Re: [time-nuts] Lady Heather Server On Raspberry Pi 2 Model B?
Ed: A few recommendations for troubleshooting. In /etc/ser2net.conf comment out the 4 default lines (/dev/ttyS0-3) so that the line Nick provided is the only config present. Stop ser2net: /etc/init.d/ser2net stop then restart: /etc/init.d/ser2net start Make sure ser2net is running: ps -ef | grep ser2net If not, tail /var/log/syslog and see if any errors were reported on statrtup. Normally you just see a single line reporting successful startup. If it is running , make sure it is listening on the socket you specified (3200): netstat -tln | grep 3200 you should see a line with 0.0.0.0:3200 under local address There is additional troubleshooting you can do depending on results of above steps. Good luck. Mike On 1/12/2016 03:58, Ed Armstrong wrote: More details please. I've installed it, but can't make it work. My USB/serial cable is /dev/ttyUSB0 just like yours. I used your .conf file. But lady heather says connection rejected. Ed On 1/11/2016 8:00 PM, Nick Sayer via time-nuts wrote: I answered my own question. :) ser2net works perfectly as a “server” for LH. I’m using a USB to serial adapter and the ser2net.conf line for it is 3200:raw:0:/dev/ttyUSB0:9600 8DATABITS NONE 1STOPBIT LOCAL And for LH, /ip=n.n.n.n:3200 works. _ time-nuts mailing 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] GPS Disciplined TCXO
There were some postings on the list for this over the summer. I think he was going to sell them on Tindie. On 10/20/2015 16:53, Bryan _ wrote: Saw this on the Hackaday site if anyone is interested. https://hackaday.io/project/6872-gps-disciplined-tcxo -=Bryan=- ___ time-nuts mailing 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] Comparing the BeagleBone Black Raspberry Pi asNTP servers
David: On this page: http://elinux.org/Beagleboard:BeagleBoneBlack_Debian#BBW.2FBBB_.28All_Revs.29 they list an alternative console only image: https://rcn-ee.com/rootfs/bb.org/release/2015-03-01/console/bone-debian-7.8-console-armhf-2015-03-01-2gb.img.xz It might be easier starting with that if you don't intend to use graphics. Mike On 3/22/2015 03:46, David J Taylor wrote: David: On the BBB, were you running the fully loaded release, or the minimum console version of the OS? Which specific version of the OS? Thanks, --- Graham = Graham, The download was: bone-debian-7.8-lxde-4gb-armhf-2015-03-01-4gb.img.xz (547,024,548 bytes) which was from the Recommended Debian Images from: http://beagleboard.org/latest-images. Perhaps there are some services or background tasks I can disable to reduce the CPU steady load from its present 16% average level? 73, David GM8ARV ___ time-nuts mailing 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] June 30 2015 leap second
The referenced article indicates that they apply the smear to their NTP servers and allow the clients to track the servers. This approach would place some limits on the minimum lead time you would need to implement the smear. 1) you would have to start early enough for the servers to detect the change. Unless Google has an internal policy to limit maxpoll you would expect the clients to be operating at the default value of 1024 seconds. They would have to start well before 1024 seconds to allow the clients to detect the change and start tracking. 2) NTP has a maximum slew rate of 500ppm ( http://doc.ntp.org/4.1.0/ntpd.htm) . In practice you wouldn't be able to use this full range because the clients would already have some error in their clocks. The scary part of the referenced article is in the third to last paragraph: and Google engineers developing code don’t have to worry about leap seconds. That seems like the kind of attitude that would have caused such a mess with computer timekeeping in the first place. On 1/11/2015 09:31, Tom Van Baak wrote: The google code is lie(t) = (1.0 - cos(pi * t / w)) / 2.0 and they are wise not to publish the actual window value, w. If it were me I'd make it somewhere between a couple of seconds or couple of minutes but I too would not make it a published or hardcoded constant. Here's the link again: http://googleblog.blogspot.com/2011/09/time-technology-and-leaping-seconds.html ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] 53132A Cooling fan
I replaced one last year. I used a Delta EFB4012HD from Digi-Key but it isn't in stock currently. I just looked up the specs on the fan I removed and matched it to the fans available. There were multiple suitable substitutes. On 1/11/2015 00:59, Loïc Moreau wrote: Hi, My 53132A cooling fan is becoming extremely noisy so I have to fix it or find ear plugs fast. If anybody as encountered the same problem witch I suppose is common I will be interested if there is replacement part easily available for that purpose. Regards Loïc ___ time-nuts mailing 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] Looking for GPSDO for home use
