Re: [time-nuts] HP 115BR Clock Repaired and Ready to go
Hi George, I like , I want to buy it I live in Italy and I collect and made by myself some equipment of time and frequency standard. Please can you quote me the shipping cost to Italy? thankyou Lucianpo timeok-it Il 2012-10-15 21:57 George Race ha scritto: I still have the HP 115BR Clock. It is fully repaired and fully functional. I really want it to go to a good home where someone will put it into service. The package includes: 4 spare power transistors, extras purchased to repair the unit. Full operators and service manual on CD, purchased for the repair. HP 115BR, fully tested and operating. It sat and ran flawlessly for 10 days on the bench. Price $170.00 including FedEx shipping anywhere within the continental 48 states. My direct email if interested: geo...@mrrace.com George ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. -- timeok ___ time-nuts mailing 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] LightSquared
The Saga just goes on...! INFO only. Rgds Ernie. Lightsquared Returns With New Proposal For GPS Fix October 4, 2012 The company asked the FCC to modify its license application so it can use its 5MHz of spectrum that haven’t caused GPS concerns. LightSquared, the now bankrupt wireless broadband venture, is seeking regulatory approval from the FCC for a plan it believes will fix interference problems with GPS technology. In two filings, LightSquared, once a darling of the FCC for its bold broadband initiative, told the commission it will now forgo using the airwaves that triggered the GPS interference problems in the first place. The Wall Street Journal reported that the filings come at a critical time in LightSquared’s Chapter 11 case, which was filed in May. The company is in court this week, seeking permission from the judge to extend the exclusive right to file a reorganization plan until this summer, reducing the threat of rival proposals. LightSquared asked the FCC to modify its license application so it can use its 5MHz of spectrum that haven’t caused GPS concerns. It also sought another 5MHz that it would share with users within the federal government. In its latest proposal, the company said it would forego using the “upper” 10MHz that have caused GPS interference concerns. It still wants the FCC to consider use of that 10MHz, but agreed to wait for and cooperate with “operating parameters and revised rules for terrestrial use of this spectrum.” There is no timetable for a response from the FCC on LightSquared’s request. Creditors in the bankruptcy case have been critical of LightSquared and the man who controls its equity, hedge fund manager Phillip Falcone. Those lenders have said a loan made prior to the bankruptcy filing to LightSquared favored Falcone and his firm, Harbinger Capital Partners, over other creditors. LightSquared received conditional FCC approval in 2011 to deploy its low-cost broadband network. But earlier this year, the FCC denied approval after the National Telecommunications and Information Administration (NTIA) found the network could interfere with GPS. Falcone and his company have spent hundreds of millions of dollars on LightSquared. Both are being sued by securities regulators for a variety of alleged violations, including misappropriation of client money, manipulating bond prices and favoritism of certain clients. Falcone has said he is innocent and will fight the charges, the Journal reported. SOURCE: LightSquared ___ time-nuts mailing 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] Hp 58503A
Hey guys, new to the group here and wanted to throw a question out there. I just picked up an HP 58503A and hooked it all up. I have it connected to my computer and I can see the system status via satstat and all looks to be working correctly. However, I notice that there is distortion on the 10 meg sine wave on the 10 meg out on the back. This distortion consists of a slightly mis-shapen negative peak. The positive peak it normal. The unit has now been on for 15 hours and no change. It is locked to gps. The 10 meg out directly from the back of the XTAL is a perfectly normal sine wave. The question: is this a problem with my unit? Is this normal? And, how can I fix it. Thanks fellas, Mark. Sent from my iPad ___ time-nuts mailing 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] Hp 58503A
Mark, Are you loading the 10Mhz output with 50 Ohms when you measure it? Said Sent from my iPad On Oct 16, 2012, at 6:52, Mark Danon mdan...@gmail.com wrote: Hey guys, new to the group here and wanted to throw a question out there. I just picked up an HP 58503A and hooked it all up. I have it connected to my computer and I can see the system status via satstat and all looks to be working correctly. However, I notice that there is distortion on the 10 meg sine wave on the 10 meg out on the back. This distortion consists of a slightlymis-shapen negative peak. The positive peak it normal. The unit has now been on for 15 hours and no change. It is locked to gps. The 10 meg out directly from the back of the XTAL is a perfectly normal sine wave. The question: is this a problem with my unit? Is this normal? And, how can I fix it. Thanks fellas, Mark. Sent from my iPad ___ time-nuts mailing 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] Hp 58503A
I guess this it what they would call a rookie move? WOW, i feel like an idiot. I just loaded it down with a 50 ohm load and looks perfect. Thanks for enlightening me. ___ time-nuts mailing 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] Hp 58503A
