Re: [time-nuts] advice

Perhaps one could use a laser stabilised to an atomic absorption line to interrogate an atomic absorption cell or equivalent in the other location via optical fiber using the absorption cell as a frequency discriminator. Trapped ion or Bose-Einstein condensates could be used in the absorption

Re: [time-nuts] advice

On Wed, 22 Feb 2017 00:54:34 -0800 Hal Murray wrote: > How stable is a good laser and/or how hard do I have to work (or how much do > I have to pay) to get one stable enough for this experiment? What's the line > width on a typical laser? How much does it wander with

Re: [time-nuts] advice

So this is the Pound-Rebka experiment with lasers instead of the original Fe57 gamma rays and Mossbauer effect? Tim N3QE Sent from my VAX-11/780 > On Feb 21, 2017, at 9:33 PM, Bill Byrom wrote: > > Review the theory and results in this paper: > >

Re: [time-nuts] advice

For a spherical body of uniform density the value of g below the surface is proportional to  the radial distance of the location from the centre of the sphere.  For a spherically symmetric body only the mass contained within the sphere  below the point has any effect on the measured value of g.

Re: [time-nuts] advice

I'm curious about what you are trying to find out with this experiment. Certainly it is not to prove that time does in fact dilate.Are you planning on using time to measure relative differences in gravity? That seems reasonable because as it turns out times is the physical quantity that

Re: [time-nuts] advice

Does gravity work differently under the surface? Maybe the redshift is different going below the surface. On Wed, Feb 22, 2017 at 3:22 AM, Bill Hawkins wrote: > In the confusion, I forgot that we are concerned with gravitational time >

Re: [time-nuts] advice

> Δf/fo = g Δh/c2 Does that work when going down below the surface as well as when up above it? (My last physics class was a long time ago. I remember doing the integrals for computing the gravity inside a sphere, but don't remember the answer. I wouldn't be surprised if a factor of 2 or

Re: [time-nuts] advice

bruce.griffi...@xtra.co.nz said: > If you have a dark fiber or 2 between the surface and the lab and a pair of > sufficiently stable lasers (one at the surface and one in the underground > lab) you could look at the change in beat frequency between the lasers > (around 50Hz for a pair of red

Re: [time-nuts] advice

Review the theory and results in this paper: http://science.sciencemag.org/content/329/5999/1630?variant=full-text[1] For small height changes on the surface of Earth, a clock that is higher by a distance ∆h runs faster by ... The gravitational shift corresponds to a clock shift of about 1.1 ×

Re: [time-nuts] advice

This short paper was issued by NIST researchers in 2010, and it discusses making accurate gravitational time dilation / redshift measurements using lasers: http://tf.boulder.nist.gov/general/pdf/2447.pdf Quoting that paper: > Differences in gravitational potential can be detected by comparing

Re: [time-nuts] advice

In the confusion, I forgot that we are concerned with gravitational time dilation, not time of flight. The University of Minnesota has a lab about 2500 feet down in the Soudan mine. The following is their brief description: "The Soudan Underground Laboratory is a general-purpose science

Re: [time-nuts] advice

Neutrinos? Look up the OPERA experiment that measured neutrinos going faster than light. Turned out to be a loose optical fiber connector to a timing instrument. Fermi Lab has/had the MINOS experiment going 500 miles from Chicago to a mine in northern Minnesota. The generated neutrinos go through

Re: [time-nuts] advice

On Tuesday, February 21, 2017 11:13:34 AM Rhoderick Beery wrote: > Greetings Time-Nuts! > > I'm a physics theorist interested in performing an experiment to measure > the gravitational time dilation beneath the surface of the Earth. Boulby > Labs in the UK is 1.1 km down which would generate a

Re: [time-nuts] advice

ewart (Not a physicist) > > > From: Rhoderick Beery <rjbe...@gmail.com> > To: time-nuts@febo.com > Sent: Tuesday, February 21, 2017 11:13 AM > Subject: [time-nuts] advice > > Greetings Time-Nuts! > > I'm a physics theorist interested in performing an experiment t

