Re: [time-nuts] Another Arduino GPSDO
No bootloader, I'm using an AVR ISP mkII to load the avr-gcc code. On Sat, Mar 29, 2014 at 5:43 AM, Lars Walenius lars.walen...@hotmail.comwrote: Do you use the Arduino bootloader and environment (code)? ___ 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] Another Arduino GPSDO
I just saw Lars' postings on his design and thought I'd throw mine in since I've been working on a similar low-end goal but doing it a different way. Not really an Arduino, either, but it's based on an AVR processor and should be portable to an Arduino. Right now it's still on a solderless breadboard but it seems to be working. I have a 5MHz OCXO feeding counter/timer 1 on a ATmega644, the 16-bit counter is set to count modulo 5000 and the 1PPS from the GPS (uBlox NEO 6M) triggers a capture of the counter, and also a capture interrupt. If the OCXO is exactly right you should get the same capture value every second. If the value changes, the frequency is off. Obviously this only tells you if the OCXO drifts off from the 1PPS by one cycle or more, so that's only 200ns resolution. To get below that I count the number of 1PPS ticks before a second cycle is dropped, then use the inverse of the time interval to correct the DAC on the OCXO. (The shorter the period, the larger the correction.) I was lucky enough to snag a Symetricom OCXO with a built-in DAC, so that's a simple matter of clocking a 16-bit value into it. Typically the thing runs at an interval of 2000 seconds or so between corrections, so that's about 1 part in 10^10. The code is pretty ad-hoc, but once it thinks it has the frequency pretty close it starts nudging the phase in a direction to where the capture count converges on zero. The object of the thing is to make a ridiculously accurate table clock, and the clock code is driven by the 1ms counter overflow interrupt, so this make the interrupt line up with the 1PPS from the GPS. I'm sure the short-term stability isn't as good as a PLL, but averaging the errors over such a long period does have the advantage of making the sawtooth error pretty much irrelevant. I also have a 1-Wire thermometer stuck to the OCXO case and record the DAC values by temperature in the AVR's EEPROM, they can be retrieved for use in holdover conditions. The DAC values that produce longer transition periods take precedence over those with shorter ones for the same temperature. -- Eric Williams WD6CMU ___ 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 Arduino GPSDO
I'm sorry, I don't recognize the reference to hanging bridges. I don't consider it a PLL because I have no way to measure phase differences within a cycle. I have some serial debugging output to see what the code's doing, but I'll have to think about how to organize it into graphs that would be meaningful. -- eric On Fri, Mar 28, 2014 at 3:43 PM, Hal Murray hmur...@megapathdsl.net wrote: [Nice description. Thanks.] wd6...@gmail.com said: I'm sure the short-term stability isn't as good as a PLL, but averaging the errors over such a long period does have the advantage of making the sawtooth error pretty much irrelevant. You don't believe in hanging bridges? What do you mean by PLL and/or why isn't what you described a PLL? Are you logging any data? It would be neat to see some graphs. -- These are my opinions. I hate spam. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Another Arduino GPSDO
OK, now I understand the reference, but not the significance in this context. The sawtooth error is below the resolution of the counter here. It does produce noise on the transition between capture counts that I am filtering out, but it should average out over the long-term integration that I'm using, right? -- eric On Fri, Mar 28, 2014 at 4:41 PM, Hal Murray hmur...@megapathdsl.net wrote: wd6...@gmail.com said: I'm sorry, I don't recognize the reference to hanging bridges. I guess it was a good thing I mentioned it. Sometimes I feel like a broken record. It gets discussed here occasionally. There will be lots of comments in the archives. Starter version: tvb: Motorola GPS M12+ Sawtooth http://www.leapsecond.com/pages/m12/sawtooth.htm Long version, very good: Tom Clark and Rick Hambly: Timing for VLBI http://gpstime.com/files/tow-time2009.pdf -- These are my opinions. I hate spam. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Another Arduino GPSDO
Right, I should be able to get that from the TIM-TP message, but then what do I do with it? Not sure how I can apply a picosecond correction in this configuration short of adding a programmable delay line chip that would cost more than the GPS receiver did. -- eric On Fri, Mar 28, 2014 at 6:40 PM, Chris Albertson albertson.ch...@gmail.comwrote: On Fri, Mar 28, 2014 at 5:15 PM, Eric Williams wd6...@gmail.com wrote: OK, now I understand the reference, but not the significance in this context. The sawtooth error is below the resolution of the counter here. I think you are right. It hardly matters for your application. I think you said this was going to drive a wall clock? But on the other hand using sawtooth is free and does not add to the parts count. All you do is read some serial data. -- 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. ___ 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] refclock - NTP server settings/tuning?
I've been hearing about PTP in a few places. Does anyone here have
experience with it to know if it would provide better performance in a
situation like this?
On Sun, Sep 29, 2013 at 5:11 AM, Anders Wallin
anders.e.e.wal...@gmail.comwrote:
Thanks for all replies,
I can try changing maxpoll to a larger value and see if the trace is
smoother.