I overlooked it also. Glad the problem is resolved. Thomas Knox Date: Tue, 16 Oct 2012 12:31:13 -0400 From: mdan...@gmail.com To: time-nuts@febo.com Subject: Re: [time-nuts] Hp 58503A I guess this it what they would call a rookie move? WOW, i feel like an idiot. I just loaded it down with a 50 ohm load and looks perfect. Thanks for enlightening me. ___ time-nuts mailing 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] HP 115BR Clock Repaired and Ready to go
Had some interesting times with the HP-113B clock, but had to mount it in an insulated cabinet with an insulated door because it made so much 1 KHz mechanical noise. No wonder the housing for the assembly is so heavy. Did they find a quieter motor for the 115B? Bill Hawkins -Original Message- From: George Race Sent: Monday, October 15, 2012 2:57 PM To: 'Discussion of precise time and frequency measurement' Subject: [time-nuts] HP 115BR Clock Repaired and Ready to go I still have the HP 115BR Clock. It is fully repaired and fully functional. ___ time-nuts mailing 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] Stanford RS620 Acting up
Thanks for all the responses. Well it was even simpler than I expected, All I had to do was a cold reset followed by an autocal. the unit now will power-up with the display active. Apparently it was not a hardware error at all. I now want to calibrate the internal 10 MHz reference. I read the cal procedure several times. I need to set the value of calbyte 4 (and 50 to minimize offset). I found and enabled the cal jumper. I accesses the cal menu. I displayed and can edit the calbyte 0 but I can't seem to figure out how to navigate to the next calbyte. How do I select the calbyte to operate on? Eric Haskell ___ time-nuts mailing 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] Looking for parts
Well, that a few of you were nice enough to help me understand my HP 58503A, I wonder if anyone out there has some parts for this unit. Specifically, I was hoping someone had an Option 1 Kit, the digital display and keypad? Any thoughts, suggestions? Thanks, Mark. ___ time-nuts mailing 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] Hp 58503A
No problem, happens to me too some times, usually the 10MHz Sine should be loaded with 50 Ohms, and the CMOS/TTL 1PPS pulses should be run open-ended (1M or higher).. I say usually.. because there are cases where proper termination is critical such as LVDS 1PPS outputs.. and where the 10MHz does not necessarily need to be loaded with 50 Ohms, resulting in a higher sine wave voltage - such as on our JLT GPSDO products.. bye, Said In a message dated 10/16/2012 09:36:25 Pacific Daylight Time, mdan...@gmail.com writes: I guess this it what they would call a rookie move? WOW, i feel like an idiot. I just loaded it down with a 50 ohm load and looks perfect. Thanks for enlightening me. ___ time-nuts mailing 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] Hp 58503A
I just loaded it down with a 50 ohm load and looks perfect. One of my design pet peeves is not anticipating what users may do. For example, not anticipating that someone might terminate an output in a high impedance rather than in the rated impedance, or leave unused outputs unterminated. I have seen several multichannel isolation amplifiers where any output not terminated in 50 ohms is in hard clipping -- even with halfway decent isolation, this can put garbage on the other outputs. The very definition of an isolation amplifier is that each output should be independent of how the other outputs are terminated -- short, open, inductor, capacitor, other signal, whatever. I understand it is not trivial to provide 1 Vrms (+13 dBm) outputs with 6 dB overhead from a 5 V (or 3.3 V) supply, but that's why they pay designers the big bucks. Best regards, Charles ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Stanford RS620 Acting up
Use the Sample Size switches Juerg Koegel 2012/10/16 Eric Haskell eric_hask...@hotmail.com: Thanks for all the responses. Well it was even simpler than I expected, All I had to do was a cold reset followed by an autocal. the unit now will power-up with the display active. Apparently it was not a hardware error at all. I now want to calibrate the internal 10 MHz reference. I read the cal procedure several times. I need to set the value of calbyte 4 (and 50 to minimize offset). I found and enabled the cal jumper. I accesses the cal menu. I displayed and can edit the calbyte 0 but I can't seem to figure out how to navigate to the next calbyte. How do I select the calbyte to operate on? Eric Haskell ___ time-nuts mailing 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] HP 115BR Clock Repaired and Ready to go
I found that a lot of the 1KHz noise on mine was caused by a bad ball bearing in the motor. I replaced it with a new bearing and the 1KHz was then only loud. It isn't the motor, it is the 1KHz drive. Airplanes with 400Hz 3 phase motors in the instrumentation are similarly loud. -Chuck Harris Bill Hawkins wrote: Had some interesting times with the HP-113B clock, but had to mount it in an insulated cabinet with an insulated door because it made so much 1 KHz mechanical noise. No wonder the housing for the assembly is so heavy. Did they find a quieter motor for the 115B? Bill Hawkins -Original Message- From: George Race Sent: Monday, October 15, 2012 2:57 PM To: 'Discussion of precise time and frequency measurement' Subject: [time-nuts] HP 115BR Clock Repaired and Ready to go I still have the HP 115BR Clock. It is fully repaired and fully functional. ___ time-nuts mailing 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] HP 115BR Clock Repaired and Ready to go
