Re: [time-nuts] Lowloss cable?
What's the best small diameter (0.25) low loss coax? I need to run about 30' from my GPS antenna to a TBolt. Best, Dick If the antenna has a pre-amp, then just use satellite TV cable, even though the losses and impedance aren't quite what you might like. Cheers, 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.
Re: [time-nuts] low-loss cable
Once again, thanks to all. The Lucent bullet antenna has an N connector on the base, so I'll just use RG-6 which I have enough of, and live with a bigger trough through the window frame or just go ahead and bore through the wall -- I originally cut the slit in the window frame to accommodate the Hawk patch antenna's permanently attached very small diameter cable and I didn't want to mess with removing and installing the BNC connector on the other end on that tiny stuff in order to take it through the wall. But with RG-6 or RG-59, no such problem. Now, question 2: fluke.l says that the Lucent bullet will work fine with the TBolt -- but is there any chance that the 26dB gain of that antenna and its preamp will cause the TBolt pain? Best, Dick ___ time-nuts mailing 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] low-loss cable
Hi Dick, See page 27 of this document (as numbered at the bottom of the page, or PDF page 29): http://trl.trimble.com/docushare/dsweb/Get/Document-388613/ThunderboltE_UG_1B.pdf The Trimble Bullet antenna for the TBolt has 28dB gain and they recommend RG-59 coax. Brooke's page ( http://www.prc68.com/I/ThunderBolt.shtml#Ant ) mentions the TBolt is happy with an antenna gain between 18 and 35dB. He also mentions to watch out for the voltage to the antenna. A lot of newer antennas run on 3.3 volts instead of the 5V being injected up the line by the Thunderbolt.I'm having a problem with Symmetricom clocks at work where they switched to injecting 12 volts up the line (previously models were 5 volts) so I had to get up on the roof and swap antennas. -Bob On Mon, Jun 13, 2011 at 1:56 AM, Dick Moore rich...@hughes.net wrote: Once again, thanks to all. The Lucent bullet antenna has an N connector on the base, so I'll just use RG-6 which I have enough of, and live with a bigger trough through the window frame or just go ahead and bore through the wall -- I originally cut the slit in the window frame to accommodate the Hawk patch antenna's permanently attached very small diameter cable and I didn't want to mess with removing and installing the BNC connector on the other end on that tiny stuff in order to take it through the wall. But with RG-6 or RG-59, no such problem. Now, question 2: fluke.l says that the Lucent bullet will work fine with the TBolt -- but is there any chance that the 26dB gain of that antenna and its preamp will cause the TBolt pain? Best, Dick ___ time-nuts mailing 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] Coining a new term
And like the biological mushrooms they resemble, have a tendency to multiply. At least for Time Nuts... -- Russell At 6:30 PM -0400 2011/06/12, William H. Fite wrote: And an old, weathered bullet might resemble a morel. ___ time-nuts mailing 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] low-loss cable
Googling flat coax cable returns a number of hits. Apparently, these flat cables can be had for a few $/piece in the US. Thanks for the suggestion. Didier KO4BB Sent from my BlackBerry Wireless thingy while I do other things... -Original Message- From: b...@lysator.liu.se Sender: time-nuts-boun...@febo.com Date: Mon, 13 Jun 2011 07:36:53 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] low-loss cable Hi Dick, To get through windows without drilling och sawing, I found a very flat flex-cable, that you can close your window over. http://www.kjell.com/content/media/images/items/30161.jpg It is probably mostly for people wanting to get a cable through to a sat dish or outside TV antenna in apartment buildings. It is probably 75ohm and has F-connectors, but for say a T-bolt you already have a 75ohm F at the receiver. -- Björn Thanks all -- I got a Lucent bullet from i.fluke, +26dB gain. Replaces a Hawk patch with lower gain, but I want to run more cable (about 2X) to get the bullet higher in the air. The Hawk patch, which works very well signal-wise, has cable that's about 3 or 4mm in diameter and about 6m long. I've sawed out a part of a plastic window frame to get the cable inside. So I don't want any cable that's bigger than 0.25 d. and preferably smaller. Hope this clarification helps a bit. Best, Dick ___ time-nuts mailing 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] low-loss cable
Funny thing. I use free cable tv .5 hardline low loss stuff but at 1575 Mhz 3.12 db per 100'. I have used a lot of RG6 and kind of funny at 1575 its 7.89 db per 100'. So I must say the work needed to install the .5 cable is a lot more trouble then the 4 db of loss. Though these days I have the correct connectors. I do plan to mount another antenna on the tower. Thinking this run will be the lazy mans approach with good ole RG6. On Mon, Jun 13, 2011 at 8:55 AM, shali...@gmail.com wrote: Googling flat coax cable returns a number of hits. Apparently, these flat cables can be had for a few $/piece in the US. Thanks for the suggestion. Didier KO4BB Sent from my BlackBerry Wireless thingy while I do other things... -Original Message- From: b...@lysator.liu.se Sender: time-nuts-boun...@febo.com Date: Mon, 13 Jun 2011 07:36:53 To: Discussion of precise time and frequency measurement time-nuts@febo.com Reply-To: Discussion of precise time and frequency measurement time-nuts@febo.com Subject: Re: [time-nuts] low-loss cable Hi Dick, To get through windows without drilling och sawing, I found a very flat flex-cable, that you can close your window over. http://www.kjell.com/content/media/images/items/30161.jpg It is probably mostly for people wanting to get a cable through to a sat dish or outside TV antenna in apartment buildings. It is probably 75ohm and has F-connectors, but for say a T-bolt you already have a 75ohm F at the receiver. -- Björn Thanks all -- I got a Lucent bullet from i.fluke, +26dB gain. Replaces a Hawk patch with lower gain, but I want to run more cable (about 2X) to get the bullet higher in the air. The Hawk patch, which works very well signal-wise, has cable that's about 3 or 4mm in diameter and about 6m long. I've sawed out a part of a plastic window frame to get the cable inside. So I don't want any cable that's bigger than 0.25 d. and preferably smaller. Hope this clarification helps a bit. Best, Dick ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] Does TB keep almanac data ?
