Re: [time-nuts] New to the list
Hi George, welcome aboard. If you are a beginner about time and frequency don't forget to get and read what was pointed out to be our introduction to the subject http://gpstime.com/files/tow-time2011.pdf written by Tom Clark and Rick Hambly. On Wed, Mar 14, 2012 at 5:27 AM, Bill Hawkins b...@iaxs.net wrote: Hi, George Is there anything that distinguishes you from the thousand others on this list? What is there about time that interests you? That makes you a nut? Do you lean towards theory or the soldering iron? Is bit twiddling your interest? Assuming that you have followed human nature and collected stuff that might be interesting, what have you collected? Who will throw it in the dumpster when you die? If you are completely new to this, where would you like to start? Something cheap from an auction site or a new hydrogen maser? Don't mind me, I've been around too long. Bill Hawkins -Original Message- From: George Allen Sent: Tuesday, March 13, 2012 9:26 PM Just a note to let you know that George, K2CM, has joined the list. George K2CM, Vestal, NY ___ 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] Austron GPS 2201a ops and serv manual uploaded to KO4BB site
I forgot to add that the IF frequency used in the Austron 2201/2202 units is 75 MHz, and the Meinberg/Odetics is 35.42MHz, so they are not compatible without additional conversion. Rob -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of b...@lysator.liu.se Sent: 14 March 2012 05:38 To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Austron GPS 2201a ops and serv manual uploaded to KO4BB site Paul, Thanks to Doug above I am trying two methods to use a Novatel starview receiver that also puts out a 35.42 Mhz IF. The methods have to do with A small typo: Starview is the evaluation software used to run the legacy CMC (Canadian Marconi) line of receivers - Allstar, Superstar and Superstar II. Would the Austron be compatible with the current Meinberg downconverting antenna? http://www.meinberg.de/download/docs/manuals/english/gpsant.pdf -- Björn ___ 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] typical phase nosie and ADEV plot of an OCXO
Hi, I'm currently writing a short article on crystal oscillators and am looking for plots of typical phase noise and ADEV of an OCXO. But unfortunately, i couldnt find any, so far. Only discrete numbers from the data sheets, or phase noise plots only from scientific papers. Does anyone have something like this at hand? Attila Kinali -- The trouble with you, Shev, is you don't say anything until you've saved up a whole truckload of damned heavy brick arguments and then you dump them all out and never look at the bleeding body mangled beneath the heap -- Tirin, The Dispossessed, U. Le Guin ___ 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] Austron GPS 2201a ops and serv manual uploaded to KO4BB site
I know that the Meinberg works with the old Odetics units, but the IF frequencies are different on the Austron units. Rob Kimberley -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of b...@lysator.liu.se Sent: 14 March 2012 05:38 To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Austron GPS 2201a ops and serv manual uploaded to KO4BB site Paul, Thanks to Doug above I am trying two methods to use a Novatel starview receiver that also puts out a 35.42 Mhz IF. The methods have to do with A small typo: Starview is the evaluation software used to run the legacy CMC (Canadian Marconi) line of receivers - Allstar, Superstar and Superstar II. Would the Austron be compatible with the current Meinberg downconverting antenna? http://www.meinberg.de/download/docs/manuals/english/gpsant.pdf -- Björn ___ 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] typical phase nosie and ADEV plot of an OCXO
On 3/14/2012 6:22 AM, Attila Kinali wrote: Hi, I'm currently writing a short article on crystal oscillators and am looking for plots of typical phase noise and ADEV of an OCXO. But unfortunately, i couldnt find any, so far. Only discrete numbers from the data sheets, or phase noise plots only from scientific papers. Does anyone have something like this at hand? Attila Kinali Attila, TVB and I each have a bunch of plots of various oscillators at our web sites. Tom's are mainly under http://www.leapsecond.com/pages and http://www.leapsecond.com/museum; mine are under http://www.febo.com/pages and particularly http://www.febo.com/pages/oscillators. John ___ 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] typical phase nosie and ADEV plot of an OCXO
And don't forget the usual PDF http://gpstime.com/files/tow-time2011.pdfwhere you can find the comparison of typical Allan Deviations from various clocks on page 7. On Wed, Mar 14, 2012 at 1:52 PM, John Ackermann N8UR j...@febo.com wrote: On 3/14/2012 6:22 AM, Attila Kinali wrote: Hi, I'm currently writing a short article on crystal oscillators and am looking for plots of typical phase noise and ADEV of an OCXO. But unfortunately, i couldnt find any, so far. Only discrete numbers from the data sheets, or phase noise plots only from scientific papers. Does anyone have something like this at hand? Attila Kinali Attila, TVB and I each have a bunch of plots of various oscillators at our web sites. Tom's are mainly under http://www.leapsecond.com/**pageshttp://www.leapsecond.com/pagesand http://www.leapsecond.com/**museum http://www.leapsecond.com/museum; mine are under http://www.febo.com/pages and particularly http://www.febo.com/pages/**oscillatorshttp://www.febo.com/pages/oscillators . John __**_ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/** mailman/listinfo/time-nutshttps://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] typical phase nosie and ADEV plot of an OCXO
On Wed, 14 Mar 2012 08:52:14 -0400 John Ackermann N8UR j...@febo.com wrote: Attila, TVB and I each have a bunch of plots of various oscillators at our web sites. Tom's are mainly under http://www.leapsecond.com/pages and http://www.leapsecond.com/museum; mine are under http://www.febo.com/pages and particularly http://www.febo.com/pages/oscillators. Blub.. had a look, both at your websites, but couldn't find them. I guess i had tomatos on my eyes. Thanks a lot! Attila Kinali -- The trouble with you, Shev, is you don't say anything until you've saved up a whole truckload of damned heavy brick arguments and then you dump them all out and never look at the bleeding body mangled beneath the heap -- Tirin, The Dispossessed, U. Le Guin ___ 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] typical phase nosie and ADEV plot of an OCXO
On Wed, 14 Mar 2012 14:05:03 +0100 Azelio Boriani azelio.bori...@screen.it wrote: And don't forget the usual PDF http://gpstime.com/files/tow-time2011.pdfwhere you can find the comparison of typical Allan Deviations from various clocks on page 7. That's for an other article :-) This time, i write only about crystal oscillators and their perfomance, if you need a bit more than just the 20-50ppm you get out of a standard crystal. The article will be geared down for decision makers who have a bit of technical background, but not too much, so it wont contain any fancy information anyone who's been here for more than a couple of months doesn't already know :-) Attila Kinali -- The trouble with you, Shev, is you don't say anything until you've saved up a whole truckload of damned heavy brick arguments and then you dump them all out and never look at the bleeding body mangled beneath the heap -- Tirin, The Dispossessed, U. Le Guin ___ 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] typical phase nosie and ADEV plot of an OCXO
Programs that try to turn text into a link will get the URL wrong due to a missing space. Fixed link: http://gpstime.com/files/tow-time2011.pdf On Wed, Mar 14, 2012 at 09:05, Azelio Boriani azelio.bori...@screen.it wrote: And don't forget the usual PDF http://gpstime.com/files/tow-time2011.pdfwhere you can find the comparison of typical Allan Deviations from various clocks on page 7. ___ 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] typical phase nosie and ADEV plot of an OCXO
On 3/14/12 6:23 AM, Attila Kinali wrote: On Wed, 14 Mar 2012 14:05:03 +0100 Azelio Borianiazelio.bori...@screen.it wrote: And don't forget the usual PDF http://gpstime.com/files/tow-time2011.pdfwhere you can find the comparison of typical Allan Deviations from various clocks on page 7. That's for an other article :-) This time, i write only about crystal oscillators and their perfomance, if you need a bit more than just the 20-50ppm you get out of a standard crystal. The article will be geared down for decision makers who have a bit of technical background, but not too much, so it wont contain any fancy information anyone who's been here for more than a couple of months doesn't already know :-) Attila Kinali John Vig's presentation is a great place to start.. There's lots of copies in various places on the web (IEEE UFFC site, for one) ___ 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] typical phase nosie and ADEV plot of an OCXO
On 03/14/2012 11:22 AM, Attila Kinali wrote: Hi, I'm currently writing a short article on crystal oscillators and am looking for plots of typical phase noise and ADEV of an OCXO. But unfortunately, i couldnt find any, so far. Only discrete numbers from the data sheets, or phase noise plots only from scientific papers. Does anyone have something like this at hand? I know I should add one to the Wikipedia Allan Deviation article. Let me know if there is anything other which is missing in that article so I can add to it. What you should have is essentially a bath-tub curve with a 1/tau slope for the white phase modulation (WPM) noise, a roughly 1/sqrt(tau) slope from the flicker phase modulation (FPM) or white frequency modulation (WFM) and then a flat part due to the flicker frequency modulation (FFM). See the table in [1]. At higher tau the systematic effect of frequency drift comes in, and if included into the Allan Deviation it rises with tau [2]. As a systematic effect, it should not really be included into the ADEV plot, but you usually see it in practical measurements. [1] http://en.wikipedia.org/wiki/Allan_variance#Power-law_noise [2] http://en.wikipedia.org/wiki/Allan_variance#Linear_response The existence of WFM and FFM noises is due to the Leeson model. 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] typical phase nosie and ADEV plot of an OCXO