Hi: I'd characterize the noise as obnoxious to the point I could not have my 113AR in the house, but only the garage. http://www.prc68.com/I/TF_rack.html Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html Chuck Harris wrote: I found that a lot of the 1KHz noise on mine was caused by a bad ball bearing in the motor. I replaced it with a new bearing and the 1KHz was then only loud. It isn't the motor, it is the 1KHz drive. Airplanes with 400Hz 3 phase motors in the instrumentation are similarly loud. -Chuck Harris Bill Hawkins wrote: Had some interesting times with the HP-113B clock, but had to mount it in an insulated cabinet with an insulated door because it made so much 1 KHz mechanical noise. No wonder the housing for the assembly is so heavy. Did they find a quieter motor for the 115B? Bill Hawkins -Original Message- From: George Race Sent: Monday, October 15, 2012 2:57 PM To: 'Discussion of precise time and frequency measurement' Subject: [time-nuts] HP 115BR Clock Repaired and Ready to go I still have the HP 115BR Clock. It is fully repaired and fully functional. ___ time-nuts mailing 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] RasberryPi, timing and GPS receivers
Hello everyone, I started a new project for myself where I would use the RasperryPi Linux board as a NTP server. My goal is to design a custom board for the Pi and mount a GPS receiver on it. With this combination, I should be able to configure NTP for the Pi and thus have the Pi act as a Stratum 1 NTP server. The new RasberryPI has 512MB memory so it should be fine for running just ntpd. Question: What GPS timing module should I go with? No more Motorola Oncore so what's best right now? Who sell modules? What are the price ranges? Your comments are most welcome. -George, N2FGX ___ time-nuts mailing 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] RasberryPi, timing and GPS receivers
uBlox LEA-5T, LEA6-T? SkyTraq Venus5? On Tue, Oct 16, 2012 at 11:06 PM, x...@darksmile.net wrote: Hello everyone, I started a new project for myself where I would use the RasperryPi Linux board as a NTP server. My goal is to design a custom board for the Pi and mount a GPS receiver on it. With this combination, I should be able to configure NTP for the Pi and thus have the Pi act as a Stratum 1 NTP server. The new RasberryPI has 512MB memory so it should be fine for running just ntpd. Question: What GPS timing module should I go with? No more Motorola Oncore so what's best right now? Who sell modules? What are the price ranges? Your comments are most welcome. -George, N2FGX ___ time-nuts mailing 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] RasberryPi, timing and GPS receivers
I have a similar setup and running now (minus the custom pcb) using a Venus638FLPx module from Sparkfun (~$50 + antenna). The module was easy to configure and had a decent 1PPS output. So far, everything is working (hardware-wise, I still have some NTP settings to tweak). I have the 256MB version of the Pi and it seems to handle the load just fine. Open Systems International, Inc. Zach Davis Software Development 4101 Arrowhead Drive Medina, Minnesota 55340-9457 Phone: 763 551 0559 Fax: 763 551 0750 E-mail: zach.da...@osii.com Website: http://www.osii.com/ -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of x...@darksmile.net Sent: Tuesday, October 16, 2012 4:06 PM To: Discussion of precise time and frequency measurement Subject: [time-nuts] RasberryPi, timing and GPS receivers Hello everyone, I started a new project for myself where I would use the RasperryPi Linux board as a NTP server. My goal is to design a custom board for the Pi and mount a GPS receiver on it. With this combination, I should be able to configure NTP for the Pi and thus have the Pi act as a Stratum 1 NTP server. The new RasberryPI has 512MB memory so it should be fine for running just ntpd. Question: What GPS timing module should I go with? No more Motorola Oncore so what's best right now? Who sell modules? What are the price ranges? Your comments are most welcome. -George, N2FGX ___ time-nuts mailing 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] RasberryPi, timing and GPS receivers
On 10/16/2012 05:06 PM, x...@darksmile.net wrote: My goal is to design a custom board for the Pi and mount a GPS receiver on it. With this combination, I should be able to configure NTP for the Pi and thus have the Pi act as a Stratum 1 NTP server. The new RasberryPI has 512MB memory so it should be fine for running just ntpd. Question: What GPS timing module should I go with? No more Motorola Oncore so what's best right now? Who sell modules? What are the price ranges? It's not a terrible idea, but the RPI has a USB ethernet transceiver so in addition to the latency/jitter of the ethernet it also has the latency/jitter of the USB. I've also heard of stability problems just keeping it running for weeks to months so you should integrate some kind of watchdog timer if you can. The actual GPS module doesn't matter much since NTP will smooth out even the worst GPS jitter. I have heard second-hand (or third-hand or fourth-...) that some have a significant persistent delay and that could be more of a problem. If you want to go for a timing-oriented receiver you can get a used Trimble Resolution T from ebay but they have a 2mm pitch header. You will want to house the RPI and GPS receiver in a box where it will not be subject to wide temperature swings, insulated and shielded from drafts. It would also be interesting to upgrade the main oscillator to a temperature-compensated model so NTP doesn't have to work as hard to keep the frequency locked. Personally I would recommend getting a more robust single-board computer, e.g. a PC Engines ALIX or Olimex olinuxino. RPI is cheap but hard to source, not open-source, and does not have good long-term prospects due to the microprocessor being used. Most of the attention is due to deliberate publicity by the manufacturer and not novelty or merit. If you must use the cheapest board then by all means do so, but just know there is better available for not much more. Happy ticking, -- 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] RasberryPi, timing and GPS receivers
