Re: [time-nuts] Discussion of precise time and frequency measurement

Longitude by Wire by Richard Stachurski : from Professional Surveyor Magazine, November 2003. http://fgg-web.fgg.uni-lj.si/~/mkuhar/pouk/SG/Seminar/Astronomska_navigacija/Astronomska_navigacija_zgodovina/Professional_Surveyor_Magazine-Longitude_By_Wire_The_American_Method-Nov03.pdf Best, 73,

Re: [time-nuts] Discussion of precise time and frequency measurement

On Mon, Nov 13, 2017 at 12:32 PM, Gregory Beat wrote: > As a second’s error in time will be about a nautical mile in US > latitudes, I wonder if anyone has measured with GPS, how good the original > surveys were? > > Sent from iPad Air >

Re: [time-nuts] Discussion of precise time and frequency measurement

On 11/13/17 9:32 AM, Gregory Beat wrote: I grew up east of the Iowa/Missouri border, so this boundary dispute was well-known ... and occurred at same time Joseph Smith (Mormons) was at Nauvoo, IL (1839-1844). In 2006, the Iowa-Missouri border was investigated with GPS, as much an archeology

Re: [time-nuts] Discussion of precise time and frequency measurement

Hi, On 11/13/2017 06:32 PM, Gregory Beat wrote: I grew up east of the Iowa/Missouri border, so this boundary dispute was well-known ... and occurred at same time Joseph Smith (Mormons) was at Nauvoo, IL (1839-1844). In 2006, the Iowa-Missouri border was investigated with GPS, as much an

Re: [time-nuts] Discussion of precise time and frequency measurement

I grew up east of the Iowa/Missouri border, so this boundary dispute was well-known ... and occurred at same time Joseph Smith (Mormons) was at Nauvoo, IL (1839-1844). In 2006, the Iowa-Missouri border was investigated with GPS, as much an archeology project as locating the historic Sullivan &

[time-nuts] Discussion of precise time and frequency measurement

and frequency measurement     time-nuts@febo.com Subject: Re: [time-nuts] GPSDO Alternatives Message-ID: c851493c-c77b-41b9-a7df-3d3f89c91...@rtty.us Content-Type: text/plain; charset=us-ascii Hi To be useful, you need an input capture that: 1) Runs at a fast enough clock (1 GHz would be nice) 2

Re: [time-nuts] Discussion of precise time and frequency measurement

t...@leapsecond.com said: Either use the PC to timestamp receive buffers, or if you have a 1pps handy, just feed your 60 Hz signal into one channel (L) and the 1 PPS into the other (R). If you have a known-good (accurate?) signal going into you audio channel, you can compute the actual

Re: [time-nuts] Discussion of precise time and frequency measurement

On Thu, Jun 30, 2011 at 12:54 AM, Hal Murray hmur...@megapathdsl.net wrote: If you have a known-good (accurate?) signal going into you audio channel, you can compute the actual clock frequency of the audio capture path. The problem is that it takes a long time to see a small error. If the

[time-nuts] Discussion of precise time and frequency measurement

The FireWire thing makes sense but is there some way to make the computer itself a slave to an external source also? ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and

Re: [time-nuts] Discussion of precise time and frequency measurement

On Wed, Jun 29, 2011 at 3:00 PM, Bill Dailey docdai...@gmail.com wrote: The FireWire thing makes sense but is there some way to make the computer itself a slave to an external source also? Why? The computer has many clocks in it and they are not all derived all from one master. So to answer

Re: [time-nuts] Discussion of precise time and frequency measurement

OK, now I understand why you wanted a sound card with a wel regulated clock. Yes they make those. The common cheap cards use a square can oscillator good to about 100PPM. Better cards can use a better and way more expensive clock source. I think knowing the sample rate is accurate is good

Re: [time-nuts] Discussion of precise time and frequency measurement

Chris, Yea, it's similar to the way you track a voltage reference or standard over time between calibrations, but here, it would be frequency instead. I don't know if it would really need to track it all the time, maybe check it so many hours a day, or so many times during peak, and night periods

Re: [time-nuts] Discussion of precise time and frequency measurement

On Wed, Jun 29, 2011 at 5:45 PM, Will Matney xfor...@citynet.net wrote: . I've never programed anything using graphs, so I'm not sure how hard it would be. I've done that kind of program. It is a lot of work but you can avoid it by just sending the data file to gnuplot. You have to send a

Re: [time-nuts] Discussion of precise time and frequency measurement

Will, For long-term tracking 60 Hz (or any audio timing signal) with a sound card you don't need a high quality. Either use the PC to timestamp receive buffers, or if you have a 1pps handy, just feed your 60 Hz signal into one channel (L) and the 1 PPS into the other (R). Either way drift in

Re: [time-nuts] 'Discussion of precise time and frequency measurement'

Joe, If you have an analog 'scope with delayed sweep, set it up with the main time base showing the 90 MHz signal in a convenient way (say 1 cycle/div) and then use the delay to look at the signal some time later (after the initial trigger) with the modulation on and off. Any phase or

[time-nuts] Discussion of precise time and frequency measurement

2007 16:09:31 -0800 From: Brooke Clarke [EMAIL PROTECTED] Subject: Re: [time-nuts] Discussion of precise time and frequency measurement To: Discussion of precise time and frequency measurement time-nuts@febo.com Message-ID: [EMAIL PROTECTED] Content-Type: text/plain; charset=us-ascii

Re: [time-nuts] Discussion of precise time and frequency measurement

: [time-nuts] Discussion of precise time and frequency measurement Since the moving option is out, perhaps I need to investigate whether I currently can get any inside or outside signal. Is ther3=e an inexpensive way given that I do not have any circuit assemble skills? The complex will allow dishes

Re: [time-nuts] Discussion of precise time and frequency measurement

Hi Ronald: Some people interested in the WAAS aspect of GPS have used the common Ku band satellite TV dishes as reflectors and mounted a GPS antenna at the focus (where the Ku band antenna would normally be located. The claim is that it works well even though the polarity of the reflected GPS

Re: [time-nuts] Discussion of precise time and frequency measurement

John, At the momet I m trying to do some similar stuff. I want to compare PPS output from two different rcvrs, the reference being Leica MC500 and the subject recvr being M12. but I am having problem with my oscilloscope which is a Tektronix one with 300 MHZ range. It is not locking on to the

Re: [time-nuts] Discussion of precise time and frequency measurement

Hi Faisal -- I use a time interval counter to compare 1pps signals -- the DUT goes to the start input, and the reference (here, GPS) to the stop input. You measure the time interval between the two, and use the change in interval to determine noise and offset. For the LORAN experiment, I used

Re: [time-nuts] Discussion of precise time and frequency measurement

To get sure your Tektronix triggers correctly, use the Manual trigger mode. This way, you won't seee any trace on the screen without a trigger source (in auto mode, the scope will show a trace regardless it's triggered or not). Also, many Tek scopes have a trig view mode which i find very useful

Re: [time-nuts] Discussion of precise time and frequency measurement

The other method i use is a homebrew programmable (thumbwheels) pulse generator (1µs resolution) to compare my DUT (an Oscilloquartz B540 OCXO) against a GPS receiver. The pulse generator divides the B540's 5MHz by 5 million to get an arbitrary 1PPS. The arb. 1PPS is then used as the START signal