Re: [time-nuts] advice

there; whether it's time or something else. Bob Stewart (Not a physicist)  From: Rhoderick Beery <rjbe...@gmail.com> To: time-nuts@febo.com Sent: Tuesday, February 21, 2017 11:13 AM Subject: [time-nuts] advice Greetings Time-Nuts! I'm a physics theorist interested in perf

Re: [time-nuts] advice

Hi! Take a look at http://www.leapsecond.com/great2005/ and http://www.leapsecond.com/great2016a/ Edésio On Tue, Feb 21, 2017 at 11:13:34AM -0600, Rhoderick Beery wrote: > Greetings Time-Nuts! > > I'm a physics theorist interested in performing an experiment to measure > the gravitational time

Re: [time-nuts] advice

- Original Message - From: "Rhoderick Beery" <rjbe...@gmail.com> To: <time-nuts@febo.com> Sent: Tuesday, February 21, 2017 9:13 AM Subject: [time-nuts] advice > Greetings Time-Nuts! > > I'm a physics theorist interested in performing an experiment to measure &g

[time-nuts] advice

Greetings Time-Nuts! I'm a physics theorist interested in performing an experiment to measure the gravitational time dilation beneath the surface of the Earth. Boulby Labs in the UK is 1.1 km down which would generate a time differential from the surface on the order of 1 part in 10^15 -- not

Re: [time-nuts] advice for buying VCXO

Hello Jim, Yes i need a VCXO or even a VCTCXO. However when I search them on ebay, unfortunately, since they included every term for XO, I am lost in the noise. Any recomendations for buying VCXO's that are surplus, and not ebay? Thank you very much, Can On Mon, Oct 5, 2015 at 11:48 PM, Jim

Re: [time-nuts] advice for buying VCXO

On 10/6/15 5:46 AM, Can Altineller wrote: Hello Jim, Yes i need a VCXO or even a VCTCXO. However when I search them on ebay, unfortunately, since they included every term for XO, I am lost in the noise. Any recomendations for buying VCXO's that are surplus, and not ebay? do you want a

Re: [time-nuts] advice for buying VCXO

Hello, I was hoping for a cheap VCXO. I think those ovenized ones are more expensive. Where would I get a brand new VCXO, that has < 1ppm, and specs that are true. (as in the declared spec would match the actual performance, these days when we buy from ebay, or aliexpress this is hardly the

Re: [time-nuts] advice for buying VCXO

On Tue, October 6, 2015 2:46 pm, Can Altineller wrote: > Where would I get a brand new VCXO, that has < 1ppm, and specs that are > true. Where does the requirement for < 1ppm come from? I assume by that you mean center of control range within 1ppm of nominal frequency. What pull range will you

Re: [time-nuts] advice for buying VCXO

On 10/6/15 12:46 PM, Can Altineller wrote: Hello, I was hoping for a cheap VCXO. I think those ovenized ones are more expensive. Where would I get a brand new VCXO, that has < 1ppm, and specs that are true. (as in the declared spec would match the actual performance, these days when we buy

Re: [time-nuts] advice for buying VCXO

Hi If you are looking for a temperature stability of better than 1 ppm, then the device you are looking for is a VCTCXO. They are more commonly listed as a TCXO. That’s because most TCXO’s these days have a voltage control input. A quick check on the Mouser site shows 103 items that are

[time-nuts] advice for buying VCXO

Hello, I am want to buy some VCXO's but really simple and cheap ones. I requested a quote from goledge.com and their prices are around 180GBP per unit, and I dont want to pay that much given you can buy a rubidium standard for comparable prices. I looked on ebay and found those candidates:

[time-nuts] Advice on sighting a roof mounted gps area please

Hi All, I am building a house extension and part of the works involves adding a new hip roof made of corrugated iron. I was thinking I would pass a 50mm pvc pipe through the roof with a tee and then mount two conical gps timing antennas on top of it. I am in a low point and don't have

