Re: [time-nuts] Divide by five
Poul-Henning, On 11/09/2014 09:44 PM, Poul-Henning Kamp wrote: In message CABbxVHtommjwSWq1i=oH-u1S=G6P=xu8e0yzekadg-vchgk...@mail.gmail.com , Chris Albertson writes: NTP does not pick the best clock. NTP finds the subset of clocks that track each other. NTP does indeed find the best clock from the subset of clocks which pass its sanity check, and then it uses only that one. There are several problems with that, and as we speak I'm developing a new algorithm which at least so far, gives much superior performance. You can read my musings about this here: http://phk.freebsd.dk/time/20141107.html My goal is to release the new NTP client before X-mas. Just as you point out, there is no easy way around the fact that delays may be asymmetric. When one analyzes the problem, the actual time-error and delays in both directions cannot be solved with the two measurements one do, three unknowns and two equations. The sum of the observations, forming the Round-Trip-Time, is however the only value we can trust, and worst case asymmetry will be that of the RTT, regardless of statistical distribution. Using RTT as a worst-case estimator is thus enough if you don't know better, and using RTT as a simple stability estimator isn't all that bad for a simple system. The NTP scatter-plot wedge is another way to present it, and finding the tip of that wedge is really about finding the min-value of delay in each direction prior to doing the two-way time-transfer equations. Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Divide by five
In message 546070b3.1010...@rubidium.dyndns.org, Magnus Danielson writes: The NTP scatter-plot wedge is another way to present it, and finding the tip of that wedge is really about finding the min-value of delay in each direction prior to doing the two-way time-transfer equations. The important part about the wedge diagram is that the wedge is not filled out. With a very large probability only one of the two packets is impacted by extra delays. The current NTP filter totally fails to exploit this fact and performs quite a bit worse because of it: A median filter is really not a suitable way to handle that situation. But steering back to the original topic again: You really should not look at NTP for clock-ensemble or clock-steering examples, the challenges NTP copes with, are nothing like the challenges you have with a bunch of local high-quality frequencies. There used to be an academic paper on timing.com's home-page about their clock-ensemble algorithm called something like Advances in Time-Scale Algorithms. It's not super detailed but it was certainly a much better place to start than NTP source or documentation -- 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] Things your mother (or FEI) didn't tell you about FE series oscillators
Hello time-nuts, I have spent a lot of time recently with Frequency Electronics, Inc. (FEI) oscillators including the FE-5680A, FE-5680B, FE-5650A, and FE405B and just wanted to pass on some of my findings. Not everything I am including here is new, but figured I would include the informattion for the sake of completeness. As already known, there are a bunch of different variations on some of the oscillators. Here is kind of a quick rundown: 1. The 'old' FE-5650A - This unit used a 50.255 MHz VCXO and placed the synthesizer outside the physics PLL. This unit could be programmed over a wide range of frequencies and is great if you need an oddball output. The digital board in the unit has the two small pushbutton switches and the nearby 5-pin connector for serial communications. 2. The 'new' FE-5650A - This unit has the same physical construction, but the circuit functionalyity is quite different. It uses a 60 MHz VCXO and the DDS is inside the physics control loop. The output is divided from the 60 MHz. Many of these units that came from the telecom industry have 15MHz output. Unit has serial communications on pins 8 9 of the DB-9 connector. 3. The 'old' FE-5680A - This unit has a different physical footprint than the 5650A, but virtually the same circuit. Again uses the 50.255 MHz VCXO and has the programmable synthesizer that can be tuned over a wide range. Circuit board has the same two push botton switches and 5-pin serial connector. Many of these units only have a 1pps output (they came off Motorola cell boards). 4. The 'new' FE-5680A - This was the popular, inexpensive unit that was available a year or two ago. Unit uses the newer 60 MHz VCXO architecture and has serial communications via pins 8 9 on the DB-9. 5. The FE-5680B - This appears to be a VERY close cousin to the new 5650A and 5680A. It is in the 5680 physical package, but has a compact DB-15 (think VGA) connector. Unit only needs single +15V supply. 6. The FE-405B - This is a crystal oscillator that is the same physical package as the 5650A. It has a 15 MHz output. The interface is the same as the FE-5650A (except no LOCK signal), including the capability to communicate over the serial interface to change its frequency. TUNING THE NEWER UNITS Now for the new information. Tuning the units with the 60 MHz VCXO has been published (see the FEI document that is archived in several places) and uses several commands to read and write a 32-bit command value. However, only the tuning sensitivity for the FE-5680A has only been published that I am aware of. FE-5680A - The tuning sensitivity of the FE-5680A is 6.8126x10E-13 for the LSB. The command value runs the full range from 00 00 00 00 to FF FF FF FF. The value is 2's complement with positive values driving the frequency higher and negative values lowering the frequency. Larger values may unlock the unit and the positive and negative values may be different (depends on how well the VCXO is centered). FE-5650A - The tuning sensitivity of the FE-5650A is 1.4900x10E-17 for the LSB. Sounds great, but wait, turns out it does not have any more resolution than the 5680A. It takes a 45,722 step of the command register to step the DDS. So, it retains the same 6.8126x10E-13 actual minimum step of the oscillator. Also, the minimum value of the control register is F0 00 00 01, maximum value is 0F FF FF FF. FE-5680B - The tuning sensitivity of the FE-5680B is 3.7248x10E-16 for the LSB. Same situation as the 5650A above, but the are 1829 counts per DDS step. Minimum value is F0 00 00 01, maximum value is 0F FF FF FF, same as the 5650A. FE-405B - The tuning sensitivity of the FE-405B is in the neighborhood of 1.143x10E-14. Minimum value is F7 33 33 34, and maximum value is 08 CC CC CC. FINDING THE RIGHT TUNING WORD So, if you know how far off frequency your oscillator is divide that by the LSB sensitivity, convert the number to HEX, and load it to the oscillator (with the right + or - sense). Enjoy! Skip Withrow ___ 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] future NTP programs...