Michael, Thank you for your most valuable information. This is why time-nuts is so amazing! My goal is actually two-fold. First, I would like to have a NTP server that I can easily hook up (well, as easily as possible) without dedicating a Linux server each time. My personal use would require 3 separate NTP servers because I am a time-nut and stratum 2 is not an option. The idea here is to create a smart piggy-back architecture where the CPU/Ethernet sits on the bottom with (perhaps) a few modules on top of that with GPS right on top (let's call it the penthouse). For obvious reasons I would put the Power supply separately. So we are looking for a very small footprint NTP server. Now, I thought the RasberryPi would be ok even though I did not like the limitations you mentioned as well. It is very popular. You mentioned the Olimex olinuxino. Wow! This is a thing of beauty indeed! https://www.olimex.com/Products/OLinuXino/A13/A13-OLinuXino/ I really like this board. My second goal is that if I go to the trouble of creating a GPS-daughterboard and all that I'd like to have other people use it as well and maybe I would make a small batch. Cost wise this should be in the 10-20 dollar range tops. I think I will do some research on this board and maybe order one. It looks very promising. I wonder if I can replace the crystal with a better high stability one. -George Quoting Michael Tharp g...@partiallystapled.com: On 10/16/2012 05:06 PM, x...@darksmile.net wrote: My goal is to design a custom board for the Pi and mount a GPS receiver on it. With this combination, I should be able to configure NTP for the Pi and thus have the Pi act as a Stratum 1 NTP server. The new RasberryPI has 512MB memory so it should be fine for running just ntpd. Question: What GPS timing module should I go with? No more Motorola Oncore so what's best right now? Who sell modules? What are the price ranges? It's not a terrible idea, but the RPI has a USB ethernet transceiver so in addition to the latency/jitter of the ethernet it also has the latency/jitter of the USB. I've also heard of stability problems just keeping it running for weeks to months so you should integrate some kind of watchdog timer if you can. The actual GPS module doesn't matter much since NTP will smooth out even the worst GPS jitter. I have heard second-hand (or third-hand or fourth-...) that some have a significant persistent delay and that could be more of a problem. If you want to go for a timing-oriented receiver you can get a used Trimble Resolution T from ebay but they have a 2mm pitch header. You will want to house the RPI and GPS receiver in a box where it will not be subject to wide temperature swings, insulated and shielded from drafts. It would also be interesting to upgrade the main oscillator to a temperature-compensated model so NTP doesn't have to work as hard to keep the frequency locked. Personally I would recommend getting a more robust single-board computer, e.g. a PC Engines ALIX or Olimex olinuxino. RPI is cheap but hard to source, not open-source, and does not have good long-term prospects due to the microprocessor being used. Most of the attention is due to deliberate publicity by the manufacturer and not novelty or merit. If you must use the cheapest board then by all means do so, but just know there is better available for not much more. Happy ticking, -- 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] RasberryPi, timing and GPS receivers
I've been looking at the Raspberry Pi for a number of projects as well, and have been running one for a few weeks. My take on the early stability concerns/complaints are that the majority of those are due to poor power supplies, with some assistance from the Raspberry Pi design. Measure what you have for DC at TP1 and TP2; it should be close to 5 volts. The polyswitch self-resetting fuse on the power input introduces series resistance (in the wrong place); on my unit it measures 0.36 ohms (4-wire measurement with my HP33401A). Couple this with a cheepie USB supply that's already below 5 volts, and you're on thin ice. Do anything that spikes power consumption, such as Ethernet, GPU, or plugging in USB devices, and you generate more of an IR drop across the polyswitch which can cause erratic operation or resets. Use a good power supply -- 5 volts at an amp. Adafruit sells one that's 5V/2A for under $10. Or you can bypass some of the protection components and connect your +5 supply to TP1 and TP2. Running mine from a solid power source the only problems I've had are with my own crummy code... Bob K6RTM -- Message: 5 Date: Tue, 16 Oct 2012 15:06:19 -0600 From: x...@darksmile.net To: Discussion of precise time and frequency measurement time-nuts@febo.com Subject: [time-nuts] RasberryPi, timing and GPS receivers Message-ID: 20121016150619.16306sbpxvjy8...@darksmile.net Content-Type: text/plain; charset=ISO-8859-1; DelSp=Yes; format=flowed Hello everyone, I started a new project for myself where I would use the RasperryPi Linux board as a NTP server. My goal is to design a custom board for the Pi and mount a GPS receiver on it. With this combination, I should be able to configure NTP for the Pi and thus have the Pi act as a Stratum 1 NTP server. The new RasberryPI has 512MB memory so it should be fine for running just ntpd. Question: What GPS timing module should I go with? No more Motorola Oncore so what's best right now? Who sell modules? What are the price ranges? Your comments are most welcome. -George, N2FGX ___ time-nuts mailing 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] RasberryPi, timing and GPS receivers