Tom: I saw you post to David on the Time Nuts list offering availability of a Thunderbolt. If you have additional units available I would be interested in one as well. Let me know if you have any available and the cost. Thanks, Mike George N3MUY On 4/15/2014 14:03, Tom Van Baak wrote: Dave, If you're just calibrating a frequency counter you may not need a GPSDO. A simple GPS 1PPS is all you need; just measure the time from the 1PPS to the 10 MHz, wait a minute or an hour or a day and do it again. This will show you the time drift, from which you can calculate the frequency error. Still, having a 10 MHz GPSDO available is usually more convenient, so I would not talk you out of it. If you don't want to spend time to design your own GPSDO, or to build one of the dozen homebrew projects on the web, I would recommend you get a Trimble Thunderbolt. They are as turn-key as you can get, but also allow great hacking if you so choose. I have some left over from the group buy. If you're interested contact me off-list. Thanks, /tvb - Original Message - From: David Feldman wb0...@yahoo.com To: time-nuts@febo.com Sent: Tuesday, April 15, 2014 8:27 AM Subject: [time-nuts] Looking for GPSDO for home use I found this reflector after searching for GPSDO that would be suitable for individual purchase/use. Each time I found an article about GPSDO projects, that lead me to a surplus GPS module that is either no longer available, not current production, undocumented, or otherwise difficult to source. I don't mind doing my own building/integration, and am not adverse to starting with a used or suplus component, I'm not sure where to start in terms of sourcing the GPS module/antenna/etc. My main need is for something to serve as a primary frequency standard (i.e., 10 MHz output) I can use to set a voltage controlled OCXO I just installed in my (otherwise cheap chinese) frequency counter. It seems there are some modules that have/had 10 kHz output; that would work too. Even 1 PPS output seems like a workable starting point, but at the expense of a different and/or more difficult path to get to a 10 MHz reference signal I seek. Any advance or pointer to source (reasonable cost, whatever that means!) would be appreciated. Thanks! Dave wb0...@yahoo.com ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing 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] Using GPS to Fine Tune a Rubidium Frequency Standard.
Anders: I am a QEX subscriber and have that issue but I haven't built the circuit. The author referenced Brooks Shera as the basis for his work. He uses a Trimble Resolution T GPS for a PPS reference and an LPRO-101 Rubidium oscillator for the 10MHz. His circuit divides the 10MHz output from Rb by 100 and compares the phase of the 100kHz against the PPS. A PIC16 MCU is the controller and uses the phase data to control an external DAC to drive the Rb frequency control pin. There were a couple of other time frequency related articles in 2013 if you decide to get the CD. Mike On 3/21/2014 09:20, Anders Time wrote: Does anyone have a copy of the QEX 2013 november article(Bill Kaune) Using GPS to Fine Tune a Rubidium Frequency Standard? I´m really interested in this subject, but I can´t find this magazine in Sweden. I have contacted QEX, but it is very difficult to buy back-issues. Have any one built this frequency standard and can tell me more about the project? You can access the source code for the project here: http://www.arrl.org/files/file/QEX%20Binaries/2013/November_13/11x13_Kaune_PIC_Code.zip /Anders ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] NIST time services
The PRUs (Programmable Realtime Unit) aren't a feature of ARM in general (they are not present on the Raspberry Pi for instance). The BeagleBone has 2 PRUs as you describe. It uses the TI Siatra ARM variant. ARM just describes the core architecture. Manufacturers tack on all sorts of proprietary peripherals depending on what they envision as it's primary target market. Mike George On 3/22/2014 15:54, Chris Albertson wrote: On Sat, Mar 22, 2014 at 12:24 PM, Chuck Forsberg WA7KGX c...@omen.com wrote: I can see a use for an inexpensive GPSDO with a built-in gigabit ethernet or USB3 port powering an NTP server. Neither of those is a good way to transfer time to an NTP server. Both Ethernet and USB are packetized. The best way is with a simple wire with a square wave pulse on it that pulses ones per second. Nothing can be more simple or accurate. The trick is to build an NTP server that can react deterministically to the pulse. I think an ARM based system could far outperform an Intel based one. ARM has two independent PRUs. These are little 32-bit processes each with 4K of memory that are build right on the same chip as the main ARM CPU. The PRUs purpose built for real time task and can handle nanosecond level timing. In most existing system the PRUs are ignored and everything is done using the ARM. The other way to improve things even better is to not even bother to have a link from the GPSDO to the NTP server. Why not simply run the NTP server software on the same processor as the GPSDO? Just one of the little PRUs is more than powerful enough to run a GPSDO. They are a 32-bit uP that runs at 200MHz, one instruction per clock. The PRUs don't run any operating system code but have access to all of the ARM's memory and interrupts. A PRU is way-overkill for a GPSDO. Doing this eliminates the link cable from the GPSDO to the NTP server. If the ARM CPU can't handle 6 billion requests per day then buy many copies the ARM based systems. They are cheap. ___ time-nuts mailing 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] NIST time services