Re: [time-nuts] Advice on sighting a roof mounted gps area please

Tim The antennas should not interfere with each other due to rf leakage because of the way the systems are designed. I will believe you are using 2 rf feeds. The more you can clear the trees the better. My very simple solution is a 90' tower. A bit of humor it does have other uses. Regards Paul

Re: [time-nuts] Advice on sighting a roof mounted gps area please

First off, why only 50mm and why plastic? The PVC will degrade in the sunlight over the years. Use galvanized iron pipe. Make the mast as tall as you can. It can extend sever feet below the roof and attach to house structure using u-bolts. (Hight limited only by appearance from the street.)

Re: [time-nuts] Advice on sighting a roof mounted gps area please

Hi If you are going to get any benefit from multiple antennas, you want to space them as far apart as possible. You are better off with one antenna and a splitter than with two close spaced antennas. The cost of mucking around on the roof is non-trivial. The world is headed to L1/L2

Re: [time-nuts] Advice on sighting a roof mounted gps area please

kb...@n1k.org said: If you are going to get any benefit from multiple antennas, you want to space them as far apart as possible. You are better off with one antenna and a splitter than with two close spaced antennas. Does anybody have data? How would I measure it? Where is the knee? I

Re: [time-nuts] Advice on sighting a roof mounted gps area please

HI Many years ago, we got dinged on customer visit when they spotted our GPS antenna array on the roof. The claim made at the time was that anything under 20’ spacing was counterproductive. I’ve seen numbers like 5, 8, 10,15 and 25 feet mentioned by different people at different times. The

[time-nuts] Advice on getting a used Agilent E4432B RF-Generator

I have gotten a nice offer on a used Agilent E4432B (No Opts) I have 10Mhz so i don't need the OCXO , but i think it's Tnut-Grade equipment. I can get it for approx 1500 US$ delivered on my doorstep (EU) , this is not a bad price. Considering a US buy would be + shipping 25% VAT on

Re: [time-nuts] Advice on getting a used Agilent E4432B RF-Generator

On Tue, 19 Nov 2013 15:44:16 +, cfo wrote: I can get it for approx 1500 US$ delivered on my doorstep (EU) , this is not a bad price. Considering a US buy would be + shipping 25% VAT on unit+ship. Correction : Price is 1350 US$ delivered CFO

Re: [time-nuts] Advice on getting a used Agilent E4432B RF-Generator

Amazing price, is there a gun involved? Thomas Knox To: time-nuts@febo.com From: xne...@luna.dyndns.dk Date: Tue, 19 Nov 2013 16:15:51 + Subject: Re: [time-nuts] Advice on getting a used Agilent E4432B RF-Generator On Tue, 19 Nov 2013 15:44:16 +, cfo wrote: I can get

Re: [time-nuts] Advice on getting a used Agilent E4432B RF-Generator

On Tue, 19 Nov 2013 09:35:00 -0700, Tom Knox wrote: Amazing price, is there a gun involved? Thomas Knox No gun , but some previous buys from same seller. And no options installed in the unit. I have just been told that the attenuator is made up of some PIN-Diodes , and is virtually immune

Re: [time-nuts] Advice on getting a used Agilent E4432B RF-Generator

On 19 November 2013 16:53, cfo xne...@luna.dyndns.dk wrote: On Tue, 19 Nov 2013 09:35:00 -0700, Tom Knox wrote: Amazing price, is there a gun involved? Thomas Knox No gun , but some previous buys from same seller. And no options installed in the unit. I have just been told that the

Re: [time-nuts] Advice on getting a used Agilent E4432B RF-Generator

Agilent has a mechanical attenuator option, so perhaps that is the reason. Thomas Knox Date: Tue, 19 Nov 2013 17:13:56 + From: drkir...@gmail.com To: time-nuts@febo.com Subject: Re: [time-nuts] Advice on getting a used Agilent E4432B RF-Generator On 19 November 2013 16:53, cfo xne

Re: [time-nuts] Advice on getting a used Agilent E4432B RF-Generator

On 11/19/13 9:13 AM, Dr. David Kirkby wrote: If it is made up from PIN diodes, I wonder what the logic of Agilent letting you read the number of times they have switched? Common firmware between units? ___ time-nuts mailing list --

Re: [time-nuts] Advice on getting a used Agilent E4432B RF-Generator

On Tue 19/11/13 8:04 PM , Jim Lux wrote:On 11/19/13 9:13 AM, Dr. David Kirkby wrote: If it is made up from PIN diodes, I wonder what the logic of Agilent letting you read the number of times they have switched? Common firmware between units?