On Wed, 14 Mar 2012 06:42:34 -0700 Jim Lux jim...@earthlink.net wrote: John Vig's presentation is a great place to start.. There's lots of copies in various places on the web (IEEE UFFC site, for one) Juup, that's where the idea for the article came from in the first place :-) And yes, there are many copies around, often of different versions. I recently uploaded the 4 versions i could find on the net on Didiers homepage. They have slight differnces, but not that many... Attila Kinali -- The trouble with you, Shev, is you don't say anything until you've saved up a whole truckload of damned heavy brick arguments and then you dump them all out and never look at the bleeding body mangled beneath the heap -- Tirin, The Dispossessed, U. Le Guin ___ 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] New to the list
I joined the list at the suggestion of Bill, Wb6BNQ. I am currently experimenting with several frequency standards, an Rb and an OCXO. While I feel that I am able to measure frequencies with reasonable accuracy, I have no way of accurately determining time, so have ordered a T-Bolt. I expect that to be here in about 2 weeks. The big question is why am I doing this? Just because I can. George K2CM From: Bill Hawkins b...@iaxs.net To: 'Discussion of precise time and frequency measurement' time-nuts@febo.com Sent: Wednesday, March 14, 2012 12:27 AM Subject: Re: [time-nuts] New to the list Hi, George Is there anything that distinguishes you from the thousand others on this list? What is there about time that interests you? That makes you a nut? Do you lean towards theory or the soldering iron? Is bit twiddling your interest? Assuming that you have followed human nature and collected stuff that might be interesting, what have you collected? Who will throw it in the dumpster when you die? If you are completely new to this, where would you like to start? Something cheap from an auction site or a new hydrogen maser? Don't mind me, I've been around too long. Bill Hawkins ___ 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] The link to the introduction
I understand the cartoon at the beginning; but, it will take me a very, very long time to understand the concepts of the paper! George K2CM Vestal, NY From: Azelio Boriani azelio.bori...@screen.it To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Wednesday, March 14, 2012 4:51 AM Subject: Re: [time-nuts] New to the list Hi George, welcome aboard. If you are a beginner about time and frequency don't forget to get and read what was pointed out to be our introduction to the subject http://gpstime.com/files/tow-time2011.pdf written by Tom Clark and Rick Hambly. On Wed, Mar 14, 2012 at 5:27 AM, Bill Hawkins b...@iaxs.net wrote: Hi, George Is there anything that distinguishes you from the thousand others on this list? What is there about time that interests you? That makes you a nut? Do you lean towards theory or the soldering iron? Is bit twiddling your interest? Assuming that you have followed human nature and collected stuff that might be interesting, what have you collected? Who will throw it in the dumpster when you die? If you are completely new to this, where would you like to start? Something cheap from an auction site or a new hydrogen maser? Don't mind me, I've been around too long. Bill Hawkins -Original Message- From: George Allen Sent: Tuesday, March 13, 2012 9:26 PM Just a note to let you know that George, K2CM, has joined the list. George K2CM, Vestal, NY ___ 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] FE5680A Calibration
Hello all, I purchased a FE5680A from a Chinese Ebay vendor. I have connected it to a 16.5V laptop supply, added 7805-based 5V rail and a PMOS Fet switch to drive a LED for the locked signal. I can communicate with it using the excellent Fe5680Calibrator software. As received the frequency offset is set to Zero and the unit seems to work well. I plan to put it into service as a workshop frequency reference and so would like to set it close to 10.0Mhz. I have various oscillator modules, signal generators, SDR receivers, GPS receivers, a scanner, some uncalibrated test-gear. I live in a river valley in North Devon UK so radio reception is a bit restricted but I receive digital television via a masthead amplifier and long downlead. Could someone please suggest a way of going about this? Regards Chris Stake ___ 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] New to the list
Good one George. It is the obsessive compulsive time correcting disorder that we all have! Raj VU2ZAP The big question is why am I doing this? Just because I can. George K2CM ___ 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] FE5680A Calibration
My fast approach would be to trigger a scope with the 1 PPS from the GPS receiver and observe the how the 10 MHz output of your Rb drifts. 1 full cycle per second is 1 e-7 so you'll need to use an stopwatch to time long periods when you are fine adjusting . Building (or buying) a GPSDO allows yo to make the comparison between both 10 MHz outputs without the jitter in the GPS receiver 1 PPS. Probably others in this list can suggest more elaborated and convenient approaches to this. On 14/03/2012 16:17, Chris Stake wrote: Hello all, I purchased a FE5680A from a Chinese Ebay vendor. I have connected it to a 16.5V laptop supply, added 7805-based 5V rail and a PMOS Fet switch to drive a LED for the locked signal. I can communicate with it using the excellent Fe5680Calibrator software. As received the frequency offset is set to Zero and the unit seems to work well. I plan to put it into service as a workshop frequency reference and so would like to set it close to 10.0Mhz. I have various oscillator modules, signal generators, SDR receivers, GPS receivers, a scanner, some uncalibrated test-gear. I live in a river valley in North Devon UK so radio reception is a bit restricted but I receive digital television via a masthead amplifier and long downlead. Could someone please suggest a way of going about this? Regards Chris Stake ___ 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] FE5680A Calibration
The first thing to consider is something to put the 5680 into. Search the list for temperature considerations. Basically you will need to heat sink the 5680. It can be run without, but won't last long. The technique I'm going to use it to heat sink the 5680 and with a pair of small variable speed fans (one as a backup) the inside of the box will be keep at a reasonably constant temperature with the set point based on keeping the 5680 in a safe region. There's been quite a bit of discussion on 10 MHz distribution. For now I'm thinking of using a surplus commercial video distribution amplifier. Most studio grade DA's are good to 15 MHz +- 3db. I also have a HP 5087A but its input is 5 MHz and the output cards are mostly 5MHz. A future project to convert. I have not decided if I want to put the Rb which maybe a LPRO, the Thunderbolt, and maybe a 10811 into one box or not. One idea is with them all on one box having the ability to adjust the Rb and the 10811 via the Thunderbolt, and one box can be looked at as a temp controlled 'oven' for all three. One could also put a DIY DA into the same box. -pete PS A friend and time-nut has be threatening to do a modern easy to build DA, many on the list need one. On Wed, Mar 14, 2012 at 8:17 AM, Chris Stake st...@btinternet.com wrote: Hello all, I purchased a FE5680A from a Chinese Ebay vendor. I have connected it to a 16.5V laptop supply, added 7805-based 5V rail and a PMOS Fet switch to drive a LED for the locked signal. I can communicate with it using the excellent Fe5680Calibrator software. As received the frequency offset is set to Zero and the unit seems to work well. I plan to put it into service as a workshop frequency reference and so would like to set it close to 10.0Mhz. I have various oscillator modules, signal generators, SDR receivers, GPS receivers, a scanner, some uncalibrated test-gear. I live in a river valley in North Devon UK so radio reception is a bit restricted but I receive digital television via a masthead amplifier and long downlead. Could someone please suggest a way of going about this? Regards Chris Stake ___ 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] FE5680A Calibration
Hi Consider that the noise on the 10 MHz output of the FE5680 is pretty bad. You may / may not want to propagate it all over your shop. At the very least, a simple band pass filter is needed. A better solution would be to lock a crystal oscillator up to the FE and use the output of the oscillator. It's a reasonable bet that you unit is within +/- 1x10^-10 of the right frequency. If you are lucky, it's 10X better than that. To observe it's frequency adequately to set it well, you will need to average it's output for at least a couple hundred seconds. You don't want to make it worse trying to set it closer If you are comparing to a normal GPS receiver, they have noise on their PPS output as well. To get to adequate stability / resolution you will need to average them for a while. Just how long depends on which one you have and a few other things. Best approach / lazy approach / provides adequate time for a beer: Look at the edge of the FE's pps relative to the pps out of the GPS on a scope. Note the offset on a piece of paper along with the time. Come back in an hour and repeat the process. Get a couple of points this way. The drift (if any) will show up as a linear trend. The noise will likely be in the 20 to 200 ns. At this point all you really are looking for is a noise estimate. Say the noise is 200 ns. If you do observations at a 200 second spacing you would get 1x10^-9. To get to 1x10^-12 you need to observe for about 1000X longer. 200,000 seconds is a couple of days. Yes indeed there are fancy math things try to speed things up. They don't fit under the lazy approach (there also are a few other reasons to take your time). Based on the noise estimate you get, and the calculations above, come up with a schedule. No need to get obsessive about it. All you are looking for is: read every day / every three days / once a week sort of spacing. Start logging your phase offset at what ever spacing makes sense. Take at least ten readings. Based on your readings, take a stab at correcting the FE. Adjust it and then go back to taking readings. Eventually it will be close enough. So much fun... Bob -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Chris Stake Sent: Wednesday, March 14, 2012 11:17 AM To: 'Discussion of precise time and frequency measurement' Subject: [time-nuts] FE5680A Calibration Hello all, I purchased a FE5680A from a Chinese Ebay vendor. I have connected it to a 16.5V laptop supply, added 7805-based 5V rail and a PMOS Fet switch to drive a LED for the locked signal. I can communicate with it using the excellent Fe5680Calibrator software. As received the frequency offset is set to Zero and the unit seems to work well. I plan to put it into service as a workshop frequency reference and so would like to set it close to 10.0Mhz. I have various oscillator modules, signal generators, SDR receivers, GPS receivers, a scanner, some uncalibrated test-gear. I live in a river valley in North Devon UK so radio reception is a bit restricted but I receive digital television via a masthead amplifier and long downlead. Could someone please suggest a way of going about this? Regards Chris Stake ___ 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] FE5680A Calibration