Every time I switch on my Thunderbolt (cold start) Lady Heather tells me that there are no almanac data. It takes a few tens of minutes before they are collected again. I was under the impression that TB had some sort of non volatile memory, and it must have it, as it is capable of remembering the position after a site survey. Why almanac data are not kept ? Not enough space in that non volatile memory ? TNX 73 Alberto I2PHD ___ time-nuts mailing 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] Does TB keep almanac data ?
Hi Alberto, Why almanac data are not kept ? Not enough space in that non volatile memory ? the thunderbolt is meant for permanent installation in mobile base stations where power outages are pretty rare, so I guess the designers didn't see it worthwhile. Chris ___ time-nuts mailing 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] Does TB keep almanac data ?
At 10:49 AM 6/13/2011, Alberto di Bene wrote... Why almanac data are not kept ? Not enough space in that non volatile memory ? Flash and EEPROMs have a limited number of write cycles available. For a timing receiver, position changes rarely - almanac data changes frequently. ___ time-nuts mailing 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] Does TB keep almanac data ?
EEPROM's do have a finite number of write cycles to any particular memory location, but it's about 100,000 or more. That's 11 years worth if written to once an hour round the clock (the same location in memory, that is). This is probably not the issue. I personally never noticed but then again, my TBolt has been on for the last 2 years, attached to a big UPS. -Bob On Mon, Jun 13, 2011 at 8:39 AM, Mike S mi...@flatsurface.com wrote: At 10:49 AM 6/13/2011, Alberto di Bene wrote... Why almanac data are not kept ? Not enough space in that non volatile memory ? Flash and EEPROMs have a limited number of write cycles available. For a timing receiver, position changes rarely - almanac data changes frequently. ___ time-nuts mailing 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] Does TB keep almanac data ?
On 06/13/2011 06:02 PM, Christian Vogel wrote: Hi Alberto, Why almanac data are not kept ? Not enough space in that non volatile memory ? the thunderbolt is meant for permanent installation in mobile base stations where power outages are pretty rare, so I guess the designers didn't see it worthwhile. Takes a SRAM chip and a battery to hold power. Not big magic, but if the application is very unlikely to need it, it will just be a waste. Almanac, position, fairly recent parameters from the oscillator and configuration would all be suitable to go in there. Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Coining a new term
On 06/13/2011 02:27 PM, Russell Rezaian wrote: And like the biological mushrooms they resemble, have a tendency to multiply. At least for Time Nuts... The term has already been used to illustrate the antenna testing at the Meinberg facility. :) I haven't picked any mushrooms there, will see if I will get a tour some day. Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] Lady Heather
We had the REAL Lady Heather on TV last night here in New Zealand! It was the CSI episode about cats. Any tenuous connection with Time-Nuts, perhaps? Murray ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Lady Heather
Lady Heather dishes out discipline. The time references are disciplined oscillators. The connection is a bit more than tenuous. --Original Message-- From: Murray Greenman Sender: time-nuts-boun...@febo.com To: time-nuts@febo.com ReplyTo: Discussion of precise time and frequency measurement Subject: [time-nuts] Lady Heather Sent: Jun 13, 2011 11:46 AM We had the REAL Lady Heather on TV last night here in New Zealand! It was the CSI episode about cats. Any tenuous connection with Time-Nuts, perhaps? Murray ___ time-nuts mailing 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] Advice on NTP server needed
Hello, I have an upcoming need for a GPS disciplined NTP server in a low cost project. Checking price on commercial units shows that these are out of reach so I have been looking into the possibility of building an NTP server. I understand that the Soekris net4501 single board computer is still available and affordable timing GPS units shows up on Ebay regularly so I assume these compnents could be used. I have found a couple of reference to ntpns software on internet, however I have not been able to figure out the exact hardware configuration required for this implementation. Does anyone on the list have any experience putting together an NTP server based on the net4501 running ntpns? Any alternative ideas for inexpensive SBC based NTP server? regards, Per ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Advice on NTP server needed
