Re: [time-nuts] L1 GPS timing signal(s) into local time on computer(s)
kuze...@gmail.com said: this is a no-name cheapo SIRF module 1) I need a computer with a serial port. The curent GPS module I'm using is INTERNALLY RS232 -- USB converter, and recognized by my windows 7 computer as: Prolific USB-to-Serial Comm Port (COM3) ... the latency and jitter is horrible, and both are seemingly random. The serial data stream basically doesn't work very well for timekeeping. The problem is a software bug. The info has a wander of roughly 100 ms. I say wander rather than jitter because it is very low frequency. You can't reasonably filter it out. The time constant is hours. http://www.megapathdsl.net/~hmurray/ntp/GPSSiRF-off.gif It is easy to correct for a constant offset. You also need a GPS unit that puts out a PPS signal. I don't know of any low cost ready-to-go units. A low cost unit is a demo board from Sure. http://www.sureelectronics.net/goods.php?id=99 http://www.satsignal.eu/ntp/Sure-GPS.htm You need to add a wire or two. You can also use the Garmin 18X LVC. Google will find directions. The other alternative is something like a Thunderbolt. It will keep good time if the GPS signals fades out - holdover. 3) I'm clueless about mounting an antenna, running cable, grounding / lightning protection, etc... Really want an easy to install one. Modern GPS receivers are much more sensitive than older gear. They may work well enough without an external antenna. On the other hand, a TBolt only needs 1 satellite after the survey. I'd suggest trying the Sure unit. It's only $35 plus shipping, and that includes antenna and power supply. You do have to add a wire or two. If it works well enough, you are done. If not, you will have learned a lot and can upgrade to a TBolt and/or try an external antenna. Also, trying to wrap my head around these: http://linuxpps.org/wiki/index.php/LinuxPPS_installation http://linuxpps.org/wiki/index.php/LinuxPPS_NTPD_support They contain a lot of noise from ages ago when the PPS stuff wasn't included in the Linux kernel. On a modern Linux system, the kernel is ready to go. You may want to install the pps-tools package. I think you need pps-tools-devel if you want to recompile ntpd and have it support PPS. You will have to do something like this before starting ntpd: if [ ! -e /dev/gps10 ]; then # GPS 18 LVC ln -s /dev/ttyS0 /dev/gps10 setserial /dev/ttyS0 low_latency ldattach PPS /dev/gps10 # makes /dev/pps0 ln -s /dev/pps0 /dev/gpspps10 fi You will also have to learn enough about general system administration to put that chunk of code in a reasonable place. The details probably depend upon which distribution you are using. On Fedora, I used to put it in /etc/sysconfig/ntpd but that broke when they switched to systemd. (I haven't worked out a clean solution yet. I just hacked it in to rc.local) For FreeBSD, I think you have to recompile the kernel to include PPS support. -- 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] L1 GPS timing signal(s) into local time on computer(s)
I will jump in a bit. I, and many have been right where you are. You are correct...USB is a no go for accurate time. Same on windows. So you need a Linux box with serial port. Anything from a Beaglebone, pandabox...or pc will work. You certainly need a gps with a pulse per second output (most have) and you can wire that up to the appropriate line on the serial cable or send to the target computer via gpio pin. The pps thing is fairly simple really. If you are receiving gps data via serial connection it takes a variable amount of time to get each status report from the gps...list time etc etc in text format and sends it repeatedly. This gets ntp to within a second or some fraction thereof...the pps part refines that..no text or anything... Just a one pulse per second separate from the gps info that acts as a exclamation point to tell ntp right here is the actual start of the second! alone the pps wouldn't be useful for time but with the time info ntp already has from the nmea sentences it is priceless for really precise time. That's about it. Once you have gps and pps configured on Linux you should be in the sub 5 microsecond range. It gets tricky getting better than that and you have to Ntpns and really worry about hardware issues that affect precision (system clock stability etc) but it can be done. Doc KX0O Sent from my iPad On Aug 18, 2012, at 11:25 PM, Sarah White kuze...@gmail.com wrote: Hi, this is my first post. First off. Windows 7 USB connection to the GPS (no serial ports / modern computer) and I'm pretty sure that is my main problem. Past few months, I've been trying to figure out my timing issues. Lots of reading trying to figure out how to best configure everything. I'm typically still off (randomly) by 20-100 miliseconds. I'd like to at least get to within 50 microseconds (nanoseconds would be wonderful) 1) I need a computer with a serial port. The curent GPS module I'm using is INTERNALLY RS232 -- USB converter, and recognized by my windows 7 computer as: Prolific USB-to-Serial Comm Port (COM3) ... the latency and jitter is horrible, and both are seemingly random. 2) I need to run my stratum 1 clock (connected to the stratum 0 time source via old-school RS232 serial) on linux or a form of BSD with support for kernel timestamps, and a version of NTP with a driver to supports my reference clock... points 1 and 2 seem fine. 3) I'm clueless about mounting an antenna, running cable, grounding / lightning protection, etc... Really want an easy to install one. For software, I've used 4.2.6 (stable / production) as well as 4.2.7 (dev version) NTP and haven't been able to tell any difference. Just using the generic NMEA driver / this is a no-name cheapo SIRF module. Also, trying to wrap my head around these: http://linuxpps.org/wiki/index.php/LinuxPPS_installation http://linuxpps.org/wiki/index.php/LinuxPPS_NTPD_support And here is where I give up. As the subject line suggests: HELP!!! I'd like to convert L1 GPS timing signal(s) into local time on computer(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. ___ time-nuts mailing 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] L1 GPS timing signal(s) into local time on computer(s)
Just one further question. When the pps input triggers, so my linux box knows a second has just ticked; is the time of that second the one the NMEA sentence has just sent, or will send next? Or to put it another way, when I receive an NMEA sentence is this the current time (as was when the sentence was constructed) or the time at the next PPS 'tick'? Thanks in advance. KenD On 19/08/12 11:23, Bill Dailey wrote: I will jump in a bit. I, and many have been right where you are. You are correct...USB is a no go for accurate time. Same on windows. So you need a Linux box with serial port. Anything from a Beaglebone, pandabox...or pc will work. You certainly need a gps with a pulse per second output (most have) and you can wire that up to the appropriate line on the serial cable or send to the target computer via gpio pin. The pps thing is fairly simple really. If you are receiving gps data via serial connection it takes a variable amount of time to get each status report from the gps...list time etc etc in text format and sends it repeatedly. This gets ntp to within a second or some fraction thereof...the pps part refines that..no text or anything... Just a one pulse per second separate from the gps info that acts as a exclamation point to tell ntp right here is the actual start of the second! alone the pps wouldn't be useful for time but with the time info ntp already has from the nmea sentences it is priceless for really precise time. That's about it. Once you have gps and pps configured on Linux you should be in the sub 5 microsecond range. It gets tricky getting better than that and you have to Ntpns and really worry about hardware issues that affect precision (system clock stability etc) but it can be done. Doc KX0O Sent from my iPad On Aug 18, 2012, at 11:25 PM, Sarah White kuze...@gmail.com wrote: Hi, this is my first post. First off. Windows 7 USB connection to the GPS (no serial ports / modern computer) and I'm pretty sure that is my main problem. Past few months, I've been trying to figure out my timing issues. Lots of reading trying to figure out how to best configure everything. I'm typically still off (randomly) by 20-100 miliseconds. I'd like to at least get to within 50 microseconds (nanoseconds would be wonderful) 1) I need a computer with a serial port. The curent GPS module I'm using is INTERNALLY RS232 -- USB converter, and recognized by my windows 7 computer as: Prolific USB-to-Serial Comm Port (COM3) ... the latency and jitter is horrible, and both are seemingly random. 2) I need to run my stratum 1 clock (connected to the stratum 0 time source via old-school RS232 serial) on linux or a form of BSD with support for kernel timestamps, and a version of NTP with a driver to supports my reference clock... points 1 and 2 seem fine. 3) I'm clueless about mounting an antenna, running cable, grounding / lightning protection, etc... Really want an easy to install one. For software, I've used 4.2.6 (stable / production) as well as 4.2.7 (dev version) NTP and haven't been able to tell any difference. Just using the generic NMEA driver / this is a no-name cheapo SIRF module. Also, trying to wrap my head around these: http://linuxpps.org/wiki/index.php/LinuxPPS_installation http://linuxpps.org/wiki/index.php/LinuxPPS_NTPD_support And here is where I give up. As the subject line suggests: HELP!!! I'd like to convert L1 GPS timing signal(s) into local time on computer(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. ___ time-nuts mailing 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] L1 GPS timing signal(s) into local time on computer(s)
The time when the names sentence was sent is the time in the sentence.. The pps signals every second..they are independent. Tat is the very nature of the problem with the nmea sentence..latency associated with the message itself. Sent from my iPad On Aug 19, 2012, at 6:11 AM, Ken Duffill k.duff...@ntlworld.com wrote: Just one further question. When the pps input triggers, so my linux box knows a second has just ticked; is the time of that second the one the NMEA sentence has just sent, or will send next? Or to put it another way, when I receive an NMEA sentence is this the current time (as was when the sentence was constructed) or the time at the next PPS 'tick'? Thanks in advance. KenD On 19/08/12 11:23, Bill Dailey wrote: I will jump in a bit. I, and many have been right where you are. You are correct...USB is a no go for accurate time. Same on windows. So you need a Linux box with serial port. Anything from a Beaglebone, pandabox...or pc will work. You certainly need a gps with a pulse per second output (most have) and you can wire that up to the appropriate line on the serial cable or send to the target computer via gpio pin. The pps thing is fairly simple really. If you are receiving gps data via serial connection it takes a variable amount of time to get each status report from the gps...list time etc etc in text format and sends it repeatedly. This gets ntp to within a second or some fraction thereof...the pps part refines that..no text or anything... Just a one pulse per second separate from the gps info that acts as a exclamation point to tell ntp right here is the actual start of the second! alone the pps wouldn't be useful for time but with the time info ntp already has from the nmea sentences it is priceless for really precise time. That's about it. Once you have gps and pps configured on Linux you should be in the sub 5 microsecond range. It gets tricky getting better than that and you have to Ntpns and really worry about hardware issues that affect precision (system clock stability etc) but it can be done. Doc KX0O Sent from my iPad On Aug 18, 2012, at 11:25 PM, Sarah White kuze...@gmail.com wrote: Hi, this is my first post. First off. Windows 7 USB connection to the GPS (no serial ports / modern computer) and I'm pretty sure that is my main problem. Past few months, I've been trying to figure out my timing issues. Lots of reading trying to figure out how to best configure everything. I'm typically still off (randomly) by 20-100 miliseconds. I'd like to at least get to within 50 microseconds (nanoseconds would be wonderful) 1) I need a computer with a serial port. The curent GPS module I'm using is INTERNALLY RS232 -- USB converter, and recognized by my windows 7 computer as: Prolific USB-to-Serial Comm Port (COM3) ... the latency and jitter is horrible, and both are seemingly random. 2) I need to run my stratum 1 clock (connected to the stratum 0 time source via old-school RS232 serial) on linux or a form of BSD with support for kernel timestamps, and a version of NTP with a driver to supports my reference clock... points 1 and 2 seem fine. 3) I'm clueless about mounting an antenna, running cable, grounding / lightning protection, etc... Really want an easy to install one. For software, I've used 4.2.6 (stable / production) as well as 4.2.7 (dev version) NTP and haven't been able to tell any difference. Just using the generic NMEA driver / this is a no-name cheapo SIRF module. Also, trying to wrap my head around these: http://linuxpps.org/wiki/index.php/LinuxPPS_installation http://linuxpps.org/wiki/index.php/LinuxPPS_NTPD_support And here is where I give up. As the subject line suggests: HELP!!! I'd like to convert L1 GPS timing signal(s) into local time on computer(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. ___ time-nuts mailing 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] L1 GPS timing signal(s) into local time on computer(s)