Nice idea, But I haven't got a DSO and the persistence of my scope isn't good enough to view 10Mhz sampled at 1pps. Chris -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of EB4APL Sent: 14 March 2012 15:46 To: time-nuts@febo.com Subject: Re: [time-nuts] FE5680A Calibration My fast approach would be to trigger a scope with the 1 PPS from the GPS receiver and observe the how the 10 MHz output of your Rb drifts. 1 full cycle per second is 1 e-7 so you'll need to use an stopwatch to time long periods when you are fine adjusting . Building (or buying) a GPSDO allows yo to make the comparison between both 10 MHz outputs without the jitter in the GPS receiver 1 PPS. Probably others in this list can suggest more elaborated and convenient approaches to this. On 14/03/2012 16:17, Chris Stake wrote: Hello all, I purchased a FE5680A from a Chinese Ebay vendor. I have connected it to a 16.5V laptop supply, added 7805-based 5V rail and a PMOS Fet switch to drive a LED for the locked signal. I can communicate with it using the excellent Fe5680Calibrator software. As received the frequency offset is set to Zero and the unit seems to work well. I plan to put it into service as a workshop frequency reference and so would like to set it close to 10.0Mhz. I have various oscillator modules, signal generators, SDR receivers, GPS receivers, a scanner, some uncalibrated test-gear. I live in a river valley in North Devon UK so radio reception is a bit restricted but I receive digital television via a masthead amplifier and long downlead. Could someone please suggest a way of going about this? Regards Chris Stake ___ 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] FE5680A Calibration
Hi Do you have a dual channel counter that you can put the GPS into on the start and the FE into as the stop? The HP 5334, 5335, and 5345 are all examples of this sort of counter. Bob -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Chris Stake Sent: Wednesday, March 14, 2012 12:49 PM To: 'Discussion of precise time and frequency measurement' Subject: Re: [time-nuts] FE5680A Calibration Nice idea, But I haven't got a DSO and the persistence of my scope isn't good enough to view 10Mhz sampled at 1pps. Chris -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of EB4APL Sent: 14 March 2012 15:46 To: time-nuts@febo.com Subject: Re: [time-nuts] FE5680A Calibration My fast approach would be to trigger a scope with the 1 PPS from the GPS receiver and observe the how the 10 MHz output of your Rb drifts. 1 full cycle per second is 1 e-7 so you'll need to use an stopwatch to time long periods when you are fine adjusting . Building (or buying) a GPSDO allows yo to make the comparison between both 10 MHz outputs without the jitter in the GPS receiver 1 PPS. Probably others in this list can suggest more elaborated and convenient approaches to this. On 14/03/2012 16:17, Chris Stake wrote: Hello all, I purchased a FE5680A from a Chinese Ebay vendor. I have connected it to a 16.5V laptop supply, added 7805-based 5V rail and a PMOS Fet switch to drive a LED for the locked signal. I can communicate with it using the excellent Fe5680Calibrator software. As received the frequency offset is set to Zero and the unit seems to work well. I plan to put it into service as a workshop frequency reference and so would like to set it close to 10.0Mhz. I have various oscillator modules, signal generators, SDR receivers, GPS receivers, a scanner, some uncalibrated test-gear. I live in a river valley in North Devon UK so radio reception is a bit restricted but I receive digital television via a masthead amplifier and long downlead. Could someone please suggest a way of going about this? Regards Chris Stake ___ 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.
Re: [time-nuts] Pretty ADEV/Tau plots
These pretty ADEV/Tau plots, do people have an automated system to produce these things? How much work is involved? How many samples are taken? Sample for a month, omputer crunching for weeks? I have no feel for what the process is like. I have two oscillators and a Racal 1992 counter. If I were to hook up the computer to the counter would I have the minimum amount of stuff needed? ___ 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] Found surfing the net - slides/presentation from FEI
may not be new to many, but to someone new on the list http://www.ieee.li/pdf/viewgraphs/precision_frequency_generation.pdf ___ 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] Pretty ADEV/Tau plots
On 3/14/2012 1:35 PM, Chris Howard wrote: These pretty ADEV/Tau plots, do people have an automated system to produce these things? How much work is involved? How many samples are taken? Sample for a month, omputer crunching for weeks? I have no feel for what the process is like. I have two oscillators and a Racal 1992 counter. If I were to hook up the computer to the counter would I have the minimum amount of stuff needed? The stuff on my pages at febo.com come primarily from two sources: 1. Screenshots from the TSC analyzer's display (actually, I trick the TSC into thinking it's network printing to a Postscript device, then I grab the incoming bitstream and convert it to .png -- not a pretty process. 2. Phase or frequency data from the TSC or other counters manually massaged using a *nix WYSIWIG graphing tool called Grace. In a few cases, I've also munged a way to automatically generate Grace plots every X minutes from live data. That, also, is not pretty. However, lately I've been using John Miles' TimeLab software (even though it's Windows...) because it is so damn easy to capture data from lots of counter types, and display multiple runs and various plot types. It just takes all the work out of it. Length of capture depends on what you're trying to do. Generally, you want a minimum data length of X times the longest tau, where X can range from 3 (but huge error bars) on out to perhaps 8 - 10 for good reliability. So if you want to plot stability out to 100K seconds, you're going to be collecting data for at least a week or two. I've had PPS measurement setups where I took data perhaps every 10 minutes for several months. That starts to be an exercise in design for reliability! John ___ 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] Found surfing the net - slides/presentation from FEI
On 14/03/2012 18:36, Pete Lancashire wrote: may not be new to many, but to someone new on the list http://www.ieee.li/pdf/viewgraphs/precision_frequency_generation.pdf ___ 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. And on page 62 there is a picture of the board where the last batch of cheap FE-5680A comes from. Ignacio, EB4APL ___ 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] New atomic clock
There's an interesting and more readable PRL by the same group, published last year on June 2 . Its on arXiv: 1110.2379v1 . or PRL 106, 223001 (2011). They have already built the trap and have laser-cooled the Thorium ions (cool pictures of the ion crystals). Their current problem is that the wavelength of the nuclear transition is not well known and its hard to build a UV laser when you don't know exactly where to tune it. Apparently the idea is due to a German physicist at the PTB named E. Peik. If you search arXiv under peik you'll find a bunch of other papers on the subject. If you google nuclear shell model you'll find a good Wikipedia article on the nuclear energy levels. Oddly enough, there is a similarity between the electronic orbitals and nucleon wavefunctions so that neutron orbits is not complete nonsense. ___ 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] FE5680A Calibration
Hi Bob, Thanks for pointing-out the noisy output of the FE5680A. I'll probably try to lock a crystal oscillator to it. Unfortunately I don't have a suitable counter. I was hoping I could use some sort of higher frequency standard but I confess I had not really grasped the fact that the unit may well be within millihertz of the nominal frequency: too delicate to twiddle with anything other than precision equipment and long timebases. Kind regards Chris -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Bob Camp Sent: 14 March 2012 16:57 To: 'Discussion of precise time and frequency measurement' Subject: Re: [time-nuts] FE5680A Calibration Hi Do you have a dual channel counter that you can put the GPS into on the start and the FE into as the stop? The HP 5334, 5335, and 5345 are all examples of this sort of counter. Bob -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Chris Stake Sent: Wednesday, March 14, 2012 12:49 PM To: 'Discussion of precise time and frequency measurement' Subject: Re: [time-nuts] FE5680A Calibration Nice idea, But I haven't got a DSO and the persistence of my scope isn't good enough to view 10Mhz sampled at 1pps. Chris -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of EB4APL Sent: 14 March 2012 15:46 To: time-nuts@febo.com Subject: Re: [time-nuts] FE5680A Calibration My fast approach would be to trigger a scope with the 1 PPS from the GPS receiver and observe the how the 10 MHz output of your Rb drifts. 1 full cycle per second is 1 e-7 so you'll need to use an stopwatch to time long periods when you are fine adjusting . Building (or buying) a GPSDO allows yo to make the comparison between both 10 MHz outputs without the jitter in the GPS receiver 1 PPS. Probably others in this list can suggest more elaborated and convenient approaches to this. On 14/03/2012 16:17, Chris Stake wrote: Hello all, I purchased a FE5680A from a Chinese Ebay vendor. I have connected it to a 16.5V laptop supply, added 7805-based 5V rail and a PMOS Fet switch to drive a LED for the locked signal. I can communicate with it using the excellent Fe5680Calibrator software. As received the frequency offset is set to Zero and the unit seems to work well. I plan to put it into service as a workshop frequency reference and so would like to set it close to 10.0Mhz. I have various oscillator modules, signal generators, SDR receivers, GPS receivers, a scanner, some uncalibrated test-gear. I live in a river valley in North Devon UK so radio reception is a bit restricted but I receive digital television via a masthead amplifier and long downlead. Could someone please suggest a way of going about this? Regards Chris Stake ___ 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 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] NIST's WWVB phase modulation format paper from PTTI 2011