On Mon, Jun 13, 2011 at 1:37 PM, Per Molund pmol...@gmail.com wrote: Hello, I have an upcoming need for a GPS disciplined NTP server in a low cost project. Checking price on commercial units shows that these are out of reach so I have been looking into the possibility of building an NTP server. Almost any PC hardware will work. If cost is an issue find a used computer. Even an old Pentium II is fast enough. Also NTP does not need it's own dedicated hardware, run NTP on any sever you happen to already have. NTp has very minimal hardware requirements. What you will need is a real hardware serial port, not a USB serial converter. So older computers really are good in that way. The ideal operating system is any recent Linux or even better BSD. But it can be made to work on most any OS. The GPS will cost more than the computer. You will need to give the antenna a clear view of the sky in all directions and then lead the cable inside to the GPS receiver. You should think about lightening protection and grounding. At some locations snow and ice on the antenna is a concern. If you need to have this work professionally done for you the cost will be more than a small computer. Next thing is to think about your requirements for reliability. If this is more than a hobby then you will likely need multiple NTP servers. How many more is an on-going debate. The answer depends if you have Internet connection and your requirement for accuracy and tolerance to down time. Even if you buy a commercial server you might think How do I know if it is serving correct time? This can be a hard problem or not depending on the details of your setup. The least expensive option is to simply run NTP on any computer you already have -- 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] Advice on NTP server needed
I've done this recently and have bought several Symmetricom GPS time servers (S200, S350, etc). I've also built the net4501 up as a time server and do not recommend it. Mine was extremely flaky and I couldn't trust it to stay up unless it was on very clean power (big UPS) and even then it seemed to lock up randomly.Sometimes it would be up for an hour, other times up for a couple weeks. I don't think I ever hit a month of uptime. What are your precision requirements? Are you attached to the Internet or do you have to rely 100% on a non-networked authoritative time source? In my case I will have networked time servers but will use GPS for when the network flakes out. Network is for if and when GPS is jammed. I didn't bother with high end oscillators since they don't buy me much of anything in the operating environment where my gear will be. I wouldn't say they're equally bad as much as I'd say they're all good enough. What's your budget like? You're welcome to contact me off list for additional info or just to chat about what might work in your case. -Bob, N3XKB On Mon, Jun 13, 2011 at 2:37 PM, Per Molund pmol...@gmail.com wrote: Hello, I have an upcoming need for a GPS disciplined NTP server in a low cost project. Checking price on commercial units shows that these are out of reach so I have been looking into the possibility of building an NTP server. I understand that the Soekris net4501 single board computer is still available and affordable timing GPS units shows up on Ebay regularly so I assume these compnents could be used. I have found a couple of reference to ntpns software on internet, however I have not been able to figure out the exact hardware configuration required for this implementation. Does anyone on the list have any experience putting together an NTP server based on the net4501 running ntpns? Any alternative ideas for inexpensive SBC based NTP server? regards, Per ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Advice on NTP server needed
Hi The Net4501 servers I've made up have been very reliable boxes. They are low power and simple to run. If you put an OCXO in them, their accuracy is as good as it gets with NTP. The clock multiplier chip wiring can be a bit exciting, that's the only crazy part. Cost wise, an Atom based machine / surplus PC would be similar. It won't be as accurate or as low power. It might do more stuff for you. A lot depends on exactly what you are doing. Bob -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Per Molund Sent: Monday, June 13, 2011 4:38 PM To: time-nuts@febo.com Subject: [time-nuts] Advice on NTP server needed Hello, I have an upcoming need for a GPS disciplined NTP server in a low cost project. Checking price on commercial units shows that these are out of reach so I have been looking into the possibility of building an NTP server. I understand that the Soekris net4501 single board computer is still available and affordable timing GPS units shows up on Ebay regularly so I assume these compnents could be used. I have found a couple of reference to ntpns software on internet, however I have not been able to figure out the exact hardware configuration required for this implementation. Does anyone on the list have any experience putting together an NTP server based on the net4501 running ntpns? Any alternative ideas for inexpensive SBC based NTP server? regards, Per ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Advice on NTP server needed
I've been moving my 24 7 tasks to an Intel Atom PC, mostly to be green. It's not all that cheap since I used a SSD in the construction. Anyway my point is running an old PC to be er um frugal might turn out to be more expensive than running an intel atom. It all depends on your power costs. My choice was the D525, which was (maybe still is) the beefiest atom at the time. It has the full 64 bit instruction set and can use 4G of ram. The D525 system I built uses 30 watts on average. My next most low power PC (an AMD low power quad core) uses 140 watts. Unfortunately, my D525 mobo doesn't have a serial port and my symetricom doesn't like the usb converter. One of these days somebody is going to make a usb coverter that really looks like a serial port. I'm probably going to buy a serial card for the box if all else fails. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Advice on NTP server needed