- that there is (eventually) a Windows implementation. I'm writing the code to be as portable as I can make it, but I have neither Windows machines nor clue how to program for their kernel-time-api. - that it responds to ntpq -pn and ntpq -crv commands so that it can be easily remotely monitored. The jury is still out on the control protocol. To be honest I don't much like it from a security point of view, and the parameters of my clock control algorithm may not map well into its datafields. Time will show... Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 == Yes, I can appreciate the Windows problems. We have more than a thousand clients running the reference NTP as ported by Meinberg very happily, but if there were a better-performing implementation that would be nice to have. Personally, I feel that the ability to monitor the workings of an NTP implementation remotely is an important feature of the (present) software. I can run on one system a single monitoring program which then checks NTP running on Windows, Linux and FreeBSD systems using exactly the same over the wire ntpq commands. Perhaps you can return dummy values where your algorithm differs? The ability to know lock status, offset and jitter (ntpq -crv) is useful for longer term checking, and the * in ntpq -p helpful for a response to a quick-look is it working? interrogation. Cheers, David -- SatSignal Software - Quality software written to your requirements Web: http://www.satsignal.eu Email: david-tay...@blueyonder.co.uk ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] future NTP programs...
In message 43713AD334A7485B8B0CCED799C6C19A@Alta, David J Taylor writes: Personally, I feel that the ability to monitor the workings of an NTP implementation remotely is an important feature of the (present) software. So, this is one thing I really don't understand... You can monitor all your clients from your server if you want to, by looing at the timestamp the client sends you. I implemented this feature in NTPns over a decade ago (see below) Why on Earth would anybody prefer to monitor it on each client separately instead of getting one central unified view ? Yes, of course you should be able to tell if your timekeeping is good on the local machine, but I don't think the control-mode NTP packets is a good idea. Poul-Henning NTPns show ntpv4 0 partner IP number port leap v m s p P offset refid Max partners: 1 total ours others partners2458855 1603 partners good 1874843 1031 partners bad 584 12572 partners 1s323 5318 partners 1s470 10460 partners 100ms 367 37330 partners 10ms 521195326 partners 1ms 777608169 NTPns show ntpv4 0 partner bad IP number port leap v m s p P offset refid 0.0.38.89 123 no 3 3 0 0 0 -0.166501269 [] 0.0.62.87 123 no 3 3 0 0 0 -0.755177799 [] 0.0.10.55 123 no 1 3 0 0 0 -0.397674942 [] 0.0.240.197123 unk 4 3 0 6 -19-3308.8 [INIT] 0.0.227.61 123 no 4 3 0 0 0 -3.024952149 [] 0.0.125.188123 no 3 3 0 0 00.185896998 [] 0.0.145.174123 no 3 3 0 0 00.465722434 [] 0.0.196.133123 no 3 3 0 0 0 -0.180700990 [] 0.0.16.190 123 unk 3 3 0 10 -6 -0.520566284 [] 0.0.68.26 123 no 3 3 8 6 -180.345824138 [CHU_AUDIO#1] [...] IP numbers obfuscated to protect the incompetent... -- 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] future NTP programs...
From: Poul-Henning Kamp [] Personally, I feel that the ability to monitor the workings of an NTP implementation remotely is an important feature of the (present) software. So, this is one thing I really don't understand... You can monitor all your clients from your server if you want to, by looing at the timestamp the client sends you. I implemented this feature in NTPns over a decade ago (see below) Why on Earth would anybody prefer to monitor it on each client separately instead of getting one central unified view ? Yes, of course you should be able to tell if your timekeeping is good on the local machine, but I don't think the control-mode NTP packets is a good idea. Poul-Henning === Poul-Henning, But if I understand NTPns correctly (I didn't know about it, by the way), it does not address the task I have in mind. I don't want to monitor clients from my server. I don't want to monitor servers from my client. I want to be able to monitor a number of servers from a central monitoring point (which might not even be running NTP), and using ntpq with its different options is, for me, an ideal way to do that. I use Perl scripts to interpret the output and plot it with MRTG. What I'm doing at the moment happens to run on Windows, but as it's a combination of ntpq, Perl and MRTG is could be run almost anywhere Cheers, David -- SatSignal Software - Quality software written to your requirements Web: http://www.satsignal.eu Email: david-tay...@blueyonder.co.uk ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] future NTP programs...
In message 647BB61DCE1F4679A45CD5C1DB1FE963@Alta, David J Taylor writes: I want to be able to monitor a number of servers from a central monitoring point (which might not even be running NTP), and using ntpq with its different options is, for me, an ideal way to do that. First of all, I'm focusing on the client software right now. That said: It goes without saying that monitoring servers is a different ball-game than monitoring clients. And no, I still don't like the ntpq stuff, because it cannot express the kind of things you'll want to monitor on a server, if you are serious about running it: How many clients report us as their REFID (is there something horribly wrong in a firewall somewhere ?) How many satelites does my GPS see ? And so on... How I'll doing the monitoring once I get to the server software remains to be seen, but it is very likely to involve a CLI interface and possibly a shared memory state Pretty much like Varnish ... feel free to wonder why ? :-) -- 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] future NTP programs...
