Re: [time-nuts] Building a GPSDO trouble using Jupiter-T
Timing GPS receivers usually have the sawtooth correction message and I saw an application of a delay line to correct the PPS before using it. Of course if you time the PPSes difference with a time-to-digital you don't need to correct the incoming hardware PPS by a delay line, but to implement an all-analog PPS PLL then it can be done. For those of you who use a 10KHz reference signal there is not even the need for a long time constant in the low pass filter: to average 1000 PPSes you need 1000 seconds but to average 1000 10KHz cycles you need only 0.1 seconds. On Mon, Jan 30, 2012 at 6:15 AM, David davidwh...@gmail.com wrote: The sawtooth error in the PPS output and how they were able to correct it externally was interesting. I have seen that kind of problem before in DDS and other applications. I wonder what other GPS receivers provide either PPS outputs without sawtooth noise or a correction message. On Sun, 29 Jan 2012 20:40:52 -0800, Hal Murray hmur...@megapathdsl.net wrote: What do you mean by average? Do you mean that the GPS and PLL must be kept on for 20 minutes to hours, or did you mean that the PLL loop filter must have a time constant of 20 minutes to several hours? You have to compare the characteristics of the oscillator with the characteristics of your GPS receiver. If your local oscillator is very stable, then you want to average over long times (hours, days). If your local oscillator is a good thermometer and you have a very good GPS receiver, then you want a shorter time constant (minutes) so you can track temperature changes. Do you know about hanging bridges? If not, please read Timing for VLBI by Tom Clark and Rick Hambly. It's got some wonderful graphs. Once you understand those, this discussion will get much more interesting. http://gpstime.com/files/tow-time2009.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. ___ 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] Building a GPSDO trouble using Jupiter-T
What about the phase jerk (details given in the datasheet) applied to the 10KHz burst once per second? Bruce Azelio Boriani wrote: Timing GPS receivers usually have the sawtooth correction message and I saw an application of a delay line to correct the PPS before using it. Of course if you time the PPSes difference with a time-to-digital you don't need to correct the incoming hardware PPS by a delay line, but to implement an all-analog PPS PLL then it can be done. For those of you who use a 10KHz reference signal there is not even the need for a long time constant in the low pass filter: to average 1000 PPSes you need 1000 seconds but to average 1000 10KHz cycles you need only 0.1 seconds. On Mon, Jan 30, 2012 at 6:15 AM, Daviddavidwh...@gmail.com wrote: The sawtooth error in the PPS output and how they were able to correct it externally was interesting. I have seen that kind of problem before in DDS and other applications. I wonder what other GPS receivers provide either PPS outputs without sawtooth noise or a correction message. On Sun, 29 Jan 2012 20:40:52 -0800, Hal Murray hmur...@megapathdsl.net wrote: What do you mean by average? Do you mean that the GPS and PLL must be kept on for 20 minutes to hours, or did you mean that the PLL loop filter must have a time constant of 20 minutes to several hours? You have to compare the characteristics of the oscillator with the characteristics of your GPS receiver. If your local oscillator is very stable, then you want to average over long times (hours, days). If your local oscillator is a good thermometer and you have a very good GPS receiver, then you want a shorter time constant (minutes) so you can track temperature changes. Do you know about hanging bridges? If not, please read Timing for VLBI by Tom Clark and Rick Hambly. It's got some wonderful graphs. Once you understand those, this discussion will get much more interesting. http://gpstime.com/files/tow-time2009.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. ___ 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] Building a GPSDO trouble using Jupiter-T
On Sun, 29 Jan 2012 00:50:35 -0600 Ray Xu rayxu...@gmail.com wrote: For those who have experience using the Jupiter T GPS: I have bought this http://www.ebay.com/itm/Navman-jupiter-T-Tu60-GPS-Kit-1pps-10khz-GPS-Module-/260790984470 Ouch... For that price you get already a new LEA-6T, which is a state of the art timing GPS receiver. Beside having the better sensitivity (more satelites in difficult conditions) it features also an frequency output that can go up to 10MHz (or 8MHz if you want low jitter). 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] Building a GPSDO trouble using Jupiter-T