Ken: From what I've read, most GPS modules which output PPS, the NMEA sentence has the timestamp of the next, upcoming pulse. Regardless of how the NMEA or other time data is, the PPS itself is only a guarantee this is the boundary for a second and NTP documentation typically recommends a second reference clock to number the seconds anyway. Everyone: Thanks everyone. I got many responses which confirm my initial conclusions. I had trouble locating a GPS thunderbolt on ebay because there is an HTC phone with thunderbolt in the name. (I got a few hits for the GPS module, but there is no way to filter out phones or I might just be bad at operating ebay) uhm... yeah. As someone pointed out. It is a total nightmare to figure out which direction my GPS time is wandering, and finding the correct offset. I'm just gonna give up on this USB module, and get a real one with PPS Also, I really hate google's new shopping experience. They started listing less content, and now push content from stores which charge 2-3 times as much. As far as existing hardware goes, I don't have any slots free in my desktop for a serial board... Despite the new google shopping headache, I was able to determine that many older computers from the windows XP era which still have serial ports, and are available refurbished from walmart of all the crazy places. (most of the time, better price than the ones being pushed by google shopping, and even have XP installed and a 1 year warranty) So no problem. I can source a suitable machine to run NTP, and for less than $200, guaranteed. Will probably be using gentoo linux, as the default configuration does NOT expect you to run any specific kernel. I can easily recompile anything I need without breaking unusual, unforeseen dependencies. (doesn't hurt that I've been using gentoo since the stage1 install was preferred, all the way back to the GCC 2.x era) I'm really aiming to run a server which ONLY runs NTP, and at most 1 or two other daemons (light duty on those) Thanks so much everyone. On 8/19/2012 7:11 AM, Ken Duffill wrote: Just one further question. When the pps input triggers, so my linux box knows a second has just ticked; is the time of that second the one the NMEA sentence has just sent, or will send next? Or to put it another way, when I receive an NMEA sentence is this the current time (as was when the sentence was constructed) or the time at the next PPS 'tick'? Thanks in advance. KenD On 19/08/12 11:23, Bill Dailey wrote: I will jump in a bit. I, and many have been right where you are. You are correct...USB is a no go for accurate time. Same on windows. So you need a Linux box with serial port. Anything from a Beaglebone, pandabox...or pc will work. You certainly need a gps with a pulse per second output (most have) and you can wire that up to the appropriate line on the serial cable or send to the target computer via gpio pin. The pps thing is fairly simple really. If you are receiving gps data via serial connection it takes a variable amount of time to get each status report from the gps...list time etc etc in text format and sends it repeatedly. This gets ntp to within a second or some fraction thereof...the pps part refines that..no text or anything... Just a one pulse per second separate from the gps info that acts as a exclamation point to tell ntp right here is the actual start of the second! alone the pps wouldn't be useful for time but with the time info ntp already has from the nmea sentences it is priceless for really precise time. That's about it. Once you have gps and pps configured on Linux you should be in the sub 5 microsecond range. It gets tricky getting better than that and you have to Ntpns and really worry about hardware issues that affect precision (system clock stability etc) but it can be done. Doc KX0O Sent from my iPad On Aug 18, 2012, at 11:25 PM, Sarah White kuze...@gmail.com wrote: Hi, this is my first post. First off. Windows 7 USB connection to the GPS (no serial ports / modern computer) and I'm pretty sure that is my main problem. Past few months, I've been trying to figure out my timing issues. Lots of reading trying to figure out how to best configure everything. I'm typically still off (randomly) by 20-100 miliseconds. I'd like to at least get to within 50 microseconds (nanoseconds would be wonderful) 1) I need a computer with a serial port. The curent GPS module I'm using is INTERNALLY RS232 -- USB converter, and recognized by my windows 7 computer as: Prolific USB-to-Serial Comm Port (COM3) ... the latency and jitter is horrible, and both are seemingly random. 2) I need to run my stratum 1 clock (connected to the stratum 0 time source via old-school RS232 serial) on linux or a form of BSD with support for kernel timestamps, and a version of NTP with a driver to supports my reference clock... points 1 and 2 seem fine. 3) I'm clueless about mounting an
[time-nuts] Modern motherboard with RS232 port
Hello The Net, For your consideration: The INTEL model DN2800mt ITX mother board uses a ATOM CPU and draws about 11 watts of AC power when configured as: (I have not measured DC power yet.) 30 GB OCZ Nocti mSATA solid state drive, WIN7 pro, 64 bit, USB keyboard and mouse APEX MI-0008 case. Also has: parallel port available on mother board, you extend to a connector RS232 serial port available on mother board, you extend to a connector a single DC power supply from 11 to 19 V DC. 1 each PCIe expansion port, I will use with a premium 4 channel sound card SATA ports available for HDD/SDD, USB ports are available, Motherboard sound, and Gigalan. I have not played with NTP, (yet), but it sounds like a decent time nut technical challenge. My application is for a remote site with only 13V DC power available from PV/batteries. Then use fiber ethernet to get off site. The INTEL website would have further details. Stan, W1LECape Cod FN41sr z ___ time-nuts mailing 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] L1 GPS timing signal(s) into local time on computer(s)
In my experience (which is admittedly less than that of many others here) the time reported is that of the PPS pulse that just happened, and the documentation usually bears that out. There's a real-time clock running inside the receiver that is synchronized to the PPS. At the top of the second, the PPS is output and the RTC increments. Some number of milliseconds later, that RTC time value is output, which is the current time, not that of the next pulse. That's certainly the way the Motorola M12+ Timing receiver (Motorola binary mode) and all of the SiRFstar-based NMEA navigation receivers I've used work. Beware of the situation where a cold-started receiver hasn't yet acquired the UTC offset portion of the almanac and will report time some number of seconds different than UTC. The SiRF receivers are especially misleading, as they can be off by just one or two seconds depending on when their firmware was built. They are programmed with default offset values that were valid at the time of their manufacture. In one case I had, it was sometimes off by one second, sometimes not. After June 30, 2012, it was now sometimes off by two seconds, and then I knew what was going on. The M12+ has a default offset of zero, which I find much more sane. It reports GPS time (a whopping 16 seconds different) until the UTC offset is received. Sent from my iPod On Aug 19, 2012, at 9:42, Sarah White kuze...@gmail.com wrote: Ken: From what I've read, most GPS modules which output PPS, the NMEA sentence has the timestamp of the next, upcoming pulse. Regardless of how the NMEA or other time data is, the PPS itself is only a guarantee this is the boundary for a second and NTP documentation typically recommends a second reference clock to number the seconds anyway. Everyone: Thanks everyone. I got many responses which confirm my initial conclusions. I had trouble locating a GPS thunderbolt on ebay because there is an HTC phone with thunderbolt in the name. (I got a few hits for the GPS module, but there is no way to filter out phones or I might just be bad at operating ebay) uhm... yeah. As someone pointed out. It is a total nightmare to figure out which direction my GPS time is wandering, and finding the correct offset. I'm just gonna give up on this USB module, and get a real one with PPS Also, I really hate google's new shopping experience. They started listing less content, and now push content from stores which charge 2-3 times as much. As far as existing hardware goes, I don't have any slots free in my desktop for a serial board... Despite the new google shopping headache, I was able to determine that many older computers from the windows XP era which still have serial ports, and are available refurbished from walmart of all the crazy places. (most of the time, better price than the ones being pushed by google shopping, and even have XP installed and a 1 year warranty) So no problem. I can source a suitable machine to run NTP, and for less than $200, guaranteed. Will probably be using gentoo linux, as the default configuration does NOT expect you to run any specific kernel. I can easily recompile anything I need without breaking unusual, unforeseen dependencies. (doesn't hurt that I've been using gentoo since the stage1 install was preferred, all the way back to the GCC 2.x era) I'm really aiming to run a server which ONLY runs NTP, and at most 1 or two other daemons (light duty on those) Thanks so much everyone. On 8/19/2012 7:11 AM, Ken Duffill wrote: Just one further question. When the pps input triggers, so my linux box knows a second has just ticked; is the time of that second the one the NMEA sentence has just sent, or will send next? Or to put it another way, when I receive an NMEA sentence is this the current time (as was when the sentence was constructed) or the time at the next PPS 'tick'? Thanks in advance. KenD On 19/08/12 11:23, Bill Dailey wrote: I will jump in a bit. I, and many have been right where you are. You are correct...USB is a no go for accurate time. Same on windows. So you need a Linux box with serial port. Anything from a Beaglebone, pandabox...or pc will work. You certainly need a gps with a pulse per second output (most have) and you can wire that up to the appropriate line on the serial cable or send to the target computer via gpio pin. The pps thing is fairly simple really. If you are receiving gps data via serial connection it takes a variable amount of time to get each status report from the gps...list time etc etc in text format and sends it repeatedly. This gets ntp to within a second or some fraction thereof...the pps part refines that..no text or anything... Just a one pulse per second separate from the gps info that acts as a exclamation point to tell ntp right here is the actual start of the second! alone the pps wouldn't be useful for time but with the time info
[time-nuts] Embedded NTP servers?
Greetings nuts, All this recent NTP discussion has me thinking about a dedicated NTP server again. The usual solution is to use commodity hardware of some persuasion (PC, mini-itx or even ARM) running ntpd, but I'm thinking we can do better. The only reason a full ntpd is needed is for its software PLLs that measure and compensate for deficiencies in the local oscillator. But if that local oscillator is replaced by a disciplined 10MHz clock, and a coincident pulse-per-second and NMEA from the GPSDO fed in, then a reasonably fitted microcontroller should do the trick. I happen to have a Ethernet-enabled widget I put together for another project as a kind of drop-in module, built on a PIC18F66J60 which has a built-in 10mbit Ethernet controller. The problem with it seems to be relatively poor and unpredictable packet servicing latency. Usually pings are 1.02ms but with some significant deviation. I imagine a lot of the deficiencies with this arrangement come from the vendor-supplied IP stack, which is not latency-optimized, but also the 10mbit link contributes some quantization type problems. Microchip also makes a 100mbit-capable standalone controller, ENC624J600. I'd probably use that and pair it with any 72MHz ARM microcontroller. The micro would be clocked by a (multiplied) 10MHz disciplined input and the pulse-per-second would come in on a input capture channel that can timestamp the pulse relative to a local counter. And since ntp is such a simple protocol, it should be pretty easy to write a appropriate ntp server routine that just hands out the time from GPS, including leap second indications. Thoughts? Has it been done before, preferably with open source? I'd love to make it myself but I have to finish the GPSDO first :-) -- m. tharp ___ time-nuts mailing 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] Modern motherboard with RS232 port
This sounds like a newer version of the board I use. The thing to check is if the CPU heat sink has a fan or not. Having no fan indicates that the CPU is not using much power. It also removes a common failure point. To reduce power even more. On an NTP server you can unplug the keyboard, mouse and monitor and if you have other servers on the LAN configure one as a boot server and have it run TFTP then your NTP server does not need a disk drive. It can run off a RAM disk. This makes it very fast, even faster than a SSD and it saves some cash. Makes backup easy too as there is nothing to backup if there is no local storage. If you don't have a TFTP server use a small notebook size disk drive. Even a 80GB drive is overkill. You can also boot from a USB thumb drive and run a RAM disk. It is worth it to look at your electric bill to find how much you pay for power. Here I'm at $0.21 per KWH. A full size PC server can use 250W or more. There are 8760 hours in a year so you get $460 per year to run that 250W PC. The little Atom will pay for itself in just a few months. The first time I did that calculation, my power hogs where given away. On Sun, Aug 19, 2012 at 7:42 AM, Stan, W1LE stanw...@verizon.net wrote: Hello The Net, For your consideration: The INTEL model DN2800mt ITX mother board uses a ATOM CPU and draws about 11 watts of AC power when configured as: (I have not measured DC power yet.) 30 GB OCZ Nocti mSATA solid state drive, WIN7 pro, 64 bit, USB keyboard and mouse APEX MI-0008 case. Also has: parallel port available on mother board, you extend to a connector RS232 serial port available on mother board, you extend to a connector a single DC power supply from 11 to 19 V DC. 1 each PCIe expansion port, I will use with a premium 4 channel sound card SATA ports available for HDD/SDD, USB ports are available, Motherboard sound, and Gigalan. I have not played with NTP, (yet), but it sounds like a decent time nut technical challenge. My application is for a remote site with only 13V DC power available from PV/batteries. Then use fiber ethernet to get off site. The INTEL website would have further details. Stan, W1LECape Cod FN41sr z __**_ 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. -- 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] Modern motherboard with RS232 port