The refclock driver is a userspace C-program (daemon) that essentially
does:
while(1) {
gettimeofday(tv,NULL) // system time, for NTP receiveTimeStamp
get_wr_time(wr_tv); // WR time, for NTP clockTimeStamp
// write tv and wr_tv to shared memory where NTP expects to see them
sleep(8);
}
This may be the cause of a constant negative offset I see, since one
time-stamp is always read before the other. Perhaps this could be improved
by reading system time both before and after get_wr_time() and reporting
the average of the two readings as receiveTimeStamp? Or measure the offset
and put it as a time1 offset-value in ntp.conf
If the driver was written as a kernel module, would that run with higher
priority and less variable delay?
I use the same piece of code to log how well system time tracks WR-time.
Here I sometimes see sudden spikes of 100s of microseconds. Could this be
caused by the OS context switching in the middle of my program between the
two timestamp-reading functions? Again, would this improve if the
time-logger was written as a kernel module, or is there some other way of
coding it that avoids context switches and keeps the two time-stamp reading
functions atomic?
Standard Ubuntu nowadays has a pre-packaged lowlatency kernel which I
think is RT-Preempt with some modifications. But I assume both the
refclock-driver and the logger would need a re-write to take advantage of
the RT-kernel. Does anyone have experienced with that?
thanks,
Anders
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Re: [time-nuts] FCC politics vs their engineers...
He tells me with some bitterness that politics triumphed over all of the objections of the engineering staff to LS and that this is not the first time that this has happened. That's how we ended up with Challenger and Columbia. On Tue, Sep 17, 2013 at 6:46 AM, Michael Baker mp...@clanbaker.org wrote: Time-Nutters-- Jim wrote: snip That's why the FCC granted a conditional waiver of the rules. It was politically expedient, and I would imagine that the engineers at the FCC thought there's no way they'll be able to demonstrate no interference Charles wrote: snip The Commission not only thought LS would demonstrate non-interference, it put its thumb on the scale until the public outcry became too loud to ignore (the GPS interests took forever to wake up -- that didn't happen until all of the comment periods were long closed). It just didn't matter what the staff engineers thought -- which is business as usual at the FCC. --**-- A friend of mine was one of the FCC lead supervisory engineers that was involved in the LS fiasco. He tells me that there were technical reports, evaluation summaries and strong opinions offered by the engineering staff that provided a number of reasons why the LS project should be denied. He tells me that most of these engineering studies got buried and ignored. He tells me with some bitterness that politics triumphed over all of the objections of the engineering staff to LS and that this is not the first time that this has happened. Mike Baker Gainesville, FL USA __**_ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/** mailman/listinfo/time-nutshttps://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 without a PC
Would be nice if someone did a Linux port of LH that could run on a Raspberry Pi or something, then you could embed it into your T-Bolt installation. Plug in a HDMI monitor if you want to look at it all the time, or come in remotely via Ethernet. -- eric On Sun, Aug 18, 2013 at 9:00 PM, Chris Albertson albertson.ch...@gmail.comwrote: On Sun, Aug 18, 2013 at 6:36 PM, Didier Juges shali...@gmail.com wrote: Go up about 7 or 8 messages. It is not a version of Lady Heather for the PocketPC, it is a monitor software for the Thunderbolt that runs on certain PocketPC (those like the iPaq that have a hardweare serial port). It is very far from the extended functionality of Lady Heather, but useful as a health indicator. Got a link to the source, it could serve as a start -- 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. ___ 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] ***SPAM*** RS232 cables - thin connectors
Maybe low-profile rs232? Something like: http://www.cablestogo.com/product/52138 On Thu, Jul 25, 2013 at 1:51 PM, Hal Murray hmur...@megapathdsl.net wrote: After all the discussions about the cost of power, I'm getting my act together and replacing my old power hungry PCs with new/modern Atom boards. I found one that has 2 RS232 connectors. Looks good. http://www.mini-box.com/Intel-D2500CCE-Mini-ITX-Motherboard The catch is that they are only 0.625 inches apart and most of the connectors on my RS232 cables are just a bit thicker than that so I can't use both at the same time. Does anybody have a source of cables with thin connectors? Is there a magic term to google for? I think I tried filing one down a while ago. Modern plastics/rubber is really tough. Maybe I should try again with a better mechanical setup, maybe build a jig to hold it. -- These are my opinions. I hate spam. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] ***SPAM*** RS232 cables - thin connectors
Or mold some Polymorph https://www.sparkfun.com/products/10951 around the DB-9. On Thu, Jul 25, 2013 at 3:28 PM, Chris Albertson albertson.ch...@gmail.comwrote: Make your own cable from a bare DB-9 connector, solder and shrink tube. On Thu, Jul 25, 2013 at 2:54 PM, Eric Williams wd6...@gmail.com wrote: Maybe low-profile rs232? Something like: http://www.cablestogo.com/product/52138 On Thu, Jul 25, 2013 at 1:51 PM, Hal Murray hmur...@megapathdsl.net wrote: After all the discussions about the cost of power, I'm getting my act together and replacing my old power hungry PCs with new/modern Atom boards. I found one that has 2 RS232 connectors. Looks good. http://www.mini-box.com/Intel-D2500CCE-Mini-ITX-Motherboard The catch is that they are only 0.625 inches apart and most of the connectors on my RS232 cables are just a bit thicker than that so I can't use both at the same time. Does anybody have a source of cables with thin connectors? Is there a magic term to google for? I think I tried filing one down a while ago. Modern plastics/rubber is really tough. Maybe I should try again with a better mechanical setup, maybe build a jig to hold it. -- These are my opinions. I hate spam. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. -- 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. ___ 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] Very stable synthesizer, alternative to PTS(Programmed Test Sources) x10 or 040?