Here is a copy of the paper NIST co-authored describing the new WWVB phase modulation format: http://jks.com/wwvb.pdf (2MB PDF) John Lowe from NIST said I could redistribute it to the list. It will be available on the NIST website sometime in April once the official PTTI 2011 proceedings are published. When that happens I'll remove my link above and you can find the paper here: http://tf.boulder.nist.gov/general/publications.htm (search for Bin Number 2591) Also of interest, a company contracted to help with the development will have silicon (and patents) at some point: http://www.xtendwave.com/xtendwave-awarded-grant-for-atomic-clock-enhancements.html http://www.xtendwave.com/atomictimekeeping.html ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] NIST's WWVB phase modulation format paper from PTTI 2011
Has anybody looked at the impact of the periodic phase reversals of BPSK on the loop of phase-tracking receivers, like the Fluke or the HP 117A? NIST does claim backward compatability for time. But what about time interval? I know you can extract the carries from BPSK with a Costas Loop (which essentially squares the signal and uses the second harmonic) but the existing, installed hardware does not do this. If I'm right, that's another broken egg in the frequency reference basket. Best, -John Here is a copy of the paper NIST co-authored describing the new WWVB phase modulation format: http://jks.com/wwvb.pdf (2MB PDF) John Lowe from NIST said I could redistribute it to the list. It will be available on the NIST website sometime in April once the official PTTI 2011 proceedings are published. When that happens I'll remove my link above and you can find the paper here: http://tf.boulder.nist.gov/general/publications.htm (search for Bin Number 2591) Also of interest, a company contracted to help with the development will have silicon (and patents) at some point: http://www.xtendwave.com/xtendwave-awarded-grant-for-atomic-clock-enhancements.html http://www.xtendwave.com/atomictimekeeping.html ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ 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] FE5680A Calibration
Hi At least the don't mess to much with it part has sunk in. That puts you ahead of most people at this point. A usable counter should be a sub $100 sort of thing either at auction or surplus. With some careful shopping it can be a sub $40 item. Bob On Mar 14, 2012, at 4:25 PM, Chris Stake st...@btinternet.com wrote: Hi Bob, Thanks for pointing-out the noisy output of the FE5680A. I'll probably try to lock a crystal oscillator to it. Unfortunately I don't have a suitable counter. I was hoping I could use some sort of higher frequency standard but I confess I had not really grasped the fact that the unit may well be within millihertz of the nominal frequency: too delicate to twiddle with anything other than precision equipment and long timebases. Kind regards Chris -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Bob Camp Sent: 14 March 2012 16:57 To: 'Discussion of precise time and frequency measurement' Subject: Re: [time-nuts] FE5680A Calibration Hi Do you have a dual channel counter that you can put the GPS into on the start and the FE into as the stop? The HP 5334, 5335, and 5345 are all examples of this sort of counter. Bob -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Chris Stake Sent: Wednesday, March 14, 2012 12:49 PM To: 'Discussion of precise time and frequency measurement' Subject: Re: [time-nuts] FE5680A Calibration Nice idea, But I haven't got a DSO and the persistence of my scope isn't good enough to view 10Mhz sampled at 1pps. Chris -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of EB4APL Sent: 14 March 2012 15:46 To: time-nuts@febo.com Subject: Re: [time-nuts] FE5680A Calibration My fast approach would be to trigger a scope with the 1 PPS from the GPS receiver and observe the how the 10 MHz output of your Rb drifts. 1 full cycle per second is 1 e-7 so you'll need to use an stopwatch to time long periods when you are fine adjusting . Building (or buying) a GPSDO allows yo to make the comparison between both 10 MHz outputs without the jitter in the GPS receiver 1 PPS. Probably others in this list can suggest more elaborated and convenient approaches to this. On 14/03/2012 16:17, Chris Stake wrote: Hello all, I purchased a FE5680A from a Chinese Ebay vendor. I have connected it to a 16.5V laptop supply, added 7805-based 5V rail and a PMOS Fet switch to drive a LED for the locked signal. I can communicate with it using the excellent Fe5680Calibrator software. As received the frequency offset is set to Zero and the unit seems to work well. I plan to put it into service as a workshop frequency reference and so would like to set it close to 10.0Mhz. I have various oscillator modules, signal generators, SDR receivers, GPS receivers, a scanner, some uncalibrated test-gear. I live in a river valley in North Devon UK so radio reception is a bit restricted but I receive digital television via a masthead amplifier and long downlead. Could someone please suggest a way of going about this? Regards Chris Stake ___ 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 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] WWVB BPSK Receiver Project?
Hi: I sure would like a WWVB BPSK receiver for the new modulation. The processing gains described in the paper John Seamons linked describes processing gains that are tens of dB above what's possible with the old AM data format. John has also measures the experimental phase modulation testing, see: http://www.jks.com/wwvb/wwvb.html The WWB paper New Improved System for WWVB Broadcast given at the 43rd PTTI November 2011 is at: http://jks.com/wwvb.pdf Part of the processing gain comes directly from the BPSK modulation and that amounts to a little over 10 dB improvement, but there's a further 18 dB gain to be had by accumulating an hours worth of data and processing that. I'm sure in time there will be plenty of low cost ICs designed to receive the new signal, but my guess is that many Time Nuts would like to be in on the ground floor. Also NIST probably would like to get reports on the new signal when they do test transmissions. How to move forward? -- Have Fun, Brooke Clarke, N6GCE http://www.PRC68.com http://www.end2partygovernment.com/Brooke4Congress.html ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] WWVB BPSK Receiver Project?
In message 4f6116ce.7080...@pacific.net, Brooke Clarke writes: I sure would like a WWVB BPSK receiver for the new modulation. I've been playing with SDR and VLF signals for ages. What you want is an antenna, a 1MSPS ADC and a fast-ish CPU. One very interesting thing you can do with that, is to make a buffer 1000 samples long, and continously average the received signal into it, round-robin format. That amounts to a comb-filter for every n*1kHz signal, and a trivial sin/cos multiplicator will give you the phase and amplitude of every single radiotransmitter on n*1kHz up to your antialias filter at the same time. If you have CPU power, you can also receive Loran-C by making the buffer GRI*10 (or *20, if you want the code) samples long. I've long thought about building a board with one of the faster ARM CPUs and a 1MSPS 16bit ADC for this, but nobody else seemed interested, so I've just used my hacked up rig. -- 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] WWVB BPSK Receiver Project?
The first move will be to familiarize with this new modulation format. Of course I can't receive the WWVB but the DCF77 maybe a good test for me. On Wed, Mar 14, 2012 at 11:08 PM, Brooke Clarke bro...@pacific.net wrote: Hi: I sure would like a WWVB BPSK receiver for the new modulation. The processing gains described in the paper John Seamons linked describes processing gains that are tens of dB above what's possible with the old AM data format. John has also measures the experimental phase modulation testing, see: http://www.jks.com/wwvb/wwvb.html The WWB paper New Improved System for WWVB Broadcast given at the 43rd PTTI November 2011 is at: http://jks.com/wwvb.pdf Part of the processing gain comes directly from the BPSK modulation and that amounts to a little over 10 dB improvement, but there's a further 18 dB gain to be had by accumulating an hours worth of data and processing that. I'm sure in time there will be plenty of low cost ICs designed to receive the new signal, but my guess is that many Time Nuts would like to be in on the ground floor. Also NIST probably would like to get reports on the new signal when they do test transmissions. How to move forward? -- Have Fun, Brooke Clarke, N6GCE http://www.PRC68.com http://www.end2partygovernment.com/Brooke4Congress.html ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ 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] WWVB BPSK Receiver Project?
Dear Time-Nuts, (new at this list, but reading for long time excellent timekeeping oscillator articles) I sure would like a WWVB BPSK receiver for the new modulation. (..) I'm sure in time there will be plenty of low cost ICs designed to receive the new signal, but my guess is that many Time Nuts would like to be in on the ground floor. Also NIST probably would like to get reports on the new signal when they do test transmissions. How to move forward? I have no experience with WWVB, since I live in central Europe, but some time ago I received quite well German DCF77 (77.5kHz) using absolutely simplistic circuit with no tuned parts except very tolerant ferrite rod antenna. The point was direct sampling into an ADC and doing all the business in a SDR fashion. I wanted to do PRBS PSK tracking and also PLL-less clock disciplining this way, but there were another priorities, though. However, if anybody would be interested in, I would be happy to return to these nice LF circuits. Greetings from Marek P.s A very little bit from DCF77, but only the pre-SDR stage: http://www.youtube.com/watch?v=Fx9bas49Uow ___ 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] WWVB BPSK Receiver Project?
