got our new FM antenna installed for WVTQ-FM on Equinox.
http://vprblog.blogspot.com/2008/12/intrepid-engineering.html
Mike
On Thu Dec 31 19:57 , sent:
FWIW...
I have one of my Z3801A running with an external LED display
that's based on one of the Dave Robinson, G4FRE PIC controllers.
His design reads the raw binary output from the internal GPS RX.
A mini-disc cam-corder was aimed at the display and caught
the leapsecond.
ie:
23:59:58
23:59:59
23:59:60
00:00:00
00:00:01
I'll try and snag a few seconds of video from the DVD around the
event
if anybody is interested. Had WWV on in the background but was not
mic'ed
very well so sound is low.
-Brian, WA1ZMS
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Re: [time-nuts] Connector source for LPRO Rb oscillator...??
I hate buying pieces one at a time. These connectors are used in many projects having to do with GPSDO's, oscillators, GPS receivers, Brooks Shera's controller board, etc. I bought a Molex MXKK-100 'Kit' of parts for about $55 that included a workable crimp tool that I have used on other connectors as well. Unfortunately, it did not come with the two row, 5 pin per row housings that are used on the LPRO-101. However, I bet you could use two of the single row, 5 pin per row, housings on the LPRO and do just fine. I ordered spare housings and spare pins in several configurations and materials and used the crimper just fine. There is also a KK-100 Kit but the crimper is not as nice. Just search for MXKK-100 on Digi-Key or Mouser, etc. Joe -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Hal Murray Sent: Thursday, January 01, 2009 5:34 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Connector source for LPRO Rb oscillator...?? The user-manual contains some info on the connector, but no info on where to make an actual purchase. Any suggestions from the list members on where to get a couple of these connectors? If the user manual has the manufacturer's part numbers, my first try would be to feed them to the search stuff on my favorite distributor. Tyco gobbled up AMP a while ago, so the manufacturer for the AMP part numbers is now Tyco. That style of connectors is a pain until you fork over the cash for a good crimp tool. Digikey has the 87133-2 (shell) for $1.68 and the 5-87165-2 (pins) for $0.49 each. Note the extra 5- on the front of the part number for the pins. That's the lead free version. If you want lead, the price is a bit higher. 87165-1 is the gold plated version. The drawing for the shell said 87124 was the part number for the pins. That's probably newer/cheaper/better. Digikey says over $500 for the hand tool. That's more than I'm willing to pay. I have the Molex version. Digikey says please call for the one I have and over $300 for the alternate. Mumble. I was thinking of $100 or so. Maybe you should hope a nearby buddy has one. -- These are my opinions, not necessarily my employer's. 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] FreeBSD 7 ntp server
I'm thinking about, for example, stock trading where the first bid wins. Sub-second resolution is needed there, I think. Advanced Message Queuing Protocol (AMQP) is what is used in some big brokerage firms. http://jira.amqp.org/confluence/display/AMQP/Advanced+Message+Queuing+Protocol Specs are here: http://jira.amqp.org/confluence/display/AMQP/Download The datetime type encodes a date and time using the 64 bit POSIX time_t format. Also http://cr.yp.to/time.html maybe of interest to Time Nuts. -- http://www.wearablesmartsensors.com/ http://www.softwaresafety.net/ http://www.designer-iii.com/ http://www.unusualresearch.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] DCF77, HBG, MSF, two out of three
Here are my preliminary reduction of the VLF recording I made: http://phk.freebsd.dk/Leap/20081231/ DCF77 got right, as always. HBG also got it right this time. MSF still fumbles the DUT1 bits. It could look like all three stations take a S/N hit due to fireworks, both local and remote, but this is purely guesswork. I wish we could persuade PTB to light the leap-pending bit more than one hour in advance, it seems that HBG already do this, so it would be pretty harmless I expect. Poul-Henning -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 p...@freebsd.org | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. ___ 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] Z3801A LED display...
Sorry, meant to send this directly to Brian.
Mike
On Thu Jan 1 8:07 , sent:
That would be neat to get a copy. I've saved a screen shot of a
Thunderbolt at 23:59:60.
Thought I'd show it at the 1/10 NEWS meeting.
Got our new FM antenna installed for WVTQ-FM on Equinox.
[1]http://vprblog.blogspot.com/2008/12/intrepid-engineering.html
Mike
On Thu Dec 31 19:57 , sent:
FWIW...
I have one of my Z3801A running with an external LED display
that's based on one of the Dave Robinson, G4FRE PIC controllers.
His design reads the raw binary output from the internal GPS RX.
A mini-disc cam-corder was aimed at the display and caught
the leapsecond.
ie:
23:59:58
23:59:59
23:59:60
00:00:00
00:00:01
I'll try and snag a few seconds of video from the DVD around the
event
if anybody is interested. Had WWV on in the background but was not
mic'ed
very well so sound is low.
-Brian, WA1ZMS
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Re: [time-nuts] Connector source for LPRO Rb oscillator...??
As a crimping tool, I use a small vise I have normally secured to my bench. That works very well. I have used it for about 15 years and made hundreds of cables for that type of connector, up to and including the 40 pin type used for hard drives (the old parallel ATA type). It is too bad that while the 10 pin connector is very common in older PCs to connect the serial ports from the mothercard to the rear panel, in that application they only crimp 9 wires (because there is a 9 pin serial connector at the other end), and the LPRO needs both wires at the end, so while you may reuse the connector itself (they are not too hard to take apart, even though you need to be careful if you intend to reuse the connector), you need to make a new cable. Didier -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Hal Murray Sent: Thursday, January 01, 2009 5:34 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Connector source for LPRO Rb oscillator...?? The user-manual contains some info on the connector, but no info on where to make an actual purchase. Any suggestions from the list members on where to get a couple of these connectors? If the user manual has the manufacturer's part numbers, my first try would be to feed them to the search stuff on my favorite distributor. Tyco gobbled up AMP a while ago, so the manufacturer for the AMP part numbers is now Tyco. That style of connectors is a pain until you fork over the cash for a good crimp tool. Digikey has the 87133-2 (shell) for $1.68 and the 5-87165-2 (pins) for $0.49 each. Note the extra 5- on the front of the part number for the pins. That's the lead free version. If you want lead, the price is a bit higher. 87165-1 is the gold plated version. The drawing for the shell said 87124 was the part number for the pins. That's probably newer/cheaper/better. Digikey says over $500 for the hand tool. That's more than I'm willing to pay. I have the Molex version. Digikey says please call for the one I have and over $300 for the alternate. Mumble. I was thinking of $100 or so. Maybe you should hope a nearby buddy has one. -- These are my opinions, not necessarily my employer's. 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] Connector source for LPRO Rb oscillator...??