Unfortunately, my D525 mobo doesn't have a serial port and my symetricom doesn't like the usb converter. One of these days somebody is going to make a usb coverter that really looks like a serial port. I'm probably going to buy a serial card for the box if all else fails. The best serial port boxes I have found, are Edgeports. They are available in 1/2/4/8/16 port versions, and I've picked up the 8 port versions for $50 on ebay. Dead solid, and reliable. I haven't hit anything that wouldn't work with them. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Advice on NTP server needed
On Mon, Jun 13, 2011 at 2:25 PM, gary li...@lazygranch.com wrote: I've been moving my 24 7 tasks to an Intel Atom PC, mostly to be green. It's not all that cheap since I used a SSD in the construction. Anyway my point is running an old PC to be er um frugal might turn out to be more expensive than running an intel atom. It all depends on your power costs. I have an Atom too. Find the version of Atom that can run with no CPU cooling fan. The model number change over time but always the lack of a fan means they don't use much power. Notebooks have always been somewhat power effisent. If you have an old notebook it can work. But cost-wiise it is impossable to beat simply adding NTP software to any erver that is already running. zero cost, zero added power and so on. Any computer that already runs 24x7 is a candidate for this. 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] FS: Datum TS-2100
$400 Plus shipping. Working without any problems. Questions or pics, drop me a note. Norm n3ykf ___ time-nuts mailing 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] Lyttleton Time Ball completly collapsed
Sadly, the Lyttleton Time Ball completly collapsed in yesterday's, Mon 13th, after-shocks. There were two quite major shocks of 5.5 at 1pm followed by a 6 at 2:20pm centered around the Sumner suberb which is close to Lyttleton. Cheers, Steve -- Steve Rooke - ZL3TUV G8KVD The only reason for time is so that everything doesn't happen at once. - Einstein ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Advice on NTP server needed
This is raising an interesting point, only vaguely relevant, but we have been testing some software for amateur radio astronomy purposes that controls intruments over serial lines RS-232 or RS-485. Whilst many application run with out problems for days on internal serial cards, we seem unable to find any USB to serial converter that performs anywhere near as well.on our loopback tests. Many of the fail rates suggest that slower speeds give a longer period between errors, but with one well-known converter we could not run at all at 57.6kB. This may not be too much of a problem with GPS control program speeds but it would seem there are few totally reliable products. It may be much more serious for NTP operations. Of the USB converters the best seemed to use the FTDI chip and driver, but even these have shown fails suggesting the problem is deeper inside the PC. All problems have been on the PC reception leg, causing corruption, and often what seemed like a driver disconnection so the serial port became disconnected from the application, and required the app restarting. Alan G3NYK - Original Message - From: David VanHorn d.vanh...@elec-solutions.com To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Monday, June 13, 2011 10:46 PM Subject: Re: [time-nuts] Advice on NTP server needed Unfortunately, my D525 mobo doesn't have a serial port and my symetricom doesn't like the usb converter. One of these days somebody is going to make a usb coverter that really looks like a serial port. I'm probably going to buy a serial card for the box if all else fails. The best serial port boxes I have found, are Edgeports. They are available in 1/2/4/8/16 port versions, and I've picked up the 8 port versions for $50 on ebay. Dead solid, and reliable. I haven't hit anything that wouldn't work with them. ___ time-nuts mailing 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] usb serial converter (was: Advice on NTP server needed)
On Mon, 13 Jun 2011 23:25:54 +0100 Alan Melia alan.me...@btinternet.com wrote: Of the USB converters the best seemed to use the FTDI chip and driver, but even these have shown fails suggesting the problem is deeper inside the PC. All problems have been on the PC reception leg, causing corruption, and often what seemed like a driver disconnection so the serial port became disconnected from the application, and required the app restarting. What OS have you been using? If it's windows, then blame the windows usb serial driver. It's the biggest piece of sh*** i've seen in a long time in the driver world. It is even able to freeze the machine without blue screen. Reliably. On the other hand, i am running an FTDI based usb-serial converter at home on a linux box to monitor another system. I did not have any problems at all in the year i use it. And given that the system runs 24/7 the slightes problem resulting in a disconnect should have shown up until now. Attila Kinali -- Why does it take years to find the answers to the questions one should have asked long ago? ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Advice on NTP server needed