Poul-Henning Kamp writes: In message 0AA8645271A94DF3968C90FE6BF94276@Alta, David J Taylor writes: - that there is (eventually) a Windows implementation. I'm writing the code to be as portable as I can make it, but I have neither Windows machines nor clue how to program for their kernel-time-api. We should talk about it - there are some options and opportunities there. H ___ 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] Anybody have experience with TimeMachines TM1000AGPS Time Server
Rick, NMEA 0138 is a standard language. Yes it does output the signal strength and visible sats, although I don't remember which output sentences give that data. I haven't looked at the serial output, so I don't know which sentences are supported. Probably good to look at the documentation for the gps chip. Norm n3ykf On Mon, Nov 10, 2014 at 12:54 AM, Rick Thomas rbtho...@pobox.com wrote: Hi Lizeth, I’ve noticed that it’s very quick to come to a preliminary lock — though the lock is often exactly 1.000 sec off for 5-10 minutes. Eventually that fixes itself. Do you know if the NMEA output (once enabled, and once there is a listener to record it) would tell which satellites are visible and at what signal strength? Mine is also just for home use for the time being. I’m planning to get another one for use at the community radio station I volunteer at. They are cheap enough that, with a grant from e.g. the NSF, we could get a bunch of them and scatter them all over the Internet. With enough of them and some open software for monitoring, we could map one-way (as opposed to round-trip) times on various Internet routes — thus giving some hard data on route asymmetry. This might prove to be interesting or even useful in diagnosing problems. Just a thought… Rick On Nov 9, 2014, at 2:07 PM, Lizeth Norman normanliz...@gmail.com wrote: Reading the manual, (page 8) the device can be set up to output NMEA over the serial port. There are a few different pieces of code to display that data. Have had mine two weeks. It got gps lock before I could point the browser at it's ip. Just syncing a bunch of cameras as well being the house time standard. On Sun, Nov 9, 2014 at 4:49 PM, Rick Thomas rbtho...@pobox.com wrote: Right. I did the reset to factory defaults jumper thing and it came back to life. I’m using it now with the default setup. I got a reply from somebody named Doug at css-timemachines suggesting that I use a different browser (I had been using Safari on my desktop Mac) so I switched to Chrome (still on the Mac) and now it seems to be a bit more friendly. In particular, it reports: Signal Strength: Satellite 1: 32 dB, Satellite 2: 31 dB, Satellite 3: 30 dB Can anybody tell if that’s good or bad? I have the antenna taped up against a window with a good view of the sky to the North-East: not too many trees in the way of a clear view out over the ocean — but somewhat occluded to the North-West: a low tree-covered ridge up to about 15 degrees above the horizon — and the bulk of the house in the way to the South. Is there a better way? I’ll report here as I explore further over the next week. Rick On Nov 9, 2014, at 2:21 AM, David C. Partridge david.partri...@perdrix.co.uk wrote: If you’re referring to this: I think he’s referring to section 4.3 Resetting to Factory Defaults You also have to reboot after a PW change ... Regards, David Partridge ___ 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] Second Units? KS-24361
Hi Right now the box with the GPS in it seems to be much more useful than the one that does not have a GPS. If they all are the same price, just buy GPS units. You can always pull the GPS out. Putting it back in is much more problematic.That assumes you are using them each on their own, and not pairing them up. If you are using them in pairs (say to get 10 MHz without any mods) then one of each would be the way to go. Bob On Nov 10, 2014, at 1:41 AM, F. W. Bray fwb...@mminternet.com wrote: Sorry, I intended to say that this question concerns the KS-24361 units. Forgot to put that in the subject line! I have one complete setup on the way. Any thoughts as to whether it is better to get a second complete set or just go for the unit that has the GPS in it? This would be as a spare or possibly actual use. Thanks. Fred KE6CD ___ 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] Divide by five -Ensemble
Hi On Nov 10, 2014, at 1:59 AM, Poul-Henning Kamp p...@phk.freebsd.dk wrote: In message 4cdc0090-dd4b-4380-acc1-40a80d3bc...@n1k.org, Bob Camp writes: Hi Here’s what I’m saying: The NTP algorithm as it is written and as it is implemented results in an output clock that does *not* improve when a number of very good clocks are being used [...] The crucial word here is good clocks. A good clock in NTP is nearby and because it is nearby, the chances of several of them overlapping is usually not high enough for any clock combining to happen. Yes, in normal NTP land it’s not in any way worth worrying about. The NTP algorithms were built for 10-100msec packet delays, not low microsecond packet delays. NTP is designed to do something very different. Bob -- 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] Divide by five
On Nov 10, 2014, at 2:49 AM, Magnus Danielson mag...@rubidium.dyndns.org wrote: On 11/09/2014 07:11 PM, Bob Camp wrote: Hi On Nov 9, 2014, at 11:18 AM, Chris Albertson albertson.ch...@gmail.com wrote: On Sat, Nov 8, 2014 at 11:13 PM, Neil Schroeder gign...@gmail.com wrote: At one point I was considering phase locking all of them together - but again that seemed less than straightforward. You can do it PLL back to back, but is there a way to have a loop that contains multiple clocks? I would think the telephone game would apply. NTP does this but on a MUCH lower frequency and longer time scale. But I think NTP's general method could apply. NTP will accept any number of reference clocks. (Yes sone people run NTP using just one GPS receiver as a reference but best practice is to use five references.) NTP compares the set of ref. clocks with each other and first tries to find the subset of clocks that track each other, assuming the outliers are wrong. It continuously checks this and maintains a set of true tickers. From these it computes a consensus time using a weighted average of the true clocks. The weights are based on the jitter and other quality measuring statistics. Using this method reference clocks can be taken on and off line without need to re-start NTP. That may (or may not) give you the best ADEV on the output. My guess is that the filtering algorithm will need to be a bit more complex. NTP’s aim is mainly to throw out bad clocks and pick one as best. We would more likely want to combine the outputs and use all of the good clocks we have. The idea is to improve on the ADEV of the *best* source you have available. The aim is to remove false-tickers and then build the best ensemble of the remaining sources and weigh them according to stability. It seems this goal is not very well met in practice, but the theory foundation is pretty good. The intent of NTP is great. The implementation is targeted at the real NTP world. A set of good clocks that all are equally good simply is not what happens in the real NTP world. They don’t address it because it does not happen often enough to matter. Bob 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. ___ 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] Electrolytic Capacitor Question