Re: [time-nuts] Advice Z3816A jumping to Holdover: 1PPS TI exceeds hold threshold, then Recovery: phase alignment for 3-4 hours.

and frequency measurement Subject: Re: [time-nuts] Advice Z3816A jumping to Holdover: 1PPS TI exceeds hold threshold, then Recovery: phase alignment for 3-4 hours. Azelio, I had an interesting experience with the same symptoms tonight. I inserted a 6 dB pad on the antenna input and it appears to alleviated

Re: [time-nuts] Advice Z3816A jumping to Holdover: 1PPS TI exceeds hold threshold, then Recovery: phase alignment for 3-4 hours.

[mailto:time-nuts-boun...@febo.com] On Behalf Of Azelio Boriani Sent: Tuesday, 16 July 2013 5:57 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Advice Z3816A jumping to Holdover: 1PPS TI exceeds hold threshold, then Recovery: phase alignment for 3-4 hours. I have

Re: [time-nuts] Advice Z3816A jumping to Holdover: 1PPS TI exceeds hold threshold, then Recovery: phase alignment for 3-4 hours.

[mailto:time-nuts-boun...@febo.com] On Behalf Of Azelio Boriani Sent: Sunday, 21 July 2013 8:24 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Advice Z3816A jumping to Holdover: 1PPS TI exceeds hold threshold, then Recovery: phase alignment for 3-4 hours. OK

Re: [time-nuts] Advice Z3816A jumping to Holdover: 1PPS TI exceeds hold threshold, then Recovery: phase alignment for 3-4 hours.

: Sunday, 21 July 2013 8:24 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Advice Z3816A jumping to Holdover: 1PPS TI exceeds hold threshold, then Recovery: phase alignment for 3-4 hours. OK, interesting but putting an attenuator on the antenna input seems

Re: [time-nuts] Advice Z3816A jumping to Holdover: 1PPS TI exceeds hold threshold, then Recovery: phase alignment for 3-4 hours.

-boun...@febo.com] On Behalf Of Bob Camp Sent: Sunday, 21 July 2013 12:06 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Advice Z3816A jumping to Holdover: 1PPS TI exceeds hold threshold, then Recovery: phase alignment for 3-4 hours. Hi Pad = resistor

Re: [time-nuts] Advice Z3816A jumping to Holdover: 1PPS TI exceeds hold threshold, then Recovery: phase alignment for 3-4 hours.

I have a 58503 that occasionally is not able to track satellites. Usually I wait until the holdover expires but then the only fix seems to restart the 58503 (SYST:PRESET) better than power cycle. It seems there is a command to reset only the GPS receiver but it is not in the 58503 manual. On Tue,

Re: [time-nuts] Advice Z3816A jumping to Holdover: 1PPS TI exceeds hold threshold, then Recovery: phase alignment for 3-4 hours.

and frequency measurement Subject: Re: [time-nuts] Advice Z3816A jumping to Holdover: 1PPS TI exceeds hold threshold, then Recovery: phase alignment for 3-4 hours. I have a 58503 that occasionally is not able to track satellites. Usually I wait until the holdover expires but then the only fix seems

[time-nuts] Advice Z3816A jumping to Holdover: 1PPS TI exceeds hold threshold, then Recovery: phase alignment for 3-4 hours.