All very nice, but if this change renders all existing receivers useless. How does that improve things? All it does is wipe out all the existing phase tracking infrastructure. The only benefit is to the government who can reuse the WWVB transmitter and frequency allocation. Everybody else will have to buy new stuff. Sounds a lot like HDTV fiasco. Making jobs (in China or Korea) by making scrap. YMMV, -John == Dear Time-Nuts, I sure would like a WWVB BPSK receiver for the new modulation. (..) I'm sure in time there will be plenty of low cost ICs designed to receive the [SNIP} ___ 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] WWVB BPSK Receiver Project?
On Wed, Mar 14, 2012 at 3:08 PM, Brooke Clarke bro...@pacific.net wrote: Hi: I sure would like a WWVB BPSK receiver for the new modulation. The processing gains described in the paper John Seamons linked describes processing gains that are tens of dB above what's possible with the old AM data format. John has also measures the experimental phase modulation testing, see: http://www.jks.com/wwvb/wwvb.html The WWB paper New Improved System for WWVB Broadcast given at the 43rd PTTI November 2011 is at: http://jks.com/wwvb.pdf Part of the processing gain comes directly from the BPSK modulation and that amounts to a little over 10 dB improvement, but there's a further 18 dB gain to be had by accumulating an hours worth of data and processing that. I'm sure in time there will be plenty of low cost ICs designed to receive the new signal, but my guess is that many Time Nuts would like to be in on the ground floor. Also NIST probably would like to get reports on the new signal when they do test transmissions. How to move forward? I'd say to go 100% SDR. In other words a simple front and that pushes as much of the functionality into software as possible. The carrier is only 60K. That is low enough that one can directly digitize the RF using an ADC that samples at only 192K/sec. 192K/Sec is a common sample rte for high-end audio and you can buy a 24-bit dual channel interface for under $200. So I'd use an antenna (the best would be a shielded loop with many turns of wire but ferrite loop stick could work) Follow that be an RF amp and very narrow filter and then the above 24-bit 192K ADC. With a 24-bit ADC you may not need any automatic gain control. So yo are almost sampling the voltage off the antenna, so that's why I called it 100% SDR Once the data are inside the computer the very next step might be an FFT. Some good easy to use software is this: http://gnuradio.org/redmine/projects/gnuradio/wiki/GNURadioCompanion Using this you simply drop function blocks on a screen and connect then with lines. It's a visual drag and drop way to build a signal processor As an example to build a spectrum analyzer you drop a block the represents your audio interface, another for the FFT operator and a third for a graph. Connect them together.Then plug in a microphone and point it as something you want to plot. If you do use the simplest possible RF front and that can still work, followed by a common off the shelf audio interface and then a simple graphical programming environment you then will have a wider community of people working on this.You could use more complex technology like an FPGA or a DSP chip but then the number of people who would know how to help will be a number close to zero. The RF front end does not need to be sophisticated because much of the selectivity and gain control is done in software. You just need a hard low pass filter to remove everything above 60KHz -- Have Fun, Brooke Clarke, N6GCE http://www.PRC68.com http://www.end2partygovernment.com/Brooke4Congress.html ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. -- 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] Austron GPS 2201a ops and serv manual uploaded to KO4BB site
There seems to be a strong likelihood that the 2201 is compatable with the mienburg. Thats what I believe Doug actually has. If there some detailed info in your link I will take a look. On Wed, Mar 14, 2012 at 1:38 AM, b...@lysator.liu.se wrote: Paul, Thanks to Doug above I am trying two methods to use a Novatel starview receiver that also puts out a 35.42 Mhz IF. The methods have to do with A small typo: Starview is the evaluation software used to run the legacy CMC (Canadian Marconi) line of receivers - Allstar, Superstar and Superstar II. Would the Austron be compatible with the current Meinberg downconverting antenna? http://www.meinberg.de/download/docs/manuals/english/gpsant.pdf -- Björn ___ 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] WWVB BPSK Receiver Project?
Asus has a $30 Xonar PCI soundcard that should do the job. I have two of the the more expensive pci-e versions. Some motherboards can do a/d at 192 but not as well as the Xonar. I made a 60 KHz antenna by winding a zillion turns on a ferrite rod and a padder going into the gate of a FET. This was in the 1970s. On 03/14/2012 03:35 PM, Chris Albertson wrote: On Wed, Mar 14, 2012 at 3:08 PM, Brooke Clarkebro...@pacific.net wrote: Hi: I sure would like a WWVB BPSK receiver for the new modulation. The processing gains described in the paper John Seamons linked describes processing gains that are tens of dB above what's possible with the old AM data format. John has also measures the experimental phase modulation testing, see: http://www.jks.com/wwvb/wwvb.html The WWB paper New Improved System for WWVB Broadcast given at the 43rd PTTI November 2011 is at: http://jks.com/wwvb.pdf Part of the processing gain comes directly from the BPSK modulation and that amounts to a little over 10 dB improvement, but there's a further 18 dB gain to be had by accumulating an hours worth of data and processing that. I'm sure in time there will be plenty of low cost ICs designed to receive the new signal, but my guess is that many Time Nuts would like to be in on the ground floor. Also NIST probably would like to get reports on the new signal when they do test transmissions. How to move forward? I'd say to go 100% SDR. In other words a simple front and that pushes as much of the functionality into software as possible. The carrier is only 60K. That is low enough that one can directly digitize the RF using an ADC that samples at only 192K/sec. 192K/Sec is a common sample rte for high-end audio and you can buy a 24-bit dual channel interface for under $200. So I'd use an antenna (the best would be a shielded loop with many turns of wire but ferrite loop stick could work) Follow that be an RF amp and very narrow filter and then the above 24-bit 192K ADC. With a 24-bit ADC you may not need any automatic gain control. So yo are almost sampling the voltage off the antenna, so that's why I called it 100% SDR Once the data are inside the computer the very next step might be an FFT. Some good easy to use software is this: http://gnuradio.org/redmine/projects/gnuradio/wiki/GNURadioCompanion Using this you simply drop function blocks on a screen and connect then with lines. It's a visual drag and drop way to build a signal processor As an example to build a spectrum analyzer you drop a block the represents your audio interface, another for the FFT operator and a third for a graph. Connect them together.Then plug in a microphone and point it as something you want to plot. If you do use the simplest possible RF front and that can still work, followed by a common off the shelf audio interface and then a simple graphical programming environment you then will have a wider community of people working on this.You could use more complex technology like an FPGA or a DSP chip but then the number of people who would know how to help will be a number close to zero. The RF front end does not need to be sophisticated because much of the selectivity and gain control is done in software. You just need a hard low pass filter to remove everything above 60KHz -- Have Fun, Brooke Clarke, N6GCE http://www.PRC68.com http://www.end2partygovernment.com/Brooke4Congress.html ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. -- Chuck Forsberg WA7KGX N2469R c...@omen.com www.omen.com Developer of Industrial ZMODEM(Tm) for Embedded Applications Omen Technology Inc The High Reliability Software 10255 NW Old Cornelius Pass Portland OR 97231 503-614-0430 ___ 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] Austron GPS 2201a ops and serv manual uploaded to KO4BB site
OK the updates. The issue is the 2201 is a 75.42 Mhz IF and most of these alternates are 35.42. Hmmm sounds like adding 40 Mhz gets you the answer. Thats exactly what I did with the odetics converter from Pete L. Took 10 Mhz from 2201 4 X to 40 mix with 35.42 buffer and send to the 2201. Locks like a champ. I feel the RF chain is not all that reproducible and could be improved. So though it works through Dougs support I have been trying out the novatels that also have a 35.42 IF. They have one other nice feature a derived 40 Mhz pecl signal. So first attempt uses a soic pecl to ttl converter driving a sa612 mixer and then a buffer... However this requires a tap off of the 35.42 Mhz saw IF filter and then a lot of gain. The Novatel also puts out a much amplified 3.90Mhz IF. This created a 3rd converter approach. 3.9XX + 71.111 Mhz mix and deliver. this is a very nice approach but at this moment I have to use a significant lock sig gen for the 71.111 Mhz. Last item with the 2201 there really is not a C/N ratio or signal strength to have any clue if A is better then B or C. Makes it sort of tough because B and C do work. I just suspect they are worse then A. Regards Paul. On Wed, Mar 14, 2012 at 6:38 PM, paul swed paulsw...@gmail.com wrote: There seems to be a strong likelihood that the 2201 is compatable with the mienburg. Thats what I believe Doug actually has. If there some detailed info in your link I will take a look. On Wed, Mar 14, 2012 at 1:38 AM, b...@lysator.liu.se wrote: Paul, Thanks to Doug above I am trying two methods to use a Novatel starview receiver that also puts out a 35.42 Mhz IF. The methods have to do with A small typo: Starview is the evaluation software used to run the legacy CMC (Canadian Marconi) line of receivers - Allstar, Superstar and Superstar II. Would the Austron be compatible with the current Meinberg downconverting antenna? http://www.meinberg.de/download/docs/manuals/english/gpsant.pdf -- Björn ___ 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] WWVB BPSK Receiver Project?