I think it may be the voltage. Do the USB converts use rs232 levels or only 5 volts? For NTP the issue is different. The PPS signal coming from the GPS needs to go into a hardware serial port so the PPS handler sees a very low but more importantly a predictable latency.The PPS depends on a very specif interface to the hardware interrupt controller. On Mon, Jun 13, 2011 at 3:25 PM, Alan Melia alan.me...@btinternet.com wrote: This is raising an interesting point, only vaguely relevant, but we have been testing some software for amateur radio astronomy purposes that controls intruments over serial lines RS-232 or RS-485. Whilst many application run with out problems for days on internal serial cards, we seem unable to find any USB to serial converter that performs anywhere near as well.on our loopback tests. Many of the fail rates suggest that slower speeds give a longer period between errors, but with one well-known converter we could not run at all at 57.6kB. This may not be too much of a problem with GPS control program speeds but it would seem there are few totally reliable products. It may be much more serious for NTP operations. Of the USB converters the best seemed to use the FTDI chip and driver, but even these have shown fails suggesting the problem is deeper inside the PC. All problems have been on the PC reception leg, causing corruption, and often what seemed like a driver disconnection so the serial port became disconnected from the application, and required the app restarting. Alan G3NYK - Original Message - From: David VanHorn d.vanh...@elec-solutions.com To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Monday, June 13, 2011 10:46 PM Subject: Re: [time-nuts] Advice on NTP server needed Unfortunately, my D525 mobo doesn't have a serial port and my symetricom doesn't like the usb converter. One of these days somebody is going to make a usb coverter that really looks like a serial port. I'm probably going to buy a serial card for the box if all else fails. The best serial port boxes I have found, are Edgeports. They are available in 1/2/4/8/16 port versions, and I've picked up the 8 port versions for $50 on ebay. Dead solid, and reliable. I haven't hit anything that wouldn't work with them. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. -- Chris Albertson Redondo Beach, California ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Advice on NTP server needed
I have to disagree with the person that said the Net4501 is not stable. I have two (soon to be 3) that run NTPns and they have never needed to be touched. I've powered them down a couple times during really bad storms because I didn't want lightning to zap them (or my other GPS equipment). If you don't have any time constraints, you can watch eBay and usually get a Net4501 for $50 - $75 shipped. You can buy the latest Motorola Oncore timing receiver (M12M+T ?) from Synergy GPS, or on eBay the user fluke.l is selling older M12+T models for $35 + $8 shipping. Get an appropriate cable to go from the GPS unit to your antenna, solder a few wires, and you are good to go. Here's a pic of mine with the M12+T: http://www.rabel.org/pics/Net4501-2.jpg Here's an article I wrote building one with a UT+ receiver.. Took a little more work but results are the same: http://www.extremeoc.com/articles/howto/Building_S1_NTP_Server_1.html John's article is also a good read: http://www.febo.com/pages/soekris/index.html I have precompiled images of NanoBSD + NTPns on my server if you want to download them (email me off-list for the URLs). One build is FreeBSD 6.3, the other is 7. I haven't built any trying newer versions of FreeBSD, I don't think there is really anything to except a bunch of build headaches. If you want something more plug play... Watch eBay for Tymserve 2100, which seem to be the most common. There was a bunch of Spectracom GPS Time servers that recently sold for ~$100 each IIRC. I don't know if anymore are available. Every now and then an EndRun or Brandywine unit will show up. Other useful keywords to search eBay would be Symmetricom, Datum, and TrueTime. Oh, and of course there's the Trimble Thunderbolt... You can hook that up to a PC / serial port as a GPS input. Since it has its own internal OCXO you also get some hold-over ability. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Lyttleton Time Ball completly collapsed
Dissapointing - I remember it being pointed out to me as we pulled into port there once. Are there others scattered around the globe? Brent On Mon, Jun 13, 2011 at 6:19 PM, Steve Rooke sar10...@gmail.com wrote: Sadly, the Lyttleton Time Ball completly collapsed in yesterday's, Mon 13th, after-shocks. There were two quite major shocks of 5.5 at 1pm followed by a 6 at 2:20pm centered around the Sumner suberb which is close to Lyttleton. Cheers, Steve -- Steve Rooke - ZL3TUV G8KVD The only reason for time is so that everything doesn't happen at once. - Einstein ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Advice on NTP server needed