Michael Tharp g...@partiallystapled.com wrote [RE: raspberry pi ntp server] It's not a terrible idea, but the RPI has a USB ethernet transceiver so in addition to the latency/jitter of the ethernet it also has the latency/jitter of the USB. I've been playing with a pair of Raspberry Pi ntp servers, one with a $15 Sure Electronics GPS evaluation board, which was very easy to interface to (3.3v uart and pps outputs) and the other connected to a Lucent RFTG, which once I figured out that the Pi apparenty tolerates the PPS out from the RFTG w/o a level shifter just fine (mostly - I was getting false extra pulses until I shielded the line, which I hadn't needed to do on the Sure GPS board). I'm a junior time-nut at best but it looks to me like jitter from the USB Ethernet is acceptably low, based on ntpq -p anyway: remote refid st t when poll reach delay offset jitter == oGPS_NMEA(0) .GPS.0 l2 16 3770.0000.003 0.004 +pi2 .PPS.1 s7 16 3770.945 -0.004 0.044 +pool-test.ntp.o 216.218.192.202 2 u 43 64 377 73.8551.382 0.262 remote refid st t when poll reach delay offset jitter == oPPS(0) .PPS.0 l18 3770.000 -0.024 0.061 +ntp .GPS.1 s 148 2520.9830.217 0.615 *tick.nullmodem. 128.252.19.1 2 u 60 64 377 35.0660.562 4.556 Some of the offset between the two might be that I am waiting for a 2nd GPS antenna to arrive for the RFTG and it's been undisciplined for a few days, it might be from the ethernet jitter, the Sure GPS might be off, or it might be from the fact that I may have a configuration issue someplace - ntpq -c rl has them at different precisions (-19 and -18), even though I think they're the same kernel and ntpd compile. I've also heard of stability problems just keeping it running for weeks to months so you should integrate some kind of watchdog timer if you can. I haven't seen the issue yet but I haven't been running more than a couple of weeks. Part of the problem may be quality of power supply, I've seen some people reporting issues if the 5v usb power in isn't capable of providing enough current and a stable voltage. You will want to house the RPI and GPS receiver in a box where it will not be subject to wide temperature swings, I haven't been running either of mine in an enclosure, both are sitting up in the unheated attic at the moment, typical offsets from loopstats seem to be under 2us, but I should graph them. It would also be interesting to upgrade the main oscillator to a temperature-compensated model so NTP doesn't have to work as hard to keep the frequency locked. I am curious if I could replace the 19.2mhz system clock crystal with a stable source generated from the 15mhz RFTG output via a clockblock, ala what I have seen reported about the Soekris. Personally I would recommend getting a more robust single-board computer I don't disagree that the Pi has its flaws but it has been fun to play with. -shaun ___ time-nuts mailing 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] RasberryPi, timing and GPS receivers
Annoyance with small Linux boards: My single biggest annoyance is that all the I/O connectors are coming out from all 4 directions. What I mean is this: It would be nice to have ethernet+LEDs+USB+VGA(HDMI) come out from one side, and Power/I/O/RS232 from the opposite side. This way if I make a case I only need to worry about what is coming out of the Ethernet side. The RPI has ethernet+usb on one side and HDMI from another. How do you make a decent case with only one side open? It is impossible. If they only had the HDMI on a header so I can break it out. Same for audio/USB -George Quoting sh...@impsec.net sh...@impsec.net: Michael Tharp g...@partiallystapled.com wrote [RE: raspberry pi ntp server] It's not a terrible idea, but the RPI has a USB ethernet transceiver so in addition to the latency/jitter of the ethernet it also has the latency/jitter of the USB. I've been playing with a pair of Raspberry Pi ntp servers, one with a $15 Sure Electronics GPS evaluation board, which was very easy to interface to (3.3v uart and pps outputs) and the other connected to a Lucent RFTG, which once I figured out that the Pi apparenty tolerates the PPS out from the RFTG w/o a level shifter just fine (mostly - I was getting false extra pulses until I shielded the line, which I hadn't needed to do on the Sure GPS board). I'm a junior time-nut at best but it looks to me like jitter from the USB Ethernet is acceptably low, based on ntpq -p anyway: remote refid st t when poll reach delay offset jitter == oGPS_NMEA(0) .GPS.0 l2 16 3770.000 0.003 0.004 +pi2 .PPS.1 s7 16 3770.945 -0.004 0.044 +pool-test.ntp.o 216.218.192.202 2 u 43 64 377 73.855 1.382 0.262 remote refid st t when poll reach delay offset jitter == oPPS(0) .PPS.0 l18 3770.000 -0.024 0.061 +ntp .GPS.1 s 148 2520.983 0.217 0.615 *tick.nullmodem. 