I have a Z3816A and it periodically jumps into holdover with error message: Holdover: 1PPS TI exceeds hold threshold Then for the next 3-4 hours it gradually adjusts the phase alignment. The error message is Recovery: phase alignment [TI +435.5 us] (when I noticed it had changed, they figure was

[time-nuts] Advice on Austron 1250A

Does anyone in the group have any experience or advice on the Austron 1250A Crystal Frequency Standard? I have a chance to buy one for $250 tomorrow at a local hamfest, but can't find anything in the archives on them. It's very clean, and the seller says that it is in perfect working order.

Re: [time-nuts] Advice on Austron 1250A

Dave Any chance that would be the MIT flea? If so another time-nut in the area. I will be there and it looks like a good day. To your question. Good standard and all. I suppose a reasonable price. But with all of the gpsdo and rbs and such available its kind of allot. Sort of depends on what you

Re: [time-nuts] Advice on Austron 1250A

Hi Dave, The Austron 1250 is a very close look alike to the hp-105 Quartz standard. A decent quartz oscillator is certainly worth having besides the usual Tbolt GPS or Rb type references. The Austron will certainly be a quieter signal then the Tbolt or Rb oscillators for short (1 to 10

Re: [time-nuts] Advice on Austron 1250A

Bill so thats what happened to Sulzer they became a part of austron. I have 2 sulzers older and good units. Regards Paul WB8TSL On Sat, Aug 18, 2012 at 10:06 PM, WB6BNQ wb6...@cox.net wrote: Hi Dave, The Austron 1250 is a very close look alike to the hp-105 Quartz standard. A decent quartz

Re: [time-nuts] Advice on Austron 1250A

] On Behalf Of Dave M Sent: Saturday, August 18, 2012 9:24 PM To: FEBO Time Nuts Subject: [time-nuts] Advice on Austron 1250A Does anyone in the group have any experience or advice on the Austron 1250A Crystal Frequency Standard? I have a chance to buy one for $250 tomorrow at a local hamfest

Re: [time-nuts] Advice on Austron 1250A

Hi Paul, No, I'm not at the MIT flea market... wish I were able to make a few of those meets. I understand lots of fine equipment changes hands there. I'm at the annual hamfest in Huntsville, Al this weekend. And thanks for the others who offered good advice. I think I'll buy the unit and

Re: [time-nuts] Advice on Austron 1250A

could be required. I would go for it if you do not have another disciplined quartz oscillator you will have fun with it. Best Wishes; Thomas Knox From: dgmin...@mediacombb.net To: time-nuts@febo.com Date: Sat, 18 Aug 2012 20:23:45 -0500 Subject: [time-nuts] Advice on Austron 1250A Does

Re: [time-nuts] Advice on Austron 1250A

:45 -0500 Subject: [time-nuts] Advice on Austron 1250A Does anyone in the group have any experience or advice on the Austron 1250A Crystal Frequency Standard? I have a chance to buy one for $250 tomorrow at a local hamfest, but can't find anything in the archives on them. It's very clean

Re: [time-nuts] Advice on Austron 1250A

From: dgmin...@mediacombb.net To: time-nuts@febo.com Date: Sat, 18 Aug 2012 20:23:45 -0500 Subject: [time-nuts] Advice on Austron 1250A Does anyone in the group have any experience or advice on the Austron 1250A Crystal Frequency Standard? I have a chance to buy one for $250 tomorrow at a local

Re: [time-nuts] Advice on Austron 1250A

On Sat, Aug 18, 2012 at 08:23:45PM -0500, Dave M wrote: Does anyone in the group have any experience or advice on the Austron 1250A Crystal Frequency Standard? I have a chance to buy one for $250 tomorrow at a local hamfest, but can't find anything in the archives on them. It's very

Re: [time-nuts] Advice on Austron 1250A

The unit I've been offered has new batteries, and is able to be disciplined, as I mentioned to Tom. The seller indicates that the unit is checked out and is fully operational, so I have a degree of confidence that I wouldn't otherwise have if buying from Ebay. As I said in my first post, the