In a message dated 01/01/2009 15:20:12 GMT Standard Time, did...@cox.net writes: As a crimping tool, I use a small vise I have normally secured to my bench. That works very well. I have used it for about 15 years and made hundreds of cables for that type of connector, up to and including the 40 pin type used for hard drives (the old parallel ATA type). It is too bad that while the 10 pin connector is very common in older PCs to connect the serial ports from the mothercard to the rear panel, in that application they only crimp 9 wires (because there is a 9 pin serial connector at the other end), and the LPRO needs both wires at the end, so while you may reuse the connector itself (they are not too hard to take apart, even though you need to be careful if you intend to reuse the connector), you need to make a new cable. -- I agree re the vise, having done the same myself, but in this instance why not just cut off part of an old floppy or hard drive cable, enough to leave the 10 sockets and attached wiring? For personal use it's not so important to have a locating lug, and smaller connectors quite often didn't have them anyway. regards Nigel GM8PZR ___ 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's Leap Log
On 12/31/08 6:06 PM, Steve Rooke sar10...@gmail.com wrote: 2009/1/1 Mark Sims hol...@hotmail.com: Note that there is an error in the first column heading in Lady Heather's Leap Log. It says UTC... should be GPS. The three line hour timestamp comment is correct (UTC). The distributed version of the program logged only time-of-week. I added the HH:MM:SS yesterday but messed up the column header (boy is Lady Heather gonna be mad when She finds out). The random spacing is due to Billy Gates Quality Control... he still can't figure out where to put CRs and LFs in an email... Well, POSIX decided on LF, Mac on CR and Billy Boy decided to hedge his bets with both LF and CR. It's little wonder I always get a lot of double spacing here then :-) Hardly microsoft's fault. Blame the teletype. Or perhaps DEC. RT-11 stored CR/LF in files, and CP/M adopted that convention, followed by DOS, etc. I imagine RT-11 did CR/LF because A) it allows use of unmodified KSR/ASR 33 TTYs without having to worry if the user has the autoLF option B) with ink on paper, the ability to do overprints (CR w/o LF) is actually useful. Them newfangled CRT based terminals can't do this (except for the Tek 401x series) Jim ___ 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] Netclock/2 Freeze
Now that the Event has passed I noticed only one weird anomaly; my Spectracom Netcloock/2 (WWVB) display froze at the 59/00 event and required a hard reset to get it back to life. All front panel LEDs stayed green just the display was stuck at xx:xx:59. I was not in the shop yesterday so could not watch things happen as the leap second was added. Anybody else have weirdness to report. Had K7MLR ___ 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] Leap seconds and POSIX
Having worked in the POSIX committee for many years, I can shed some light on how POSIX handles leap seconds: In short, POSIX adamantly ignores leap seconds. All days in POSIX have the same length, 86,400 seconds. This omission is not by accident, instead having been violently debated at length, and voted upon. The rationale is that one cannot assume that all POSIX systems have access to leap second information, or even the correct time, and yet must work in a reasonable manner. In particular, file modification timestamps must allow one to determine causal order (to within one second in the old days) by comparison of timestamps. (Yes, people do realize that timestamps are not the perfect way to establish causal order, but are nonetheless widely used in non-critical applications. Critical applications instead use some kind of atomic sequence-number scheme.) So, at least in theory, POSIX time is a form of TAI, having a constant offset from TAI. In practice, in platforms that have access to GPS, NTP is used to servo the local computer clock into alignment with UTC (or GPS System Time (UTC without the accumulated leaps) in systems that abhor time steps), and there is a transient error just after a leap second while NTP recovers. Joe ___ 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] Lady Heather's Leap Log
All the CR/LF strangeness that I have been having are absolutely positively Microsoft's fault. Hotmail is a web based email. You enter your text in a standard web form. Words wrap at the right margin. When you get to the end of a paragraph you press RETURN to start a new paragraph and RETURN RETURN to start a new paragraph with a blank line between them. This is the way every web form works. And it is the way Hotmail has worked for the last 10+ years. A couple months ago, Billy G decided to pimp out the Hotmail user interface and in usual Microsoft style totally screwed things up. Besides requiring three times as many clicks to log in, many features either do not work or mess up. The paragraph/RETURN thing is just one. Sometimes you get your paragraph/spacing, other times you don't. Sometimes a button works, sometimes it don't. Sometimes you can log in, sometimes you don't. Sometimes it locks up, sometimes it don't. This occurs with both Firefox and Safari. I don't use Internet Exploder. I doubt that problems that are as apparent as these would have gone unnoticed and unfixed... I can only assume the Microsoft has yet again intentionally hobbled a product so that it does not work with competitors products/browsers. Luckily Hotmail is the sole Microsoft product that I have to use. _ Life on your PC is safer, easier, and more enjoyable with Windows Vista®. http://clk.atdmt.com/MRT/go/127032870/direct/01/ ___ 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] Leap seconds and POSIX
In message: p06240822c582a02c4...@[192.168.1.212] Joe Gwinn joegw...