We use an Agilent 8644B where I work as the master oscillator for an electron cyclotron storage ring. Electrons at 2GeV don't like to be pushed around and are very sensitive to phase noise, so the feedback loop that adjusts the frequency uses the FM input for fine adjustment. -- eric On Wed, Jul 10, 2013 at 3:57 AM, Bob Camp li...@rtty.us wrote: Hi Having hooked up a 9854 and tried it with realistic settings - it's not that great. If you run it at magic frequencies (where it's essentially just a divider) it looks like a divider. Bob On Jul 9, 2013, at 5:03 AM, Anders Time anderst...@gmail.com wrote: Thanks a lot for the input. I have been looking at the Fluke 6160b, but I thought that there might be something as good out there that is not 40years old! I want to use the synthesizer as a flexible offset source for beat frequency measurements. So the frequency range is 5 to 30MHz approx. I read Rubiola et al. Phase noise and amplitude noise in DDS yesterday and thinks that it might be worth a try to test the AD9854 or AD9912 to see if it is good enough. If I understand the paper right they get really good results. Is there any one with experience? Thanks Anders ___ 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] Lead acid battery noise levels
I wonder if lithium batteries would have a good noise figure. The nano-structure of the electrodes give them very large surface area and low resistance, but the charge carriers are different than other types of chemistry and I don't know if that's good or bad. On Wed, Jul 10, 2013 at 9:01 AM, Hal Murray hmur...@megapathdsl.net wrote: a...@bardagjy.com said: The SRS 560 and 570, low noise voltage and current preamplifiers respectively, both use bog standard sealed lead acid batteries. Is that to reduce power supply noise or to get a clean ground that isn't connected to wall power? -- These are my opinions. I hate spam. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] net4501 oscillator
For those running a net4501 NTP server with the original clock, there are some 33.333MHz TCXO modules on ebay for sale, item #181008085393. I haven't received mine yet so I can't guarantee they will work, but they're 3.3v parts, so I think they will. They are Chrystek CXOHV8-HF3-33.333MHz, data sheet at http://www.crystek.com/crystal/spec-sheets/tcxo/CXOHV8.pdf -- 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] looking for low-power system for gps ntp timekeeping
What did they leave out of the hardware? Hard to tell what to look for when it's not there. Thanks for sharing your experience. -- eric On Mon, Jul 1, 2013 at 10:43 PM, NeonJohn j...@neon-john.com wrote: Before anyone wastes his money on a BeagleBone, I suggest you join the mailing list and read the hundreds of messages each day that pass through, most of them citing problems, mostly with the Linux implementation. Basically, the ancient implementation of Angstrom Linux is a POS. Just barely enough code to be able to say, for example, that SPI works. It does - sorta - but not well enough for any application where clock timing or jitter matters. I had intended to embed the BB white in my next revision induction heater. After several months of frustration and a considerable amount of money to a kernel programmer to write drivers that actually worked, I gave up. I could easily had a man-year in the application that I can do bare metal in a few months. The thing that finally canned the BB for me was the short SD card life. Even though the implementation uses a virtualized root file system, it still writes to the SD card about once a second. The result is that even industrial grade SD cards rarely live over a year. With the Black they tried to address the problem by putting some NAND memory on board but that only prolongs the problem and with components that are not easily changed. A final negative is the support. The team member, a guy named Gerald, who provides official support on the mailing lists is one of the most hateful persons I've encountered on the net. No, I never personally had an encounter with him but I daily shook my head in amazement that TI would let such a person rep them. PS: Before you go to buy the Black, take a careful look at what all they left off in an effort to compete with the Pi. PSS: I have a couple of Whites, one unopened, and a prototyping board for sale. Cheap :-) John On 07/01/2013 11:14 AM, Chris Albertson wrote: Thanks. I didn't know there were two kinds. This is more useful for only $5 more. -- John DeArmond Tellico Plains, Occupied TN http://www.fluxeon.com -- THE source for induction heaters http://www.neon-john.com-- email from here http://www.johndearmond.com -- Best damned Blog on the net PGP key: wwwkeys.pgp.net: BCB68D77 ___ 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] Beaglebone NTP server
I have a practical application for this, I'm anxious to see your web page on how to do it. Thanks. -- eric On Thu, Jun 20, 2013 at 12:37 PM, Gabs Ricalde gsrica...@gmail.com wrote: On Thu, Jun 20, 2013 at 3:39 AM, Chris Howard ch...@elfpen.com wrote: Are you using the original BeagleBone or the new BeagleBone Black? I'm using the original BeagleBone. it should work on the BeagleBone Black. Will you have any details available about what parts are needed to set it up? If your GPS receiver is using 3.3V logic, wiring it up is straightforward, similar to the Raspberry Pi NTP server. I will probably setup a page describing this. ___ 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] display on sale
I ran a modified wall clock driven by a homebrew Oncore/AVR uController box for a few years. It worked pretty well even though it was open loop, I had code for synchronizing the second hand with the GPS, and it would wind itself forward to adjust for DST. Eventually it broke down, so I bought an OnTime analog PoE display/clock and have been very happy with it, the Symmetricom looks like the same thing re-branded and at less than half the price. On Wed, May 29, 2013 at 10:26 AM, Michael Tharp g...@partiallystapled.comwrote: On 5/29/2013 12:11, Robert Darlington wrote: I ordered two PoE clocks, one with the 12 hour face, one with the 24 hour face.Earlier this week I considered using the Vetenari Clock project circuit board to control a cheap analog clock movement and have it do my bididng -however I can't write the code in $99 of my free time! Note that the clock in the Vetenari kit is just a cheap quartz clock like you could get anywhere, and the replacement board it comes with isn't of any use if you're trying to do something different. Basic quartz clocks are not a good choice for hacking into a precision display because they can only tick forward in one second increments, with no way to know what time is being displayed nor a reasonable way to adjust forward or backward an hour for daylight time changes. In other words, you can make it tick precisely but you can't really set it. I'm sort of interested in getting an analog WWVB type clock and seeing how much work it would be to coopt *that* hardware since it is designed to set arbitrary times, but I have a feeling I'd be better served making my own mechanics with a stepper motor and reduction gear. Of course a digital clock would be much less complicated, which is what Miguel was asking about to begin with, but that's not nearly as much fun. -- m. tharp __**_ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/** mailman/listinfo/time-nutshttps://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] NTP Clock suggestions?