I will share my few bits of worked experience. But it may seem obvious. I'd say to go 100% SDR. In other words a simple front and that pushes as much of the functionality into software as possible. The carrier is only 60K. That is low enough that one can directly digitize the RF using an ADC that samples at only 192K/sec. Not necesarilly. I received 77.5kHz very well in first sampling mirror, sampling using ADS7813 16bit ADC @44ksps, yielding carrier at 10.5kHz in discrete-time domain. 192K/Sec is a common sample rte for high-end audio and you can buy a 24-bit dual channel interface for under $200. Beware, there are lots of sigma-delta ADCs for this purpose and I am in doubt whether they could perform better than less-bits SAR ADC. So I'd use an antenna (the best would be a shielded loop with many turns of wire but ferrite loop stick could work) Follow that be an RF amp and very narrow filter and then the above 24-bit 192K ADC. I must object a little bit against RF and very narrow -- I have used very slw amplifiers (they were in a shack, original purpose DC measurement up to some 100s of kHz) and nothing narrow (or even tuned) -- except the ferrite rod itself. The rest were 2 ICs (amp ADC) and simple RC network. Worked very well, including few centimeters from laptop's CCFL inverter. Best regards, Marek ___ 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] FE5680A Calibration
On Wed, Mar 14, 2012 at 8:17 AM, Chris Stake st...@btinternet.com wrote: Hello all, I purchased a FE5680A from a Chinese Ebay vendor. I have connected it to a 16.5V laptop supply, added 7805-based 5V rail and a PMOS Fet switch to drive a LED for the locked signal. I can communicate with it using the excellent Fe5680Calibrator software. As received the frequency offset is set to Zero and the unit seems to work well. What you need to do is build a GPSDO using your FE5680A as the O. You can use digital logic or a human in the control loop. Either way it works the same. Get a 7400 series flip flop A 74AC74 costs about 50 cents. Wite it so the PPS for the GPS flips it on and the next edge of the 10MHz out from the FE5680 re-sets the signal. A simple XOR can also work. Now what you do is measure the time the signal is high. The classic way is to use the signal to charge a capacitor then measure the voltage on the cap. So now you can use a DMM to measure time. The controller adjusts the FE5680A's frequency so as to keep the time the signal is high (and the voltage on the cap) at some arbitrary fixed value People have built the above using all kinds of methods, from pure analog to micro controllers, 7400 logic and even a human in the loop. If you want to build a working system fast look at using an Arduino and divide the 10Mhz signal down by at least 10 or 20 so that (1) the speed is compatible with solderless breadboards and the flip flop's output will stay high longer and will be easier to measure. 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] WWVB BPSK Receiver Project?
In message Pine.LNX.4.64.1203142345310.2459@tesla, Marek Peca writes: I will share my few bits of worked experience. But it may seem obvious. I'd say to go 100% SDR. In other words a simple front and that pushes as much of the functionality into software as possible. The carrier is only 60K. That is low enough that one can directly digitize the RF using an ADC that samples at only 192K/sec. Not necesarilly. I received 77.5kHz very well in first sampling mirror, sampling using ADS7813 16bit ADC @44ksps, yielding carrier at 10.5kHz in discrete-time domain. Here's a really interesting platform for VLF SDR work: http://www.seeedstudio.com/depot/dso-nano-v2-p-681.html?cPath=174 1MSPS 12 bit ADC, input amplifier/attenuator, display, USB interface, and rechargeable lithium battery. For $89... Too bad it doesn't have a 10MHz reference clock input for time-nuttery. -- 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] New atomic clock
If neutrinos can have mass, then I guess neutrons can have orbits. But what do I know? It's all Greek (letters) to me :-) Joe Gray W5JG If you google nuclear shell model you'll find a good Wikipedia article on the nuclear energy levels. Oddly enough, there is a similarity between the electronic orbitals and nucleon wavefunctions so that neutron orbits is not complete nonsense. ___ 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] FE5680A Calibration
I picked up a gimpy Beckman UC10 universal counter not long ago for about $10 from Ebay. Even better, I just repaired a Tektronix 7D15 (it has a whole board full of those junk TI integrated circuit sockets which need to be replaced) although you need to leave an entire oscilloscope mainframe on to use it. The advantage of the later is adjustable slope, sensitivity, and triggering. On Wed, 14 Mar 2012 17:50:28 -0400, Bob Camp li...@rtty.us wrote: At least the don't mess to much with it part has sunk in. That puts you ahead of most people at this point. A usable counter should be a sub $100 sort of thing either at auction or surplus. With some careful shopping it can be a sub $40 item. On Mar 14, 2012, at 4:25 PM, Chris Stake st...@btinternet.com wrote: Hi Bob, Thanks for pointing-out the noisy output of the FE5680A. I'll probably try to lock a crystal oscillator to it. Unfortunately I don't have a suitable counter. I was hoping I could use some sort of higher frequency standard but I confess I had not really grasped the fact that the unit may well be within millihertz of the nominal frequency: too delicate to twiddle with anything other than precision equipment and long timebases. Kind regards Chris -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Bob Camp Sent: 14 March 2012 16:57 To: 'Discussion of precise time and frequency measurement' Subject: Re: [time-nuts] FE5680A Calibration Hi Do you have a dual channel counter that you can put the GPS into on the start and the FE into as the stop? The HP 5334, 5335, and 5345 are all examples of this sort of counter. Bob -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Chris Stake Sent: Wednesday, March 14, 2012 12:49 PM To: 'Discussion of precise time and frequency measurement' Subject: Re: [time-nuts] FE5680A Calibration Nice idea, But I haven't got a DSO and the persistence of my scope isn't good enough to view 10Mhz sampled at 1pps. Chris -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of EB4APL Sent: 14 March 2012 15:46 To: time-nuts@febo.com Subject: Re: [time-nuts] FE5680A Calibration My fast approach would be to trigger a scope with the 1 PPS from the GPS receiver and observe the how the 10 MHz output of your Rb drifts. 1 full cycle per second is 1 e-7 so you'll need to use an stopwatch to time long periods when you are fine adjusting . Building (or buying) a GPSDO allows yo to make the comparison between both 10 MHz outputs without the jitter in the GPS receiver 1 PPS. Probably others in this list can suggest more elaborated and convenient approaches to this. On 14/03/2012 16:17, Chris Stake wrote: Hello all, I purchased a FE5680A from a Chinese Ebay vendor. I have connected it to a 16.5V laptop supply, added 7805-based 5V rail and a PMOS Fet switch to drive a LED for the locked signal. I can communicate with it using the excellent Fe5680Calibrator software. As received the frequency offset is set to Zero and the unit seems to work well. I plan to put it into service as a workshop frequency reference and so would like to set it close to 10.0Mhz. I have various oscillator modules, signal generators, SDR receivers, GPS receivers, a scanner, some uncalibrated test-gear. I live in a river valley in North Devon UK so radio reception is a bit restricted but I receive digital television via a masthead amplifier and long downlead. Could someone please suggest a way of going about this? Regards Chris Stake ___ 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 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] WWVB BPSK Receiver Project?
Hi John: They are going to maintain the existing AM modulation format so all the WWVB Atomic Clocks will still work. The phase modulation is added on top of that. Yes, I expect my HP 117 may no longer work, but I'd much rather have the improved s/n and timing accuracy. Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/Brooke4Congress.html J. Forster wrote: All very nice, but if this change renders all existing receivers useless. How does that improve things? All it does is wipe out all the existing phase tracking infrastructure. The only benefit is to the government who can reuse the WWVB transmitter and frequency allocation. Everybody else will have to buy new stuff. Sounds a lot like HDTV fiasco. Making jobs (in China or Korea) by making scrap. YMMV, -John == Dear Time-Nuts, I sure would like a WWVB BPSK receiver for the new modulation. (..) I'm sure in time there will be plenty of low cost ICs designed to receive the [SNIP} ___ 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] WWVB BPSK Receiver Project?
Brooke, As I've said, I don't care about the Time. The time determined by the start of TV or radio programs is plenty good enough to keep any appointments. My only interest is as a standard of Time Interval as a reference for synthesizers, counters, etc. If you think about it, unless you are doing something like occultation or eclipse timing or eBay, the ToD rarely matters. They killed LORAN, which worked beautifully. Now it looks like they are going to kill WWVB, which is a bit more involved, but works. GPS is not an option without a tall tower. This is NOT progress, IMO. -John == Hi John: They are going to maintain the existing AM modulation format so all the WWVB Atomic Clocks will still work. The phase modulation is added on top of that. Yes, I expect my HP 117 may no longer work, but I'd much rather have the improved s/n and timing accuracy. Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/Brooke4Congress.html J. Forster wrote: All very nice, but if this change renders all existing receivers useless. How does that improve things? All it does is wipe out all the existing phase tracking infrastructure. The only benefit is to the government who can reuse the WWVB transmitter and frequency allocation. Everybody else will have to buy new stuff. Sounds a lot like HDTV fiasco. Making jobs (in China or Korea) by making scrap. YMMV, -John == Dear Time-Nuts, I sure would like a WWVB BPSK receiver for the new modulation. (..) I'm sure in time there will be plenty of low cost ICs designed to receive the [SNIP} ___ 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] broadband MPX signal stereo
Hi! I'm looking for a sampled wave-file from a radio receiver MPX-signal including the RDS frequency band around 57KHz. I searched the Net but found just nothing that worked. So I ask here. Maybe someone has the possibility to sample a couple of seconds. Thank you all! - Henry -- ehydra.dyndns.info ___ 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] WWVB BPSK Receiver Project?