I've taken a hybrid approach I'm using an in circuit ESR meter to determine whether cap needs to be replaced Tantalum capacitors usually fail because of running them too close or at rated voltage. HP unlike others in the industry did not tend to do this so I've had a low incidence of tantalum caps fail. Generally the only ones I would replace are ones called out in service notes or manual updates for uprating in value. As others have said electrolytics and tantalums look quite different on a network analyzer and HP frequently selected parts for their performance characteristics As to electrolytics the Panasonics are good but personally I've spent the extra money and used exact replacement Vishay Sprague electrolytics and Tantalums since they were the OEM for most of those parts when gear was built Sent from my iPhone On Nov 8, 2014, at 6:32 PM, Perry Sandeen via time-nuts time-nuts@febo.com wrote: List, OK everybody, let’s not get our pacemakers wound upG The problem. (Long Intro) I have about 15 pieces or so of older HP test equipment. 3586B, 5370B, 5335A to name a few. Because of their age of 20+ years a few have failed and need repair. I have decided to go on a wholesale electrolytic capacitor replacement on all of them. (Mouser will be able to declare an extra dividend) For all the *standard* types I’ve chosen mostly Panasonic 105C 10,000 hour caps. So far, so good. Now I come to the issue of the wet-slug tantalums that were used. At the time of manufacture, these were the best and most expensive low voltage electrolytics available. The question is: can one replace the tantalums with the high grade (105C) Panasonic or Nichicon capacitors with an equal or higher capacitance value? Even using the *tear drop* new replacements one is looking at very heavy $$$. Regards, Perrier ___ 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] 5 to 10 MHz Qrad Driven Mixer Doubler
A linear 5 to 10 MHz doubler that may be of interest is described in the March-April 2011 issue of QEX. I use it to double the output of an Vectron double oven 5 MHz standard to 10 MHz. Extensive design and performance data is provided for the basic breadboard, a PC version of the breadboard and a complete subsystem including an +13 dBm output line driver amplifier with a 50 OHM source impedance. I did not measure the phase noise or ADEY as my applications did not require such. For grins, the basic doubler can be implemented with a connectorized hanging bread board consisting of a double balanced mixer, a power splitter, and a 90 degrees phase shift network. Data on such an arrangement is in the article. The article may be found on the ARRL web site -73 john roos k6iql ___ 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] DIP Is Dead R.I.P
As long as the chip in question is still available in surface mount, one can use a SM to DIP adapter. I use these all the time to evaluate and prototype with SM chips. It would be expensive to rechip a whole unit, but onesies in case of a failure is OK. David On 11/9/14 10:36 PM, Bob Camp wrote: Hi There is one thing to consider: At the point that the monthly rent on the storage spaces equals Y — and — As you add more spares it goes to 2 x Y — and — There 12 months in a year — and — This *will* go on for years How much is a brand new bench full of gear? How much is a bench full of stuff you use on a regular basis? H…… Ok, here’s my numbers: Storage is $500 a month right now. It’s full. Probably 80% of what is over there has been there or someplace just like it for 10 years. ( = I’ve run that sort of bill for 10 years) Maybe 50% of what is over there, is 20 years. ( = I’ve run ~2/3 that bill for a lot longer) Ok, so let’s use 10 years for a start. That’s 6K a year times 10 years…. $60K …. Ok but that’s not all. I’ve moved the stuff twice on inter-state moves. I also *paid* for it with *cash* that I no longer have. That cash could have been earning interest for the last 10 or more years. The same cash in the bank applies to the rent money. Then there’s the time it will take to troubleshoot / cal / revitalize each of the gizmos. It does not just take parts. I think it’s over $100K and close to $200K without a lot of thought going into it. That’s a lot of test gear if you buy the cheap PC connected modern stuff. H ….. how may more spares? Ok, so how many KS-24361’s was that ??? Bob (anyone who relays *any* of those numbers to my wife will be shot …) On Nov 8, 2014, at 7:47 PM, Perry Sandeen via time-nuts time-nuts@febo.com wrote: List, Wrote: The days of DIP parts are drawing to a close. I was shocked, absolutely shocked, really, when I looked at the latest Mouser catalog about the lack of PDIP I.C.’s. That said, we are faced with a dilemma. In all my HP test equipment I probably have 500 or more PDip IC’s, so what to do to keep the equipment running properly? My first two thoughts are to re-cap all the power supplies and attempt to have greater cooling, especially in the notoriously hot 5370B units. For them I've given thought to using external switching regulator supplies or removing the heat sink and making it a separate module or external dropping resistors. Another choice maybe is to replace some of the original 74 series with LPS or similar later types to reduce internal instrument heat. It may be time to get a number of *running spares* from reputable Ebay sellers. Perhaps all of the above in different proportions. I have far, far too much money in HP test equipment just to sit and watch my units fail one by one. Regards, Perrier ___ 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] Anybody have experience with TimeMachines TM1000AGPS Time Server
The GPGSV is the sentence that reports satellites' SNR. See also: http://www.gpsinformation.org/dale/nmea.htm#GSV On Mon, Nov 10, 2014 at 10:59 AM, Lizeth Norman normanliz...@gmail.com wrote: Rick, NMEA 0138 is a standard language. Yes it does output the signal strength and visible sats, although I don't remember which output sentences give that data. I haven't looked at the serial output, so I don't know which sentences are supported. Probably good to look at the documentation for the gps chip. Norm n3ykf On Mon, Nov 10, 2014 at 12:54 AM, Rick Thomas rbtho...@pobox.com wrote: Hi Lizeth, I’ve noticed that it’s very quick to come to a preliminary lock — though the lock is often exactly 1.000 sec off for 5-10 minutes. Eventually that fixes itself. Do you know if the NMEA output (once enabled, and once there is a listener to record it) would tell which satellites are visible and at what signal strength? Mine is also just for home use for the time being. I’m planning to get another one for use at the community radio station I volunteer at. They are cheap enough that, with a grant from e.g. the NSF, we could get a bunch of them and scatter them all over the Internet. With enough of them and some open software for monitoring, we could map one-way (as opposed to round-trip) times on various Internet routes — thus giving some hard data on route asymmetry. This might prove to be interesting or even useful in diagnosing problems. Just a thought… Rick On Nov 9, 2014, at 2:07 PM, Lizeth Norman normanliz...@gmail.com wrote: Reading the manual, (page 8) the device can be set up to output NMEA over the serial port. There are a few different pieces of code to display that data. Have had mine two weeks. It got gps lock before I could point the browser at it's ip. Just syncing a bunch of cameras as well being the house time standard. On Sun, Nov 9, 2014 at 4:49 PM, Rick Thomas rbtho...@pobox.com wrote: Right. I did the reset to factory defaults jumper thing and it came back to life. I’m using it now with the default setup. I got a reply from somebody named Doug at css-timemachines suggesting that I use a different browser (I had been using Safari on my desktop Mac) so I switched to Chrome (still on the Mac) and now it seems to be a bit more friendly. In particular, it reports: Signal Strength: Satellite 1: 32 dB, Satellite 2: 31 dB, Satellite 3: 30 dB Can anybody tell if that’s good or bad? I have the antenna taped up against a window with a good view of the sky to the North-East: not too many trees in the way of a clear view out over the ocean — but somewhat occluded to the North-West: a low tree-covered ridge up to about 15 degrees above the horizon — and the bulk of the house in the way to the South. Is there a better way? I’ll report here as I explore further over the next week. Rick On Nov 9, 2014, at 2:21 AM, David C. Partridge david.partri...@perdrix.co.uk wrote: If you’re referring to this: I think he’s referring to section 4.3 Resetting to Factory Defaults You also have to reboot after a PW change ... Regards, David Partridge ___ 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. ___ 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] 2.5V reference IC in HP E1938 oscillator.