On Mon, 13 Jun 2011 15:37:13 -0700 Chris Albertson albertson.ch...@gmail.com wrote: For NTP the issue is different. The PPS signal coming from the GPS needs to go into a hardware serial port so the PPS handler sees a very low but more importantly a predictable latency.The PPS depends on a very specif interface to the hardware interrupt controller. The interrupt latency for USB is predictable. You can read out the bInterval setting of the interrupt endpoint of your serial converter (use something like lsusb or similar), this is the maximum poll interval in ms (for USB FS devices). Most devices i've seen, set this to 1 Given that USB port is fully loaded, then you will get an average delay of 0.5ms (uniform distribution). With an unloaded USB port, this will be much better. (for exact values, check the source of your OS/driver or use an USB debugger like the beagle to measure it) NTP will filter out the jitters of the PPS input using its control loop, so in the end, all that's left is the average delay as offset. Considering that anything below 1ms is negligible when comming to NTP, then i'd say that a USB serial port is good enough. Of course, 1ms timing uncertainty is not time-nuts class, but then again, ntp isnt time-nuts class ;-) Attila Kinali -- Why does it take years to find the answers to the questions one should have asked long ago? ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Advice on NTP server needed
Same here, my Net4501 has been running over 2 years without a reset. A Soekris-based NTP server uses the counter/timer built-in to its embedded processor to give you better precision interval measurement than a serial port, but if you're not interested in anything better than ms accuracy then it's probably not an issue. -- eric On Mon, Jun 13, 2011 at 3:45 PM, Jason Rabel ja...@extremeoverclocking.com wrote: I have to disagree with the person that said the Net4501 is not stable. I have two (soon to be 3) that run NTPns and they have never needed to be touched. I've powered them down a couple times during really bad storms because I didn't want lightning to zap them (or my other GPS equipment). If you don't have any time constraints, you can watch eBay and usually get a Net4501 for $50 - $75 shipped. You can buy the latest Motorola Oncore timing receiver (M12M+T ?) from Synergy GPS, or on eBay the user fluke.l is selling older M12+T models for $35 + $8 shipping. Get an appropriate cable to go from the GPS unit to your antenna, solder a few wires, and you are good to go. Here's a pic of mine with the M12+T: http://www.rabel.org/pics/Net4501-2.jpg Here's an article I wrote building one with a UT+ receiver.. Took a little more work but results are the same: http://www.extremeoc.com/articles/howto/Building_S1_NTP_Server_1.html John's article is also a good read: http://www.febo.com/pages/soekris/index.html I have precompiled images of NanoBSD + NTPns on my server if you want to download them (email me off-list for the URLs). One build is FreeBSD 6.3, the other is 7. I haven't built any trying newer versions of FreeBSD, I don't think there is really anything to except a bunch of build headaches. If you want something more plug play... Watch eBay for Tymserve 2100, which seem to be the most common. There was a bunch of Spectracom GPS Time servers that recently sold for ~$100 each IIRC. I don't know if anymore are available. Every now and then an EndRun or Brandywine unit will show up. Other useful keywords to search eBay would be Symmetricom, Datum, and TrueTime. Oh, and of course there's the Trimble Thunderbolt... You can hook that up to a PC / serial port as a GPS input. Since it has its own internal OCXO you also get some hold-over ability. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Advice on NTP server needed
In message BANLkTi=i4u-ng7ly6o2ybl_ypcqp95v...@mail.gmail.com, Eric Williams writes: Same here, my Net4501 has been running over 2 years without a reset. That is more a matter of power-supply than anything else: critter phk ssh root@xdcf uptime 11:04PM up 764 days, 4:01, 0 users, load averages: 0.20, 0.16, 0.10 As far as I know, the NET4501 is still undisputed king of the NTP hill. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 p...@freebsd.org | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] usb serial converter (was: Advice on NTP server needed)
Hi Attila you got it in one (givethe man a kewpie doll :-)) ) Yes it was so far on windows machines I have not got to the Linus machine yet but I am expecting better performancethe trouble is 70-80 or our users will use Windows. Thanks for your comments that is very reassuring. Alan - Original Message - From: Attila Kinali att...@kinali.ch To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Monday, June 13, 2011 11:36 PM Subject: [time-nuts] usb serial converter (was: Advice on NTP server needed) On Mon, 13 Jun 2011 23:25:54 +0100 Alan Melia alan.me...@btinternet.com wrote: Of the USB converters the best seemed to use the FTDI chip and driver, but even these have shown fails suggesting the problem is deeper inside the PC. All problems have been on the PC reception leg, causing corruption, and often what seemed like a driver disconnection so the serial port became disconnected from the application, and required the app restarting. What OS have you been using? If it's windows, then blame the windows usb serial driver. It's the biggest piece of sh*** i've seen in a long time in the driver world. It is even able to freeze the machine without blue screen. Reliably. On the other hand, i am running an FTDI based usb-serial converter at home on a linux box to monitor another system. I did not have any problems at all in the year i use it. And given that the system runs 24/7 the slightes problem resulting in a disconnect should have shown up until now. Attila Kinali -- Why does it take years to find the answers to the questions one should have asked long ago? ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Advice on NTP server needed