Why not just use a raspberry pi? Uses a whole 2w at idle. Ntp might bump that to 2.01. On Aug 19, 2012, at 13:06, Chris Albertson albertson.ch...@gmail.com wrote: This sounds like a newer version of the board I use. The thing to check is if the CPU heat sink has a fan or not. Having no fan indicates that the CPU is not using much power. It also removes a common failure point. To reduce power even more. On an NTP server you can unplug the keyboard, mouse and monitor and if you have other servers on the LAN configure one as a boot server and have it run TFTP then your NTP server does not need a disk drive. It can run off a RAM disk. This makes it very fast, even faster than a SSD and it saves some cash. Makes backup easy too as there is nothing to backup if there is no local storage. If you don't have a TFTP server use a small notebook size disk drive. Even a 80GB drive is overkill. You can also boot from a USB thumb drive and run a RAM disk. It is worth it to look at your electric bill to find how much you pay for power. Here I'm at $0.21 per KWH. A full size PC server can use 250W or more. There are 8760 hours in a year so you get $460 per year to run that 250W PC. The little Atom will pay for itself in just a few months. The first time I did that calculation, my power hogs where given away. On Sun, Aug 19, 2012 at 7:42 AM, Stan, W1LE stanw...@verizon.net wrote: Hello The Net, For your consideration: The INTEL model DN2800mt ITX mother board uses a ATOM CPU and draws about 11 watts of AC power when configured as: (I have not measured DC power yet.) 30 GB OCZ Nocti mSATA solid state drive, WIN7 pro, 64 bit, USB keyboard and mouse APEX MI-0008 case. Also has: parallel port available on mother board, you extend to a connector RS232 serial port available on mother board, you extend to a connector a single DC power supply from 11 to 19 V DC. 1 each PCIe expansion port, I will use with a premium 4 channel sound card SATA ports available for HDD/SDD, USB ports are available, Motherboard sound, and Gigalan. I have not played with NTP, (yet), but it sounds like a decent time nut technical challenge. My application is for a remote site with only 13V DC power available from PV/batteries. Then use fiber ethernet to get off site. The INTEL website would have further details. Stan, W1LECape Cod FN41sr z __**_ 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. -- 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] L1 GPS timing signal(s) into local time on computer(s)
On Sat, Aug 18, 2012 at 10:23 PM, li...@lazygranch.com wrote: If you are using a desktop, I'd suggest putting in a serial card. The Netmos chip based cards work on windows and linux, though your should do an internet search on the particular card before you buy. I have the prolific based converter. It didn't work with my Starloc. (The netmos worked fine with Lady Heather.) I just got a Gearmo branded FTDI based usb to serial. I haven't tried it on the Starloc, but it works well on other I just worked out the cost of power. If you, like me are paying $0.21/KHW a new Atom based PC will pay for itself in less then 6 months . It is astonishing when you actually compute the cost to run a PC 24x7 for one year. A normal desktop or notebook PC is not so expensive to run because it spends most time either powered off or in sleep mode. But an NTP server needs to stay active 24x7.A standard desktop PC can burn $400 or more in electric cost per year. A notebook PC is almost as bad (Notice the 100+ watt rating on the notebook's power brick) The new Atom boards are about 6W and costs only $100 at Amazon.com But, yes, I agree stuffing a PCI serial card in a desktop PC can get you the serial port you need. They work well. Just remember that the desktop will have to stay powered up 24x7 for years. 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] Modern motherboard with RS232 port
Hi Onboard ethernet on the pi model B is hooked into the CPU via the USB port. That may not be best for accurate time. Bob On Aug 19, 2012, at 1:16 PM, bownes bow...@gmail.com wrote: Why not just use a raspberry pi? Uses a whole 2w at idle. Ntp might bump that to 2.01. On Aug 19, 2012, at 13:06, Chris Albertson albertson.ch...@gmail.com wrote: This sounds like a newer version of the board I use. The thing to check is if the CPU heat sink has a fan or not. Having no fan indicates that the CPU is not using much power. It also removes a common failure point. To reduce power even more. On an NTP server you can unplug the keyboard, mouse and monitor and if you have other servers on the LAN configure one as a boot server and have it run TFTP then your NTP server does not need a disk drive. It can run off a RAM disk. This makes it very fast, even faster than a SSD and it saves some cash. Makes backup easy too as there is nothing to backup if there is no local storage. If you don't have a TFTP server use a small notebook size disk drive. Even a 80GB drive is overkill. You can also boot from a USB thumb drive and run a RAM disk. It is worth it to look at your electric bill to find how much you pay for power. Here I'm at $0.21 per KWH. A full size PC server can use 250W or more. There are 8760 hours in a year so you get $460 per year to run that 250W PC. The little Atom will pay for itself in just a few months. The first time I did that calculation, my power hogs where given away. On Sun, Aug 19, 2012 at 7:42 AM, Stan, W1LE stanw...@verizon.net wrote: Hello The Net, For your consideration: The INTEL model DN2800mt ITX mother board uses a ATOM CPU and draws about 11 watts of AC power when configured as: (I have not measured DC power yet.) 30 GB OCZ Nocti mSATA solid state drive, WIN7 pro, 64 bit, USB keyboard and mouse APEX MI-0008 case. Also has: parallel port available on mother board, you extend to a connector RS232 serial port available on mother board, you extend to a connector a single DC power supply from 11 to 19 V DC. 1 each PCIe expansion port, I will use with a premium 4 channel sound card SATA ports available for HDD/SDD, USB ports are available, Motherboard sound, and Gigalan. I have not played with NTP, (yet), but it sounds like a decent time nut technical challenge. My application is for a remote site with only 13V DC power available from PV/batteries. Then use fiber ethernet to get off site. The INTEL website would have further details. Stan, W1LECape Cod FN41sr z __**_ 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. -- 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. ___ time-nuts mailing 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] Modern motherboard with RS232 port
On Sun, Aug 19, 2012 at 10:16 AM, bownes bow...@gmail.com wrote: Why not just use a raspberry pi? Uses a whole 2w at idle. Ntp might bump that to 2.01. You certainly could run ntpd on that box. But I wonder how the PPS is supported in hardware? What is the standard deviation of interrupt latency on the DCD pin on the serial port. Perhaps some one who has a pi could measure this. All the data should be in the system log as each PPS is time stamped and written to the log. If the DCD pin is polled you are not going to get decent results. Maybe someone could read the PPS drive code. -- 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] Embedded NTP servers?
On Sun, Aug 19, 2012 at 8:21 AM, Michael Tharp g...@partiallystapled.comwrote: Thoughts? Has it been done before, preferably with open source? I'd love to make it myself but I have to finish the GPSDO first :-) NTP is not as easy as you think. Just doing the cryptography to handle authentication is more then I would want to write. When a free open source ntpd exists it will be really hard to get people to help work on re-inventing it. But your idea to use a GPSDO to drive the system clock is good. People have done that and it works. You basically unsolder a TTL can oscillator and put a small connector in it's place. -- 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] Embedded NTP servers?
I have a soekris box but got hung up on the compact free bsd install. Wish I had more time to get a handle on that. I am certain the thing would be hard to beat power wise and it is all in one nice tidy box. Doc Sent from my iPhone On Aug 19, 2012, at 12:38 PM, Chris Albertson albertson.ch...@gmail.com wrote: On Sun, Aug 19, 2012 at 8:21 AM, Michael Tharp g...@partiallystapled.comwrote: Thoughts? Has it been done before, preferably with open source? I'd love to make it myself but I have to finish the GPSDO first :-) NTP is not as easy as you think. Just doing the cryptography to handle authentication is more then I would want to write. When a free open source ntpd exists it will be really hard to get people to help work on re-inventing it. But your idea to use a GPSDO to drive the system clock is good. People have done that and it works. You basically unsolder a TTL can oscillator and put a small connector in it's place. -- 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] Embedded NTP servers?
Hi Bill -- Your lucky day may be at hand -- I've been struggling to get my herd of Soekris 4501s running again and thought the process of updating from BSD 4 to 9 would be simple. Well, several months later I have a working CF image and am just getting the four 4501s Soekris's (Soekri?) running again today. I had to do some hand tweaking on the images to make things work, so I don't feel comfortable sending the config files, but I am happy to make the image available to you -- you could either snail-mail me a 2GB CF card, or we could see how much the image compresses and I can host it on febo.com. John Bill Dailey said the following on 08/19/2012 01:55 PM: I have a soekris box but got hung up on the compact free bsd install. Wish I had more time to get a handle on that. I am certain the thing would be hard to beat power wise and it is all in one nice tidy box. Doc Sent from my iPhone On Aug 19, 2012, at 12:38 PM, Chris Albertson albertson.ch...@gmail.com wrote: On Sun, Aug 19, 2012 at 8:21 AM, Michael Tharp g...@partiallystapled.comwrote: Thoughts? Has it been done before, preferably with open source? I'd love to make it myself but I have to finish the GPSDO first :-) NTP is not as easy as you think. Just doing the cryptography to handle authentication is more then I would want to write. When a free open source ntpd exists it will be really hard to get people to help work on re-inventing it. But your idea to use a GPSDO to drive the system clock is good. People have done that and it works. You basically unsolder a TTL can oscillator and put a small connector in it's place. -- 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. ___ time-nuts mailing 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] Tidbit for Soekris 4501 NTP users
This is probably something that very, very few other people are going to encounter, but thought I would note it here for posterity. I'm using the Soekris 4501 with high-resolution Elan CPU for nanosecond timestamps as documented at http://www.febo.com/pages/soekris. When using a PPS-only refclock (e.g., pulse from a cesium clock with no serial timecode), I found that the PPS signal was not being seen unless some other process held the serial port open. In the non-time-nuts (or even semi-time-nuts) world, you'd never see this because the PPS is always associated with a GPS or other device that is sending a serial timecode. But with a PPS-only setup (where the prefer peer is a remote host), the symptom is that the PPS source is never seen. The simple cure is to do cat /dev/pps0 /dev/null as part of the startup script. There's probably a more elegant way, though. John ___ time-nuts mailing 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] Embedded NTP servers?
On 08/19/2012 01:38 PM, Chris Albertson wrote: NTP is not as easy as you think. Just doing the cryptography to handle authentication is more then I would want to write. When a free open source ntpd exists it will be really hard to get people to help work on re-inventing it. But your idea to use a GPSDO to drive the system clock is good. People have done that and it works. You basically unsolder a TTL can oscillator and put a small connector in it's place. This is specifically *not* a full ntp implementation. There's no client, no PLLs or clock correction, nothing but using 10MHz+PPS+NMEA to feed an internal clock and serving it out over ntp to more intelligent clients. I haven't written any code yet but from nosing around in wireshark it seems like the ntp part of the project wouldn't take more than an hour or two to write. The only tricky part is keeping a calendar so it knows when to insert a leap second. I'm not initially interested in authentication, although I do have all my PCs at home running in authenticated broadcast mode. So I might add auth later so it can participate, but I would be satisfied without it. -- m. tharp ___ time-nuts mailing 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] Embedded NTP servers?