128.252.19.1 2 u 60 64 377 35.066 0.562 4.556 Some of the offset between the two might be that I am waiting for a 2nd GPS antenna to arrive for the RFTG and it's been undisciplined for a few days, it might be from the ethernet jitter, the Sure GPS might be off, or it might be from the fact that I may have a configuration issue someplace - ntpq -c rl has them at different precisions (-19 and -18), even though I think they're the same kernel and ntpd compile. I've also heard of stability problems just keeping it running for weeks to months so you should integrate some kind of watchdog timer if you can. I haven't seen the issue yet but I haven't been running more than a couple of weeks. Part of the problem may be quality of power supply, I've seen some people reporting issues if the 5v usb power in isn't capable of providing enough current and a stable voltage. You will want to house the RPI and GPS receiver in a box where it will not be subject to wide temperature swings, I haven't been running either of mine in an enclosure, both are sitting up in the unheated attic at the moment, typical offsets from loopstats seem to be under 2us, but I should graph them. It would also be interesting to upgrade the main oscillator to a temperature-compensated model so NTP doesn't have to work as hard to keep the frequency locked. I am curious if I could replace the 19.2mhz system clock crystal with a stable source generated from the 15mhz RFTG output via a clockblock, ala what I have seen reported about the Soekris. Personally I would recommend getting a more robust single-board computer I don't disagree that the Pi has its flaws but it has been fun to play with. -shaun ___ time-nuts mailing 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] RasberryPi, timing and GPS receivers
On 10/16/2012 06:28 PM, sh...@impsec.net wrote: I'm a junior time-nut at best but it looks to me like jitter from the USB Ethernet is acceptably low, based on ntpq -p anyway: It's a minor problem at worst. There are many worse conflating factors and NTP adjusts very slowly anyway to deal with receiving time over the internet. Supporting a more precise protocol like PTP, or even better CERN's White Rabbit extensions to it, is another matter and at that point you're using all custom hardware including switches. Not good for the bank account. That said, I have considered a project almost identical to what George is describing -- a very simple Linux-powered board that consumes negligible power and whose sole purpose in life is to run a NTP server from GPS. My focus was on doing it from scratch as a single PCB (except the GPS module, for now), but it seems the choices for easily sourceable Linux-capable microprocessors that are in 1mm BGA, let alone non-BGA, can be counted on one hand. AM1707 was the chip that I would use for the off the shelf microprocessor approach. It may actually be more effective -- and cool -- to use a FPGA and implement a microprocessor inside that instead! I have booted linux on a ORPSoC soft processor, but that was on a $300 dev board. Scaling it down to a cheap single-board computer would be challenging but not unthinkable. That particular SoC requires quite a lot of FPGA resources so something else would be required to avoid needing a $30 FPGA. But my current plans, not fully baked nor on any sort of schedule, involve neither linux nor a conventional ntpd. I'm designing a low-cost GPSDO around an ARM microcontroller that keeps its own time and is capable of acting as a dumb NTP server -- it would respond to requests from clients but would not receive time from other nodes. The loop would be stabilized solely by GPS although the loop algorithms will probably be adopted from NTPns because they are quite similar to what the GPSDO itself needs to do. I was originally planning to only support an ovenized oscillator as the LO, but it would also be possible to use a tunable TXCO or perhaps a small OCXO that could reside on the board and not take up much space or power. Connect 3 of these to the network and you've got a great stratum 1 pool. Right now I have a prototype GPSDO working although the loop algorithm is amateurish. I've been putting off working on it for a few weeks now, I need to sit down and study NTPns so I can implement a similar algorithm. The current one would be good enough for NTP but does not yet track time of day. The network components are not in the prototype, but I have written some sample code into another project that does have ethernet and it seems to work, so putting the two pieces together should result in a great NTP server. Oh dear, now I've written quite a lot and probably raised some eyebrows. Better quit while I'm behind. Happy ticking, -- 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] RasberryPi, timing and GPS receivers
On Tue, Oct 16, 2012 at 3:26 PM, x...@darksmile.net wrote: Michael, Thank you for your most valuable information. This is why time-nuts is so amazing! My goal is actually two-fold. First, I would like to have a NTP server that I can easily hook up (well, as easily as possible) without dedicadting a Linux server each time. One does NOT need a dedicated server for NTP. NTP can run on a linux system that is also a web and mail server or on e linux desktop system that you use for web surfing and web browse ring, just as long as the box stays running and you don't turn it off. My personal use would require 3 separate NTP servers because I am a time-nut and stratum 2 is not an option. What level of accuracy is required? Don't say as good as posable because that can be quite expensive. What really do you need? About the best you can expect from NTP without exotic hardware is 2 u-sec level. But maybe you'd be happy with 2 milli seconds. The idea here is to create a smart piggy-back architecture where the CPU/Ethernet sits on the bottom with (perhaps) a few modules on top of that with GPS right on top (let's call it the penthouse). Remember