Ah, is it a burst of 10KHz once a second? I don't have a Jupiter-T and I'm a PPS-type discplining fan but I thought it was a continuous 10KHz. On Mon, Jan 30, 2012 at 10:33 AM, Attila Kinali att...@kinali.ch wrote: On Sun, 29 Jan 2012 00:50:35 -0600 Ray Xu rayxu...@gmail.com wrote: For those who have experience using the Jupiter T GPS: I have bought this http://www.ebay.com/itm/Navman-jupiter-T-Tu60-GPS-Kit-1pps-10khz-GPS-Module-/260790984470 Ouch... For that price you get already a new LEA-6T, which is a state of the art timing GPS receiver. Beside having the better sensitivity (more satelites in difficult conditions) it features also an frequency output that can go up to 10MHz (or 8MHz if you want low jitter). 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. ___ 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] Building a GPSDO trouble using Jupiter-T
On Mon, 30 Jan 2012 11:03:36 +0100 Azelio Boriani azelio.bori...@screen.it wrote: Ah, is it a burst of 10KHz once a second? I don't have a Jupiter-T and I'm a PPS-type discplining fan but I thought it was a continuous 10KHz. No, the 10kHz signal is running continously. But the controller will correct it's phase/frequency when ever it calculated a new timing solution to ensure that it's synchronous with the 1PPS. This can be seen in the 10kHz signal as phase jumps. 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] Building a GPSDO trouble using Jupiter-T
The 10kHz is continuous but its phase jerked on the second. The new phase is held until the next jerk. Bruce Azelio Boriani wrote: Ah, is it a burst of 10KHz once a second? I don't have a Jupiter-T and I'm a PPS-type discplining fan but I thought it was a continuous 10KHz. On Mon, Jan 30, 2012 at 10:33 AM, Attila Kinaliatt...@kinali.ch wrote: On Sun, 29 Jan 2012 00:50:35 -0600 Ray Xurayxu...@gmail.com wrote: For those who have experience using the Jupiter T GPS: I have bought this http://www.ebay.com/itm/Navman-jupiter-T-Tu60-GPS-Kit-1pps-10khz-GPS-Module-/260790984470 Ouch... For that price you get already a new LEA-6T, which is a state of the art timing GPS receiver. Beside having the better sensitivity (more satelites in difficult conditions) it features also an frequency output that can go up to 10MHz (or 8MHz if you want low jitter). 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. ___ 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] Building a GPSDO trouble using Jupiter-T
OK, now I know and wonder if other GPS receivers that have frequency outputs behave in this manner. For example the Motorola 100PPS output, the uBlox 800Hz, the Navsync variable frequency output and so on. It is possible to compute solutions from GPS satellite at greater than 1 second rate so the phase of these signals should be adjustable at a rate that could minimize the phase jump... this is only my opinion, not the real possibility. On Mon, Jan 30, 2012 at 11:15 AM, Bruce Griffiths bruce.griffi...@xtra.co.nz wrote: The 10kHz is continuous but its phase jerked on the second. The new phase is held until the next jerk. Bruce Azelio Boriani wrote: Ah, is it a burst of 10KHz once a second? I don't have a Jupiter-T and I'm a PPS-type discplining fan but I thought it was a continuous 10KHz. On Mon, Jan 30, 2012 at 10:33 AM, Attila Kinaliatt...@kinali.ch wrote: On Sun, 29 Jan 2012 00:50:35 -0600 Ray Xurayxu...@gmail.com wrote: For those who have experience using the Jupiter T GPS: I have bought this http://www.ebay.com/itm/**Navman-jupiter-T-Tu60-GPS-Kit-** 1pps-10khz-GPS-Module-/**260790984470http://www.ebay.com/itm/Navman-jupiter-T-Tu60-GPS-Kit-1pps-10khz-GPS-Module-/260790984470 Ouch... For that price you get already a new LEA-6T, which is a state of the art timing GPS receiver. Beside having the better sensitivity (more satelites in difficult conditions) it features also an frequency output that can go up to 10MHz (or 8MHz if you want low jitter). 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-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-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-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] Building a GPSDO trouble using Jupiter-T