If your design gets off the ground, I'd surely try to replicate it from your part list or buy a kit from you or whatever. Sounds great. On 8/19/2012 2:19 PM, Michael Tharp wrote: On 08/19/2012 01:38 PM, Chris Albertson wrote: NTP is not as easy as you think. Just doing the cryptography to handle authentication is more then I would want to write. When a free open source ntpd exists it will be really hard to get people to help work on re-inventing it. But your idea to use a GPSDO to drive the system clock is good. People have done that and it works. You basically unsolder a TTL can oscillator and put a small connector in it's place. This is specifically *not* a full ntp implementation. There's no client, no PLLs or clock correction, nothing but using 10MHz+PPS+NMEA to feed an internal clock and serving it out over ntp to more intelligent clients. I haven't written any code yet but from nosing around in wireshark it seems like the ntp part of the project wouldn't take more than an hour or two to write. The only tricky part is keeping a calendar so it knows when to insert a leap second. I'm not initially interested in authentication, although I do have all my PCs at home running in authenticated broadcast mode. So I might add auth later so it can participate, but I would be satisfied without it. -- m. tharp ___ time-nuts mailing 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] Modern motherboard with RS232 port
It's important to remember that on a computer, the wattage shown has no relationship to the wattage pulled from the socket. The numbers shown are maximum values. You have to measure the power draw and you have to measure it in volt-amps, not watts because that's how residential power is measured (at least in North America). Buy an energy meter that shows volt-amps. They're relatively cheap - typically less than $50. Ed On 8/19/2012 11:06 AM, Chris Albertson wrote: This sounds like a newer version of the board I use. The thing to check is if the CPU heat sink has a fan or not. Having no fan indicates that the CPU is not using much power. It also removes a common failure point. To reduce power even more. On an NTP server you can unplug the keyboard, mouse and monitor and if you have other servers on the LAN configure one as a boot server and have it run TFTP then your NTP server does not need a disk drive. It can run off a RAM disk. This makes it very fast, even faster than a SSD and it saves some cash. Makes backup easy too as there is nothing to backup if there is no local storage. If you don't have a TFTP server use a small notebook size disk drive. Even a 80GB drive is overkill. You can also boot from a USB thumb drive and run a RAM disk. It is worth it to look at your electric bill to find how much you pay for power. Here I'm at $0.21 per KWH. A full size PC server can use 250W or more. There are 8760 hours in a year so you get $460 per year to run that 250W PC. The little Atom will pay for itself in just a few months. The first time I did that calculation, my power hogs where given away. On Sun, Aug 19, 2012 at 7:42 AM, Stan, W1LE stanw...@verizon.net wrote: Hello The Net, For your consideration: The INTEL model DN2800mt ITX mother board uses a ATOM CPU and draws about 11 watts of AC power when configured as: (I have not measured DC power yet.) 30 GB OCZ Nocti mSATA solid state drive, WIN7 pro, 64 bit, USB keyboard and mouse APEX MI-0008 case. Also has: parallel port available on mother board, you extend to a connector RS232 serial port available on mother board, you extend to a connector a single DC power supply from 11 to 19 V DC. 1 each PCIe expansion port, I will use with a premium 4 channel sound card SATA ports available for HDD/SDD, USB ports are available, Motherboard sound, and Gigalan. I have not played with NTP, (yet), but it sounds like a decent time nut technical challenge. My application is for a remote site with only 13V DC power available from PV/batteries. Then use fiber ethernet to get off site. The INTEL website would have further details. Stan, W1LECape Cod FN41sr z ___ time-nuts mailing 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] Modern motherboard with RS232 port
Hi Ed; I may not have had enough coffee yet, but if Volt X Amps = Watts why would there be a difference? Best Wishes; Thomas Knox Date: Sun, 19 Aug 2012 12:35:51 -0600 From: ed_pal...@sasktel.net To: time-nuts@febo.com Subject: Re: [time-nuts] Modern motherboard with RS232 port It's important to remember that on a computer, the wattage shown has no relationship to the wattage pulled from the socket. The numbers shown are maximum values. You have to measure the power draw and you have to measure it in volt-amps, not watts because that's how residential power is measured (at least in North America). Buy an energy meter that shows volt-amps. They're relatively cheap - typically less than $50. Ed On 8/19/2012 11:06 AM, Chris Albertson wrote: This sounds like a newer version of the board I use. The thing to check is if the CPU heat sink has a fan or not. Having no fan indicates that the CPU is not using much power. It also removes a common failure point. To reduce power even more. On an NTP server you can unplug the keyboard, mouse and monitor and if you have other servers on the LAN configure one as a boot server and have it run TFTP then your NTP server does not need a disk drive. It can run off a RAM disk. This makes it very fast, even faster than a SSD and it saves some cash. Makes backup easy too as there is nothing to backup if there is no local storage. If you don't have a TFTP server use a small notebook size disk drive. Even a 80GB drive is overkill. You can also boot from a USB thumb drive and run a RAM disk. It is worth it to look at your electric bill to find how much you pay for power. Here I'm at $0.21 per KWH. A full size PC server can use 250W or more. There are 8760 hours in a year so you get $460 per year to run that 250W PC. The little Atom will pay for itself in just a few months. The first time I did that calculation, my power hogs where given away. On Sun, Aug 19, 2012 at 7:42 AM, Stan, W1LE stanw...@verizon.net wrote: Hello The Net, For your consideration: The INTEL model DN2800mt ITX mother board uses a ATOM CPU and draws about 11 watts of AC power when configured as: (I have not measured DC power yet.) 30 GB OCZ Nocti mSATA solid state drive, WIN7 pro, 64 bit, USB keyboard and mouse APEX MI-0008 case. Also has: parallel port available on mother board, you extend to a connector RS232 serial port available on mother board, you extend to a connector a single DC power supply from 11 to 19 V DC. 1 each PCIe expansion port, I will use with a premium 4 channel sound card SATA ports available for HDD/SDD, USB ports are available, Motherboard sound, and Gigalan. I have not played with NTP, (yet), but it sounds like a decent time nut technical challenge. My application is for a remote site with only 13V DC power available from PV/batteries. Then use fiber ethernet to get off site. The INTEL website would have further details. Stan, W1LECape Cod FN41sr z ___ time-nuts mailing 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] : L1 GPS timing signal(s) into local time on computer(s)
Sarah, If you want to filter in ebay, you can use a- for a subject that you don't want to see. It is the same syntax as you can use in a browser. Regards, Willy -Oorspronkelijk bericht- Van: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] Namens time-nuts-requ...@febo.com Verzonden: zondag 19 augustus 2012 19:07 Aan: time-nuts@febo.com Onderwerp: time-nuts Digest, Vol 97, Issue 48 Send time-nuts mailing list submissions to time-nuts@febo.com To subscribe or unsubscribe via the World Wide Web, visit https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts or, via email, send a message with subject or body 'help' to time-nuts-requ...@febo.com You can reach the person managing the list at time-nuts-ow...@febo.com When replying, please edit your Subject line so it is more specific than Re: Contents of time-nuts digest... Today's Topics: 1. Re: L1 GPS timing signal(s) into local time oncomputer(s) (Sarah White) 2. Modern motherboard with RS232 port (Stan, W1LE) 3. Re: L1 GPS timing signal(s) into local time oncomputer(s) (KD0GLS) 4. Embedded NTP servers? (Michael Tharp) 5. Re: Modern motherboard with RS232 port (Chris Albertson) -- Message: 1 Date: Sun, 19 Aug 2012 10:41:39 -0400 From: Sarah White kuze...@gmail.com To: time-nuts@febo.com Subject: Re: [time-nuts] L1 GPS timing signal(s) into local time on computer(s) Message-ID: 5030fb23.7040...@gmail.com Content-Type: text/plain; charset=ISO-8859-1 Ken: From what I've read, most GPS modules which output PPS, the NMEA sentence has the timestamp of the next, upcoming pulse. Regardless of how the NMEA or other time data is, the PPS itself is only a guarantee this is the boundary for a second and NTP documentation typically recommends a second reference clock to number the seconds anyway. Everyone: Thanks everyone. I got many responses which confirm my initial conclusions. I had trouble locating a GPS thunderbolt on ebay because there is an HTC phone with thunderbolt in the name. (I got a few hits for the GPS module, but there is no way to filter out phones or I might just be bad at operating ebay) uhm... yeah. As someone pointed out. It is a total nightmare to figure out which direction my GPS time is wandering, and finding the correct offset. I'm just gonna give up on this USB module, and get a real one with PPS Also, I really hate google's new shopping experience. They started listing less content, and now push content from stores which charge 2-3 times as much. As far as existing hardware goes, I don't have any slots free in my desktop for a serial board... Despite the new google shopping headache, I was able to determine that many older computers from the windows XP era which still have serial ports, and are available refurbished from walmart of all the crazy places. (most of the time, better price than the ones being pushed by google shopping, and even have XP installed and a 1 year warranty) So no problem. I can source a suitable machine to run NTP, and for less than $200, guaranteed. Will probably be using gentoo linux, as the default configuration does NOT expect you to run any specific kernel. I can easily recompile anything I need without breaking unusual, unforeseen dependencies. (doesn't hurt that I've been using gentoo since the stage1 install was preferred, all the way back to the GCC 2.x era) I'm really aiming to run a server which ONLY runs NTP, and at most 1 or two other daemons (light duty on those) Thanks so much everyone. On 8/19/2012 7:11 AM, Ken Duffill wrote: Just one further question. When the pps input triggers, so my linux box knows a second has just ticked; is the time of that second the one the NMEA sentence has just sent, or will send next? Or to put it another way, when I receive an NMEA sentence is this the current time (as was when the sentence was constructed) or the time at the next PPS 'tick'? Thanks in advance. KenD On 19/08/12 11:23, Bill Dailey wrote: I will jump in a bit. I, and many have been right where you are. You are correct...USB is a no go for accurate time. Same on windows. So you need a Linux box with serial port. Anything from a Beaglebone, pandabox...or pc will work. You certainly need a gps with a pulse per second output (most have) and you can wire that up to the appropriate line on the serial cable or send to the target computer via gpio pin. The pps thing is fairly simple really. If you are receiving gps data via serial connection it takes a variable amount of time to get each status report from the gps...list time etc etc in text format and sends it repeatedly. This gets ntp to within a second or some fraction thereof...the pps part refines that..no text or anything... Just a one pulse per second separate from the gps info that acts as a exclamation point to tell ntp right here
Re: [time-nuts] : L1 GPS timing signal(s) into local time on computer(s)
oh wow, thanks. I'll try that. Also, I figured out that typing in trimble thunderbolt instead of thunderbolt gps gives me zero hits for phone... but fewer hits for the GPSDO too :( On 8/19/2012 3:21 PM, Willy Willemse wrote: Sarah, If you want to filter in ebay, you can use a- for a subject that you don't want to see. It is the same syntax as you can use in a browser. Regards, Willy -Oorspronkelijk bericht- Van: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] Namens time-nuts-requ...@febo.com Verzonden: zondag 19 augustus 2012 19:07 Aan: time-nuts@febo.com Onderwerp: time-nuts Digest, Vol 97, Issue 48 Send time-nuts mailing list submissions to time-nuts@febo.com To subscribe or unsubscribe via the World Wide Web, visit https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts or, via email, send a message with subject or body 'help' to time-nuts-requ...@febo.com You can reach the person managing the list at time-nuts-ow...@febo.com When replying, please edit your Subject line so it is more specific than Re: Contents of time-nuts digest... Today's Topics: 1. Re: L1 GPS timing signal(s) into local time on computer(s) (Sarah White) 2. Modern motherboard with RS232 port (Stan, W1LE) 3. Re: L1 GPS timing signal(s) into local time on computer(s) (KD0GLS) 4. Embedded NTP servers? (Michael Tharp) 5. Re: Modern motherboard with RS232 port (Chris Albertson) -- Message: 1 Date: Sun, 19 Aug 2012 10:41:39 -0400 From: Sarah White kuze...@gmail.com To: time-nuts@febo.com Subject: Re: [time-nuts] L1 GPS timing signal(s) into local time on computer(s) Message-ID: 5030fb23.7040...@gmail.com Content-Type: text/plain; charset=ISO-8859-1 Ken: From what I've read, most GPS modules which output PPS, the NMEA sentence has the timestamp of the next, upcoming pulse. Regardless of how the NMEA or other time data is, the PPS itself is only a guarantee this is the boundary for a second and NTP documentation typically recommends a second reference clock to number the seconds anyway. Everyone: Thanks everyone. I got many responses which confirm my initial conclusions. I had trouble locating a GPS thunderbolt on ebay because there is an HTC phone with thunderbolt in the name. (I got a few hits for the GPS module, but there is no way to filter out phones or I might just be bad at operating ebay) uhm... yeah. As someone pointed out. It is a total nightmare to figure out which direction my GPS time is wandering, and finding the correct offset. I'm just gonna give up on this USB module, and get a real one with PPS Also, I really hate google's new shopping experience. They started listing less content, and now push content from stores which charge 2-3 times as much. As far as existing hardware goes, I don't have any slots free in my desktop for a serial board... Despite the new google shopping headache, I was able to determine that many older computers from the windows XP era which still have serial ports, and are available refurbished from walmart of all the crazy places. (most of the time, better price than the ones being pushed by google shopping, and even have XP installed and a 1 year warranty) So no problem. I can source a suitable machine to run NTP, and for less than $200, guaranteed. Will probably be using gentoo linux, as the default configuration does NOT expect you to run any specific kernel. I can easily recompile anything I need without breaking unusual, unforeseen dependencies. (doesn't hurt that I've been using gentoo since the stage1 install was preferred, all the way back to the GCC 2.x era) I'm really aiming to run a server which ONLY runs NTP, and at most 1 or two other daemons (light duty on those) Thanks so much everyone. On 8/19/2012 7:11 AM, Ken Duffill wrote: Just one further question. When the pps input triggers, so my linux box knows a second has just ticked; is the time of that second the one the NMEA sentence has just sent, or will send next? Or to put it another way, when I receive an NMEA sentence is this the current time (as was when the sentence was constructed) or the time at the next PPS 'tick'? Thanks in advance. KenD On 19/08/12 11:23, Bill Dailey wrote: I will jump in a bit. I, and many have been right where you are. You are correct...USB is a no go for accurate time. Same on windows. So you need a Linux box with serial port. Anything from a Beaglebone, pandabox...or pc will work. You certainly need a gps with a pulse per second output (most have) and you can wire that up to the appropriate line on the serial cable or send to the target computer via gpio pin. The pps thing is fairly simple really. If you are receiving gps data via serial connection it takes a variable amount of time to get each