Inova Solutions OnTime Analog Clocks http://www.inovasolutions.com/network-clocks/products/analog-wall-clock.htm On Mon, May 27, 2013 at 11:47 PM, Doug Calvert dfc-l...@douglasfcalvert.net wrote: Your message is the only place google has ever seen OnTime dial clock Did you mean a dial clock that displays the correct time and left out the space between on and time? On Mon, May 27, 2013 at 11:21 AM, Eric Williams wd6...@gmail.com wrote: If you want a project, you should be able to get an older Android tablet or a Chumby 8 for $100 or less and hack it to do what you want. Hard to beat the price for the hardware you get. I'm happy with my OnTime dial clock. On Mon, May 27, 2013 at 8:14 AM, Bob Camp li...@rtty.us wrote: Hi On May 27, 2013, at 10:56 AM, Miguel Barbosa Gonçalves m...@mbg.pt wrote: Hi Bob! On 27 May 2013 14:56, Bob Camp li...@rtty.us wrote: Hi Correct answer: I don't think there is such a beast. Once you get away from the radio controlled (WWVB etc) clocks the cost goes up quickly. I don't understand why a microprocessor with an Ethernet controller and a 7 segment display would cost so much to manufacture... I think I'll build my own. … and that's really my point. You can build one easier than you can buy one. Also correct, but a bit of a joke answer: Raspberry PI driving your television set. Alternatively make the Pi feed control signals to a hacked normal clock. Good joke :-) I imagine the electricity bill at the end of the month. The Pi isn't all that power hungry. The TV set - yes it's going to be a bit of a hog. Even with the Pi's i/o limitations you should be able to get it to run some sort of low power external display. Bob I would like to have a clock sync with my super precise stratum 1 servers :-) what's the point in having them if I can see the time anywhere? :-) Cheers, Miguel ___ 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] NTP Clock suggestions?
If you want a project, you should be able to get an older Android tablet or a Chumby 8 for $100 or less and hack it to do what you want. Hard to beat the price for the hardware you get. I'm happy with my OnTime dial clock. On Mon, May 27, 2013 at 8:14 AM, Bob Camp li...@rtty.us wrote: Hi On May 27, 2013, at 10:56 AM, Miguel Barbosa Gonçalves m...@mbg.pt wrote: Hi Bob! On 27 May 2013 14:56, Bob Camp li...@rtty.us wrote: Hi Correct answer: I don't think there is such a beast. Once you get away from the radio controlled (WWVB etc) clocks the cost goes up quickly. I don't understand why a microprocessor with an Ethernet controller and a 7 segment display would cost so much to manufacture... I think I'll build my own. … and that's really my point. You can build one easier than you can buy one. Also correct, but a bit of a joke answer: Raspberry PI driving your television set. Alternatively make the Pi feed control signals to a hacked normal clock. Good joke :-) I imagine the electricity bill at the end of the month. The Pi isn't all that power hungry. The TV set - yes it's going to be a bit of a hog. Even with the Pi's i/o limitations you should be able to get it to run some sort of low power external display. Bob I would like to have a clock sync with my super precise stratum 1 servers :-) what's the point in having them if I can see the time anywhere? :-) Cheers, Miguel ___ 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] WWVB Clocks don't sync anymore (revisited)
I also have a SkyScan clock that is claiming to be synced to WWVB, but is slowly drifting off. I've replaced the battery and it synced at least once after DST conversion, Two other WWVB clocks are working as they should. On Tue, Mar 19, 2013 at 1:55 PM, Clint Turner tur...@ussc.com wrote: A few weeks ago I posted a question/comment about some of my WWVB-based Atomic clocks no longer setting themselves properly. These two clocks, SkyScan #86716, would show the symbol indicating that they had set themselves, but their time was drifting away from UTC. Interestingly, they *would* set themselves exactly once upon installation of the battery, but never again. Since that time, I've done a bit of digging around. The first suspicion was that, perhaps, the NIST had fudged a bit in the WWVB timecode recently, so I manually decoded a few frames and analyzed them: Nothing suspicious there. The next question was if the addition of the BPSK somehow skewed the timing of the TRF's AGC/threshold - but logically, this didn't make sense since the clock *did* set itself exactly ONCE - and it wouldn't have been able to do this at all were this the case. Out of curiosity I poked around on the board and found the trace containing the time code and found that despite the BPSK, its timing was exactly as it should have been: No surprise there. This left the clock itself, so I did what any other Time Nut would do: I built a WWVB simulator. Initially, I set it to a 2010 date - a time that I knew that the clock worked properly. I had two clocks: One that I'd just reset by pulling and replacing the battery while the other had been stuck for a few weeks, not resetting itself nightly as it should. I put both of these in the coupling loops from my WWVB simulator and over the next few days, the recently re-set clock happily synchronized itself while the other one with the 2013 date was still stuck. I then reset that clock and it, too, behaved itself from then on. I then reset the clock on the simulator to a February 2013 date and time. Initially, both clocks reset themselves