@comcast.net writes: : Having worked in the POSIX committee for many years, I can shed some : light on how POSIX handles leap seconds: : : In short, POSIX adamantly ignores leap seconds. All days in POSIX : have the same length, 86,400 seconds. : : This omission is not by accident, instead having been violently : debated at length, and voted upon. : : The rationale is that one cannot assume that all POSIX systems have : access to leap second information, or even the correct time, and yet : must work in a reasonable manner. In particular, file modification : timestamps must allow one to determine causal order (to within one : second in the old days) by comparison of timestamps. (Yes, people do : realize that timestamps are not the perfect way to establish causal : order, but are nonetheless widely used in non-critical applications. : Critical applications instead use some kind of atomic sequence-number : scheme.) If POSIX had allowed for the system time to be TAI, and have the offset applied for the display of times, then there would be no ambiguity. However, this is not allowed because one must be able to do math on time_t such that time_t % 86400 is midnight. : So, at least in theory, POSIX time is a form of TAI, having a : constant offset from TAI. Except that the offset isn't constant :(. : In practice, in platforms that have access to GPS, NTP is used to : servo the local computer clock into alignment with UTC (or GPS System : Time (UTC without the accumulated leaps) in systems that abhor time : steps), and there is a transient error just after a leap second while : NTP recovers. When the INS bit is set in the NTP packets, NTP tells the kernel about it, which replays the last second of the day to keep in step. I'm not sure this is a transient error or not, since ntp_gettime can be used to determine that this is the leap second for applications that care. However, it does introduce a glitch in the data produced by system interfaces that don't have leap second indicators... Warner ___ 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's Leap Log
The reason for CR/LF is that CR takes a while on a teletype, while LF is fast, so sending both allowed enough time for the paper/print head to be in the right place before printing the next char. If you sent LF/CR on a teletype instead of CR/LF, you could see right away the reason :-) Didier PS: while writing this, I suddenly realized that it really dates me, doesn't it? -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Lux, James P Sent: Thursday, January 01, 2009 10:10 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Lady Heather's Leap Log On 12/31/08 6:06 PM, Steve Rooke sar10...@gmail.com wrote: 2009/1/1 Mark Sims hol...@hotmail.com: Note that there is an error in the first column heading in Lady Heather's Leap Log. It says UTC... should be GPS. The three line hour timestamp comment is correct (UTC). The distributed version of the program logged only time-of-week. I added the HH:MM:SS yesterday but messed up the column header (boy is Lady Heather gonna be mad when She finds out). The random spacing is due to Billy Gates Quality Control... he still can't figure out where to put CRs and LFs in an email... Well, POSIX decided on LF, Mac on CR and Billy Boy decided to hedge his bets with both LF and CR. It's little wonder I always get a lot of double spacing here then :-) Hardly microsoft's fault. Blame the teletype. Or perhaps DEC. RT-11 stored CR/LF in files, and CP/M adopted that convention, followed by DOS, etc. I imagine RT-11 did CR/LF because A) it allows use of unmodified KSR/ASR 33 TTYs without having to worry if the user has the autoLF option B) with ink on paper, the ability to do overprints (CR w/o LF) is actually useful. Them newfangled CRT based terminals can't do this (except for the Tek 401x series) Jim ___ 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] Another LPRO-101 Rb Osc question...
Note the position of the connector. This is really a filter plate with leads that also extend into the connector on the oscillator. Remove the two spacer nuts. Pull the filter plate out. Remove the cover. When you reassemble the cover, make sure that you install the filter plate correctly. I would like to know what the other connector is for and what the headers inside the oscillator are for. These are not mentioned in the manual available on the web. 73 Glenn WB4UIV At 01:21 PM 1/1/2009, you wrote: Hello, Time-Nutters-- In looking at the LPRO-101 unit I'm holding in my grubby little paw, I note that the base of the case has a thin layer of some sort of pale-green slippery material glued to it. Is this the heat-transfer tape/pad mentioned in the user manual that must be placed on the base before bolting to a heat-sink? I notice six threaded insert holes in the bottom for bolting to a heat sink-- The user's manual gives mounting screw clearance info for the bottom plate. However: I would like to place a small terminal strip on the top of the case with an RF connector and some easy/convenient connection lugs for power and monitoring, etc. Question--: how much clearance is there between the top of the case and internal components? It is not clear to me how to remove the top case section for a look inside to check on component clearance-- The top cover does not appear to be screwed in place, but I am reluctant to just try some experimental prying. Does the case slide off? There appear to be what look like tiny detent-dimples all around the sides of the upper case lid. Is this what retains the upper case in place? Does it lift off with very careful prying? Has anyone done this before? Thanks-- Mike Baker WA4HFR Gainesville, FL ___ 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] Leap seconds and POSIX
In message: 20090101.112803.179959520@bsdimp.com M. Warner Losh i...@bsdimp.com writes: : If POSIX had allowed for the system time to be TAI, and have the : offset applied for the display of times, then there would be no : ambiguity. However, this is not allowed because one must be able to : do math on time_t such that time_t % 86400 is midnight. time_t %86400 == 0 is midnight I should have said... Warner ___ 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's Leap Log
Mark, First, I do not like Billy Gate either. But I find your insistence that all you have is HOTMAIL for your email facilities a bit disingenuous. Your message header indicates you are getting to the WEB through Southwest Bell, a division of ATT Internet services. If that is correct, then you have the ability to have a normal Email service account through ATT. So my question is why are you restricting yourself to such limited means as WEB mail ? Particularly when better processes are available no matter how F-upped Billy G and Microsoft are. BillWB6BNQ Mark Sims wrote: All the CR/LF strangeness that I have been having are absolutely positively Microsoft's fault. Hotmail is a web based email. You enter your text in a standard web form. Words wrap at the right margin. When you get to the end of a paragraph you press RETURN to start a new paragraph and RETURN RETURN to start a new paragraph with a blank line between them. This is the way every web form works. And it is the way Hotmail has worked for the last 10+ years. A couple months ago, Billy G decided to pimp out the Hotmail user interface and in usual Microsoft style totally screwed things up. Besides requiring three times as many clicks to log in, many features either do not work or mess up. The paragraph/RETURN thing is just one. Sometimes you get your paragraph/spacing, other times you don't. Sometimes a button works, sometimes it don't. Sometimes you can log in, sometimes you don't. Sometimes it locks up, sometimes it don't. This occurs with both Firefox and Safari. I don't use Internet Exploder. I doubt that problems that are as apparent as these would have gone unnoticed and unfixed... I can only assume the Microsoft has yet again intentionally hobbled a product so that it does not work with competitors products/browsers. Luckily Hotmail is the sole Microsoft product that I have to use. _ Life on your PC is safer, easier, and more enjoyable with Windows Vista®. http://clk.atdmt.com/MRT/go/127032870/direct/01/ ___ 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's Leap Log