Re: [time-nuts] Modern motherboard with RS232 port
Ed: you're sorta right, but only on a really basic level of electrical engineering. Induction and capacitance and random transformer magnetic flux nonsense that makes AC currents act in unexpected ways. The difference between volt-amp versus RMS watt versus peak watts, etc, etc. can be off by more than you'd expect. It really comes into play when you're trying to build power supplies (regulated or otherwise) On 8/19/2012 3:19 PM, Tom Knox wrote: Hi Ed; I may not have had enough coffee yet, but if Volt X Amps = Watts why would there be a difference? Best Wishes; Thomas Knox Date: Sun, 19 Aug 2012 12:35:51 -0600 From: ed_pal...@sasktel.net To: time-nuts@febo.com Subject: Re: [time-nuts] Modern motherboard with RS232 port It's important to remember that on a computer, the wattage shown has no relationship to the wattage pulled from the socket. The numbers shown are maximum values. You have to measure the power draw and you have to measure it in volt-amps, not watts because that's how residential power is measured (at least in North America). Buy an energy meter that shows volt-amps. They're relatively cheap - typically less than $50. Ed On 8/19/2012 11:06 AM, Chris Albertson wrote: This sounds like a newer version of the board I use. The thing to check is if the CPU heat sink has a fan or not. Having no fan indicates that the CPU is not using much power. It also removes a common failure point. To reduce power even more. On an NTP server you can unplug the keyboard, mouse and monitor and if you have other servers on the LAN configure one as a boot server and have it run TFTP then your NTP server does not need a disk drive. It can run off a RAM disk. This makes it very fast, even faster than a SSD and it saves some cash. Makes backup easy too as there is nothing to backup if there is no local storage. If you don't have a TFTP server use a small notebook size disk drive. Even a 80GB drive is overkill. You can also boot from a USB thumb drive and run a RAM disk. It is worth it to look at your electric bill to find how much you pay for power. Here I'm at $0.21 per KWH. A full size PC server can use 250W or more. There are 8760 hours in a year so you get $460 per year to run that 250W PC. The little Atom will pay for itself in just a few months. The first time I did that calculation, my power hogs where given away. On Sun, Aug 19, 2012 at 7:42 AM, Stan, W1LE stanw...@verizon.net wrote: Hello The Net, For your consideration: The INTEL model DN2800mt ITX mother board uses a ATOM CPU and draws about 11 watts of AC power when configured as: (I have not measured DC power yet.) 30 GB OCZ Nocti mSATA solid state drive, WIN7 pro, 64 bit, USB keyboard and mouse APEX MI-0008 case. Also has: parallel port available on mother board, you extend to a connector RS232 serial port available on mother board, you extend to a connector a single DC power supply from 11 to 19 V DC. 1 each PCIe expansion port, I will use with a premium 4 channel sound card SATA ports available for HDD/SDD, USB ports are available, Motherboard sound, and Gigalan. I have not played with NTP, (yet), but it sounds like a decent time nut technical challenge. My application is for a remote site with only 13V DC power available from PV/batteries. Then use fiber ethernet to get off site. The INTEL website would have further details. Stan, W1LECape Cod FN41sr z ___ time-nuts mailing 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] Modern motherboard with RS232 port
Power factor. -Original Message- From: Tom Knox act...@hotmail.com Sender: time-nuts-boun...@febo.com Date: Sun, 19 Aug 2012 13:19:20 To: Time-Nutstime-nuts@febo.com Reply-To: Discussion of precise time and frequency measurement time-nuts@febo.com Subject: Re: [time-nuts] Modern motherboard with RS232 port Hi Ed; I may not have had enough coffee yet, but if Volt X Amps = Watts why would there be a difference? Best Wishes; Thomas Knox Date: Sun, 19 Aug 2012 12:35:51 -0600 From: ed_pal...@sasktel.net To: time-nuts@febo.com Subject: Re: [time-nuts] Modern motherboard with RS232 port It's important to remember that on a computer, the wattage shown has no relationship to the wattage pulled from the socket. The numbers shown are maximum values. You have to measure the power draw and you have to measure it in volt-amps, not watts because that's how residential power is measured (at least in North America). Buy an energy meter that shows volt-amps. They're relatively cheap - typically less than $50. Ed On 8/19/2012 11:06 AM, Chris Albertson wrote: This sounds like a newer version of the board I use. The thing to check is if the CPU heat sink has a fan or not. Having no fan indicates that the CPU is not using much power. It also removes a common failure point. To reduce power even more. On an NTP server you can unplug the keyboard, mouse and monitor and if you have other servers on the LAN configure one as a boot server and have it run TFTP then your NTP server does not need a disk drive. It can run off a RAM disk. This makes it very fast, even faster than a SSD and it saves some cash. Makes backup easy too as there is nothing to backup if there is no local storage. If you don't have a TFTP server use a small notebook size disk drive. Even a 80GB drive is overkill. You can also boot from a USB thumb drive and run a RAM disk. It is worth it to look at your electric bill to find how much you pay for power. Here I'm at $0.21 per KWH. A full size PC server can use 250W or more. There are 8760 hours in a year so you get $460 per year to run that 250W PC. The little Atom will pay for itself in just a few months. The first time I did that calculation, my power hogs where given away. On Sun, Aug 19, 2012 at 7:42 AM, Stan, W1LE stanw...@verizon.net wrote: Hello The Net, For your consideration: The INTEL model DN2800mt ITX mother board uses a ATOM CPU and draws about 11 watts of AC power when configured as: (I have not measured DC power yet.) 30 GB OCZ Nocti mSATA solid state drive, WIN7 pro, 64 bit, USB keyboard and mouse APEX MI-0008 case. Also has: parallel port available on mother board, you extend to a connector RS232 serial port available on mother board, you extend to a connector a single DC power supply from 11 to 19 V DC. 1 each PCIe expansion port, I will use with a premium 4 channel sound card SATA ports available for HDD/SDD, USB ports are available, Motherboard sound, and Gigalan. I have not played with NTP, (yet), but it sounds like a decent time nut technical challenge. My application is for a remote site with only 13V DC power available from PV/batteries. Then use fiber ethernet to get off site. The INTEL website would have further details. Stan, W1LECape Cod FN41sr z ___ time-nuts mailing 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] Modern motherboard with RS232 port
There is no difference for a resistive load. For a reactive load, you have to take in account the phase angle between the current and the voltage. If I remember correctly, power = Volts X Amps X cosine of the phase angle. Some refer to the phase angle as the power factor. John WA4WDL -- From: Tom Knox act...@hotmail.com Sent: Sunday, August 19, 2012 3:19 PM To: Time-Nuts time-nuts@febo.com Subject: Re: [time-nuts] Modern motherboard with RS232 port Hi Ed; I may not have had enough coffee yet, but if Volt X Amps = Watts why would there be a difference? Best Wishes; Thomas Knox Date: Sun, 19 Aug 2012 12:35:51 -0600 From: ed_pal...@sasktel.net To: time-nuts@febo.com Subject: Re: [time-nuts] Modern motherboard with RS232 port It's important to remember that on a computer, the wattage shown has no relationship to the wattage pulled from the socket. The numbers shown are maximum values. You have to measure the power draw and you have to measure it in volt-amps, not watts because that's how residential power is measured (at least in North America). Buy an energy meter that shows volt-amps. They're relatively cheap - typically less than $50. Ed On 8/19/2012 11:06 AM, Chris Albertson wrote: This sounds like a newer version of the board I use. The thing to check is if the CPU heat sink has a fan or not. Having no fan indicates that the CPU is not using much power. It also removes a common failure point. To reduce power even more. On an NTP server you can unplug the keyboard, mouse and monitor and if you have other servers on the LAN configure one as a boot server and have it run TFTP then your NTP server does not need a disk drive. It can run off a RAM disk. This makes it very fast, even faster than a SSD and it saves some cash. Makes backup easy too as there is nothing to backup if there is no local storage. If you don't have a TFTP server use a small notebook size disk drive. Even a 80GB drive is overkill. You can also boot from a USB thumb drive and run a RAM disk. It is worth it to look at your electric bill to find how much you pay for power. Here I'm at $0.21 per KWH. A full size PC server can use 250W or more. There are 8760 hours in a year so you get $460 per year to run that 250W PC. The little Atom will pay for itself in just a few months. The first time I did that calculation, my power hogs where given away. On Sun, Aug 19, 2012 at 7:42 AM, Stan, W1LE stanw...@verizon.net wrote: Hello The Net, For your consideration: The INTEL model DN2800mt ITX mother board uses a ATOM CPU and draws about 11 watts of AC power when configured as: (I have not measured DC power yet.) 30 GB OCZ Nocti mSATA solid state drive, WIN7 pro, 64 bit, USB keyboard and mouse APEX MI-0008 case. Also has: parallel port available on mother board, you extend to a connector RS232 serial port available on mother board, you extend to a connector a single DC power supply from 11 to 19 V DC. 1 each PCIe expansion port, I will use with a premium 4 channel sound card SATA ports available for HDD/SDD, USB ports are available, Motherboard sound, and Gigalan. I have not played with NTP, (yet), but it sounds like a decent time nut technical challenge. My application is for a remote site with only 13V DC power available from PV/batteries. Then use fiber ethernet to get off site. The INTEL website would have further details. Stan, W1LECape Cod FN41sr z ___ time-nuts mailing 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] Modern motherboard with RS232 port
If you live near a Fry's, get a basic Kill-A-Watt. About $20. Often less on sale. You don't need the fancy version that computes cost versus time of day, etc. -Original Message- From: Ed Palmer ed_pal...@sasktel.net Sender: time-nuts-boun...@febo.com Date: Sun, 19 Aug 2012 12:35:51 To: Discussion of precise time and frequency measurementtime-nuts@febo.com Reply-To: Discussion of precise time and frequency measurement time-nuts@febo.com Subject: Re: [time-nuts] Modern motherboard with RS232 port It's important to remember that on a computer, the wattage shown has no relationship to the wattage pulled from the socket. The numbers shown are maximum values. You have to measure the power draw and you have to measure it in volt-amps, not watts because that's how residential power is measured (at least in North America). Buy an energy meter that shows volt-amps. They're relatively cheap - typically less than $50. Ed On 8/19/2012 11:06 AM, Chris Albertson wrote: This sounds like a newer version of the board I use. The thing to check is if the CPU heat sink has a fan or not. Having no fan indicates that the CPU is not using much power. It also removes a common failure point. To reduce power even more. On an NTP server you can unplug the keyboard, mouse and monitor and if you have other servers on the LAN configure one as a boot server and have it run TFTP then your NTP server does not need a disk drive. It can run off a RAM disk. This makes it very fast, even faster than a SSD and it saves some cash. Makes backup easy too as there is nothing to backup if there is no local storage. If you don't have a TFTP server use a small notebook size disk drive. Even a 80GB drive is overkill. You can also boot from a USB thumb drive and run a RAM disk. It is worth it to look at your electric bill to find how much you pay for power. Here I'm at $0.21 per KWH. A full size PC server can use 250W or more. There are 8760 hours in a year so you get $460 per year to run that 250W PC. The little Atom will pay for itself in just a few months. The first time I did that calculation, my power hogs where given away. On Sun, Aug 19, 2012 at 7:42 AM, Stan, W1LE stanw...@verizon.net wrote: Hello The Net, For your consideration: The INTEL model DN2800mt ITX mother board uses a ATOM CPU and draws about 11 watts of AC power when configured as: (I have not measured DC power yet.) 30 GB OCZ Nocti mSATA solid state drive, WIN7 pro, 64 bit, USB keyboard and mouse APEX MI-0008 case. Also has: parallel port available on mother board, you extend to a connector RS232 serial port available on mother board, you extend to a connector a single DC power supply from 11 to 19 V DC. 1 each PCIe expansion port, I will use with a premium 4 channel sound card SATA ports available for HDD/SDD, USB ports are available, Motherboard sound, and Gigalan. I have not played with NTP, (yet), but it sounds like a decent time nut technical challenge. My application is for a remote site with only 13V DC power available from PV/batteries. Then use fiber ethernet to get off site. The INTEL website would have further details. Stan, W1LECape Cod FN41sr z ___ time-nuts mailing 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] Modern motherboard with RS232 port