At 06:25 PM 6/13/2011, Alan Melia wrote... Of the USB converters the best seemed to use the FTDI chip and driver, but I agree. The Prolific ones seem not to be as reliable, plus I understand that many don't use a real Prolific chip, but a Chinese clone which is even worse. I've got a Moxa nPort 5610 Ethernet-serial server, which seems to be very reliable. They're inconsistent in updating the Linux drivers, and the code is butt-ugly, but it is open-source (for Linux). I use their real COM mode, which makes it look like a /dev/tty device (COMx: for Windows). One neat thing is that up to 4 computers can be simultaneously connected, so I can for instance run Lady Heather against my Thunderbolt from a Windows VM _and_ also point the Linux side NTP at it with no conflict (PPS comes in a real serial port). The biggest drawback is they use RJ45 jacks for the RS-232 ports, with a completely non-standard pinout (it's not EIA/TIA-561 or Yost). I've restarted the Moxa with both Heather and NTP using the Thunderbolt, and other than the expected glitch, everything picks up where it left off without any problem. Oh, and my NET4501s have been very stable - other than one of the wall wart power supplies dying. Replaced it with a beefier one, and all's good. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Advice on NTP server needed
OK so the USB works at the ms level. That compares to the us level I'm getting. So I have 500 to 1,000 times better performance using an $85 Intel Atom board. That's $85 with the CPU and the serial port soldered down on-board. I did need to add a 1GB RAM and a micro-atx size case but I'm still under $200 for the entire server. I was able to get it all from Amazon.com and not have to hassle with eBay If I had to spend a ton of money to get that 500X better performance then I'd think about it I did not pay extra I can get ms level performance using pool servers on the Internet, If milliseconds is all you need then don't bother with GPS. but then I have an Ethernet equivalent Internet connection. You should expect a handful of us error from a GPS driven NPT server and ms level from Ethernet connected clients If you are willing to invest much effort you can do better than 1uS. THAT would be in the Time Nut Range On Mon, Jun 13, 2011 at 3:59 PM, Attila Kinali att...@kinali.ch wrote: On Mon, 13 Jun 2011 15:37:13 -0700 Chris Albertson albertson.ch...@gmail.com wrote: For NTP the issue is different. The PPS signal coming from the GPS needs to go into a hardware serial port so the PPS handler sees a very low but more importantly a predictable latency. The PPS depends on a very specif interface to the hardware interrupt controller. The interrupt latency for USB is predictable. You can read out the bInterval setting of the interrupt endpoint of your serial converter (use something like lsusb or similar), this is the maximum poll interval in ms (for USB FS devices). Most devices i've seen, set this to 1 Given that USB port is fully loaded, then you will get an average delay of 0.5ms (uniform distribution). With an unloaded USB port, this will be much better. (for exact values, check the source of your OS/driver or use an USB debugger like the beagle to measure it) NTP will filter out the jitters of the PPS input using its control loop, so in the end, all that's left is the average delay as offset. Considering that anything below 1ms is negligible when comming to NTP, then i'd say that a USB serial port is good enough. Of course, 1ms timing uncertainty is not time-nuts class, but then again, ntp isnt time-nuts class ;-) Attila Kinali -- Why does it take years to find the answers to the questions one should have asked long ago? ___ time-nuts mailing 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] Advice on NTP server needed
When I set up gpsd (linux gps daemon), I noticed it has a hook to discipline your RTC, much like NTP. I have no idea if it is any good. As far as I can tell, gpsd isn't a real daemon. That is, it doesn't show up under services. You have to start it up by other means. ___ time-nuts mailing 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] Lyttleton Time Ball completly collapsed