Seems to me that CR CR LF was often used to leave a bit more time. Was a long time ago, but we were very young then :) -- Alan, wb6zqz On Thu, Jan 1, 2009 at 10:32 AM, Didier did...@cox.net wrote: The reason for CR/LF is that CR takes a while on a teletype, while LF is fast, so sending both allowed enough time for the paper/print head to be in the right place before printing the next char. If you sent LF/CR on a teletype instead of CR/LF, you could see right away the reason :-) Didier PS: while writing this, I suddenly realized that it really dates me, doesn't it? -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Lux, James P Sent: Thursday, January 01, 2009 10:10 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Lady Heather's Leap Log On 12/31/08 6:06 PM, Steve Rooke sar10...@gmail.com wrote: 2009/1/1 Mark Sims hol...@hotmail.com: Note that there is an error in the first column heading in Lady Heather's Leap Log. It says UTC... should be GPS. The three line hour timestamp comment is correct (UTC). The distributed version of the program logged only time-of-week. I added the HH:MM:SS yesterday but messed up the column header (boy is Lady Heather gonna be mad when She finds out). The random spacing is due to Billy Gates Quality Control... he still can't figure out where to put CRs and LFs in an email... Well, POSIX decided on LF, Mac on CR and Billy Boy decided to hedge his bets with both LF and CR. It's little wonder I always get a lot of double spacing here then :-) Hardly microsoft's fault. Blame the teletype. Or perhaps DEC. RT-11 stored CR/LF in files, and CP/M adopted that convention, followed by DOS, etc. I imagine RT-11 did CR/LF because A) it allows use of unmodified KSR/ASR 33 TTYs without having to worry if the user has the autoLF option B) with ink on paper, the ability to do overprints (CR w/o LF) is actually useful. Them newfangled CRT based terminals can't do this (except for the Tek 401x series) Jim ___ 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] Lady Heather's Leap Log
On 1/1/09 8:37 AM, Chuck Harris cfhar...@erols.com wrote: Lux, James P wrote: The fault was in the thinking that there would never be more than one or two terminal types used as consoles and I/O devices, so the applications programs should handle I/O directly. That fault was fixed once and for all with unix's termcap... the idea that the driver should present as common as possible of an interface to the application. MSDOS was a microcomputer OS and inherited most of the features of other microcomputer OSes at the time. Termcap was a royal pain in the rear to deal with, and consumed significant (scarce) resources on machines where 32K of RAM was the whole load. I can't fault MS for the choice they made back then. And, in a small resource system that's talking to a glass TTY as a console, why not just code for what's out there. (after all, all you had between your application and the hardware was a BIOS call.. CP/M provided almost nothing between file and console, e.g. PIP) Granted, by the time they were building real operating systems (say, from NT onwards) they should and did have a more sophisticated scheme. But by that time, lots of folks had invested in compatibility with the earlier MSDOS,CP/M style stuff. And, besides, MS was already heading towards windowing environments where the OS would manage the video display directly with bitblts etc, rather than worrying about supporting hundreds of different serial console hardware and terminals. I remember looking at various Unix implementations in the mid 80s for microcomputers (remember Charles River Data Systems, for example), as well as Unix-like implementations (Cromix).. My roommate at the time was toiling on 68k systems, including porting the original SUN workstation stuff to another 68k platform, and I well remember his comments that the curses package (which uses termcap) was well named. I think there were also some licensing/copyright issues with the plethora of Unixes around at the time. MS had ample opportunity to follow that example, as it was well established back in the early 1970's. They chose instead to reinvent the wheel, and ignore most of the advances that came before them. Not really.. I'd venture that MS has NEVER aimed their OS towards supporting serial consoles in any serious manner, so why would they care about termcap and all it's associated cruft. They've always worked in terms of a memory mapped display of some sort (viz the horrible serial port support in the IBM PC BIOS and Int14 in MS-DOS). They still do. As do lots of other folks. You choose what works for you in your situation as you have it. Sometimes, a Unix derivative works best, other times, something else does. -Chuck Harris ___ 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] Count up/down DAC circuit
Steve Here is another opinion to help add to your choices. The hunting problem is EASY to fix many different ways. It is basically done by anticipating what is going to happen next. If it is done wrong It would indeed: exasperate any problems trying to lock a fast moving oxco or achieving lock in the first place If done correct, that does not need to be an issue. To do it 'right' may not be easer to implement than something with a dead-zone BUT more accurate. As far As for achieving lock in the first place with this idea This need not be a big issue, It needs to only depend on what the uncertainty of the 1PPS sync signal is, so as not to resync on the wrong clock. That is max Jitter plus the down time phase error time. As far as down time hold-over, It need not be a big problem as long as you have something in there that is digital such as the DAC. Just detect the fact that the GPS is down someway and shut down the Dac updates, but don't try to use an analog holdover circuit if you want to hold more than a few minutes. And I must agree mostly with what Said said: implementing a standard PI controller (in a micro etc), and calculating it's stability etc is much easier than getting this to work properly That is it is easier IF you are good at using micro's, mostly because that is the way it is usually done. If you don't or can't use a micro, then its easier to do it without one. The real problem is just how do you get an accurate signal to lock on to in the first place? WarrenS *** - Original Message - From: Steve Rooke sar10...