Re: [time-nuts] Advice on Austron 1250A

Hi Dave; The ext VCO input is nice, what I was referring to was something that would sync directly to an ext ref of 5-10MHz Best Wishes; Thomas Knox From: dgmin...@mediacombb.net To: time-nuts@febo.com Date: Sat, 18 Aug 2012 23:00:24 -0500 Subject: Re: [time-nuts] Advice on Austron 1250A

Re: [time-nuts] Advice on good reception for radio clocks

So it might just have been the weather. I'm getting quite good reception this evening - losing one bit in every 200 or so. Enough to write a crappy decoder that can display the time and the DCF77 leapsecond warning bit. 25 minutes to go, ish! Tony. -- f.anthony.n.finch d...@dotat.at

Re: [time-nuts] Advice on good reception for radio clocks

Went ok: https://p.twimg.com/AwrS0WgCIAAyTmM.jpg:large Amusingly reception has turned to mush since then, but you can see the leapsecond warning bit has gone to 0 - 001001 vs. 001011. Even though this is fairly crappy as clocks go, it has been fun. https://p.twimg.com/AwrHE_mCQAEcRIf.jpg:large

[time-nuts] Advice on good reception for radio clocks

Are there any basic steps I should take to improve the reception quality of a radio clock? I have a cheap and cheerful DCF77 receiver for connecting to some GPIO pins, but its PPS output is basically noise with maybe a one-second period. Perhaps it's just cheap and nasty. I am in Cambridge. Tony

Re: [time-nuts] Advice on good reception for radio clocks

Hi Tony: The loopstick antenna has a pattern with a couple of nulls so the orientation is important. Also during the daytime there's probably too much noise to receive a good signal so best to listen around local midnight. Have Fun, Brooke Clarke http://www.PRC68.com

Re: [time-nuts] Advice on good reception for radio clocks

Hi Tony, On 27 June 2012 15:04, Tony Finch d...@dotat.at wrote: Are there any basic steps I should take to improve the reception quality of a radio clock? I have a cheap and cheerful DCF77 receiver for connecting to some GPIO pins, but its PPS output is basically noise with maybe a one-second

Re: [time-nuts] Advice on good reception for radio clocks

Andrew Back and...@carrierdetect.com wrote: I got one of those SYMTRIK modules working but the antenna orientation did seem a bit fiddly, and this was MSF and not DCF77. http://www.designspark.com/content/atomic-time-raspberry-pi Don't suppose you're using a Raspberry Pi for this? I'd

Re: [time-nuts] Advice on good reception for radio clocks

On 06/27/2012 04:04 PM, Tony Finch wrote: Are there any basic steps I should take to improve the reception quality of a radio clock? I have a cheap and cheerful DCF77 receiver for connecting to some GPIO pins, but its PPS output is basically noise with maybe a one-second period. Perhaps it's

Re: [time-nuts] Advice on good reception for radio clocks

Yes, this last is exactly my same experience with the DCF77: the receiver used alone with a linear power supply was running fine, connected to the PC or a microproccesor board with a switching power supply was a problem. On Wed, Jun 27, 2012 at 5:59 PM, Kasper Pedersen time-n...@kasperkp.dkwrote:

Re: [time-nuts] Advice on good reception for radio clocks

One trick that works, place the entire receiver. on a pole (black ABS pipe) fixed to the back yard fence. This places it as far from any house or power line. I don't think the pole needs to be tall. 8 feet get should be enough.Of course now you need a long wire and a pair of RS422 driver

Re: [time-nuts] Advice on good reception for radio clocks

Good idea... do you think to use batteries or along the differential line run a power line? Power... only a few mA would be enough. On Wed, Jun 27, 2012 at 6:20 PM, Chris Albertson albertson.ch...@gmail.comwrote: One trick that works, place the entire receiver. on a pole (black ABS pipe) fixed

Re: [time-nuts] Advice on good reception for radio clocks

Kasper Pedersen time-n...@kasperkp.dk wrote: When I did my DCF77 receiver, my first source of interference was the common noise on the output of the supply I was powering it off of. So I'm using a cheap and cheerful (there's a theme here) wall wart with micro-USB connector which I guess is

Re: [time-nuts] Advice on good reception for radio clocks

: Re: [time-nuts] Advice on good reception for radio clocks Kasper Pedersen time-n...@kasperkp.dk wrote: When I did my DCF77 receiver, my first source of interference was the common noise on the output of the supply I was powering it off of. So I'm using a cheap and cheerful (there's a theme here

Re: [time-nuts] Advice on Synergy M12+ adapter and SYMTRIK SYM-RFT-XX.