The PRU on the BeagleBone each include an enhanced capture module that can be used as you describe. It has a 32 bit timer that is latched into one of the capture registers. The timers are independent of the timer used by the Linux system so I'm not sure how you would tie them into use with NTP. But they do look like they would be useful for monitoring a GPSDO as Chris described. There are 4 capture registers in each eCAP so they would also be useful for monitoring/timestamping other signals. On 3/22/2014 17:44, Hal Murray wrote: albertson.ch...@gmail.com said: Would you know which other systems include the PRUs? Is it only in the TI products? It seems like an ideal solution to the problem of non-deterministic latency. There is a much simpler solution - avoid the latency by using a counter/timer to capture the counter on an external event. (That may assume you are using the same counter for timekeeping.) Many ARM chips come with a blizzard of peripherals. Good counter/timers are common. ___ time-nuts mailing 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] NIST time services
PRU appears to be unique to TI. I have only used Raspberry Pi, Beaglebone, and Cubieboard. The Cubieboard (Allwinner CPU) has a lot of IO pins like the Beaglebone but nothing like a PRU. Mike George On 3/22/2014 16:53, Chris Albertson wrote: Thanks, Yes of course ARM refers only to ARM Would you know which other systems include the PRUs? Is it only in the TI products? It seems like an ideal solution to the problem of non-deterministic latency. This may not even be required. There is no point to extreme levels of accuracy because the weak link with any NTP server is the Internet. NTP's purpose is to transfer time over unreliable data links and these links will always be the limiting factor. On Sat, Mar 22, 2014 at 1:23 PM, Mike George mgeo...@tuffmail.us wrote: The PRUs (Programmable Realtime Unit) aren't a feature of ARM in general (they are not present on the Raspberry Pi for instance). The BeagleBone has 2 PRUs as you describe. It uses the TI Siatra ARM variant. ARM just describes the core architecture. Manufacturers tack on all sorts of proprietary peripherals depending on what they envision as it's primary target market. Mike George On 3/22/2014 15:54, Chris Albertson wrote: On Sat, Mar 22, 2014 at 12:24 PM, Chuck Forsberg WA7KGX c...@omen.com wrote: I can see a use for an inexpensive GPSDO with a built-in gigabit ethernet or USB3 port powering an NTP server. Neither of those is a good way to transfer time to an NTP server. Both Ethernet and USB are packetized. The best way is with a simple wire with a square wave pulse on it that pulses ones per second. Nothing can be more simple or accurate. The trick is to build an NTP server that can react deterministically to the pulse. I think an ARM based system could far outperform an Intel based one. ARM has two independent PRUs. These are little 32-bit processes each with 4K of memory that are build right on the same chip as the main ARM CPU. The PRUs purpose built for real time task and can handle nanosecond level timing. In most existing system the PRUs are ignored and everything is done using the ARM. The other way to improve things even better is to not even bother to have a link from the GPSDO to the NTP server. Why not simply run the NTP server software on the same processor as the GPSDO? Just one of the little PRUs is more than powerful enough to run a GPSDO. They are a 32-bit uP that runs at 200MHz, one instruction per clock. The PRUs don't run any operating system code but have access to all of the ARM's memory and interrupts. A PRU is way-overkill for a GPSDO. Doing this eliminates the link cable from the GPSDO to the NTP server. If the ARM CPU can't handle 6 billion requests per day then buy many copies the ARM based systems. They are cheap. ___ time-nuts mailing 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] HP53131A Fan/Blower
Tony: I replaced a fan in a 53132 by looking up the specs on the existing fan and matching to one that was available. On the 53132 I used Digi-Key 603-1009-ND. The fan was part of the power supply as you said. The wires are soldered to the board. Good Luck, Mike George On 2/27/2014 18:35, Tony Greene wrote: Has anyone found a suitable replacement or a source for the fan/blower in the HP53131A ? I have talked to Agilent and the fan/blower is not a seperate item, its part of the power supply board. TRY FREE IM TOOLPACK at http://www.imtoolpack.com/default.aspx?rc=if5 Capture screenshots, upload images, edit and send them to your friends through IMs, post on Twitter®, Facebook®, MySpace™, LinkedIn® – FAST! ___ time-nuts mailing 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.