I have seen no pictures of the current site but the quakes have downed several more buildings and many more are now added to the list of those that will need to be demolished. It will become a ghost town if this continues to happen. People are sick of the shocks and more are leaving as they are scared of living here. Many were injured and two are still in hospital with serious injuries. Existing delays in repair payments from the Government are causing considerable grief and anger with the people here and this is likely to add to it. New Zealanders have paid a national insurance scheme for earthquake coverage for decades and that should be available but it seems to not be forthcoming in any reasonable timeframe unfortunately. The mob is getting their pitchforks sharpened and torches ready; Gerry Brownley, Minister for EQC, had better beware! Steve On 14 June 2011 10:49, brent evers brent.ev...@gmail.com wrote: Dissapointing - I remember it being pointed out to me as we pulled into port there once. Are there others scattered around the globe? Brent On Mon, Jun 13, 2011 at 6:19 PM, Steve Rooke sar10...@gmail.com wrote: Sadly, the Lyttleton Time Ball completly collapsed in yesterday's, Mon 13th, after-shocks. There were two quite major shocks of 5.5 at 1pm followed by a 6 at 2:20pm centered around the Sumner suberb which is close to Lyttleton. Cheers, Steve -- Steve Rooke - ZL3TUV G8KVD The only reason for time is so that everything doesn't happen at once. - Einstein ___ time-nuts mailing 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. -- Steve Rooke - ZL3TUV G8KVD The only reason for time is so that everything doesn't happen at once. - Einstein ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Advice on NTP server needed
tick# uptime 1:12AM up 844 days, 16:52, 1 user, load averages: 0.03, 0.03, 0.00 Yes, that's true, but only when the system's basic reliability reaches a very high level. (QED) -- eric On Mon, Jun 13, 2011 at 4:05 PM, Poul-Henning Kamp p...@phk.freebsd.dk wrote: In message BANLkTi=i4u-ng7ly6o2ybl_ypcqp95v...@mail.gmail.com, Eric Williams writes: Same here, my Net4501 has been running over 2 years without a reset. That is more a matter of power-supply than anything else: critter phk ssh root@xdcf uptime 11:04PM up 764 days, 4:01, 0 users, load averages: 0.20, 0.16, 0.10 As far as I know, the NET4501 is still undisputed king of the NTP hill. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 p...@freebsd.org | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Advice on NTP server needed
As far as I can tell, gpsd isn't a real daemon. That is, it doesn't show up under services. You have to start it up by other means. [I know next to nothing about Windows so if under services means Windows, this may be irrelevant.] gpsd works fine as a daemon. The details depend upon which OS and/or distribution you are using. There are two ways to setup gpsd. One is to grab the source tar file, build, install... The other is to get a version of gpsd and ancillary files setup for your distribution. If you do a yum install gpsd on Fedora, it will install a udev rule to start gpsd when a USB TTY device is plugged in. It also comes with /etc/rc.d/init.d/gpsd and /etc/sysconfig/gpsd so it should be easy to modify things to start on booting if you want it to use something like /dev/ttyS0 -- These are my opinions, not necessarily my employer's. 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] Coining a new term
And like the biological mushrooms they resemble, have a tendency to multiply. Do they grow in fairy rings? http://en.wikipedia.org/wiki/Fairy_ring - well.. when you put a puck on top of a 6 foot length of conduit, it really does look like a mushroom (sort of like Enoki) Some of the GPS antennas I've seen are hemispherical. Those look much more like mushrooms. -- These are my opinions, not necessarily my employer's. 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] Lyttleton Time Ball completly collapsed
'Before' and 'after' yesterdays quake - pix of the timeball station plus an item about it that appeared in a suburban newspaper last week. http://homepages.ihug.co.nz/~tractorb/timeball/ DaveB Christchurch, NZ - Original Message - From: Steve Rooke sar10...@gmail.com To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Tuesday, June 14, 2011 12:43 PM Subject: Re: [time-nuts] Lyttleton Time Ball completly collapsed I have seen no pictures of the current site but the quakes have downed several more buildings and many more are now added to the list of those that will need to be demolished. It will become a ghost town if this continues to happen. People are sick of the shocks and more are leaving as they are scared of living here. Many were injured and two are still in hospital with serious injuries. Existing delays in repair payments from the Government are causing considerable grief and anger with the people here and this is likely to add to it. New Zealanders have paid a national insurance scheme for earthquake coverage for decades and that should be available but it seems to not be forthcoming in any reasonable timeframe unfortunately. The mob is getting their pitchforks sharpened and torches ready; Gerry Brownley, Minister for EQC, had better beware! Steve On 14 June 2011 10:49, brent evers brent.ev...@gmail.com wrote: Dissapointing - I remember it being pointed out to me as we pulled into port there once. Are there others scattered around the globe? Brent On Mon, Jun 13, 2011 at 6:19 PM, Steve Rooke sar10...@gmail.com wrote: Sadly, the Lyttleton Time Ball completly collapsed in yesterday's, Mon 13th, after-shocks. There were two quite major shocks of 5.5 at 1pm followed by a 6 at 2:20pm centered around the Sumner suberb which is close to Lyttleton. Cheers, Steve -- Steve Rooke - ZL3TUV G8KVD The only reason for time is so that everything doesn't happen at once. - Einstein ___ time-nuts mailing 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. -- Steve Rooke - ZL3TUV G8KVD The only reason for time is so that everything doesn't happen at once. - Einstein ___ time-nuts mailing 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.