to the current time and date at their next midnight, but after that, they got stuck, never resetting themselves at night again. So, it appears to be a problem with Broken Sand (e.g. a silicon problem). For the morbidly curious, I have documented my efforts here: http://ka7oei.blogspot.com/**2013/02/did-nist-break-bunch-**of-radio.htmlhttp://ka7oei.blogspot.com/2013/02/did-nist-break-bunch-of-radio.html- The initial testing http://ka7oei.blogspot.com/**2013/03/yes-nist-did-break-** bunch-of-radio.htmlhttp://ka7oei.blogspot.com/2013/03/yes-nist-did-break-bunch-of-radio.html- The testing with the WWVB simulator 73, Clint KA7OEI __**_ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/** mailman/listinfo/time-nutshttps://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] space-time crystal: ultimate time?
http://newscenter.lbl.gov/news-releases/2012/09/24/a-clock-that-will-last-forever/ ___ 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] space-time crystal: ultimate time?
What I can't figure out is, if the crystal has to stay in its lowest quantum state, how are you ever going to get a signal out of it to read it? -- eric On Tue, Sep 25, 2012 at 10:42 AM, paul swed paulsw...@gmail.com wrote: I always new crystals were better then these CS and RB power sucking things. Hmm just need an ion trap or two. Maybe I will have to stick to GPS and WWVB for a bit. Regards Paul WB8TSL On Tue, Sep 25, 2012 at 1:12 PM, Eric Williams wd6...@earthlink.net wrote: http://newscenter.lbl.gov/news-releases/2012/09/24/a-clock-that-will-last-forever/ ___ 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] Motorola UT+ Interface Board
Item # 180688345029, Buy It Now, $3.99, free shipping. On Mon, Aug 13, 2012 at 6:31 PM, Chris Albertson albertson.ch...@gmail.comwrote: On Mon, Aug 13, 2012 at 6:20 PM, paul swed paulsw...@gmail.com wrote: impressive Shame there is not a buy now. 1cent plus $4 shipping and you have to wait 2 days to see if you won the bid. Or am I missing something? Yes, There are MANY other auctions for this same product. Some have buy it now with free shipping but a $6 price. Some will give you a better deal if you buy several. They've got all options covered 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. ___ 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 second coming...
My nptns server didn't register the leap second. Did I do something wrong? -- eric tick# telnet localhost 123 Trying 127.0.0.1... Connected to localhost. Escape character is '^]'. NTPns show leap Source StateUnknown No Insert Delete oncore_0 UTC 8.000--- 209.132.176.4UTC -1.000-- 66.187.233.4 UTC -1.000-- 132.163.4.103UTC -1.000-- 132.163.4.101UTC -1.000-- Total 8.0004.0000.0000.000 System Leap state: No Leap second today NTPns show oncore 0 serial port = /dev/cuad1 state = 12 visible/track/lock = 11/8/0 dop = 0.0 [m] 2012-06-30 23:51:03.000696811 lat = 136595634 (37.943232), lon = 3854625296 (-122.317222), ht 5422 (54.22) http://maps.google.com/maps?ll=37.943232,-122.317222spn=0.03,0.08t=k rcv_status = 0x8 = AcqSat/PosHold utc_offset = 15 site_survey = 2 (~0 sec left) Sat Dopler Elev Azi Health Mode SigStr IODE Status Offset 2 3376 15 181 00 840 0a2 0.033556707 4 2905 37 151 00 846 0a2 0.06739 9 2504 42 312 00 849 0a2 0.150997219 15 -1955 24 253 00 847 0a2 0.251660515 17 -1658 60 42 00 847 0a2 0.285214947 26 -3534 17 209 00 842 0a2 0.436209891 27 1416 58 304 00 845 0a2 0.452987107 28 -1591 37 76 00 844 0a2 0.469764323 NTPns ___ 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] LightSquared in the news again
Typical of technology companies that have more lawyers on staff than engineers. On Mon, Jun 4, 2012 at 5:09 PM, Tom Knox act...@hotmail.com wrote: Lightsquared is like a cockroach every time you think it is dead it shows up again. Thomas Knox 1-303-554-0307 Date: Mon, 4 Jun 2012 19:25:22 -0400 To: time-nuts@febo.com From: charles_steinm...@lavabit.com Subject: [time-nuts] LightSquared in the news again From today's communications news (fair use): LightSquared stressed its intention to deploy a nationwide 4G wireless broadband network, during a meeting with Angela Giancarlo, chief of staff to FCC Commissioner Robert McDowell. The commission has some legal and policy responses it can take to address the inability of a limited number of GPS receivers to operate properly in spectrum that has not been allocated for GPS use, the company said in an ex parte filing. It said the actions proposed in the commission's Feb. 15 public notice revoking its ancillary terrestrial component are disproportionate and inappropriate, especially in light of the current administrative record. http://apps.fcc.gov/ecfs/document/view;jsessionid=PbLJPNCL1F1v170xHrQhXLJlClpRjS2DfgWX7c4CqvvhwQlgG2nn!-1221852939!NONE?id=7021921317 ___ 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] NTP jitter with Linux