@gmail.com To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Tuesday, December 30, 2008 8:31 PM Subject: Re: [time-nuts] Count up/down DAC circuit Hi Said, Yes, I could see that my idea would suffer from this hunting in the locked state problem an was wondering if this could be perhaps 'cured' with a simple low-pass filter stage between the count up/down DAC and the EFC, IE, the DAC would hunt up and down with a duty cycle equal to the difference between the two DAC levels filtered by the LPF, thereby giving a constant frequency. This, of course, would further exasperate any problems trying to lock a fast moving oxco or achieving lock in the first place. Some tuning of the LPF time constant would be required to stop ringing as the PLL moved into lock. Do you think that would work as it would probably be easier to implement than something to implement a dead-zone? As for achieving lock in the first place with this idea, I'm thinking now that it could take a very lon time for the DAC to count up/down with output from a phase detector at 1PPS. I was really only thinking about this whole idea as it seemed to be a natural to hold the EFC voltage during lack of PPS if the GPS goes down. Without the PPS, the phase detector will output no pulses so the DAC would remain frozen in it's last state. Implementing a GPSDO via a phase detector followed by a LPF would obviously be easier but in the absence of the PPS, I imagine that leakage in the circuit would make the EFC voltage drift. I guess I could buffer it with a source-follower or something like that, or perhaps some form of sample and hokld circuit. I was just bouncing around ideas as I know there are a lot of great brains on this list. 73, Steve 2008/12/31 saidj...@aol.com: Hi Steve, I played with such a circuit a long time ago. The slope is limited to the clocking of your circuit (one LSB digit per clock typ), which can present an issue if you cannot follow the OCXO's EFC changes fast enough. You could be chasing the OCXO voltage and this may lead to instability. Even if it is locked, the circuit will constantly be chasing the OCXO, unless you implement a dead-zone where the circuit stops counting up/down when you are close enough to your target frequency. This chasing may cause the frequency to modulate up and down, and could lead to large-scale oscillations. Tough to get this to work properly, but with circuitry to add a deadzone, and to dampen the lock, and maybe to introduce gain (jump more than one LSB when far off etc) it may work. Then again implementing a standard PI controller (in a micro etc), and calculating it's stability etc is much easier than getting this to work properly. bye, Said In a message dated 12/29/2008 21:30:54 Pacific Standard Time, sar10...@gmail.com writes: As part of the current idea I have with the hockey-pucks, I'm thinking about feeding the D1 and U1 phase difference pulses out of an MC4044 out to some circuit that could clock up and down an analog output which would ultimately go to the EFC of a ocxo, IE D1 pulses when the phase of one input signal is advanced and visa versa for the U1 pin. Anyone seen a circuit like that please? Thanks 73, Steve -- Steve Rooke - ZL3TUV G8KVD JAKDTTNW Omnium finis imminet
[time-nuts] Another LPRO-101 Rb Osc question...
Do NOT drill, distort, or otherwise manipulate the LPRO case. It is actually a mu-metal magnetic shield. These are fabricated and then specially annealed. If you bend it, etc you can destroy the shielding properties. If you want to mount a terminal strip, etc to the case use something like double sided tape. The case top does just snap onto the base. Remove the hex jack screws on the interface connector. Gently pry the top cover off... beware of the above warning. It is very easy to bend the case getting it off. Yes, the rubbery film on the bottom of the case is a silicone rubber heat transfer pad. If you mess yours up you can use regular heat sink grease (well known for mysteriously coating everything within a 10 foot radius with white goo once you open the container) - I would like to place a small terminal strip on the top of the case with an RF connector and some easy/convenient connection lugs for power and monitoring, etc. _ It’s the same Hotmail®. If by “same” you mean up to 70% faster. http://windowslive.com/online/hotmail?ocid=TXT_TAGLM_WL_hotmail_acq_broad1_122008 ___ 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's Leap Log
On 1/1/09 10:32 AM, Didier did...@cox.net wrote: The reason for CR/LF is that CR takes a while on a teletype, while LF is fast, so sending both allowed enough time for the paper/print head to be in the right place before printing the next char. If you sent LF/CR on a teletype instead of CR/LF, you could see right away the reason :-) Didier PS: while writing this, I suddenly realized that it really dates me, doesn't it? Only if you're generating the 50/60 Hz for your TTYs synchronous motor from dividing down your 10 MHz house standard... A new timenuts thing... Does the slight frequency error from an integer division from 10MHz to 60.00024 affect the CR/LF timing... Clearly, the folks using 50Hz and the corresponding gearing in the TTY have it better, because it's an exact division. ___ 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] Lady Heather's Leap Log
I use web based email services for two main reasons. First is that I know I can (and do) access my email from anywhere in the world . Second is that it does not lock me into a particular ISP. I am currently using SBC DSL for my home internet access. Like every broadband supplier, they keep raising their rates thinking that you will either not notice or that switching to a new supplier (and having to change email addresses) is too much of a hassle. The next time SBC attempts to raise my rates, they lose me as a customer and I switch to a different supplier and the cycle repeats. I have had the same Hotmail addresses for over 10 years... makes it easy for people to keep in touch. Yes, I could get my own domain name and set up a permanent email address that way, but that can make reason #1 more difficult. -- So my question is why are you restricting yourself to such limited means as WEB mail ? _ It’s the same Hotmail®. If by “same” you mean up to 70% faster. http://windowslive.com/online/hotmail?ocid=TXT_TAGLM_WL_hotmail_acq_broad1_122008 ___ 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's Leap Log
In message c58257a0.3e7a%james.p@jpl.nasa.gov, Lux, James P writes: A new timenuts thing... Does the slight frequency error from an integer division from 10MHz to 60.00024 [...] Real timenuts use a synthesizer or PLL to get the correct 60.00... Hz :-) (See Toms nixe-clock :-) -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 p...@freebsd.org | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. ___ 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] Leap seconds and POSIX