that you cn buy a fully integrated Intel Atom mainboard that is a bout 6 square and uses only a few watts for $90. The Atom will run NTP and mail and web servers and allow web surfing all at the same time and costs $90 including the soldered down CPU. It will have a real RS232 port and a good built-in Eithernet. These boards don't require fan cooling. For obvious reasons I would put the Power supply separately. Why? I hate power cubes So we are looking for a very small footprint NTP server. Now, I thought the RasberryPi would be ok even though I did not like the limitations you mentioned as well. It is very popular. It is popular for some applications. But a statum 1 NTP server needs the PPS from the GPS to go to a hardware interrupt and it needs a solid Ethernet controller with low latency. You mentioned the Olimex olinuxino. Wow! This is a thing of beauty indeed! https://www.olimex.com/Products/OLinuXino/A13/A13-OLinuXino/ Look at this one: http://www.newegg.com/Product/Product.aspx?Item=N82E16813121442 It is directly usable for NTP with no circuit design or soldering and the NTP server will run at the few u-sec level while also running as a file seder, web server and runing LLady Heather inside a virtual Windows under VMware. Not heat or fan noise. -- 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] RasberryPi, timing and GPS receivers
One does NOT need a dedicated server for NTP. NTP can run on a linux system that is also a web and mail server or on e linux desktop system that you use for web surfing and web browse ring, just as long as the box stays running and you don't turn it off. It's been discussed before, but probably worth repeating. Don't overlook the cost of power. If you have an old power-hungry CPU that you use for mail and web, leaving it on all the time can cost a lot. The payoff time for replacing it with a low power system can be as low as a year or two. -- 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] RasberryPi, timing and GPS receivers
Coincidentally, I just ordered a R-Pi yesterday. I have other potential uses for it, not NTP. If you are not in a hurry, it is possible to find the Soekris boards on ebay for a decent price. I got one last year, in a case, for $50. Joe Gray W5JG ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] RasberryPi, timing and GPS receivers
On Tue, Oct 16, 2012 at 4:37 PM, Hal Murray hmur...@megapathdsl.net wrote: One does NOT need a dedicated server for NTP. NTP can run on a linux system that is also a web and mail server or on e linux desktop system that you use for web surfing and web browse ring, just as long as the box stays running and you don't turn it off. It's been discussed before, but probably worth repeating. Don't overlook the cost of power. If you have an old power-hungry CPU that you use for mail and web, leaving it on all the time can cost a lot. Yes. You are right. that is why I posted a like to this http://www.newegg.com/Product/Product.aspx?Item=N82E16813121442 this board uses very little power and as you say will pay for itself quickly. You can reast your hand of the heat sink and notice there is no fan. It uses just a few watts. and can run VMware, and multiple servers The payoff time for replacing it with a low power system can be as low as a year or two. -- 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. -- 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] RasberryPi, timing and GPS receivers
Question: What GPS timing module should I go with? No more Motorola Oncore so what's best right now? Who sell modules? What are the price ranges? One option would be just a DE-9 connector with power on pin ??? (I forget). You may need inverters and/or level shifters on Rx and Tx. That would let you connect up any of the serial GPS devices. -- 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] RasberryPi, timing and GPS receivers
The miniITX mobos are quite impressive. There is no argument there. However, My simple idea was this: Since I want to keep time at 3 separate locations and wanted stratum 1 NTP, I didn't want overkill. Actually my reason for 3 different locations is simple: Internet is flakey some places and sometimes just down. I'd like to have correct time no matter what happens to the internet. The other thing I want to do is create a very small footprint NTP server that basically looks like 3-4 cartons of cigarettes stacked on top of each other. Maybe even have the power supply on the bottom of the stack. I don't know if I'll be able to do this but this is the general idea. I think maybe something like this: GPS Receiver + antenna connector --- Interface board --- CPU main board --- Shield board (mostly ground plane) --- Power supply --- If I could put this in a nice aluminum case I think it would look beautiful. -G Quoting Chris Albertson albertson.ch...@gmail.com: On Tue, Oct 16, 2012 at 4:37 PM, Hal Murray hmur...@megapathdsl.net wrote: One does NOT need a dedicated server for NTP. NTP can run on a linux system that is also a web and mail server or on e linux desktop system that you use for web surfing and web browse ring, just as long as the box stays running and you don't turn it off. It's been discussed before, but probably worth repeating. Don't overlook the cost of power. If you have an old power-hungry CPU that you use for mail and web, leaving it on all the time can cost a lot. Yes. You are right. that is why I posted a like to this http://www.newegg.com/Product/Product.aspx?Item=N82E16813121442 this board uses very little power and as you say will pay for itself quickly. You can reast your hand of the heat sink and notice there is no fan. It uses just a few watts. and can run VMware, and multiple servers The payoff time for replacing it with a low power system can be as low as a year or two. -- 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. -- 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] RasberryPi, timing and GPS receivers