The 100PPS output from Motorola receivers is phase jerked every second in the same fashion. Bruce Azelio Boriani wrote: OK, now I know and wonder if other GPS receivers that have frequency outputs behave in this manner. For example the Motorola 100PPS output, the uBlox 800Hz, the Navsync variable frequency output and so on. It is possible to compute solutions from GPS satellite at greater than 1 second rate so the phase of these signals should be adjustable at a rate that could minimize the phase jump... this is only my opinion, not the real possibility. On Mon, Jan 30, 2012 at 11:15 AM, Bruce Griffiths bruce.griffi...@xtra.co.nz wrote: The 10kHz is continuous but its phase jerked on the second. The new phase is held until the next jerk. Bruce Azelio Boriani wrote: Ah, is it a burst of 10KHz once a second? I don't have a Jupiter-T and I'm a PPS-type discplining fan but I thought it was a continuous 10KHz. On Mon, Jan 30, 2012 at 10:33 AM, Attila Kinaliatt...@kinali.ch wrote: On Sun, 29 Jan 2012 00:50:35 -0600 Ray Xurayxu...@gmail.com wrote: For those who have experience using the Jupiter T GPS: I have bought this http://www.ebay.com/itm/**Navman-jupiter-T-Tu60-GPS-Kit-** 1pps-10khz-GPS-Module-/**260790984470http://www.ebay.com/itm/Navman-jupiter-T-Tu60-GPS-Kit-1pps-10khz-GPS-Module-/260790984470 Ouch... For that price you get already a new LEA-6T, which is a state of the art timing GPS receiver. Beside having the better sensitivity (more satelites in difficult conditions) it features also an frequency output that can go up to 10MHz (or 8MHz if you want low jitter). 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-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-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-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. ___ 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] Building a GPSDO trouble using Jupiter-T
On Mon, 30 Jan 2012 11:31:58 +0100 Azelio Boriani azelio.bori...@screen.it wrote: OK, now I know and wonder if other GPS receivers that have frequency outputs behave in this manner. For example the Motorola 100PPS output, the uBlox 800Hz, the Navsync variable frequency output and so on. It is possible to compute solutions from GPS satellite at greater than 1 second rate so the phase of these signals should be adjustable at a rate that could minimize the phase jump... this is only my opinion, not the real possibility. The LEA-6T has two modi. If i understood the documentation correctly one is constant frequency w/o phase jerks and the other is aligned to the 1PPS and thus has phase jerks. 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] Building a GPSDO trouble using Jupiter-T
Where can you get a LEA-6T for $ 65? Bert Kehren In a message dated 1/30/2012 5:34:56 A.M. Eastern Standard Time, bruce.griffi...@xtra.co.nz writes: The 100PPS output from Motorola receivers is phase jerked every second in the same fashion. Bruce Azelio Boriani wrote: OK, now I know and wonder if other GPS receivers that have frequency outputs behave in this manner. For example the Motorola 100PPS output, the uBlox 800Hz, the Navsync variable frequency output and so on. It is possible to compute solutions from GPS satellite at greater than 1 second rate so the phase of these signals should be adjustable at a rate that could minimize the phase jump... this is only my opinion, not the real possibility. On Mon, Jan 30, 2012 at 11:15 AM, Bruce Griffiths bruce.griffi...@xtra.co.nz wrote: The 10kHz is continuous but its phase jerked on the second. The new phase is held until the next jerk. Bruce Azelio Boriani wrote: Ah, is it a burst of 10KHz once a second? I don't have a Jupiter-T and I'm a PPS-type discplining fan but I thought it was a continuous 10KHz. On Mon, Jan 30, 2012 at 10:33 AM, Attila Kinaliatt...@kinali.ch wrote: On Sun, 29 Jan 2012 00:50:35 -0600 Ray Xurayxu...@gmail.comwrote: For those who have experience using the Jupiter T GPS: I have bought this http://www.ebay.com/itm/**Navman-jupiter-T-Tu60-GPS-Kit-** 1pps-10khz-GPS-Module-/**260790984470http://www.ebay.com/itm/Navman-jupiter-T-Tu60-GPS-Kit-1pps-10khz-GPS-Module-/260790984470 Ouch... For that price you get already a new LEA-6T, which is a state of the art timing GPS receiver. Beside having the better sensitivity (more satelites in difficult conditions) it features also an frequency output that can go up to 10MHz (or 8MHz if you want low jitter). 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-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-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-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. ___ 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] Thank you Tom and Rick MUST READ
Having been on the list for only three years somehow tow-time 2009 had escaped me. Thank you Tom and Rick for putting together such an informative document. Probably one of the best contributions. Every member of the list should have a copy and I strongly urge those having joined more recently like my self download this. Thanks again Bert Kehren http://gpstime.com/files/tow-time2009.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] Building a GPSDO trouble using Jupiter-T