Hi Chris, On 19 April 2012 19:54, Chris Albertson albertson.ch...@gmail.com wrote: Here is what you need to do... 1) Get NTP working on the Linux system using Internet peers as the reference clock.  Use pool servers.   This is very easy to do and don't skip this step.  It verifies NTP works

[time-nuts] Advice on Synergy M12+ adapter and SYMTRIK SYM-RFT-XX.

Hello, I seem to have been steadily collecting time related equipment and doing very little with it, finally decided I should do something with this, and I'd like to start out simple. So, I have a Motorola M12+ GPS receiver in a Synergy Systems adapter board, and one of those little Symtrik MSF

Re: [time-nuts] Advice on Synergy M12+ adapter and SYMTRIK SYM-RFT-XX.

and...@carrierdetect.com said: So, I have a Motorola M12+ GPS receiver in a Synergy Systems adapter board, and one of those little Symtrik MSF receiver boards. I'd like to try and get both working under Linux with ntpd (not at the same time!), and was hoping that someone might be able to

Re: [time-nuts] Advice on Synergy M12+ adapter and SYMTRIK SYM-RFT-XX.

On Thu, Apr 19, 2012 at 6:18 AM, Andrew Back and...@carrierdetect.comwrote: So, I have a Motorola M12+ GPS receiver in a Synergy Systems adapter board, and one of those little Symtrik MSF receiver boards. I'd like to try and get both working under Linux with ntpd (not at the same time!), and

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. Gary, I found one

Re: [time-nuts] Advice on NTP server needed

-nuts@febo.com Reply-To: Discussion of precise time and frequency measurement 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

Re: [time-nuts] Advice on NTP server needed

Hello again! First I want to thank all respondents on the list for a number of advices to my questions although it is not exactly 'time-nuts' stuff! I have now decided to monitor eBay for commercial units for some days in a hope to find a unit in an reasonable priceclass (and a seller willing to

Re: [time-nuts] Advice on NTP server needed

On Tue, 14 Jun 2011 18:12:52 +0200 Per Molund pmol...@gmail.com wrote: The reason for this is mostly based on the installation environment. I am 'piggy-backing' on an commerical site (ie. for free) and rack-space and electricity are premium. I have also a need to have the installation look

Re: [time-nuts] Advice on NTP server needed

I'm surprised there is not already some computer you could run NTP on. As you've found out here NTP is a very light load even for a 0.4Ghz 486 class machine. There has to be a computer already in the rack that can run NTP. What about your client machines? one or more of them could connect to a

Re: [time-nuts] Advice on NTP server needed

As for Internet, yes we do have an connection, but via GPRS so it is not any good for ntp use. As for performance I am seeing 200-400 ms today with GPRS which is not good enough for my application, I hope to get down into low or sub ms range. It would be an interesting experiment to see how

[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

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

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

Re: [time-nuts] Advice on NTP server needed

, 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

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.

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

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

Re: [time-nuts] Advice on NTP server needed

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

Re: [time-nuts] Advice on NTP server needed

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

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

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

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

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

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

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

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.

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

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

Re: [time-nuts] advice: frequency calibration to 1 ppm possible without GPSDO?

Hi Kasper, Thank you, your nft program looks very interesting! It turns out the local ISP that provides my DSL, sonic.net runs a GPS-driven NTP server and I have a pretty low and stable latency, so this may work well. To measure a relative frequency offset, I presume that what limits accuracy

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