Err... I meant packs of cigarettes NOT cartons :) Quoting x...@darksmile.net: The miniITX mobos are quite impressive. There is no argument there. However, My simple idea was this: Since I want to keep time at 3 separate locations and wanted stratum 1 NTP, I didn't want overkill. Actually my reason for 3 different locations is simple: Internet is flakey some places and sometimes just down. I'd like to have correct time no matter what happens to the internet. The other thing I want to do is create a very small footprint NTP server that basically looks like 3-4 cartons of cigarettes stacked on top of each other. Maybe even have the power supply on the bottom of the stack. I don't know if I'll be able to do this but this is the general idea. I think maybe something like this: GPS Receiver + antenna connector --- Interface board --- CPU main board --- Shield board (mostly ground plane) --- Power supply --- If I could put this in a nice aluminum case I think it would look beautiful. -G Quoting Chris Albertson albertson.ch...@gmail.com: On Tue, Oct 16, 2012 at 4:37 PM, Hal Murray hmur...@megapathdsl.net wrote: One does NOT need a dedicated server for NTP. NTP can run on a linux system that is also a web and mail server or on e linux desktop system that you use for web surfing and web browse ring, just as long as the box stays running and you don't turn it off. It's been discussed before, but probably worth repeating. Don't overlook the cost of power. If you have an old power-hungry CPU that you use for mail and web, leaving it on all the time can cost a lot. Yes. You are right. that is why I posted a like to this http://www.newegg.com/Product/Product.aspx?Item=N82E16813121442 this board uses very little power and as you say will pay for itself quickly. You can reast your hand of the heat sink and notice there is no fan. It uses just a few watts. and can run VMware, and multiple servers The payoff time for replacing it with a low power system can be as low as a year or two. -- 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. -- 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] RasberryPi, timing and GPS receivers
By the way, you need not use a USB serial adapter. Several folks are doing PPS on the gpio pins. Take a look here https://github.com/davidk/adafruit-raspberrypi-linux-pps And here http://www.frambozenbier.org/index.php/raspi-community-news/4439-george-lu-on-ntp-pps On Oct 16, 2012, at 22:03, x...@darksmile.net wrote: The miniITX mobos are quite impressive. There is no argument there. However, My simple idea was this: Since I want to keep time at 3 separate locations and wanted stratum 1 NTP, I didn't want overkill. Actually my reason for 3 different locations is simple: Internet is flakey some places and sometimes just down. I'd like to have correct time no matter what happens to the internet. The other thing I want to do is create a very small footprint NTP server that basically looks like 3-4 cartons of cigarettes stacked on top of each other. Maybe even have the power supply on the bottom of the stack. I don't know if I'll be able to do this but this is the general idea. I think maybe something like this: GPS Receiver + antenna connector --- Interface board --- CPU main board --- Shield board (mostly ground plane) --- Power supply --- If I could put this in a nice aluminum case I think it would look beautiful. -G Quoting Chris Albertson albertson.ch...@gmail.com: On Tue, Oct 16, 2012 at 4:37 PM, Hal Murray hmur...@megapathdsl.net wrote: One does NOT need a dedicated server for NTP. NTP can run on a linux system that is also a web and mail server or on e linux desktop system that you use for web surfing and web browse ring, just as long as the box stays running and you don't turn it off. It's been discussed before, but probably worth repeating. Don't overlook the cost of power. If you have an old power-hungry CPU that you use for mail and web, leaving it on all the time can cost a lot. Yes. You are right. that is why I posted a like to this http://www.newegg.com/Product/Product.aspx?Item=N82E16813121442 this board uses very little power and as you say will pay for itself quickly. You can reast your hand of the heat sink and notice there is no fan. It uses just a few watts. and can run VMware, and multiple servers The payoff time for replacing it with a low power system can be as low as a year or two. -- 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. -- 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] RasberryPi, timing and GPS receivers
Hello everyone, I started a new project for myself where I would use the RasperryPi Linux board as a NTP server. [] Question: What GPS timing module should I go with? No more Motorola Oncore so what's best right now? Who sell modules? What are the price ranges? Your comments are most welcome. -George, N2FGX = Excellent project! As well as the Garmin GPS 18x LVC (US $70), there is a low-cost (US $35) evaluation board from Sure Electronics: http://www.satsignal.eu/ntp/FreeBSD-GPS-PPS.htm http://www.satsignal.eu/ntp/Sure-GPS.htm I'd be interested to see a write-up of your results. 73, David GM8ARV -- SatSignal Software - Quality software written to your requirements Web: http://www.satsignal.eu Email: david-tay...@blueyonder.co.uk ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