OK, so it is a common practice. On Mon, Jan 30, 2012 at 11:43 AM, ewkeh...@aol.com wrote: Where can you get a LEA-6T for $ 65? Bert Kehren In a message dated 1/30/2012 5:34:56 A.M. Eastern Standard Time, bruce.griffi...@xtra.co.nz writes: The 100PPS output from Motorola receivers is phase jerked every second in the same fashion. Bruce Azelio Boriani wrote: OK, now I know and wonder if other GPS receivers that have frequency outputs behave in this manner. For example the Motorola 100PPS output, the uBlox 800Hz, the Navsync variable frequency output and so on. It is possible to compute solutions from GPS satellite at greater than 1 second rate so the phase of these signals should be adjustable at a rate that could minimize the phase jump... this is only my opinion, not the real possibility. On Mon, Jan 30, 2012 at 11:15 AM, Bruce Griffiths bruce.griffi...@xtra.co.nz wrote: The 10kHz is continuous but its phase jerked on the second. The new phase is held until the next jerk. Bruce Azelio Boriani wrote: Ah, is it a burst of 10KHz once a second? I don't have a Jupiter-T and I'm a PPS-type discplining fan but I thought it was a continuous 10KHz. On Mon, Jan 30, 2012 at 10:33 AM, Attila Kinaliatt...@kinali.ch wrote: On Sun, 29 Jan 2012 00:50:35 -0600 Ray Xurayxu...@gmail.comwrote: For those who have experience using the Jupiter T GPS: I have bought this http://www.ebay.com/itm/**Navman-jupiter-T-Tu60-GPS-Kit-** 1pps-10khz-GPS-Module-/**260790984470 http://www.ebay.com/itm/Navman-jupiter-T-Tu60-GPS-Kit-1pps-10khz-GPS-Module-/260790984470 Ouch... For that price you get already a new LEA-6T, which is a state of the art timing GPS receiver. Beside having the better sensitivity (more satelites in difficult conditions) it features also an frequency output that can go up to 10MHz (or 8MHz if you want low jitter). 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 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 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 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] ANN: UK - Notification of GPS Jamming - 2012 April 9-20
Folks, I have received the following: NOTIFICATION OF GPS JAMMING EXERCISES RAF SPADEADAM, CUMBRIA, 9TH APRIL 2012 Dates: Between 9th and 20th April 2012 inclusive (weekdays only). Times: 0700 - 1800 GMT. Location of MULTIPLE jammers: Land based within 5km of N55° 04.000' W002° 34.000'. Frequency: A 24 MHz band centred around 1575.42MHz (GPS L1). Total Power: Up to 10 Watts EIRP. It is stressed that, as in previous exercises, Safety of Life operations will at all times take precedence over exercise activities. Cheers, David -- SatSignal software - quality software written to your requirements Web: http://www.satsignal.eu Email: david-tay...@blueyonder.co.uk ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Thank you Tom and Rick MUST READ
I'm rather new to this list too but I'm working on precision time and frequency since 1999. Learned more since I've joined the list than before, especially from the practical side: various GPSDOs behaviour, GPS receivers tips and tricks, high performance test equipment to watch for. Papers that are a must. Thank you all. On Mon, Jan 30, 2012 at 12:02 PM, ewkeh...@aol.com wrote: Having been on the list for only three years somehow tow-time 2009 had escaped me. Thank you Tom and Rick for putting together such an informative document. Probably one of the best contributions. Every member of the list should have a copy and I strongly urge those having joined more recently like my self download this. Thanks again Bert Kehren http://gpstime.com/files/tow-time2009.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. ___ 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] Building a GPSDO trouble using Jupiter-T
On Mon, 30 Jan 2012 05:43:18 -0500 (EST) ewkeh...@aol.com wrote: Where can you get a LEA-6T for $ 65? Send a mail to u-blox sales. Single pieces in the online shop are... Well, expensive. But if you buy them from sales as engineering samples, you get quite a lot cheaper. Sorry, cannot give you the exact number as i'm not sure whether that information is under NDA. (Yes, it's a strange world we live in) But as a reference point, i bought one surplus LEA-6T from someone who bought a bigger lot (couple dozen devices) for 50CHF. 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] Building a GPSDO trouble using Jupiter-T