I am afraid that like John my concern is the frequency reference. Time? Heck it comes by the internet, WWV or GPS and lastly good old watches that do pretty well these days. No comments on celphones. So the term is screwed. All of the sampling and computer processing may indeed loose the primary reference quality for frequency measurement. So is all lost? Well maybe not completely. Those old receivers are actually pretty nice for filtering the incoming signal and such. A Singer I have has a good collins 60 Kc filter. So perhaps as a gain stage they still have value. It gets interesting at the next step and thats what to do about the reversals of the carrier. A question I have is this. Since the samples are actually slow on the comparison. Would a 117 even see it. Is it perhaps just adding additional filtering. All speculation on my part. I need to read the dock we have just received more carefully to get a better understanding. Happy to run up the fluke 207 and a 117 perhaps on the next set of tests and see what happens. (207 is actually Johns old unit) Also have a spectracom 8170. But thats really a clock and as stated should work fine. Regards Paul. WB8TSL On Wed, Mar 14, 2012 at 8:13 PM, J. Forster j...@quikus.com wrote: Brooke, As I've said, I don't care about the Time. The time determined by the start of TV or radio programs is plenty good enough to keep any appointments. My only interest is as a standard of Time Interval as a reference for synthesizers, counters, etc. If you think about it, unless you are doing something like occultation or eclipse timing or eBay, the ToD rarely matters. They killed LORAN, which worked beautifully. Now it looks like they are going to kill WWVB, which is a bit more involved, but works. GPS is not an option without a tall tower. This is NOT progress, IMO. -John == Hi John: They are going to maintain the existing AM modulation format so all the WWVB Atomic Clocks will still work. The phase modulation is added on top of that. Yes, I expect my HP 117 may no longer work, but I'd much rather have the improved s/n and timing accuracy. Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/Brooke4Congress.html J. Forster wrote: All very nice, but if this change renders all existing receivers useless. How does that improve things? All it does is wipe out all the existing phase tracking infrastructure. The only benefit is to the government who can reuse the WWVB transmitter and frequency allocation. Everybody else will have to buy new stuff. Sounds a lot like HDTV fiasco. Making jobs (in China or Korea) by making scrap. YMMV, -John == Dear Time-Nuts, I sure would like a WWVB BPSK receiver for the new modulation. (..) I'm sure in time there will be plenty of low cost ICs designed to receive the [SNIP} ___ 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] WWVB BPSK Receiver Project?
Brooke, In speaking with John Lowe of NIST (Group Leader for Time Frequency service), he stated that the absolute time recovery of their intended new modulation scheme is 10 milliseconds. Nothing stellar there ! BUT you are right, all of us that have hp-117 type receivers are just out of luck. John Lowe did say they are going to produce a PIC (Microchip) project that will grab the data stream and reconstruct the carrier signal so that can then be fed back into a hp-117 type receiver so it can still be used. However, he did say that is a dream at the moment as they have not really started to work on it. He then said I could do it and they would consider my efforts. While I had a number of thoughts running though mind when he said that; I did hold my comments back. I have to tell you, John Lowe sounded like he was drinking the Kool-Aid because I told him I was quite negative to the whole idea and he went into a nonstop mode of telling me all the good things that were going to come about with this modulation scheme. The same kind of hype that occurred with the HDTV. By the way, all those good things have nothing to do with anything Time-nutty except for pissing us off, as it were. His enthusiasm was aimed totally at new products. Although he admitted it leaves all the real Timenut type people, actually using the system for its intended purpose, out in the cold, he really did not seem to care. Pointing out that a failure with the GPS system left WWVB as the only alternate did not seem to matter either. OH Well, BillWB6BNQ Brooke Clarke wrote: Hi John: They are going to maintain the existing AM modulation format so all the WWVB Atomic Clocks will still work. The phase modulation is added on top of that. Yes, I expect my HP 117 may no longer work, but I'd much rather have the improved s/n and timing accuracy. Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/Brooke4Congress.html J. Forster wrote: All very nice, but if this change renders all existing receivers useless. How does that improve things? All it does is wipe out all the existing phase tracking infrastructure. The only benefit is to the government who can reuse the WWVB transmitter and frequency allocation. Everybody else will have to buy new stuff. Sounds a lot like HDTV fiasco. Making jobs (in China or Korea) by making scrap. YMMV, -John == Dear Time-Nuts, I sure would like a WWVB BPSK receiver for the new modulation. (..) I'm sure in time there will be plenty of low cost ICs designed to receive the [SNIP} ___ 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] WWVB BPSK Receiver Project?
OK thats great a maybe pic chip answer. They do cure all ill's after all. Really scratching my head here. But I do think there is an answer as long as the phase reversal is accurately controlled and still referenced to the reference standard. A I say I need to read. Regards Paul On Wed, Mar 14, 2012 at 9:14 PM, WB6BNQ wb6...@cox.net wrote: Brooke, In speaking with John Lowe of NIST (Group Leader for Time Frequency service), he stated that the absolute time recovery of their intended new modulation scheme is 10 milliseconds. Nothing stellar there ! BUT you are right, all of us that have hp-117 type receivers are just out of luck. John Lowe did say they are going to produce a PIC (Microchip) project that will grab the data stream and reconstruct the carrier signal so that can then be fed back into a hp-117 type receiver so it can still be used. However, he did say that is a dream at the moment as they have not really started to work on it. He then said I could do it and they would consider my efforts. While I had a number of thoughts running though mind when he said that; I did hold my comments back. I have to tell you, John Lowe sounded like he was drinking the Kool-Aid because I told him I was quite negative to the whole idea and he went into a nonstop mode of telling me all the good things that were going to come about with this modulation scheme. The same kind of hype that occurred with the HDTV. By the way, all those good things have nothing to do with anything Time-nutty except for pissing us off, as it were. His enthusiasm was aimed totally at new products. Although he admitted it leaves all the real Timenut type people, actually using the system for its intended purpose, out in the cold, he really did not seem to care. Pointing out that a failure with the GPS system left WWVB as the only alternate did not seem to matter either. OH Well, BillWB6BNQ Brooke Clarke wrote: Hi John: They are going to maintain the existing AM modulation format so all the WWVB Atomic Clocks will still work. The phase modulation is added on top of that. Yes, I expect my HP 117 may no longer work, but I'd much rather have the improved s/n and timing accuracy. Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/Brooke4Congress.html J. Forster wrote: All very nice, but if this change renders all existing receivers useless. How does that improve things? All it does is wipe out all the existing phase tracking infrastructure. The only benefit is to the government who can reuse the WWVB transmitter and frequency allocation. Everybody else will have to buy new stuff. Sounds a lot like HDTV fiasco. Making jobs (in China or Korea) by making scrap. YMMV, -John == Dear Time-Nuts, I sure would like a WWVB BPSK receiver for the new modulation. (..) I'm sure in time there will be plenty of low cost ICs designed to receive the [SNIP} ___ 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.
Re: [time-nuts] WWVB BPSK Receiver Project?
In thinking about it a bit further, one might be able to take the 60 kHz received sine at some point in the receiver, full wave rectify and HP filter it (which doubles the frequency) then divide by two in a Flip-Flop and heavily filter the resultant. This is a hybrid solution... analog and digital... with not a uP in sight!! That would preserve the frequency, but ditch the phase reversals of the BPSK. Depending on the guts of the particular receiver, it might be possible to simply retrofit a PCB. The 180 degree phase reversal of the BPSK is just about the worst possible thing for a PLL of typical receicers. If the ratio of 1s to 0s is 50% the loop just thrashes. -John OK thats great a maybe pic chip answer. They do cure all ill's after all. Really scratching my head here. But I do think there is an answer as long as the phase reversal is accurately controlled and still referenced to the reference standard. A I say I need to read. Regards Paul On Wed, Mar 14, 2012 at 9:14 PM, WB6BNQ wb6...@cox.net wrote: Brooke, In speaking with John Lowe of NIST (Group Leader for Time Frequency service), he stated that the absolute time recovery of their intended new modulation scheme is 10 milliseconds. Nothing stellar there ! BUT you are right, all of us that have hp-117 type receivers are just out of luck. John Lowe did say they are going to produce a PIC (Microchip) project that will grab the data stream and reconstruct the carrier signal so that can then be fed back into a hp-117 type receiver so it can still be used. However, he did say that is a dream at the moment as they have not really started to work on it. He then said I could do it and they would consider my efforts. While I had a number of thoughts running though mind when he said that; I did hold my comments back. I have to tell you, John Lowe sounded like he was drinking the Kool-Aid because I told him I was quite negative to the whole idea and he went into a nonstop mode of telling me all the good things that were going to come about with this modulation scheme. The same kind of hype that occurred with the HDTV. By the way, all those good things have nothing to do with anything Time-nutty except for pissing us off, as it were. His enthusiasm was aimed totally at new products. Although he admitted it leaves all the real Timenut type people, actually using the system for its intended purpose, out in the cold, he really did not seem to care. Pointing out that a failure with the GPS system left WWVB as the only alternate did not seem to matter either. OH Well, BillWB6BNQ Brooke Clarke wrote: Hi John: They are going to maintain the existing AM modulation format so all the WWVB Atomic Clocks will still work. The phase modulation is added on top of that. Yes, I expect my HP 117 may no longer work, but I'd much rather have the improved s/n and timing accuracy. Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/Brooke4Congress.html J. Forster wrote: All very nice, but if this change renders all existing receivers useless. How does that improve things? All it does is wipe out all the existing phase tracking infrastructure. The only benefit is to the government who can reuse the WWVB transmitter and frequency allocation. Everybody else will have to buy new stuff. Sounds a lot like HDTV fiasco. Making jobs (in China or Korea) by making scrap. YMMV, -John == Dear Time-Nuts, I sure would like a WWVB BPSK receiver for the new modulation. (..) I'm sure in time there will be plenty of low cost ICs designed to receive the [SNIP} ___ 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 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] WWVB New Modulation Scheme Compatibility
I guess that will mean that my bullet proof Tracor 599J will become a paper weight. I have a couple of units that were surplussed years ago from the USNO. Great receivers. Sam W3OHM ___ 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] WWVB BPSK Receiver Project?