Warner, At 6:35 PM + 1/1/09, time-nuts-requ...@febo.com wrote: Message: 6 Date: Thu, 01 Jan 2009 11:28:03 -0700 (MST) From: M. Warner Losh i...@bsdimp.com Subject: Re: [time-nuts] Leap seconds and POSIX To: time-nuts@febo.com, joegw...@comcast.net Message-ID: 20090101.112803.179959520@bsdimp.com Content-Type: Text/Plain; charset=us-ascii In message: p06240822c582a02c4...@[192.168.1.212] Joe Gwinn joegw...@comcast.net writes: : Having worked in the POSIX committee for many years, I can shed some : light on how POSIX handles leap seconds: : : In short, POSIX adamantly ignores leap seconds. All days in POSIX : have the same length, 86,400 seconds. : : This omission is not by accident, instead having been violently : debated at length, and voted upon. : : The rationale is that one cannot assume that all POSIX systems have : access to leap second information, or even the correct time, and yet : must work in a reasonable manner. In particular, file modification : timestamps must allow one to determine causal order (to within one : second in the old days) by comparison of timestamps. (Yes, people do : realize that timestamps are not the perfect way to establish causal : order, but are nonetheless widely used in non-critical applications. : Critical applications instead use some kind of atomic sequence-number : scheme.) If POSIX had allowed for the system time to be TAI, and have the offset applied for the display of times, then there would be no ambiguity. However, this is not allowed because one must be able to do math on time_t such that time_t % 86400 is midnight. Defining a formal equivalence of some kind to TAI was proposed, but was not accepted, largely because they had were not linked at the beginning, and there would be many details that were not quite right. : So, at least in theory, POSIX time is a form of TAI, having a : constant offset from TAI. Except that the offset isn't constant :(. True, as discussed next. : In practice, in platforms that have access to GPS, NTP is used to : servo the local computer clock into alignment with UTC (or GPS System : Time (UTC without the accumulated leaps) in systems that abhor time : steps), and there is a transient error just after a leap second while : NTP recovers. When the INS bit is set in the NTP packets, NTP tells the kernel about it, which replays the last second of the day to keep in step. I'm not sure this is a transient error or not, since ntp_gettime can be used to determine that this is the leap second for applications that care. However, it does introduce a glitch in the data produced by system interfaces that don't have leap second indicators... Platforms vary because NTP is at the mercy of the kernel developers. From the standpoint of the average user, there is a transient error. Not that many average users will notice, so long as nothing crashes or hangs. In systems where the transient error and possibility of a crash or hang cannot be tolerated, one common dodge is to lie to NTP by configuring the GPS receiver and NTP timeserver to emit GPS System Time, and live with the fact that the local computer clocks are ~14+ seconds off of UTC. Purpose-built user displays are programmed to compute and use the correct time. Joe ___ 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] Leap seconds and POSIX
In message p06240823c582ce020...@[192.168.1.212], Joe Gwinn writes: Not that many average users will notice, so long as nothing crashes or hangs. If the above statement reflects the POSIX attitude to operating system quality and reliability, then I understand, for the first time, how POSIX can contain so many mistakes, omissions and bad ideas usually terribly executed. Poul-Henning -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 p...@freebsd.org | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. ___ 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] Leap quirks
Two of my Linux systems hung. One was running a 2.6.25 kernel and one 2.6.26. A system running 2.6.23 worked fine. I saw a couple of notes on comp.protocols.time.ntp about Linux systems locking up. One said that it was a kernel bug in ntp.c but I haven't seen any details. My Garmin GPS 18x USB was off by a second for about 2.5 hours. I thought it had fixed itself, but it's still bouncing around between reasonably close and off by a second. I'll get a graph one of these days. (Poke me off list if you want to see it before I get around to it.) Hopefully it will fix itself soon. My 18 LVC and 18 USB (no x) both did the right thing. The 18x is the new version. Physically, it looks the same. The receiver is much more sensitive, but the timing has lots more jitter. [My 18x LVC died a while ago so I didn't get any leap data from it.] A couple of SiRF systems are off by a second now. These are the systems that got confused when the leap second announcement started back in Aug. http://www.megapathdsl.net/~hmurray/ntp/leap-gps2.gif They were clean for the first 18 hours of this year. Mumble. I'll have to wait for more data. -- These are my opinions, not necessarily my employer's. 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.
Re: [time-nuts] Leap seconds and POSIX
-Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Poul-Henning Kamp Sent: Thursday, January 01, 2009 2:03 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Leap seconds and POSIX In message p06240823c582ce020...@[192.168.1.212], Joe Gwinn writes: Not that many average users will notice, so long as nothing crashes or hangs. If the above statement reflects the POSIX attitude to operating system quality and reliability, then I understand, for the first time, how POSIX can contain so many mistakes, omissions and bad ideas usually terribly executed. Poul-Henning I take this as being one user's pragmatic opinion, not a statement of policy. Not that I would disagree with you if it were. POSIX is like the government in a democracy: necessary evil. Didier ___ 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's Leap Log
And at full CR/LF has been standard practice on mechanical printers (teleprinters) from the beginning, to give the carriage time to return to the left position. Otherwise, you can wind up with the first character of the new line being printed in the middle of the line, as it tried to print with the carriage in flight to the starting position. Lester B Veenstra MØYCM K1YCM les...@veenstras.com m0...@veenstras.com k1...@veenstras.com US Postal Address: PSC 45 Box 781 APO AE 09468 USA UK Postal Address: Dawn Cottage Norwood, Harrogate HG3 1SD, UK Telephones: Office: +44-(0)1423-846-385 Home: +44-(0)1943-880-963 Guam Cell: +1-671-788-5654 UK Cell: +44-(0)7716-298-224 US Cell: +1-240-425-7335 Jamaica: +1-876-352-7504 This e-mail and any documents attached hereto contain confidential or privileged information. The information is intended to be for use only by the individual or entity to whom they are addressed. If you are not the intended recipient or the person responsible for delivering the e-mail to the intended recipient, be aware that any disclosure, copying, distribution or use of the contents of this e-mail or any documents attached hereto is prohibited. -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Lux, James P Sent: Thursday, January 01, 2009 4:10 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Lady Heather's Leap Log On 12/31/08 6:06 PM, Steve Rooke sar10...