Maybe we should consider a group buy. With all the FE 5680A purchases it would make sense to combine them with a good GPS receiver and a digital loop. Since there a uP's out there that have timing functions that will be a low cost simple solution with only a few external components. A $ 2 PIC or some other uP along with a $ 1 G/A will also do. Rb GPS digital loop all for $ 100!!! I do not think we can do better than that. Bert Kehren In a message dated 1/30/2012 6:40:22 A.M. Eastern Standard Time, att...@kinali.ch writes: On Mon, 30 Jan 2012 05:43:18 -0500 (EST) ewkeh...@aol.com wrote: Where can you get a LEA-6T for $ 65? Send a mail to u-blox sales. Single pieces in the online shop are... Well, expensive. But if you buy them from sales as engineering samples, you get quite a lot cheaper. Sorry, cannot give you the exact number as i'm not sure whether that information is under NDA. (Yes, it's a strange world we live in) But as a reference point, i bought one surplus LEA-6T from someone who bought a bigger lot (couple dozen devices) for 50CHF. 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/c gi-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] Building a GPSDO trouble using Jupiter-T
Hi The GPS ops signal (or 10 KHz signal) you will be trying to track will be moving by 10's or 100's of ns per second. 10 ns per second is 10 ppb. 10 ppb at 10 GHz is 100 Hz. You need to smooth this out or your LO will be moving all over the place. Bob On Jan 29, 2012, at 10:20 PM, Ray Xu wrote: Hi Chris Thanks for your helpful input. What do you mean by average? Do you mean that the GPS and PLL must be kept on for 20 minutes to hours, or did you mean that the PLL loop filter must have a time constant of 20 minutes to several hours? To me, the latter seems really unpractical for analog filters...Yet I have seen many of them built using analog filters. Especially JAmes Miller's http://www.jrmiller.demon.co.uk/projects/ministd/frqstd.htm and his FAQ says that the time to wait is perhaps 15 minutes or so to be usable. The previous GPSDO that James built has its schematic; the filter he used doesn't look like they're anywhere close to a time constant of 20 minutes. I may consider the Rb standard, but I'm more inclined on using GPS since I actually get to build some stuff on my own :-) Thanks again Ray Xu On Sun, Jan 29, 2012 at 6:52 PM, Chris Albertson albertson.ch...@gmail.comwrote: On Sat, Jan 28, 2012 at 10:50 PM, Ray Xu rayxu...@gmail.com wrote: Also, what is the advantage of using a OCXO instead of a VCXO in terms of short-term accuracy? If the PLL time constant is only a few seconds, then a crystal shouldn't deviate in frequency by too much within a few seconds, assuming I'm using a crystal bought from a well-known manufacturer...or could it? I am inclined towards using oscillators that do not require any significant warm up time... GPS is only a good reference if you average it over a long time period. (1000 to 10,000 seconds) There is more short term jitter in the GPS then in a decent crystal oscillator. So a very short time constant does you no good. Why use an OCXO? Because of the required long time constant. You need to average GPS for such a length of time (20 minutes to hours) that the ambient temperature will change during the averaging time. Of course you could take care that the temperature does not change but that is what an oven does.You can buy a pretty good OCXO for $20 or $25 How long? That depends on the required accuracy. You want 1Hz at 10GHz. That is 1E-10. Not super hard but no way will you have that 10 minutes after you apply power. If you need a portable standard look at those $40 rubidium nuts that are on eBay.It the 1E-10 level, after you calibrate it, if would stay on-frequency for days and not require much warm up. 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. -- __ 73, Ray Xu KF5LJO ___ 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] FE-.5680A trimming resolution
Hi It's the whole unlock and relock thing that I was trying to get around. In any PLL, the VCXO / VCO will need to pull a bit further than the lock range, just to get things lined up. Testing this sort of thing can be a pain. Bob On Jan 30, 2012, at 2:20 AM, Javier Herrero wrote: Hello, Also I expect that the range would be somewhat limited by the unit software, since the control word is 32-bit, same as the DDS program word with, and I don't think that the little thing would enable to program the DDS from zero to 32-bit. In any case, my idea was first to only monitor the DDS word (at serial port) and serial port offset message limits, and also to test in that way the lock range of the 5680A - this can be a bit tedious since when I programmed a 10Hz offset, the unit unlocked ant took several seconds to lock again. Regards, Javier El 29/01/2012 21:41, Bob Camp escribió: Hi If you try to do full scale, check the range of your VCXO first. The digital test is much easier if you already know where your VCXO stops tuning. Bob On Jan 29, 2012, at 1:45 PM, Javier Herrerojherr...