Dear Rick, When asking questions such as this, it is helpful to know why you need to know the part number. Basically to complete my documentation, but there is more to it... Please let me start with a nut shell introduction. I'm going to build a GPSDO and will use the following key building blocks:GPS receiver (Oncore UT+) with an outdoor antenna for a precise 1PPS.HQ 10MHz oscillator with EFC (initially the 10811, later switched to the E1938).Dividers (HC390) to come to 1Hz.PLL (HC7046) to compare 1PPS 1Hz and tune the oscillator.Power supply, to feed the animals. Nothing exiting so far. To check on the outside if the instrument is working properly, I want to have some checks:Oven error LED, is the oven on temperature (not too cold, not too hot). LED on = error.1PPS from GPS LED, only flashing when at least five satellites are contributing.PLL Lock LED, on when 1PPS 1Hz are in sync.EFC voltage readout (3½ digit), to monitor excessive drift. Now about the oven warning LED. The idea is to use the Thermistor Bridge out pin (8) on the 15P 'Puck' D-sub and the Them. Bridge Reference (pin 15) for this.So, I connected with two wires (40mm/1.6 length) both above mentioned pins with the not used pins 19 20 in the special D-sub. Now I can connect the oscillator board with one cable (20cm/8) to my own PCB and use two comparators to make a small window for an alarm. The reference I only will use to determine the 'on temperature voltage'.However, when reading your article A LOW-PROFILE HIGH-PERFORMANCE CRYSTAL OSCILLATOR FOR TIMEKEEPING APPLICATIONS I noticed that you talk about 'picking up noise due to a long path from reference to the controller board'. That brought me to the schematics of the reference voltage and the IC. My doubt now is that my leads will increase the chance on errors in the delicate control system.Can you please elaborate on that, is there indeed a risk? I do remember that I originally used some convenient reference which seemed OK from the data sheet, but turned out to be too noisy. I changed it to a different one. That emphasises my earlier mentioned feeling, but also brings me to a next questions:I have two different versions of the E1938. One contains two DAC IC's, the other only one DAC.What is the reason for changing this?Was the noisy reference IC ever used in production (so, might it be present in the two DAC version)?Is it possible to publish an older revision of the schematics that reflects the two DAC version that was produced (and if applicable the oscillator unit)? Best regards, Rob. ___ 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] Anybody have experience with TimeMachines TM1000AGPS Time Server
Thanks! Getting hooked up to the serial output will be my next step. Rick On Nov 10, 2014, at 6:20 AM, Azelio Boriani azelio.bori...@gmail.com wrote: The GPGSV is the sentence that reports satellites' SNR. See also: http://www.gpsinformation.org/dale/nmea.htm#GSV On Mon, Nov 10, 2014 at 10:59 AM, Lizeth Norman normanliz...@gmail.com wrote: Rick, NMEA 0138 is a standard language. Yes it does output the signal strength and visible sats, although I don't remember which output sentences give that data. I haven't looked at the serial output, so I don't know which sentences are supported. Probably good to look at the documentation for the gps chip. Norm n3ykf On Mon, Nov 10, 2014 at 12:54 AM, Rick Thomas rbtho...@pobox.com wrote: Hi Lizeth, I’ve noticed that it’s very quick to come to a preliminary lock — though the lock is often exactly 1.000 sec off for 5-10 minutes. Eventually that fixes itself. Do you know if the NMEA output (once enabled, and once there is a listener to record it) would tell which satellites are visible and at what signal strength? Mine is also just for home use for the time being. I’m planning to get another one for use at the community radio station I volunteer at. They are cheap enough that, with a grant from e.g. the NSF, we could get a bunch of them and scatter them all over the Internet. With enough of them and some open software for monitoring, we could map one-way (as opposed to round-trip) times on various Internet routes — thus giving some hard data on route asymmetry. This might prove to be interesting or even useful in diagnosing problems. Just a thought… Rick On Nov 9, 2014, at 2:07 PM, Lizeth Norman normanliz...@gmail.com wrote: Reading the manual, (page 8) the device can be set up to output NMEA over the serial port. There are a few different pieces of code to display that data. Have had mine two weeks. It got gps lock before I could point the browser at it's ip. Just syncing a bunch of cameras as well being the house time standard. On Sun, Nov 9, 2014 at 4:49 PM, Rick Thomas rbtho...@pobox.com wrote: Right. I did the reset to factory defaults jumper thing and it came back to life. I’m using it now with the default setup. I got a reply from somebody named Doug at css-timemachines suggesting that I use a different browser (I had been using Safari on my desktop Mac) so I switched to Chrome (still on the Mac) and now it seems to be a bit more friendly. In particular, it reports: Signal Strength: Satellite 1: 32 dB, Satellite 2: 31 dB, Satellite 3: 30 dB Can anybody tell if that’s good or bad? I have the antenna taped up against a window with a good view of the sky to the North-East: not too many trees in the way of a clear view out over the ocean — but somewhat occluded to the North-West: a low tree-covered ridge up to about 15 degrees above the horizon — and the bulk of the house in the way to the South. Is there a better way? I’ll report here as I explore further over the next week. Rick On Nov 9, 2014, at 2:21 AM, David C. Partridge david.partri...@perdrix.co.uk wrote: If you’re referring to this: I think he’s referring to section 4.3 Resetting to Factory Defaults You also have to reboot after a PW change ... Regards, David Partridge ___ 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. ___ 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] Communicating with the Lucent KS-24361
I had been unsuccessful communicating with these units using the RS232 to RS422 cable hack that Stewart Cobb described in his original post (https://www.febo.com/pipermail/time-nuts/2014-October/087274.html). I was able to see, via a scope, the data coming out of the REF 1 unit, but it was never picked up on the PC. I finally bought a USB to RS422/RS485 cable. That didn't work out of the box - I needed to use the supplied breakout board to remap the pins to a DB9-M connector as follows (Tx- to pin 8, Tx+ to pin 4, Rx- to pin 9, Rx+ to pin 5, Gnd to pin 7). All 4 wires were needed for this to work. Thanks to Bob Camp and Tom Van Baak for their help on this Anthony ___ 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] Communicating with the Lucent KS-24361
Yes indeed for a real RS232 to RS 422 all 4 wires are required. Its a balanced communications protocol. The RS232 trick has been around many years. It ha sa low noise margin and does work with most modern RS232 3.3-5V type adapters. Its simple and generally works as it did for me. Regards Paul WB8TSL On Mon, Nov 10, 2014 at 12:15 PM, Anthony Roby ar...@antamy.com wrote: I had been unsuccessful communicating with these units using the RS232 to RS422 cable hack that Stewart Cobb described in his original post ( https://www.febo.com/pipermail/time-nuts/2014-October/087274.html). I was able to see, via a scope, the data coming out of the REF 1 unit, but it was never picked up on the PC. I finally bought a USB to RS422/RS485 cable. That didn't work out of the box - I needed to use the supplied breakout board to remap the pins to a DB9-M connector as follows (Tx- to pin 8, Tx+ to pin 4, Rx- to pin 9, Rx+ to pin 5, Gnd to pin 7). All 4 wires were needed for this to work. Thanks to Bob Camp and Tom Van Baak for their help on this Anthony ___ 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] Divide by five