@gmail.com wrote: 2009/1/1 Mark Sims hol...@hotmail.com: Note that there is an error in the first column heading in Lady Heather's Leap Log. It says UTC... should be GPS. The three line hour timestamp comment is correct (UTC). The distributed version of the program logged only time-of-week. I added the HH:MM:SS yesterday but messed up the column header (boy is Lady Heather gonna be mad when She finds out). The random spacing is due to Billy Gates Quality Control... he still can't figure out where to put CRs and LFs in an email... Well, POSIX decided on LF, Mac on CR and Billy Boy decided to hedge his bets with both LF and CR. It's little wonder I always get a lot of double spacing here then :-) Hardly microsoft's fault. Blame the teletype. Or perhaps DEC. RT-11 stored CR/LF in files, and CP/M adopted that convention, followed by DOS, etc. I imagine RT-11 did CR/LF because A) it allows use of unmodified KSR/ASR 33 TTYs without having to worry if the user has the autoLF option B) with ink on paper, the ability to do overprints (CR w/o LF) is actually useful. Them newfangled CRT based terminals can't do this (except for the Tek 401x series) Jim ___ 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] Leap quirks
My friend has a sealed GPS puck made by what looks like GreenLeaf (apparently an anonymous Chinese company). It totally locked up at leap time. It had to be power cycled to resume operations. Unknown as to what's inside the puck. Voltage in, RS-232 out. He is thinking that it is still a second off. _ Life on your PC is safer, easier, and more enjoyable with Windows Vista®. http://clk.atdmt.com/MRT/go/127032870/direct/01/ ___ 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's Leap Log
At 110 baud the ASR-33 needed a null charter or two as well or you would get the first two charters on top of each other. So it was CR,LF,Null,Null. Stanley http://www.pdp8.net/asr33/asr33.shtml From: Lester Veenstra m0...@veenstras.com To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Thursday, January 1, 2009 4:34:19 PM Subject: Re: [time-nuts] Lady Heather's Leap Log And at full CR/LF has been standard practice on mechanical printers (teleprinters) from the beginning, to give the carriage time to return to the left position. Otherwise, you can wind up with the first character of the new line being printed in the middle of the line, as it tried to print with the carriage in flight to the starting position. Lester B Veenstra MØYCM K1YCM les...@veenstras.com m0...@veenstras.com k1...@veenstras.com US Postal Address: PSC 45 Box 781 APO AE 09468 USA UK Postal Address: Dawn Cottage Norwood, Harrogate HG3 1SD, UK Telephones: Office: +44-(0)1423-846-385 Home: +44-(0)1943-880-963 Guam Cell: +1-671-788-5654 UK Cell: +44-(0)7716-298-224 US Cell: +1-240-425-7335 Jamaica: +1-876-352-7504 This e-mail and any documents attached hereto contain confidential or privileged information. The information is intended to be for use only by the individual or entity to whom they are addressed. If you are not the intended recipient or the person responsible for delivering the e-mail to the intended recipient, be aware that any disclosure, copying, distribution or use of the contents of this e-mail or any documents attached hereto is prohibited. -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Lux, James P Sent: Thursday, January 01, 2009 4:10 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Lady Heather's Leap Log On 12/31/08 6:06 PM, Steve Rooke sar10...@gmail.com wrote: 2009/1/1 Mark Sims hol...@hotmail.com: Note that there is an error in the first column heading in Lady Heather's Leap Log. It says UTC... should be GPS. The three line hour timestamp comment is correct (UTC). The distributed version of the program logged only time-of-week. I added the HH:MM:SS yesterday but messed up the column header (boy is Lady Heather gonna be mad when She finds out). The random spacing is due to Billy Gates Quality Control... he still can't figure out where to put CRs and LFs in an email... Well, POSIX decided on LF, Mac on CR and Billy Boy decided to hedge his bets with both LF and CR. It's little wonder I always get a lot of double spacing here then :-) Hardly microsoft's fault. Blame the teletype. Or perhaps DEC. RT-11 stored CR/LF in files, and CP/M adopted that convention, followed by DOS, etc. I imagine RT-11 did CR/LF because A) it allows use of unmodified KSR/ASR 33 TTYs without having to worry if the user has the autoLF option B) with ink on paper, the ability to do overprints (CR w/o LF) is actually useful. Them newfangled CRT based terminals can't do this (except for the Tek 401x series) Jim ___ 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] Colima GPSDO stopped working?
Perfect since I discovered it two months back, the online plot is no longer updated since this morning. http://resco.ucol.mx/Fury/gpsstat.htm Does anybody know what's happening? Thanks, Antonio I8IOV ___ 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] leapsecond on long-, medium- and shortwave
During the leap second, I recorded 6 parts of the radio spectrum, containing a few time and frequency stations, and a lot of AM broadcast stations. An analysis of these recordings is now here: http://wwwhome.cs.utwente.nl/~ptdeboer/ham/sdr/leapsecond-2008.html Out of 33 long- and mediumwave broadcasters that transmitted some sort of time signal (e.g., a few 1 kHz beeps near the top of the hour), only 17 got the leap second right. In fact, it turned out that several of the signals are not just off by the leapsecond, but by several seconds more. Also, many are off by a fraction of a second, presumably due to delays between the studio and the transmitter, e.g. via a satellite link. Regards, Pieter-Tjerk ___ 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] Another LPRO-101 Rb Osc question...
These pictures could suggest an idea: http://fotoalbum.alice.it/iovane/LPRO Antonio I8IOV ___ 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] Motorola M12+T - On board oscillator phase noise specand/or part number
Hi All, Has anyone been able to figure out the part number and/or measured the phase noise of the quartz oscillator on board the Motorola M12+T? This will be an interesting figure to see. Regards, Stephan. This is an ADEV+MDEV plot for the 100 Hz output of an M12+ in free-run mode (no gps lock). http://www.leapsecond.com/pages/m12-adev/m12-free.gif If you want more data let me know. /tvb ___ 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] Connector source for LPRO Rb oscillator...??