@hvsistemas.es wrote: I'm now gathering the unit self-updating of DDS data, that will take somewhat long... so I will try later or tomorrow. Since we have seen that the DDS values are reported back in a response to a command, it is easy to do without the need to have anything hooked to the SPI bus :) Regards, Javier El 29/01/2012 19:37, Scott Newell escribió: At 05:45 AM 1/29/2012, Javier Herrero wrote: For example, the following data has been gathered: Serial offset 00 00 00 00 DDS A word: 44 02 62 F6 = 1141007094 = 5 313 228.32219 Hz DDS B word: 43 FD CC 8E = 1140706446 = 5 311 828.32085 Hz Can you do a test at +/- fullscale offset as well? This is a very exciting discovery. Nice work! ___ 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. -- Javier Herrero Chief Technology Officer EMAIL: jherr...@hvsistemas.com HV Sistemas S.L. PHONE: +34 949 336 806 Los Charcones, 17 FAX: +34 949 336 792 19170 El Casar - Guadalajara - Spain WEB: http://www.hvsistemas.com ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Building a GPSDO trouble using Jupiter-T
Hi My guess is that they don't want to handle the support the LEA-6T requires on a large scale basis. That's not to say that it's a flaky part, only that there are a lot of cute little things in there to ask questions about … Bob On Jan 30, 2012, at 6:40 AM, Attila Kinali wrote: On Mon, 30 Jan 2012 05:43:18 -0500 (EST) ewkeh...@aol.com wrote: Where can you get a LEA-6T for $ 65? Send a mail to u-blox sales. Single pieces in the online shop are... Well, expensive. But if you buy them from sales as engineering samples, you get quite a lot cheaper. Sorry, cannot give you the exact number as i'm not sure whether that information is under NDA. (Yes, it's a strange world we live in) But as a reference point, i bought one surplus LEA-6T from someone who bought a bigger lot (couple dozen devices) for 50CHF. 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. ___ 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] FE-5680A decoded - another piece of the puzzle
Skip previously in these threads there was a direct real analog control that was discovered. I have used it and it works well. The thread describes how to get to it. Regards Paul On Sun, Jan 29, 2012 at 11:22 PM, Skip Withrow skip.with...@gmail.comwrote: Hello Nuts, I've been trying to get the analog EFC to work on the FE-5650A (a very close cousin of the FE-5680A). On these oscillators it is normally on pin-8 of the DB-9 (Option 12 and 30). As one of the serial lines is on this pin, I traced the jumper that is placed for the EFC option(s). However, changing the voltage on the pin does not seem to move the frequency (or at least not very much if it does). Anybody know the nominal EFC sensitivity of the 5680? On tracing things further, I have found that this input goes into the (4 channel) A/D associated with the microproccesor. Changing the voltage gives a value in message 5A that also changes a corresponding amount. The EFC bytes are bytes 5 6 of the 5A message, first byte is low second byte is high. Appears to be 12-bit value (0FFF max). The question is - how do you enable the EFC? Maybe it is a bit that has to be set in one of the other messages. (But then how does the uP communicate the EFC value to the physics package?) It (more likely) may be that I have not found the true C-field control circuitry yet and the A/D is just a monitor. I recall someone implementing C-field control on a FE-5680A with the pot disabled, but cannot find it now. If someone can point me to that post I sure would appreciate it. Thanks in advance. Regards, Skip Withrow ___ 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] HP5334B with 10544 OCXO
Hello. I recently bough an HP-5334B counter with option 010 from the big E. A Google search seems to indicate the OCXO should be a 10811 type OCXO but mine has a type 10544. Other than taking longer to warm up does anybody see any problems with this? Basic testing shows the unit seems to work OK. It is reading 1.7 Hz low compared to my Thunderbolt at 10 MHz - I have not tried adjusting the trimmer on the 10544 yet. Comments and thoughts appreciated. Regards. Mark. VE6NTP -- Mark Allwright ___ 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] HP5334B with 10544 OCXO
I think the 10811 was the newer improved replacement for the 10544, with the same connections and external signals, and a little better performance. In that era of equipment you may see either one. They should be interchangeable, and the manuals and specs for both are readily available. Ed ___ 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] HP5334B with 10544 OCXO