Could the CPU be reducing its clock rate when it's not being loaded? Just a guess, most multi-core processors these days have power saving features like that. -- eric On Wed, Apr 4, 2012 at 3:22 PM, Mike S mi...@flatsurface.com wrote: I asked this on an NTP list, got some guesses, but no knowledgeable responses. I've got a Trimble Thunderbolt PPS source for NTP, Linux 2.6.35, on a quad core CPU. PPS source is coming into a multiport serial card, which /proc/interrupts shows is sharing IRQ with some inactive USB ports (IRQ 17). It's a PCI-E card, so it would be using MSI interrupts. My understanding is that those aren't really shared, in the traditional sense, but IDK. The kernel clocksource is TSC, which is claimed to be core invariant on my processor (AMD Athlon II 610e). Changing to HPET doesn't help. Running normally, I'll get about +- 20 us ptp of jitter (as reported by ntpq -p, and in loopstats). If I load up the CPU (load average 4 is swell), jitter will shrink to +- 1-2 us. I've played around with different cpufreq setting, thinking it might be related to the processor speed during an IRQ varying, but that seems to have minimal impact (performance vs. conservative vs. ondemand). I've also tried irqbalance, with no change in performance. So, running a process(es) which keep the CPU completely busy reduces the jitter. The busier, the better. Why? I'm guessing it has something to do with interrupt latency, but why does a busy CPU make it more consistent - I'd expect the opposite? The difference is very obvious. Is there something else I can do to keep the jitter low? Aside: Something which I believe was discussed here a few weeks ago - clocksource speeds changing between reboots. I patched the kernel to allow statically setting the TSC frequency ( http://old.nabble.com/-PATCH--** tsc_khz%3D-boot-option-to-**avoid-TSC-calibration-** variance-td23494975.htmlhttp://old.nabble.com/-PATCH--tsc_khz%3D-boot-option-to-avoid-TSC-calibration-variance-td23494975.html). This eliminates the semi-random, often 30-40 ppm change in frequency reported by NTP between reboots. After tweaking, it's now consistently 1 us, reboots be damned. This should be in the mainline kernel! This made no difference to the jitter mentioned above, although non was expected. __**_ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/** mailman/listinfo/time-nutshttps://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] AF General says White House pressured him to change LightSquared testimony
http://www.thedailybeast.com/articles/2011/09/15/lightsquared-did-white-house-pressure-general-shelton-to-help-donor.html ___ 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] Advice on NTP server needed
Same here, my Net4501 has been running over 2 years without a reset. A Soekris-based NTP server uses the counter/timer built-in to its embedded processor to give you better precision interval measurement than a serial port, but if you're not interested in anything better than ms accuracy then it's probably not an issue. -- eric On Mon, Jun 13, 2011 at 3:45 PM, Jason Rabel ja...@extremeoverclocking.com wrote: I have to disagree with the person that said the Net4501 is not stable. I have two (soon to be 3) that run NTPns and they have never needed to be touched. I've powered them down a couple times during really bad storms because I didn't want lightning to zap them (or my other GPS equipment). If you don't have any time constraints, you can watch eBay and usually get a Net4501 for $50 - $75 shipped. You can buy the latest Motorola Oncore timing receiver (M12M+T ?) from Synergy GPS, or on eBay the user fluke.l is selling older M12+T models for $35 + $8 shipping. Get an appropriate cable to go from the GPS unit to your antenna, solder a few wires, and you are good to go. Here's a pic of mine with the M12+T: http://www.rabel.org/pics/Net4501-2.jpg Here's an article I wrote building one with a UT+ receiver.. Took a little more work but results are the same: http://www.extremeoc.com/articles/howto/Building_S1_NTP_Server_1.html John's article is also a good read: http://www.febo.com/pages/soekris/index.html I have precompiled images of NanoBSD + NTPns on my server if you want to download them (email me off-list for the URLs). One build is FreeBSD 6.3, the other is 7. I haven't built any trying newer versions of FreeBSD, I don't think there is really anything to except a bunch of build headaches. If you want something more plug play... Watch eBay for Tymserve 2100, which seem to be the most common. There was a bunch of Spectracom GPS Time servers that recently sold for ~$100 each IIRC. I don't know if anymore are available. Every now and then an EndRun or Brandywine unit will show up. Other useful keywords to search eBay would be Symmetricom, Datum, and TrueTime. Oh, and of course there's the Trimble Thunderbolt... You can hook that up to a PC / serial port as a GPS input. Since it has its own internal OCXO you also get some hold-over ability. ___ 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] Advice on NTP server needed
tick# uptime 1:12AM up 844 days, 16:52, 1 user, load averages: 0.03, 0.03, 0.00 Yes, that's true, but only when the system's basic reliability reaches a very high level. (QED) -- eric On Mon, Jun 13, 2011 at 4:05 PM, Poul-Henning Kamp p...@phk.freebsd.dk wrote: In message BANLkTi=i4u-ng7ly6o2ybl_ypcqp95v...@mail.gmail.com, Eric Williams writes: Same here, my Net4501 has been running over 2 years without a reset. That is more a matter of power-supply than anything else: critter phk ssh root@xdcf uptime 11:04PM up 764 days, 4:01, 0 users, load averages: 0.20, 0.16, 0.10 As far as I know, the NET4501 is still undisputed king of the NTP hill. -- 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 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] LCD display connector