Phase angle/power factor Don Tom Knox Hi Ed; I may not have had enough coffee yet, but if Volt X Amps = Watts why would there be a difference? Best Wishes; Thomas Knox Date: Sun, 19 Aug 2012 12:35:51 -0600 From: ed_pal...@sasktel.net To: time-nuts@febo.com Subject: Re: [time-nuts] Modern motherboard with RS232 port It's important to remember that on a computer, the wattage shown has no relationship to the wattage pulled from the socket. The numbers shown are maximum values. You have to measure the power draw and you have to measure it in volt-amps, not watts because that's how residential power is measured (at least in North America). Buy an energy meter that shows volt-amps. They're relatively cheap - typically less than $50. Ed On 8/19/2012 11:06 AM, Chris Albertson wrote: This sounds like a newer version of the board I use. The thing to check is if the CPU heat sink has a fan or not. Having no fan indicates that the CPU is not using much power. It also removes a common failure point. To reduce power even more. On an NTP server you can unplug the keyboard, mouse and monitor and if you have other servers on the LAN configure one as a boot server and have it run TFTP then your NTP server does not need a disk drive. It can run off a RAM disk. This makes it very fast, even faster than a SSD and it saves some cash. Makes backup easy too as there is nothing to backup if there is no local storage. If you don't have a TFTP server use a small notebook size disk drive. Even a 80GB drive is overkill. You can also boot from a USB thumb drive and run a RAM disk. It is worth it to look at your electric bill to find how much you pay for power. Here I'm at $0.21 per KWH. A full size PC server can use 250W or more. There are 8760 hours in a year so you get $460 per year to run that 250W PC. The little Atom will pay for itself in just a few months. The first time I did that calculation, my power hogs where given away. On Sun, Aug 19, 2012 at 7:42 AM, Stan, W1LE stanw...@verizon.net wrote: Hello The Net, For your consideration: The INTEL model DN2800mt ITX mother board uses a ATOM CPU and draws about 11 watts of AC power when configured as: (I have not measured DC power yet.) 30 GB OCZ Nocti mSATA solid state drive, WIN7 pro, 64 bit, USB keyboard and mouse APEX MI-0008 case. Also has: parallel port available on mother board, you extend to a connector RS232 serial port available on mother board, you extend to a connector a single DC power supply from 11 to 19 V DC. 1 each PCIe expansion port, I will use with a premium 4 channel sound card SATA ports available for HDD/SDD, USB ports are available, Motherboard sound, and Gigalan. I have not played with NTP, (yet), but it sounds like a decent time nut technical challenge. My application is for a remote site with only 13V DC power available from PV/batteries. Then use fiber ethernet to get off site. The INTEL website would have further details. Stan, W1LECape Cod FN41sr z ___ time-nuts mailing 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. -- Neither the voice of authority nor the weight of reason and argument are as significant as experiment, for thence comes quiet to the mind. R. Bacon If you don't know what it is, don't poke it. Ghost in the Shell Dr. Don Latham AJ7LL Six Mile Systems LLP 17850 Six Mile Road POB 134 Huson, MT, 59846 VOX 406-626-4304 www.lightningforensics.com www.sixmilesystems.com ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Modern motherboard with RS232 port
On 08/19/2012 03:38 PM, Christopher Brown wrote: Though I am a little surprised about residential power being measured/billed in VA not KW/h in North America. Pretty sure the US is in North America, even Alaska in slightly more North America. Never seen a VA/h meter in the US. Was guessing it was a CA thing, even though I had never run across any mention of VA billing in CA, but am looking at Manitoba Hydro, NB power and SaskPower billing rates right now in KW/h. Ed, can you chime in here, where is power billed by VA (outside of some commercial/industrial and private generation agreements)? VA is used all over the place in electrical systems calculations and equipment specs but have never seen billing on it. It's also my understanding that homes are always billed by the watt. Even in industrial scale they charge a fee for poor power factor but they aren't billing by VA, according to Wikipedia at least. Still, a good plug-in power meter is a great tool for any home. I would have one already but everything is already plugged into a battery backup with a watt-meter built in and I'm not terribly concerned about accuracy. -- m. tharp ___ time-nuts mailing 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] Modern motherboard with RS232 port
Is it just me, or has this thread gone off topic a tad ?? 73, Dick, W1KSZ -Original Message- From: Michael Tharp g...@partiallystapled.com Sent: Aug 19, 2012 12:42 PM To: time-nuts@febo.com Subject: Re: [time-nuts] Modern motherboard with RS232 port On 08/19/2012 03:38 PM, Christopher Brown wrote: Though I am a little surprised about residential power being measured/billed in VA not KW/h in North America. Pretty sure the US is in North America, even Alaska in slightly more North America. Never seen a VA/h meter in the US. Was guessing it was a CA thing, even though I had never run across any mention of VA billing in CA, but am looking at Manitoba Hydro, NB power and SaskPower billing rates right now in KW/h. Ed, can you chime in here, where is power billed by VA (outside of some commercial/industrial and private generation agreements)? VA is used all over the place in electrical systems calculations and equipment specs but have never seen billing on it. It's also my understanding that homes are always billed by the watt. Even in industrial scale they charge a fee for poor power factor but they aren't billing by VA, according to Wikipedia at least. Still, a good plug-in power meter is a great tool for any home. I would have one already but everything is already plugged into a battery backup with a watt-meter built in and I'm not terribly concerned about accuracy. -- m. tharp ___ time-nuts mailing 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] Modern motherboard with RS232 port
No it is not. VA * PF = W for VA = volt amps, PF = power factor, W = watts (or true power) PF = the cos of the phase angle between the current and the voltage (assuming both are sine waves) + Peak Volts * 0.707 = RMS volts, again for sine waves only. + - Original Message - From: Christopher Brown cbr...@woods.net To: time-nuts@febo.com Sent: Sunday, August 19, 2012 3:38 PM Subject: Re: [time-nuts] Modern motherboard with RS232 port Converting VA to W is same as converting peak V to RMS V. ___ time-nuts mailing 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] Modern motherboard with RS232 port
Cosine of the phase angle is the power factor, a number between 0 and 1 But only for sine waves. - Original Message - From: jmfranke jmfra...@cox.net To: Time-Nuts time-nuts@febo.com Sent: Sunday, August 19, 2012 3:36 PM Subject: Re: [time-nuts] Modern motherboard with RS232 port There is no difference for a resistive load. For a reactive load, you have to take in account the phase angle between the current and the voltage. If I remember correctly, power = Volts X Amps X cosine of the phase angle. Some refer to the phase angle as the power factor. John WA4WDL -- From: Tom Knox act...@hotmail.com Sent: Sunday, August 19, 2012 3:19 PM To: Time-Nuts time-nuts@febo.com Subject: Re: [time-nuts] Modern motherboard with RS232 port Hi Ed; I may not have had enough coffee yet, but if Volt X Amps = Watts why would there be a difference? Best Wishes; Thomas Knox Date: Sun, 19 Aug 2012 12:35:51 -0600 From: ed_pal...@sasktel.net To: time-nuts@febo.com Subject: Re: [time-nuts] Modern motherboard with RS232 port It's important to remember that on a computer, the wattage shown has no relationship to the wattage pulled from the socket. The numbers shown are maximum values. You have to measure the power draw and you have to measure it in volt-amps, not watts because that's how residential power is measured (at least in North America). Buy an energy meter that shows volt-amps. They're relatively cheap - typically less than $50. Ed On 8/19/2012 11:06 AM, Chris Albertson wrote: This sounds like a newer version of the board I use. The thing to check is if the CPU heat sink has a fan or not. Having no fan indicates that the CPU is not using much power. It also removes a common failure point. To reduce power even more. On an NTP server you can unplug the keyboard, mouse and monitor and if you have other servers on the LAN configure one as a boot server and have it run TFTP then your NTP server does not need a disk drive. It can run off a RAM disk. This makes it very fast, even faster than a SSD and it saves some cash. Makes backup easy too as there is nothing to backup if there is no local storage. If you don't have a TFTP server use a small notebook size disk drive. Even a 80GB drive is overkill. You can also boot from a USB thumb drive and run a RAM disk. It is worth it to look at your electric bill to find how much you pay for power. Here I'm at $0.21 per KWH. A full size PC server can use 250W or more. There are 8760 hours in a year so you get $460 per year to run that 250W PC. The little Atom will pay for itself in just a few months. The first time I did that calculation, my power hogs where given away. On Sun, Aug 19, 2012 at 7:42 AM, Stan, W1LE stanw...@verizon.net wrote: Hello The Net, For your consideration: The INTEL model DN2800mt ITX mother board uses a ATOM CPU and draws about 11 watts of AC power when configured as: (I have not measured DC power yet.) 30 GB OCZ Nocti mSATA solid state drive, WIN7 pro, 64 bit, USB keyboard and mouse APEX MI-0008 case. Also has: parallel port available on mother board, you extend to a connector RS232 serial port available on mother board, you extend to a connector a single DC power supply from 11 to 19 V DC. 1 each PCIe expansion port, I will use with a premium 4 channel sound card SATA ports available for HDD/SDD, USB ports are available, Motherboard sound, and Gigalan. I have not played with NTP, (yet), but it sounds like a decent time nut technical challenge. My application is for a remote site with only 13V DC power available from PV/batteries. Then use fiber ethernet to get off site. The INTEL website would have further details. Stan, W1LECape Cod FN41sr z ___ time-nuts mailing 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] Modern motherboard with RS232 port
I stand corrected, shows what I get for listening to a UPS vendors documentation. On 8/19/12 11:52 AM, Tom Miller wrote: No it is not. VA * PF = W for VA = volt amps, PF = power factor, W = watts (or true power) PF = the cos of the phase angle between the current and the voltage (assuming both are sine waves) + Peak Volts * 0.707 = RMS volts, again for sine waves only. + - Original Message - From: Christopher Brown cbr...@woods.net To: time-nuts@febo.com Sent: Sunday, August 19, 2012 3:38 PM Subject: Re: [time-nuts] Modern motherboard with RS232 port Converting VA to W is same as converting peak V to RMS V. ___ time-nuts mailing 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] Modern motherboard with RS232 port
ed_pal...@sasktel.net said: You have to measure the power draw and you have to measure it in volt-amps, not watts because that's how residential power is measured (at least in North America). Are you sure about that? I've never seen that claim before. Here is PGE's blurb that covers their residential rates: http://www.pge.com/tariffs/tm2/pdf/ELEC_RULES_2.pdf I didn't find a section that says we bill by watts not VA. I did find a section that discusses tariffs based on horsepower vs watts and it mentioned volt-amps. They clearly know about the difference. My bill says Kwh not Kvah. act...@hotmail.com said: I may not have had enough coffee yet, but if Volt X Amps = Watts why would there be a difference? The magic word is power factor. In AC, the power is volts*amps*cos(angle). http://en.wikipedia.org/wiki/Power_factor Consider an inductor. The voltage and current are 90 degrees out of phase. Half the time, one of them has the wrong sign. Sometimes you are putting energy into the magnetic field. Sometimes the field is putting power back into the line. -- 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] Modern motherboard with RS232 port
In message 503141b7.6070...@partiallystapled.com, Michael Tharp writes: On 08/19/2012 03:38 PM, Christopher Brown wrote: VA is used all over the place in electrical systems calculations and equipment specs but have never seen billing on it. Billing VA is usually a kWh price and a KVAR surcharge. -- 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] Modern motherboard with RS232 port
On Sun, Aug 19, 2012 at 12:19 PM, Tom Knox act...@hotmail.com wrote: Hi Ed; I may not have had enough coffee yet, but if Volt X Amps = Watts why would there be a difference? That relationship holds for DC but with AC the phase relationship between voltage and current depends of the complex impedance of the load.If the load is reactive the phase will not be exactly 90 degrees. When we do the math inour heads most of us always simplify and don't bother with complex numbers but in real life impedance is complex. But for simple back of envelope calculations we can pretend the power is DC and just say Volt X Amps = Watts Another simple way to know if your PC is going to cost you an arm and a leg to run 24x7 is to place your hand over the cooling fan exhaust vent if hot air is coming out you can know for sure that you are paying $$$ to heat that air Even if the PC consumes only 50W that works out to 438 KWH per year at 20 cents per KWH you can still pay for a new $100 Atom motherboard with the savings in power and see a profit 2 years. If gets worse in the summer if you need to run the AC. Let's say the PC burns 1W. That dumps 1W of heat into the building and if your air conditioning runs on a thermostat it will burn a little over 1W to remove the extra heat. The AC is a multiplier of the power used in the house. Using this logic someone at work figured out it was cost effective to trash very old CRT monitor in the building. Same for the light bulbs, we pay a lot to cool the lighting load. (I would have simply installed windows that open and saved even more money.) -- 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] Modern motherboard with RS232 port