Hi Mark, I was the project manager for the 5334B counter. A rule at HP was that all 10544 sockets are required to work OK with a 10811 plugged in. There is no rule about the other way around, however its likely to be workable. The 10544 was long out of production in 1987 when the 5334B was introduced and I never worried about whether it would work. The 10544 is slower to stabilize from a cold start because the AT cut has thermal transients. If you keep it warmed up all the time, then there isn't such a disadvantage to the 10544. Rick Karlquist N6RK Allwright, Mark wrote: Hello. I recently bough an HP-5334B counter with option 010 from the big E. A Google search seems to indicate the OCXO should be a 10811 type OCXO but mine has a type 10544. Other than taking longer to warm up does anybody see any problems with this? Basic testing shows the unit seems to work OK. It is reading 1.7 Hz low compared to my Thunderbolt at 10 MHz - I have not tried adjusting the trimmer on the 10544 yet. Comments and thoughts appreciated. Regards. Mark. VE6NTP -- Mark Allwright ___ 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] Building a GPSDO trouble using Jupiter-T
On Sun, Jan 29, 2012 at 7:20 PM, Ray Xu rayxu...@gmail.com wrote: Hi Chris Thanks for your helpful input. What do you mean by average? Do you mean that the GPS and PLL must be kept on for 20 minutes to hours, or did you mean that the PLL loop filter must have a time constant of 20 minutes to several hours? To me, the latter seems really unpractical for analog filters... here was talk here a while back abut if you even could build a GPSDO using a simple analog PLL. The problem it turns out is the long time constant and of leaking or temperature sensitive caps will be a problem. Most people end up useng a micro controller, a PIC or the like. And then the filter is in the uP memory.I think you need hundreds or even 1000 seconds in the loop. Look at the Allen deviation of your GPS. When does it reach the 1E-11 figure that you want? Most GPSes are not that good in the short term. You can answer the question of How long if you have a plot of your GPS. Don't worry, if you use the Rb then you get to build about the same thing. How else would you calibrate it? You ned to compare the phase of the Rb to GPS and send rs232 commands to adjust it. Pretty much the same thing. Yet I have seen many of them built using analog filters. Especially JAmes Miller's http://www.jrmiller.demon.co.uk/projects/ministd/frqstd.htm and his FAQ says that the time to wait is perhaps 15 minutes or so to be usable. The previous GPSDO that James built has its schematic; the filter he used doesn't look like they're anywhere close to a time constant of 20 minutes. I may consider the Rb standard, but I'm more inclined on using GPS since I actually get to build some stuff on my own :-) Thanks again Ray Xu On Sun, Jan 29, 2012 at 6:52 PM, Chris Albertson albertson.ch...@gmail.comwrote: On Sat, Jan 28, 2012 at 10:50 PM, Ray Xu rayxu...@gmail.com wrote: Also, what is the advantage of using a OCXO instead of a VCXO in terms of short-term accuracy? If the PLL time constant is only a few seconds, then a crystal shouldn't deviate in frequency by too much within a few seconds, assuming I'm using a crystal bought from a well-known manufacturer...or could it? I am inclined towards using oscillators that do not require any significant warm up time... GPS is only a good reference if you average it over a long time period. (1000 to 10,000 seconds) There is more short term jitter in the GPS then in a decent crystal oscillator. So a very short time constant does you no good. Why use an OCXO? Because of the required long time constant. You need to average GPS for such a length of time (20 minutes to hours) that the ambient temperature will change during the averaging time. Of course you could take care that the temperature does not change but that is what an oven does. You can buy a pretty good OCXO for $20 or $25 How long? That depends on the required accuracy. You want 1Hz at 10GHz. That is 1E-10. Not super hard but no way will you have that 10 minutes after you apply power. If you need a portable standard look at those $40 rubidium nuts that are on eBay. It the 1E-10 level, after you calibrate it, if would stay on-frequency for days and not require much warm up. 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. -- __ 73, Ray Xu KF5LJO ___ 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] Building a GPSDO trouble using Jupiter-T