I knew someone who worked with 100% isopropanol who said there was some safety issue with using it in that, if it ignited, the flame was virtually invisible. On Mon, Jan 3, 2011 at 4:21 PM, jimlux jim...@earthlink.net wrote: li...@lazygranch.com wrote: Most drug store isopropal contain other chemicals to keep your skin from drying out. You can buy electronics grade isopropal. Cheap enough ($5 for a large bottle) if you have a store that stocks it. Fry's Electronics has it. Of course grain alcohol will do the job. cheap grain neutral spirits aka plain vodka works very nicely for many cleaning/solvent uses. Except you are paying the $20/proof gallon tax. you can also buy 200 proof/100% ethanol at a drugstore, although, obviously, once you've opened it, it rapidly starts dropping to 95% because it's quite hygroscopic. We use ethanol to clean spacecraft stuff at work. I can't remember why we don't use isopropanol... obviously, we can buy it without any additives so it's not the rubbing alcohol problem. Other space folks do use isopropanol, but maybe JPL had some bad experience and once burned, 5000 times shy. Isopropanol forms an azeotrope with a bit higher water percentage than ethanol, but I wouldn't think that's a big deal. The problem with most denatured ethanol is that what they add to denature it may be fine in perfume or as shellac thinner, but might not be compatible with your electronics. ___ 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] GPS Display clock
If you can GPS-sync your network with NTP, you can run an Inova OnTime clock with it. They can be had for as low as $250 or so. On Tue, Mar 30, 2010 at 8:12 AM, Dave Lance bassguitarm...@yahoo.com wrote: I would like to buy a reasonably priced GPS synced display clock. It would need an external antenna. All of the one I have found are for commercial use and well over $500 in cost. I have a number of different atomic synced WWV clocks but they are unreliable for me in northern Ohio. ___ 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] any WWV audio recordings available?
Ed, As I recall, the Heath receiver scanned three WWV frequencies (5, 10, and 15MHz?) and stopped on the one with the strongest signal. It would stay there for a minute or two and move on if it couldn't hear the burst tone at the top of the minute. If it heard the tone, it would stay put and try to decode the sub-audible tone time signals. I think it only resumed scanning if it started missing the burst tones again. Over the course of the day it would walk up and down the band as the propagation changed. -- eric On Fri, Feb 12, 2010 at 3:46 PM, Ed Palmer ed_pal...@sasktel.net wrote: I think I remember that, years ago, the situation was reversed. You could only hear WWV at night. Does your clock only listen at certain times of day? ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] any WWV audio recordings available?
First thing, clean the tin-plated board edge connectors and the corresponding connectors on the motherboard. I always had to do that every year or two to keep mine working. Squirt some cleaner on the spring contacts and work the board up and down. -- eric On Tue, Feb 9, 2010 at 10:35 PM, Don Latham d...@montana.com wrote: I was told that there were a couple of adjustment pots that went bad; I cannot remember which ones but they are in the feed from the receiver to the digital control if that makes sense. I sold the one I had a year or so ago. Don - Original Message - From: Majdi S. Abbas m...@latt.net To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Tuesday, February 09, 2010 11:13 PM Subject: Re: [time-nuts] any WWV audio recordings available? On Tue, Feb 09, 2010 at 07:33:07PM -0800, Scott Burris wrote: Does anyone know if there are any 5min recordings of WWV audio available? I'm trying to track down some problems with my Heathkit GC-1000 clock and it sure would be nice if I could inject some known good audio recording and see if the clock picks up the time from that. I've found a couple recordings by googling, but they are both too short to be useful. Try this: (Rather noisy; WWV-5 just now; WWVH-5 in the background.) http://puck.nether.net/~majdi/WWV-5MHZ.wavhttp://puck.nether.net/%7Emajdi/WWV-5MHZ.wav --msa ___ 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] Clock Project Help
Don't know if you are more interested in building such a clock, or just having one. If the latter, one possible option is the Innova OnTime series, which are NTP time displays. One place to buy them is here: http://www.networkcablesonline.com/Network-Clocks/c97/index.html These commercial clocks get their time from SNTP and run on Power-over-Ethernet. No alarm function, though, and the configuration is via telnet rather than USB. They also might be bigger than you want, they're more for time displays in offices and buildings, but I have one of the dial clocks in my home driven by my Soekris-based GPS NTP server. -- eric On Wed, Oct 28, 2009 at 1:44 AM, J. Mike Needham iain_ni...@att.net wrote: Hello fellow time nuts: I am interested in building a clock that will use embedded technology and self set using the Network Time Protocol (NTP) from a given server. The clock will be setup via USB and then get it's signals from either a RJ-45 network connection or via WIFI. I believe the software will be simple enough, probably some form of embedded Linux ideally. Where the problem lies is that I need to find the IC chips for clocks and build a display . ideally my whole house would sport these clocks and get their signal from my own NTP server or any of the public ones. My prototype clock would be a bedside alarm clock with only alarm set functions for any buttons, the actual time setting would be as described above. If anyone can direct me to suppliers for these parts that is what I really need as well as to know what parts I need J Thank-you in advance. J. Mike Needham iain_ni...@att.net Internet Specialist Lawrence, Kansas USA ___ 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] Obscure terms