Winford Engineering seems to be the cheapest I've ever found: http://www.winfordeng.com/products/dsi.php this assumes that you have 10 (or more) conductor ribbon cable laying around -Eric On Wed, Dec 31, 2008 at 9:21 PM, Mark Sims hol...@hotmail.com wrote: Any standard 10 pin flat ribbon cable header will fit on the pins just fine. You can probably salvage one off an ancient PC motherboard serial port header to DB-9 type RS-232 connector cable. Or see Ebay item 350112294584. The same seller has shorter cables for less. Or search Ebay for 10 pin idc (without the quotes). _ It's the same Hotmail(R). If by same you mean up to 70% faster. http://windowslive.com/online/hotmail?ocid=TXT_TAGLM_WL_hotmail_acq_broad1_122008 ___ 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. -- --Eric _ Eric Garner ___ 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] Leap seconds and POSIX
2009/1/2 Joe Gwinn joegw...@comcast.net: Platforms vary because NTP is at the mercy of the kernel developers. From the standpoint of the average user, there is a transient error. Not that many average users will notice, so long as nothing crashes or hangs. In systems where the transient error and possibility of a crash or hang cannot be tolerated, one common dodge is to lie to NTP by configuring the GPS receiver and NTP timeserver to emit GPS System Time, and live with the fact that the local computer clocks are ~14+ seconds off of UTC. Purpose-built user displays are programmed to compute and use the correct time. Examples please. 73, Steve -- Steve Rooke - ZL3TUV G8KVD JAKDTTNW Omnium finis imminet ___ 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] Count up/down DAC circuit
Hi Steve, not sure if the LPF would help, some issues with analog sample and holds with long time-constants were recently discussed on this group. I am not a fan of these to implement a GPSDO loop. I guess it depends on your dac steps too. If you have a 16 bit dac over a 5V EFC, then you have +/-32K steps, or 32K seconds to adjust.That's a very slow slope. Also, take into consideration that the GPS and the OCXO will jump over the course of a typical day, and you need to track these jumps. Your tracking speed may not be fast enough here. Our best double-oven OCXO's still have ~+/-50 microvolt variations, and a typical single oven may have +/-15mV variations over a 24 hour period. If you don't have enough resolution, you will unnecessarily introduce quantization noise, and if you do you would be lagging behind these natural changes. What would probably work is if you over-sample the counter circuit to say 100x to 1000x (or in other words being able to take 100 to 1000 LSB steps per second). That may prove to work out ok, and give you enough DAC resolution and DAC speed. With an M12+ set to 100PPS you may just make this work well enough! My gut feeling is it won't work with 1PPS, but may work with 100PPS. And if your DAC LSB step is very small, say 5E-013, then your tracking noise would be quite small. Let's see, 100 steps per second, at 5E-13 per step would give you a tracking speed of 5E-011 per second. That's probably good enough. A typical crystal jump of ~1E-09 would thus take only 20 seconds to correct. Sounds reasonable to me. Note that this is a frequency locked loop rather than a phase locked loop. Let me know if you try it, and if you get it to work. bye, Said In a message dated 12/30/2008 20:32:50 Pacific Standard Time, sar10...@gmail.com writes: Hi Said, Yes, I could see that my idea would suffer from this hunting in the locked state problem an was wondering if this could be perhaps 'cured' with a simple low-pass filter stage between the count up/down DAC and the EFC, IE, the DAC would hunt up and down with a duty cycle equal to the difference between the two DAC levels filtered by the LPF, thereby giving a constant frequency. This, of course, would further exasperate any problems trying to lock a fast moving oxco or achieving lock in the first place. Some tuning of the LPF time constant would be required to stop ringing as the PLL moved into lock. Do you think that would work as it would probably be easier to implement than something to implement a dead-zone? As for achieving lock in the first place with this idea, I'm thinking now that it could take a very lon time for the DAC to count up/down with output from a phase detector at 1PPS. I was really only thinking about this whole idea as it seemed to be a natural to hold the EFC voltage during lack of PPS if the GPS goes down. Without the PPS, the phase detector will output no pulses so the DAC would remain frozen in it's last state. Implementing a GPSDO via a phase detector followed by a LPF would obviously be easier but in the absence of the PPS, I imagine that leakage in the circuit would make the EFC voltage drift. I guess I could buffer it with a source-follower or something like that, or perhaps some form of sample and hokld circuit. I was just bouncing around ideas as I know there are a lot of great brains on this list. 73, Steve 2008/12/31 saidj...@aol.com: Hi Steve, I played with such a circuit a long time ago. The slope is limited to the clocking of your circuit (one LSB digit per clock typ), which can present an issue if you cannot follow the OCXO's EFC changes fast enough. You could be chasing the OCXO voltage and this may lead to instability. Even if it is locked, the circuit will constantly be chasing the OCXO, unless you implement a dead-zone where the circuit stops counting up/down when you are close enough to your target frequency. This chasing may cause the frequency to modulate up and down, and could lead to large-scale oscillations. Tough to get this to work properly, but with circuitry to add a deadzone, and to dampen the lock, and maybe to introduce gain (jump more than one LSB when far off etc) it may work. Then again implementing a standard PI controller (in a micro etc), and calculating it's stability etc is much easier than getting this to work properly. bye, Said In a message dated 12/29/2008 21:30:54 Pacific Standard Time, sar10...@gmail.com writes: As part of the current idea I have with the hockey-pucks, I'm thinking about feeding the D1 and U1 phase difference pulses out of an MC4044 out to some circuit that could clock up and down an analog output which would ultimately go to the EFC of a ocxo, IE D1 pulses when the phase of one input signal is advanced and visa versa for the U1 pin. Anyone seen a circuit like that please? Thanks 73, Steve
Re: [time-nuts] Motorola M12+T - On board oscillator phase noise spec and/or part number
The crystal on my M12+T is marked top to bottom: 32.768 KDS0530 I would imagine it is a custom device from KDS http://www.kds.info/index_en.htm On Tue, 23 Dec 2008 11:06:30 +0200, Stephan Sandenbergh step...@rrsg.ee.uct.ac.za wrote: Hi All, Has anyone been able to figure out the part number and/or measured the phase noise of the quartz oscillator on board the Motorola M12+T? -- kc0ukk at msosborn dot 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.