Poul-Henning, On 11/10/2014 09:16 AM, Poul-Henning Kamp wrote: In message 546070b3.1010...@rubidium.dyndns.org, Magnus Danielson writes: The NTP scatter-plot wedge is another way to present it, and finding the tip of that wedge is really about finding the min-value of delay in each direction prior to doing the two-way time-transfer equations. The important part about the wedge diagram is that the wedge is not filled out. With a very large probability only one of the two packets is impacted by extra delays. The current NTP filter totally fails to exploit this fact and performs quite a bit worse because of it: A median filter is really not a suitable way to handle that situation. Completely agree. Also, NTP uses far too few packets to get any meaningful statistics on the edges of the wedge, which is to say the minimum value in either direction. Also, long-term averaging makes the TE part draw towards zero, so if there is a sufficiently long run with high asymmetric delay, the node tracks in the precieved offset error and thus asymmetric delay will affect the time of the node. But steering back to the original topic again: You really should not look at NTP for clock-ensemble or clock-steering examples, the challenges NTP copes with, are nothing like the challenges you have with a bunch of local high-quality frequencies. Fully agree. In fact, missing this point is part of the problem that NTP has. There used to be an academic paper on timing.com's home-page about their clock-ensemble algorithm called something like Advances in Time-Scale Algorithms. PTTI 24, Sam Steins work: http://tycho.usno.navy.mil/ptti/1992papers/Vol%2024_28.pdf It's not super detailed but it was certainly a much better place to start than NTP source or documentation I think the simplest case is that of Dave Allan and friends put down in the NBS Monograph 140, chapter 9: http://tf.boulder.nist.gov/general/pdf/194.pdf They have even thrown in the Fortran code that they used. I think it originally ran on a PDP-7 or something. You do want to read the 9.3 part, as it is the runner-up to the 9.4 part which gets dirty into how to do it. I think that will give a first concrete starting-point, and there is more development in both NBS/NIST, USNO etc. (see NIST and USNO PTTI archives). I've long toyed with the idea of building ensemble clock, but never got around to it. 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.
[time-nuts] 5 to 10 MHz Qrad Driven Mixer Doubler
John, thank you for your post on the time-nuts list. Unfortunately, I couldn't locate the article you are refering to. All I could find are just two associated files, a BOM and an Excel sheet. Could you please send me a link or a copy of the article? Thanks, Adrian ___ 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] Divide by five -Ensemble
On 11/09/2014 10:54 PM, Chris Albertson wrote: On Sun, Nov 9, 2014 at 12:45 PM, Bob Camp kb...@n1k.org wrote: Hi The main point is that NTP picks *one* source from among it’s batch of inputs and uses that. The ADEV of the output can be no better than the ADEV of the output. The statement above is not correct. NTP does not select just one clock. The statement below is correct and is what NTP actually does. If you look at the output from ntpstat you might think NTP selects one clock but internally it's not going that. The display is misleading. In the case of an ensemble of clocks combined with a better approach the ADEV of the output can be better than the ADEV of the best clock in the group. It's best to read this http://www.eecis.udel.edu/~mills/ntp/html/warp.html In simple terms it searches for consensus range of time where all the error bars of the various clock overlap and then eliminate clocks who d't agree with the consensus. Of those still in it figures out and kind of weighted average. I think you could do the same thing. First find the set of 10MHz oscillators who are in phase with each other to within some statistical limit and then you compute the weighted average phase Maybe start with Clock Select Algorithm. Free-running oscillators won't be agreeing on phase. As they have different independent frequency that we observe without steering, they won't agree on phase. NTP on the other hand assumes that the sources is sources of UTC, and thus have one way or another been coordinated with that unifying phase, then and only then it makes sense to compare the phase of the individual sources, but it's not really independent clocks. What you can do is to have a set of free-running oscillators, use them to build a ensemble paper-clock average, which when weighing them against the stability of the ensemble clock the individual stability will expose itself, and that ensemble clock will have some weighted frequency, and the individual clocks offset from that average frequency would be known, and momentary phases and prediction of those phases into the future can be done, and well deviations from that gives new info. However, the average frequency won't be a true frequency, and if the clocks is way to similar, there will be considerable common mode effect from the environment, but it will be some improved stability in there. If you compare it to some outside clock, long-term frequency and phase adjustments can be done to align it up to some time-scale, and that source would also give a measure of the ensemble stability and precision. This is similar to how EAL is a ensemble-clock out of about 450 atomic clocks, and that a few of them is considered phase-accurate is used to correct into the TAI clock. Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Divide by five
Hi On Nov 10, 2014, at 6:33 PM, Magnus Danielson mag...@rubidium.se wrote: Bob, On 11/10/2014 01:17 PM, Bob Camp wrote: On Nov 10, 2014, at 2:49 AM, Magnus Danielson mag...@rubidium.dyndns.org wrote: On 11/09/2014 07:11 PM, Bob Camp wrote: Hi That may (or may not) give you the best ADEV on the output. My guess is that the filtering algorithm will need to be a bit more complex. NTP’s aim is mainly to throw out bad clocks and pick one as best. We would more likely want to combine the outputs and use all of the good clocks we have. The idea is to improve on the ADEV of the *best* source you have available. The aim is to remove false-tickers and then build the best ensemble of the remaining sources and weigh them according to stability. It seems this goal is not very well met in practice, but the theory foundation is pretty good. The intent of NTP is great. The implementation is targeted at the real NTP world. A set of good clocks that all are equally good simply is not what happens in the real NTP world. They don’t address it because it does not happen often enough to matter. Who said equally good? Rather, they are sufficiently near each other so that some weighted average can be formed. My original example that started this whole sub sub thread … I was trying very hard to keep things simple. Bob However, some of the issues is in getting close enough. Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] future NTP programs...