On Sun, Aug 19, 2012 at 1:16 PM, Chris Albertson albertson.ch...@gmail.comwrote: If the load is reactive the phase will not be exactly 90 degrees. The above is not what I meant. I meant voltage and current might not be in phase and might even be 90 out of phase. Then you can see that each phase is multiplied by zero. 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] Thanks: Watts vs VA
Hi; Thanks for the responses. I did not mean to steer the thread off course. I understand all the theroy, I just didn't understand that VA automatically included PFC or crest factor where watts did not. I would have assumed the opposite since watts is based on RMS. Thanks; Thomas Knox From: albertson.ch...@gmail.com Date: Sun, 19 Aug 2012 13:16:08 -0700 To: time-nuts@febo.com Subject: Re: [time-nuts] Modern motherboard with RS232 port On Sun, Aug 19, 2012 at 12:19 PM, Tom Knox act...@hotmail.com wrote: Hi Ed; I may not have had enough coffee yet, but if Volt X Amps = Watts why would there be a difference? That relationship holds for DC but with AC the phase relationship between voltage and current depends of the complex impedance of the load.If the load is reactive the phase will not be exactly 90 degrees. When we do the math inour heads most of us always simplify and don't bother with complex numbers but in real life impedance is complex. But for simple back of envelope calculations we can pretend the power is DC and just say Volt X Amps = Watts Another simple way to know if your PC is going to cost you an arm and a leg to run 24x7 is to place your hand over the cooling fan exhaust vent if hot air is coming out you can know for sure that you are paying $$$ to heat that air Even if the PC consumes only 50W that works out to 438 KWH per year at 20 cents per KWH you can still pay for a new $100 Atom motherboard with the savings in power and see a profit 2 years. If gets worse in the summer if you need to run the AC. Let's say the PC burns 1W. That dumps 1W of heat into the building and if your air conditioning runs on a thermostat it will burn a little over 1W to remove the extra heat. The AC is a multiplier of the power used in the house. Using this logic someone at work figured out it was cost effective to trash very old CRT monitor in the building. Same for the light bulbs, we pay a lot to cool the lighting load. (I would have simply installed windows that open and saved even more money.) -- 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] new member with questions NTP, PRS, GPS, ocxo
On Sat, Aug 18, 2012 at 9:20 AM, David J Taylor david-tay...@blueyonder.co.uk wrote: From: Chris Albertson Sent: Saturday, August 18, 2012 4:55 PM [] Power is a bigger issue. It really does cost a bit to keep some machines owered up 24x7 and NTP needs to run all the time. It takes NTP hours to stabilize and you want to wait 24 hours after to measure performance. [] Chris Albertson Redondo Beach, California ==**== I see this hours or many hours figure quoted, and yet here NTP is sufficiently accurate within a few minutes. For most uses sufficiently is about 0.1 seconds. Maybe 0.01 seconds for some critical data logging. But this being a time nuts list sufficiently means unable, even with great effort to make it better. But also what is the point of a server it you don't run it 24x7? 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] Modern motherboard with RS232 port
I was afraid that this topic would turn into a swamp and I didn't help things by getting it backwards. Yes, the residential meter measures WattHours, not VoltAmpHours. My apologies for adding confusion to an already confusing topic. While new PCs may have power factor corrected power supplies, many of us at least consider reusing old PCs. The differences between watts and volt-amps are significant on these machines. I powered up an old Compaq 1 GHz P3 and found that it draws ~60 watts and ~92 VA. Both are much lower than the stated draw of 4 amps @ 110 V. It actually draws ~0.75A. My main computer is a Dell Precision 490 Workstation. It draws ~180W and ~180 VA so it has power factor correction. But the stated rating is 6 amps @ 110V while it only draws ~1.5 amps. Any difference between Watts and VoltAmps can become an issue when you deal with a UPS (Uninterruptible Power Supply). I would hope that an NTP server would be plugged into a UPS. Most UPSs have different ratings for Watts and VoltAmps. You need an accurate measurement of your load to size the UPS correctly. So my basic point is still valid. For computers, don't believe the values stated on the labels. Measure them first. Ed On 8/19/2012 1:38 PM, Christopher Brown wrote: IIRC... VA for AC is peak volts times amps, not RMS volts. The whole point of dealing with RMS being that it makes AC and DC equiv for purposes of V * A = W. Converting VA to W is same as converting peak V to RMS V. Though I am a little surprised about residential power being measured/billed in VA not KW/h in North America. Pretty sure the US is in North America, even Alaska in slightly more North America. Never seen a VA/h meter in the US. Was guessing it was a CA thing, even though I had never run across any mention of VA billing in CA, but am looking at Manitoba Hydro, NB power and SaskPower billing rates right now in KW/h. Ed, can you chime in here, where is power billed by VA (outside of some commercial/industrial and private generation agreements)? VA is used all over the place in electrical systems calculations and equipment specs but have never seen billing on it. On 8/19/12 11:19 AM, Tom Knox wrote: Hi Ed; I may not have had enough coffee yet, but if Volt X Amps = Watts why would there be a difference? Best Wishes; Thomas Knox Date: Sun, 19 Aug 2012 12:35:51 -0600 From:ed_pal...@sasktel.net To:time-nuts@febo.com Subject: Re: [time-nuts] Modern motherboard with RS232 port It's important to remember that on a computer, the wattage shown has no relationship to the wattage pulled from the socket. The numbers shown are maximum values. You have to measure the power draw and you have to measure it in volt-amps, not watts because that's how residential power is measured (at least in North America). Buy an energy meter that shows volt-amps. They're relatively cheap - typically less than $50. Ed On 8/19/2012 11:06 AM, Chris Albertson wrote: This sounds like a newer version of the board I use. The thing to check is if the CPU heat sink has a fan or not. Having no fan indicates that the CPU is not using much power. It also removes a common failure point. To reduce power even more. On an NTP server you can unplug the keyboard, mouse and monitor and if you have other servers on the LAN configure one as a boot server and have it run TFTP then your NTP server does not need a disk drive. It can run off a RAM disk. This makes it very fast, even faster than a SSD and it saves some cash. Makes backup easy too as there is nothing to backup if there is no local storage. If you don't have a TFTP server use a small notebook size disk drive. Even a 80GB drive is overkill. You can also boot from a USB thumb drive and run a RAM disk. It is worth it to look at your electric bill to find how much you pay for power. Here I'm at $0.21 per KWH. A full size PC server can use 250W or more. There are 8760 hours in a year so you get $460 per year to run that 250W PC. The little Atom will pay for itself in just a few months. The first time I did that calculation, my power hogs where given away. On Sun, Aug 19, 2012 at 7:42 AM, Stan, W1LEstanw...@verizon.net wrote: Hello The Net, For your consideration: The INTEL model DN2800mt ITX mother board uses a ATOM CPU and draws about 11 watts of AC power when configured as: (I have not measured DC power yet.) 30 GB OCZ Nocti mSATA solid state drive, WIN7 pro, 64 bit, USB keyboard and mouse APEX MI-0008 case. Also has: parallel port available on mother board, you extend to a connector RS232 serial port available on mother board, you extend to a connector a single DC power supply from 11 to 19 V DC. 1 each PCIe expansion port, I will use with a premium 4 channel sound card SATA ports available for HDD/SDD, USB ports are available, Motherboard sound, and Gigalan. I have not played with NTP, (yet), but it sounds like a decent time nut technical challenge. My application is
Re: [time-nuts] Thanks: Watts vs VA
On 19 August 2012 21:36, Tom Knox act...@hotmail.com wrote: I would have assumed the opposite since watts is based on RMS. Thanks; Thomas Knox Power measured in Watts RMS is a useless unit. Sure you can mathematically calculate the RMS value of power, but it does not have any physical meaning, like the mean value does. ___ time-nuts mailing 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] L1 GPS timing signal(s) into local time on computer(s)
Another option is a low end laptop. I use a Dell D400 laptop, with a 1.8GHz Pentium M and it draws about 20W from A/C with the display blanked, which is the way an NTP server will be most of the time. The power brick rating assumes running the laptop AND charging the battery at the same time. The D400 comes with a 60W power brick. Yet, it comes fully packaged with a hardware serial port and when you need to do anything with it, there is no need to hunt for a monitor or a keyboard, and they have built-in battery backup. Try to configure your Atom board similarly and see how much money and time you spend. I have 4 of those at home, they are workhorses. They can be found on Ebay for well under $100. Didier KO4BB Chris Albertson albertson.ch...@gmail.com wrote: On Sat, Aug 18, 2012 at 10:23 PM, li...@lazygranch.com wrote: If you are using a desktop, I'd suggest putting in a serial card. The Netmos chip based cards work on windows and linux, though your should do an internet search on the particular card before you buy. I have the prolific based converter. It didn't work with my Starloc. (The netmos worked fine with Lady Heather.) I just got a Gearmo branded FTDI based usb to serial. I haven't tried it on the Starloc, but it works well on other I just worked out the cost of power. If you, like me are paying $0.21/KHW a new Atom based PC will pay for itself in less then 6 months . It is astonishing when you actually compute the cost to run a PC 24x7 for one year. A normal desktop or notebook PC is not so expensive to run because it spends most time either powered off or in sleep mode. But an NTP server needs to stay active 24x7.A standard desktop PC can burn $400 or more in electric cost per year. A notebook PC is almost as bad (Notice the 100+ watt rating on the notebook's power brick) The new Atom boards are about 6W and costs only $100 at Amazon.com But, yes, I agree stuffing a PCI serial card in a desktop PC can get you the serial port you need. They work well. Just remember that the desktop will have to stay powered up 24x7 for years. 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. -- Sent from my Motorola Droid Razr 4G LTE wireless tracker while I do other things. ___ time-nuts mailing 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] Tidbit for Soekris 4501 NTP users
On Aug 19, 2012, at 12:15 PM, John Ackermann N8UR j...@febo.com wrote: This is probably something that very, very few other people are going to encounter, but thought I would note it here for posterity. Thanks! You've already helped one person. I ran up against that problem when testing one of my 4501's with only a PPS signal. Kevin ___ time-nuts mailing 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] Modern motherboard with RS232 port
Hi The pi doesn't have a conventional serial port. It does have a TTL serial on the 28 pin connector. There are also IRQ pins on the same connector. Since they go directly to the CPU chip, hardware latency should be pretty good. It should interface directly to a TTL output gps receiver like a LEA-6T. You probably would need to tune up a driver to get it to work. Since it's Linux, you should be able to get some sort of ntp running on it. AFIK there are no neat counters like on a 45xx board. You also don't have a well tuned ntp since it's LInux. Bob On Aug 19, 2012, at 1:31 PM, Chris Albertson albertson.ch...@gmail.com wrote: On Sun, Aug 19, 2012 at 10:16 AM, bownes bow...@gmail.com wrote: Why not just use a raspberry pi? Uses a whole 2w at idle. Ntp might bump that to 2.01. You certainly could run ntpd on that box. But I wonder how the PPS is supported in hardware? What is the standard deviation of interrupt latency on the DCD pin on the serial port. Perhaps some one who has a pi could measure this. All the data should be in the system log as each PPS is time stamped and written to the log. If the DCD pin is polled you are not going to get decent results. Maybe someone could read the PPS drive code. -- 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] Modern motherboard with RS232 port
On Sun, Aug 19, 2012 at 5:21 PM, Bob Camp li...@rtty.us wrote: Hi The pi doesn't have a conventional serial port. It does have a TTL serial on the 28 pin connector. There are also IRQ pins on the same connector. Since they go directly to the CPU chip, hardware latency should be pretty good. Is there a PPS device driver on the version of Linux that runs on this board?In theory all you need is the interrupt pin and a high speed (usec or nanosec counter) counter that can be captured by the device driver. But even with this hardware has anyone written the device driver? I don't understand the comment about no well tuned ntp. 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] Modern motherboard with RS232 port
Hi There has been a lot of work done on FreeBSD kernel timing and ntp. That and the work PHK has done on some of the drivers makes it a tough thing to beat. Since the pi is ARM hardware, a lot of the 386 specific work isn't going to apply to it. Still that's less of an issue than the USB to Ethernet connection on the pi. Bob On Aug 19, 2012, at 8:38 PM, Chris Albertson albertson.ch...@gmail.com wrote: On Sun, Aug 19, 2012 at 5:21 PM, Bob Camp li...@rtty.us wrote: Hi The pi doesn't have a conventional serial port. It does have a TTL serial on the 28 pin connector. There are also IRQ pins on the same connector. Since they go directly to the CPU chip, hardware latency should be pretty good. Is there a PPS device driver on the version of Linux that runs on this board?In theory all you need is the interrupt pin and a high speed (usec or nanosec counter) counter that can be captured by the device driver. But even with this hardware has anyone written the device driver? I don't understand the comment about no well tuned ntp. 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.