I used to work with CDF. Wildfires are measured in chains, not acres. Property lots in the US are located by range and township. It's a system where the origin moves from place to place. I was told the founding fathers invented it to make it purposely hard for a central government to find things. On Thu, Aug 20, 2009 at 3:56 PM, WarrenS warrensjmail-...@yahoo.com wrote: Jim Silly question, You must not live in California. Of course it is 1/640 of a square mile or was it 1/460 of a square something else? In any case, everyone in California knows it is 1/50,000 of what an average wild fire burns. ws ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] GPS disciplined mechanical clocks
Bryan Mumford (bmumford.com) did a lot of work developing pendulum clocks that were driven by a Fedchenko electromagnetic drive. The drive circuit would both put energy into the pendulum and use the pulse to drive an electric clock face to display the time. He never got to the point of disciplining the clock, but he did note that you could make fine adjustments in the period by varying the drive current which changed the amplitude of the pendulum swing and changed the period. (Larger swings ran slower, as I recall.) You could theoretically discipline such a clock by varying the current to lock the pendulum to a GPS source. It wouldn't really be mechanical, more of a hybrid, but I don't know how you'd discipline a mechanical clock with a system that had to drive in parallel with the escape mechanism, the two would fight each other. On Wed, Mar 4, 2009 at 3:52 AM, Steve Rooke sar10...@gmail.com wrote: Has anyone looked at locking an old mechanical clock to precise time? What I'm thinking of is something like an old cuckoo clock. The rule is that the clock remains basically standard and is only steered by the external source, say, by a magnetic pulse to the pendulum, IE. no physical connection. Obviously the correct period of the pulse would have to fit the timing of the pendulum. OK, it seems pointless as you can't read time with any real accuracy on something like a cuckoo clock but I'm sure there is the likelihood of something like this being done by someone like us. 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. ___ 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 command line modification question...
If someone is taking suggestions, I just thought it would be nice if I could get 9 values for the accumulated amount of time spent receiving N satellites, where N goes from 0 to 8. (Or more, for newer T-Bolts.) Seems like it would be useful for evaluating and comparing the quality of antenna sites. Thanks! ___ 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] Antennas, roofs
Yup, running my T-bolt on an indoor patch antenna hoisted to the apex of a skylight. Works fine. My GPS NTP server uses a bullet antenna mounted on a short (~1ft) pole bolted to a block of wood on the side of the house, feedthrough is PVC pipe going through the wall with a 45-degree coupler on the outside pointing down to keep out rain. On Tue, Feb 17, 2009 at 4:18 PM, Hal Murray hmur...@megapathdsl.net wrote: A slightly crazy idea... Has anybody poked antennas up inside a skylight? I'm thinking of the setup which has a hole in the ceiling of a room, a box from that hole through the attic space up to and through the roof, and a plastic dome on top. A shelf or bracket on the inside of the box would get the antennas almost on the outside. ___ 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] Sound cards
I've been using a Edirol FA-66, a firewire box with two balanced inputs plus four more unbalanced. I think it can handle 192ks/24bit on 4 channels. A lot of hams use it for software defined radios, but I just know it has better sound, especially the lows, for playing MP3s compared to most sound cards and iPods. Rex wrote: I'd be interested to hear what any of the group has to share about relative merits of current sound cards that can be interfaced for measurements like what was being discussed in that earlier thread. (And some before and since.) From my own point of view, I'd most like to hear about any that are external -- connected by USB or 1394, rather than an internal card. This makes it more portable and easier to move between different PC's. ___ 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] He is a Time-Nut Troublemaker....
Michael Baker wrote: Just ducked out of my cave to let you know that you are a troublemaker. Get another T-bolt... Right. --Just what I need... another techno-addiction. As far as sweet innocence is concerned, I lost all I ever had when I jumped head-first into bench-rest rifle competition 15 years ago. You have your addiction-- I already have mine in the never ending search to find the magic combination of details that produce the holy-grail of a 10-shot half-inch group at 400 yards... the instructions there. I have my 3-shot half-inch group at 600 yards, that's enough for me. Yeah, I know, it's not statistically significant. I guess it's like having only one clock. ___ 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.