David and Poul-Henning, On 11/10/2014 10:34 AM, Poul-Henning Kamp wrote: In message 647BB61DCE1F4679A45CD5C1DB1FE963@Alta, David J Taylor writes: I want to be able to monitor a number of servers from a central monitoring point (which might not even be running NTP), and using ntpq with its different options is, for me, an ideal way to do that. First of all, I'm focusing on the client software right now. That said: It goes without saying that monitoring servers is a different ball-game than monitoring clients. And no, I still don't like the ntpq stuff, because it cannot express the kind of things you'll want to monitor on a server, if you are serious about running it: How many clients report us as their REFID (is there something horribly wrong in a firewall somewhere ?) How many satelites does my GPS see ? And so on... How I'll doing the monitoring once I get to the server software remains to be seen, but it is very likely to involve a CLI interface and possibly a shared memory state Pretty much like Varnish ... feel free to wonder why ? :-) I think it is fair to consider that over time, we need to revisit how things was designed and make changes. It might be better to run a separate daemon for the monitoring protocol, and it could be providing the traditional monitoring protocol or something new, or both. Monitoring as such is an important task, and some of the NTP clients might be servers in other contexts, and then it makes sense to monitor that they got their NTP time into shape. There is however many ways to slice that fish. Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] future NTP programs...
In message 546152ac.8090...@rubidium.dyndns.org, Magnus Danielson writes:
Monitoring as such is an important task, and some of the NTP clients
might be servers in other contexts, and then it makes sense to monitor
that they got their NTP time into shape.
For which there has existed a system call for 20 years now:
ntp_gettime() has as argument a struct ntptimeval * with the following
members:
struct ntptimeval {
struct timeval time;/* current time (ro) */
long maxerror; /* maximum error (us) (ro) */
long esterror; /* estimated error (us) (ro) */
};
These have the following meaning:
time Current time (read-only).
maxerror Maximum error in microseconds (read-only).
esterror Estimated error in microseconds (read-only).
--
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.
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Re: [time-nuts] future NTP programs...
Poul-Henning,
On 11/11/2014 01:15 AM, Poul-Henning Kamp wrote:
In message 546152ac.8090...@rubidium.dyndns.org, Magnus Danielson writes:
Monitoring as such is an important task, and some of the NTP clients
might be servers in other contexts, and then it makes sense to monitor
that they got their NTP time into shape.
For which there has existed a system call for 20 years now:
ntp_gettime() has as argument a struct ntptimeval * with the following
members:
struct ntptimeval {
struct timeval time;/* current time (ro) */
long maxerror; /* maximum error (us) (ro) */
long esterror; /* estimated error (us) (ro) */
};
These have the following meaning:
time Current time (read-only).
maxerror Maximum error in microseconds (read-only).
esterror Estimated error in microseconds (read-only).
Sure. So that's what another daemon could be pulling out.
I'm just saying that the NTP processing and the NTP monitoring may not
need to run by the same daemon necessarily, just because we did that in
the past. Pulling things from the kernel provide more isolation, and the
monitor daemon can have special code to handle security issues of
monitoring, without making the processing dito suffer from it, beyond
making sure the data is available somewhere.
Cheers,
Magnus
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Re: [time-nuts] Electrolytic Capacitor Question
Hi Perry: (shameless plug) Have you measured the tantalum caps? I sell a combined ESR Capacity meter that does in circuit tests on powered down circuits. http://www.prc68.com/P/Prod.html#ESR For an example of it's use on a Heathkit GC-1000 WWV clock see: http://www.prc68.com/I/HeathkitGC1000.shtml#Rx and scroll down for more boards. Notice that sometimes the ESR is high and other times the capacitance is low for the bad caps. The tantalum caps were OK, but almost all the electrolytic caps were bad. Mail_Attachment -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html http://www.prc68.com/I/DietNutrition.html Perry Sandeen via time-nuts wrote: List, OK everybody, let’s not get our pacemakers wound upG The problem. (Long Intro) I have about 15 pieces or so of older HP test equipment. 3586B, 5370B, 5335A to name a few. Because of their age of 20+ years a few have failed and need repair. I have decided to go on a wholesale electrolytic capacitor replacement on all of them. (Mouser will be able to declare an extra dividend) For all the *standard* types I’ve chosen mostly Panasonic 105C 10,000 hour caps. So far, so good. Now I come to the issue of the wet-slug tantalums that were used. At the time of manufacture, these were the best and most expensive low voltage electrolytics available. The question is: can one replace the tantalums with the high grade (105C) Panasonic or Nichicon capacitors with an equal or higher capacitance value? Even using the *tear drop* new replacements one is looking at very heavy $$$. Regards, Perrier ___ 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] future NTP programs...
I don't think ntp requires nor should have anything like a dedicated multi
system monitoring platform of its own.
The fact is that today's modern data collection methods are more than
adequate - ntpd need only store its values in an accessible place and
a graphite agent or ajna or your choice of robust system data mining tools
can scrape them regularly and store them for posterity.
A server-local cli infrastructure is clearly invaluable to the
troubleshooting process. But overall health monitoring is a wheel not in
need of an overhaul
On Monday, November 10, 2014, Magnus Danielson mag...@rubidium.dyndns.org
wrote:
Poul-Henning,
On 11/11/2014 01:15 AM, Poul-Henning Kamp wrote:
In message 546152ac.8090...@rubidium.dyndns.org, Magnus Danielson
writes:
Monitoring as such is an important task, and some of the NTP clients
might be servers in other contexts, and then it makes sense to monitor
that they got their NTP time into shape.
For which there has existed a system call for 20 years now:
ntp_gettime() has as argument a struct ntptimeval * with the
following
members:
struct ntptimeval {
struct timeval time;/* current time (ro) */
long maxerror; /* maximum error (us) (ro) */
long esterror; /* estimated error (us) (ro) */
};
These have the following meaning:
time Current time (read-only).
maxerror Maximum error in microseconds (read-only).
esterror Estimated error in microseconds (read-only).