[time-nuts] Lucent GPS and RB pair
Hi, I am looking for opinions on the RFT Gm II- XO and RFT Gm II- RB combination compared to TBolt or HP 3815A. I can get the Lucent pair at a very reasonable price. Are manuals easily obtained for them? Thanks Jerry K1JOS ___ time-nuts mailing 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] Lucent GPS and RB pair
Hi Compared to the other two, there is a lot less support for the RFTG parts. Lady Heather is a *very* good reason to use a TBolt. Bob On Aug 19, 2012, at 9:06 PM, Jerry jster...@att.net wrote: Hi, I am looking for opinions on the RFT Gm II- XO and RFT Gm II- RB combination compared to TBolt or HP 3815A. I can get the Lucent pair at a very reasonable price. Are manuals easily obtained for them? Thanks Jerry K1JOS ___ time-nuts mailing 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] Modern motherboard with RS232 port
It comes w ntp out of the box if you run fedora. On Aug 19, 2012, at 20:21, Bob Camp li...@rtty.us wrote: Hi The pi doesn't have a conventional serial port. It does have a TTL serial on the 28 pin connector. There are also IRQ pins on the same connector. Since they go directly to the CPU chip, hardware latency should be pretty good. It should interface directly to a TTL output gps receiver like a LEA-6T. You probably would need to tune up a driver to get it to work. Since it's Linux, you should be able to get some sort of ntp running on it. AFIK there are no neat counters like on a 45xx board. You also don't have a well tuned ntp since it's LInux. Bob On Aug 19, 2012, at 1:31 PM, Chris Albertson albertson.ch...@gmail.com wrote: On Sun, Aug 19, 2012 at 10:16 AM, bownes bow...@gmail.com wrote: Why not just use a raspberry pi? Uses a whole 2w at idle. Ntp might bump that to 2.01. You certainly could run ntpd on that box. But I wonder how the PPS is supported in hardware? What is the standard deviation of interrupt latency on the DCD pin on the serial port. Perhaps some one who has a pi could measure this. All the data should be in the system log as each PPS is time stamped and written to the log. If the DCD pin is polled you are not going to get decent results. Maybe someone could read the PPS drive code. -- 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. ___ time-nuts mailing 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] Modern motherboard with RS232 port
Hi But you still need: 1) Porting of the kernel timing stuff to the ARM6 architecture. Once it's ported, you need it debugged and fine tuned. 2) The low level drivers in NTP ported to the ARM6 i/o setup. They also need some work to reduce latency. 3) The timing work on the USB to Ethernet interface. I'm not knocking the pi, it's a fine little gizmo. However it's just that, a little gizmo, at this point. There's still a lot of work to be done on it. Getting a solid implementation of anything takes significant work. There are other reasonably cheap / low power platforms where people have already put in the man years to ring things out. Bob On Aug 19, 2012, at 9:49 PM, bownes bow...@gmail.com wrote: It comes w ntp out of the box if you run fedora. On Aug 19, 2012, at 20:21, Bob Camp li...@rtty.us wrote: Hi The pi doesn't have a conventional serial port. It does have a TTL serial on the 28 pin connector. There are also IRQ pins on the same connector. Since they go directly to the CPU chip, hardware latency should be pretty good. It should interface directly to a TTL output gps receiver like a LEA-6T. You probably would need to tune up a driver to get it to work. Since it's Linux, you should be able to get some sort of ntp running on it. AFIK there are no neat counters like on a 45xx board. You also don't have a well tuned ntp since it's LInux. Bob On Aug 19, 2012, at 1:31 PM, Chris Albertson albertson.ch...@gmail.com wrote: On Sun, Aug 19, 2012 at 10:16 AM, bownes bow...@gmail.com wrote: Why not just use a raspberry pi? Uses a whole 2w at idle. Ntp might bump that to 2.01. You certainly could run ntpd on that box. But I wonder how the PPS is supported in hardware? What is the standard deviation of interrupt latency on the DCD pin on the serial port. Perhaps some one who has a pi could measure this. All the data should be in the system log as each PPS is time stamped and written to the log. If the DCD pin is polled you are not going to get decent results. Maybe someone could read the PPS drive code. -- 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. ___ time-nuts mailing 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] Modern motherboard with RS232 port
On Sun, Aug 19, 2012 at 6:49 PM, bownes bow...@gmail.com wrote: It comes w ntp out of the box if you run fedora. You can run NTP without a Pulse Per Second (PPS) driver. It will work just fine. Most NTP installations don't use PPS. But if you want to connect a GPS receiver and use it for precision timing you must have PPS support. So having a working NTP out of the box is not enough. 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] Modern motherboard with RS232 port
Residential power is traditionally measured in watts, not V-A. Commercial power is typically measured in V-A, with an additional fee for power factor problems. -Chuck Harris Ed Palmer wrote: It's important to remember that on a computer, the wattage shown has no relationship to the wattage pulled from the socket. The numbers shown are maximum values. You have to measure the power draw and you have to measure it in volt-amps, not watts because that's how residential power is measured (at least in North America). Buy an energy meter that shows volt-amps. They're relatively cheap - typically less than $50. Ed ___ time-nuts mailing 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] Modern motherboard with RS232 port
The long and the short of it is that when AC encounters a reactive load, it results in a current that is not in phase with the voltage. Power is equal to volts x amps only when the current and voltage are in phase which can only happen if the load is purely resistive. If you hang a perfect capacitor across the power line, or a perfect inductor, you will draw lots of current, but no power. -Chuck Harris Tom Knox wrote: Hi Ed; I may not have had enough coffee yet, but if Volt X Amps = Watts why would there be a difference? Best Wishes; Thomas Knox ___ time-nuts mailing 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] Modern motherboard with RS232 port
Agreed. Just pointing out there isn't a big porting effort to get ntpd itself up and running. On Aug 19, 2012, at 22:24, Chris Albertson albertson.ch...@gmail.com wrote: On Sun, Aug 19, 2012 at 6:49 PM, bownes bow...@gmail.com wrote: It comes w ntp out of the box if you run fedora. You can run NTP without a Pulse Per Second (PPS) driver. It will work just fine. Most NTP installations don't use PPS. But if you want to connect a GPS receiver and use it for precision timing you must have PPS support. So having a working NTP out of the box is not enough. 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] Lucent GPS and RB pair
Boy do I agree with Bobs comment. But I have several of the lucent RBs and at least most of mine are quite old. Hey $20 you can't really argue. Or as they say you get what you pay for. So reasonable is a curious question. Or a caution. By the way I am not at all complaining actually. Regards Paul. WB8TSL On Sun, Aug 19, 2012 at 9:13 PM, Bob Camp li...@rtty.us wrote: Hi Compared to the other two, there is a lot less support for the RFTG parts. Lady Heather is a *very* good reason to use a TBolt. Bob On Aug 19, 2012, at 9:06 PM, Jerry jster...@att.net wrote: Hi, I am looking for opinions on the RFT Gm II- XO and RFT Gm II- RB combination compared to TBolt or HP 3815A. I can get the Lucent pair at a very reasonable price. Are manuals easily obtained for them? Thanks Jerry K1JOS ___ time-nuts mailing 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] Lucent GPS and RB pair
Hi Paul; Has anyone played with these Lucent units much to see if LH could be tweaked to work? Thanks; Thomas Knox Date: Sun, 19 Aug 2012 22:44:38 -0400 From: paulsw...@gmail.com To: time-nuts@febo.com Subject: Re: [time-nuts] Lucent GPS and RB pair Boy do I agree with Bobs comment. But I have several of the lucent RBs and at least most of mine are quite old. Hey $20 you can't really argue. Or as they say you get what you pay for. So reasonable is a curious question. Or a caution. By the way I am not at all complaining actually. Regards Paul. WB8TSL On Sun, Aug 19, 2012 at 9:13 PM, Bob Camp li...@rtty.us wrote: Hi Compared to the other two, there is a lot less support for the RFTG parts. Lady Heather is a *very* good reason to use a TBolt. Bob On Aug 19, 2012, at 9:06 PM, Jerry jster...@att.net wrote: Hi, I am looking for opinions on the RFT Gm II- XO and RFT Gm II- RB combination compared to TBolt or HP 3815A. I can get the Lucent pair at a very reasonable price. Are manuals easily obtained for them? Thanks Jerry K1JOS ___ time-nuts mailing 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] Trimble T Lassen 2 - suitable antenna....advice.....questions
It's a pain to capture on any scope, but really easy to see with an LED across the output. it's not bright, but definitely easy to see on my tbolt. -Bob On Mon, Jul 23, 2012 at 10:11 AM, Stephen Farthing squir...@gmail.com wrote: Hi Guys, I have a couple of Trimble T Lassen 2 boards I bought at a Hamfest - the guy told me they were left over from a contract he had and were brand new. He had a load and i bought a couple for use as a precision 1 PPS output for radio stuff. They were packed in static protection. When I apply power to both units I can hear the oscillator (12.504 MHz) on my comms RX. So I am assuming that they work. I bought what claims to be a Trimble compatible active antenna on EBay. I hooked it up to one of the boards and applied power, and put the scope on the one pps pin. However after 20 mins (which I assume is much longer than the unit requires to get a lock) I see no 1pps trace on the screen. :-( So my working assumption is that the antenna is not working. The antenna position is fine as my elderly Garmin GPS2 which must be 12 years old sees 6 satellites there. Can anyone recommend a suitable antenna? I have a number of DIY designs I can try (Patch, Turnstile) but the Trimble docs say it needs an active antenna so I guess I'll have to spend money :-( While i am on, can anyone suggest a reasonably priced unit that has a 1pps output, NMEA and a built in antenna. Because I want to use this with an 8 bit embedded system I am probably not going to be able to hack one of the many cheap USB dongle GPS's. Lastly, has anyone found a GPS that will work with an Ipad. What the man in the Apple shop failed to tell me was the non 3g model lacked the built in GPS :-( Thanks in advice Steve -- Wisdom demands a new orientation of science and technology towards the organic, the gentle, the non-violent, the elegant and beautiful. E. F. Schumacher ___ time-nuts mailing 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] Modern motherboard with RS232 port
On 8/19/12 7:26 PM, Chuck Harris wrote: Residential power is traditionally measured in watts, not V-A. Commercial power is typically measured in V-A, with an additional fee for power factor problems. residential meters measure watts (active power) not VA... What you want is the Kill-A-Watt.. a $30 widget that measures all the parameters.. A great little deviec. -Chuck Harris Ed Palmer wrote: It's important to remember that on a computer, the wattage shown has no relationship to the wattage pulled from the socket. The numbers shown are maximum values. You have to measure the power draw and you have to measure it in volt-amps, not watts because that's how residential power is measured (at least in North America). Buy an energy meter that shows volt-amps. They're relatively cheap - typically less than $50. Ed ___ time-nuts mailing 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] Trimble T Lassen 2 - suitable antenna....advice.....questions
On Sun, Aug 19, 2012 at 9:27 PM, Robert Darlington rdarling...@gmail.comwrote: It's a pain to capture on any scope, but really easy to see with an LED across the output. it's not bright, but definitely easy to see on my tbolt. That is true. One must have very good eyes to see a one microsecond pulse that only happens one per second. Blink and you miss it. The LED might work but the for sure way is to send the PPS to a flip flop so you can see the state change at 1Hz. Use a solderless bread board and 5V power supply. -- 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.