John Like your thought. I seem to remember costas loops work like that to recover the carrier. Paul, It recovers a bipolar signal to steer the local VCO as well as the data.. It also needs a quadratue hybrid at the VCO frequency (although it might be fairly easy to make a quadrature oscillator vat 60 kHz.) Had seen it in amsat many years ago. So perhaps an approach is to limit if possible the incoming signal. I'm not sure if it works properly with clipped (digital) dignals, off hand. Though further simple dumb thought. A NE602 or SA602 or also teh 612 series. All the same mixer circuit (Or multiplier)will double the incoming frequency if you delay the incoming by 90 degrees I think. Sine and Cosine are orthogonal. You need to do (Sine)*(Sine) sin^2 (wt) = 1/2(1 - cos (2wt) Its a sensitive chip and has a 17 db conversion gain and is $2.40 at digikey. 8 pin dip. though what ever the delay at 60KC thats a long delay. ;-) The delay (phase shift) is not needed. Best, -John = Regards Paul On Wed, Mar 14, 2012 at 10:12 PM, David I. Emery d...@dieconsulting.comwrote: On Wed, Mar 14, 2012 at 05:13:47PM -0700, J. Forster wrote: Now it looks like they are going to kill WWVB, which is a bit more involved, but works. GPS is not an option without a tall tower. Everything you say up to this makes perfect sense, but what makes you think GPS timing fails to work with less than a tall tower ? I believe it is readily possible to get to the 10-30 ns of UTC/TAI TOD area with just reasonable sky view, not 100% as implied by a tower. And certainly 1E-11 or 1E-12 frequency accuracy is also readily available with less than perfect sky view depending on your taus... Perhaps ultimate performance requires really unobstructed sky view in order to absolutely minimize multipath but then you are probably talking 1E-13 or better... This is NOT progress, IMO. Virtually ANY GPS timing solution ought to easily get you inside of a couple of microseconds of UTC/TAI, I am pretty sure it is quite difficult to get within 10-100 us with the current AM modulation of WWVB, possibly even 1-10 ms is difficult. And anything close to this requires accurate knowledge of geographic position and 60 KHz propagation corrections. I'm not clear how accurately one can resolve the phase transition in the new scheme, but I suspect probably unambiguously to 1 cycle of the 60 KHz... and from there is merely a function of how accurately one can resolve the phase of the 60 KHz.This potentially can supply a much higher resolution time hack than the AM envelope. The real question being how important is preserving backward compatibility with antique equipment versus better performance... I agree that ALWAYS is a trade off... -John == Hi John: They are going to maintain the existing AM modulation format so all the WWVB Atomic Clocks will still work. The phase modulation is added on top of that. Yes, I expect my HP 117 may no longer work, but I'd much rather have the improved s/n and timing accuracy. Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/Brooke4Congress.html J. Forster wrote: All very nice, but if this change renders all existing receivers useless. How does that improve things? All it does is wipe out all the existing phase tracking infrastructure. The only benefit is to the government who can reuse the WWVB transmitter and frequency allocation. Everybody else will have to buy new stuff. Sounds a lot like HDTV fiasco. Making jobs (in China or Korea) by making scrap. YMMV, -John == Dear Time-Nuts, I sure would like a WWVB BPSK receiver for the new modulation. (..) I'm sure in time there will be plenty of low cost ICs designed to receive the [SNIP} ___ 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. -- Dave Emery N1PRE/AE, d...@dieconsulting.com DIE Consulting, Weston, Mass 02493 An empty zombie mind with a forlorn barely readable weatherbeaten 'For Rent' sign still vainly flapping outside on the weed encrusted pole - in celebration of what could have been, but wasn't and is not to be now either. ___ 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
Re: [time-nuts] WWVB BPSK Receiver Project?
On 3/14/12 8:07 PM, J. Forster wrote: John Like your thought. I seem to remember costas loops work like that to recover the carrier. Paul, It recovers a bipolar signal to steer the local VCO as well as the data.. It also needs a quadratue hybrid at the VCO frequency (although it might be fairly easy to make a quadrature oscillator vat 60 kHz.) One easy scheme is to make your VCO run at a multiple and divide down to generate the two quadrature square waves. Had seen it in amsat many years ago. So perhaps an approach is to limit if possible the incoming signal. I'm not sure if it works properly with clipped (digital) dignals, off hand. Yes it will. Though further simple dumb thought. A NE602 or SA602 or also teh 612 series. All the same mixer circuit (Or multiplier)will double the incoming frequency if you delay the incoming by 90 degrees I think. Sine and Cosine are orthogonal. You need to do (Sine)*(Sine) sin^2 (wt) = 1/2(1 - cos (2wt) This is like the classic squaring technique to receive PN coded signals without knowing the code. (it's used in some codeless GPS receivers.. you can retrieve frequency and phase) ___ 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] WWVB BPSK Receiver Project?
I know I am not one of the good-ole-boys here but I'd say go 100% SDR with your PC without an external A/D converter. Ok, how would you do this? You use under sampling. Many A/D converter systems use a sample and hold before the A/D converter. If you do the same before your sound card (your A/D converter) and drive the SH with an audio output from your sound card, say at 6.1 kHz you would get a 1 kHz signal into your sound card to process. You can call it under sampling aliasing or whatever. By the way Ten Tec patented an under sampling scheme many years ago when they started into the SDR business. ___ 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] WWVB BPSK Receiver Project?
On 3/14/12 8:07 PM, J. Forster wrote: John Like your thought. I seem to remember costas loops work like that to recover the carrier. Paul, It recovers a bipolar signal to steer the local VCO as well as the data.. It also needs a quadratue hybrid at the VCO frequency (although it might be fairly easy to make a quadrature oscillator vat 60 kHz.) One easy scheme is to make your VCO run at a multiple and divide down to generate the two quadrature square waves. Doesn't look like that works with the HP 117A. I don't know about other receivers. Had seen it in amsat many years ago. So perhaps an approach is to limit if possible the incoming signal. I'm not sure if it works properly with clipped (digital) dignals, off hand. Yes it will. Not w/o a quadrature drive to the mixer/multiplier. A square wave, multiplied by itself, has the same output as input. Though further simple dumb thought. A NE602 or SA602 or also teh 612 series. All the same mixer circuit (Or multiplier)will double the incoming frequency if you delay the incoming by 90 degrees I think. Sine and Cosine are orthogonal. You need to do (Sine)*(Sine) sin^2 (wt) = 1/2(1 - cos (2wt) This is like the classic squaring technique to receive PN coded signals without knowing the code. (it's used in some codeless GPS receivers.. you can retrieve frequency and phase) A Costas Loop recovers the bit stream and the carrier frequency (from the local VCO) from a BPSK. It is self syncronizing. I'm beginning to think that, for the HP 117A at least, a fix could be built on a small daughter board. Also, I think that NIST should do the engineering and maybe run the boards too. -John === ___ 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] WWVB BPSK Receiver Project?
Bill wrote: [BPSK] leaves all the real Timenut type people, actually using the system for its intended purpose, out in the cold To be fair to NIST, there really aren't many people using WWVB as a source of laboratory-grade timing signals. As others have pointed out, it isn't accurate enough for true time nut performance, and to get all of what it *is* capable of requires heroic efforts. So in truth, the real market for WWVB is not time nuts -- it is people who want to know the time of day to within a second (the atomic clock crowd). And there are LOTS of them. So the change is likely to provide a modest upgrade path for the vast majority of actual users, at the expense of a few die-hards (hobbyists, mostly) who are trying to get more out of an LF timing source than it is really capable of delivering. From a public policy standpoint it seems to make good sense, however much it may offend time nuts' sensibilities. Best regards, Charles ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