Sure. So that's what another daemon could be pulling out.
I'm just saying that the NTP processing and the NTP monitoring may not
need to run by the same daemon necessarily, just because we did that in the
past. Pulling things from the kernel provide more isolation, and the
monitor daemon can have special code to handle security issues of
monitoring, without making the processing dito suffer from it, beyond
making sure the data is available somewhere.
Cheers,
Magnus
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Re: [time-nuts] Electrolytic Capacitor Question
I bought one of those ESR testers some time ago. It works very well. It is from Russia, but ordering from Brooke is much easier :-) Joe Gray W5JG On Mon, Nov 10, 2014 at 6:51 PM, Brooke Clarke bro...@pacific.net wrote: Hi Perry: (shameless plug) Have you measured the tantalum caps? I sell a combined ESR Capacity meter that does in circuit tests on powered down circuits. http://www.prc68.com/P/Prod.html#ESR For an example of it's use on a Heathkit GC-1000 WWV clock see: http://www.prc68.com/I/HeathkitGC1000.shtml#Rx and scroll down for more boards. Notice that sometimes the ESR is high and other times the capacitance is low for the bad caps. The tantalum caps were OK, but almost all the electrolytic caps were bad. Mail_Attachment -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html http://www.prc68.com/I/DietNutrition.html Perry Sandeen via time-nuts wrote: List, OK everybody, let's not get our pacemakers wound upG The problem. (Long Intro) I have about 15 pieces or so of older HP test equipment. 3586B, 5370B, 5335A to name a few. Because of their age of 20+ years a few have failed and need repair. I have decided to go on a wholesale electrolytic capacitor replacement on all of them. (Mouser will be able to declare an extra dividend) For all the *standard* types I've chosen mostly Panasonic 105C 10,000 hour caps. So far, so good. Now I come to the issue of the wet-slug tantalums that were used. At the time of manufacture, these were the best and most expensive low voltage electrolytics available. The question is: can one replace the tantalums with the high grade (105C) Panasonic or Nichicon capacitors with an equal or higher capacitance value? Even using the *tear drop* new replacements one is looking at very heavy $$$. Regards, Perrier ___ 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] future NTP programs...
I'm just saying that the NTP processing and the NTP monitoring may not need to run by the same daemon necessarily, just because we did that in the past. Pulling things from the kernel provide more isolation, and the monitor daemon can have special code to handle security issues of monitoring, without making the processing dito suffer from it, beyond making sure the data is available somewhere. Because once you get past the simplest item you can monitor, the time NTP thinks it is. Then the only process that would have the informations ntpd. For example if you want to know the round rip ping time from some peer to your server then what can you do but ask the server? Mostly the thinks you monitor are NTP internal states and statistics. -- 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] Divide by five -Ensemble
What you can do is to have a set of free-running oscillators, use them to build a ensemble paper-clock average, which when weighing them against the stability of the ensemble clock the individual stability will expose itself, and that ensemble clock will have some weighted frequency, and the individual clocks offset from that average frequency would be known, and momentary phases and prediction of those phases into the future can be done, and well deviations from that gives new info. I like the term paper clock. I assume it means an oscillator that does not physically exist but if it did would have the minimum weighted difference relative to the set of physical clocks when measured over some time span. Your final ensemble time then would be the output of any oscillator plus a data stream that gives difference between it and the paper clock. Of course the controller would select a good oscillator and try and discipline it well but there will still be an error. This is like what a GPS does when it outputs a sawtooth function. The GPS does it's best to put the PPS at theocracy time. It can't get it perfect but it can determine the error -- 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] future NTP programs...
Poul-Henning Kamp writes:
In message 546152ac.8090...@rubidium.dyndns.org, Magnus Danielson writes:
Monitoring as such is an important task, and some of the NTP clients
might be servers in other contexts, and then it makes sense to monitor
that they got their NTP time into shape.
For which there has existed a system call for 20 years now:
ntp_gettime() has as argument a struct ntptimeval * with the following
members:
struct ntptimeval {
struct timeval time;/* current time (ro) */
long maxerror; /* maximum error (us) (ro) */
long esterror; /* estimated error (us) (ro) */
};
These have the following meaning:
time Current time (read-only).
maxerror Maximum error in microseconds (read-only).
esterror Estimated error in microseconds (read-only).
And those fields have value, and they are not enough. The aim of
NTF's General Timestamp API is to have a timestamp with enough values
in it.
--
Harlan Stenn st...@ntp.org
http://networktimefoundation.org - be a member!
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[time-nuts] 10 MHz OCXO recommendations
From the current crop of ebay OCXO's available, what have you actually used that you would recommend for the following? Sine output, either 5V or 12V, better than 0.2ppm stability after warmup. I plan on putting things in a sealed box, so there shouldn't be too wide a temperature fluctuation. Everything will be located indoors. I want to use it as a standalone reference to PLL a 14.4 MHz VCXO. With the right divisors, I can get both the 10 MHz (/10/10) and the 14.4 MHz (/16/9) down to 100 KHz. I could use a GPSDO, but that means needing a GPS antenna, plus costing a lot more. Joe Gray W5JG ___ 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] 10 MHz OCXO recommendations
jg...@zianet.com said: I want to use it as a standalone reference to PLL a 14.4 MHz VCXO. With the right divisors, I can get both the 10 MHz (/10/10) and the 14.4 MHz (/16/9) down to 100 KHz. You can run at 400 KHz by dividing by 5/5 and 4/9. I could use a GPSDO, but that means needing a GPS antenna, plus costing a lot more. You said 0.2ppm stability. What do you need for accuracy and/or how are you going to calibrate your setup? -- 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.
Re: [time-nuts] 10 MHz OCXO recommendations
You can run at 400 KHz by dividing by 5/5 and 4/9. True. Either will work. You said 0.2ppm stability. What do you need for accuracy and/or how are you going to calibrate your setup? I will initially calibrate the OXCO against my HP GPSDO. Idealy, it will only need checking against the GPSDO once a year. Is that asking too much for it to be stable over that length of time? I could simply look up the specs for the various models that I find on ebay. However, I know that a lot of the stuff that is sold has been through the mill and may not meet spec any more. Thus my request for recommendations for models that someone here has actually purchased and tested. Joe Gray W5JG ___ 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.