On Mon, 30 Jan 2012 07:37:41 -0500 (EST) ewkeh...@aol.com wrote: Maybe we should consider a group buy. With all the FE 5680A purchases it would make sense to combine them with a good GPS receiver and a digital loop. Since there a uP's out there that have timing functions that will be a low cost simple solution with only a few external components. A $ 2 PIC or some other uP along with a $ 1 G/A will also do. Rb GPS digital loop all for $ 100!!! I do not think we can do better than that. I could handle such a group buy. How many people would be interested? The price breaks u-blox has are IIRC 1-50, 50-100,... Attila Kinali -- Why does it take years to find the answers to the questions one should have asked long ago? ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Building a GPSDO trouble using Jupiter-T
I take 2 Bert Kehren In a message dated 1/30/2012 11:52:07 A.M. Eastern Standard Time, att...@kinali.ch writes: On Mon, 30 Jan 2012 07:37:41 -0500 (EST) ewkeh...@aol.com wrote: Maybe we should consider a group buy. With all the FE 5680A purchases it would make sense to combine them with a good GPS receiver and a digital loop. Since there a uP's out there that have timing functions that will be a low cost simple solution with only a few external components. A $ 2 PIC or some other uP along with a $ 1 G/A will also do. Rb GPS digital loop all for $ 100!!! I do not think we can do better than that. I could handle such a group buy. How many people would be interested? The price breaks u-blox has are IIRC 1-50, 50-100,... Attila Kinali -- Why does it take years to find the answers to the questions one should have asked long ago? ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Building a GPSDO trouble using Jupiter-T
With a Rb we are talking loop time in excess of 20 minutes. Any thing other than digital is out of reach. To day I should get my second Rb and I will put it on aging test. The present one is better than 2 E-12 per month! I am still hoping some one else will do an independent test. Key is temperature control. Higher temperature may speed up aging. Bert Kehren In a message dated 1/30/2012 11:39:57 A.M. Eastern Standard Time, albertson.ch...@gmail.com writes: On Sun, Jan 29, 2012 at 7:20 PM, Ray Xu rayxu...@gmail.com wrote: Hi Chris Thanks for your helpful input. What do you mean by average? Do you mean that the GPS and PLL must be kept on for 20 minutes to hours, or did you mean that the PLL loop filter must have a time constant of 20 minutes to several hours? To me, the latter seems really unpractical for analog filters... here was talk here a while back abut if you even could build a GPSDO using a simple analog PLL. The problem it turns out is the long time constant and of leaking or temperature sensitive caps will be a problem. Most people end up useng a micro controller, a PIC or the like. And then the filter is in the uP memory. I think you need hundreds or even 1000 seconds in the loop. Look at the Allen deviation of your GPS. When does it reach the 1E-11 figure that you want? Most GPSes are not that good in the short term. You can answer the question of How long if you have a plot of your GPS. Don't worry, if you use the Rb then you get to build about the same thing. How else would you calibrate it? You ned to compare the phase of the Rb to GPS and send rs232 commands to adjust it. Pretty much the same thing. Yet I have seen many of them built using analog filters. Especially JAmes Miller's http://www.jrmiller.demon.co.uk/projects/ministd/frqstd.htm and his FAQ says that the time to wait is perhaps 15 minutes or so to be usable. The previous GPSDO that James built has its schematic; the filter he used doesn't look like they're anywhere close to a time constant of 20 minutes. I may consider the Rb standard, but I'm more inclined on using GPS since I actually get to build some stuff on my own :-) Thanks again Ray Xu On Sun, Jan 29, 2012 at 6:52 PM, Chris Albertson albertson.ch...@gmail.comwrote: On Sat, Jan 28, 2012 at 10:50 PM, Ray Xu rayxu...@gmail.com wrote: Also, what is the advantage of using a OCXO instead of a VCXO in terms of short-term accuracy? If the PLL time constant is only a few seconds, then a crystal shouldn't deviate in frequency by too much within a few seconds, assuming I'm using a crystal bought from a well-known manufacturer...or could it? I am inclined towards using oscillators that do not require any significant warm up time... GPS is only a good reference if you average it over a long time period. (1000 to 10,000 seconds) There is more short term jitter in the GPS then in a decent crystal oscillator. So a very short time constant does you no good. Why use an OCXO? Because of the required long time constant. You need to average GPS for such a length of time (20 minutes to hours) that the ambient temperature will change during the averaging time. Of course you could take care that the temperature does not change but that is what an oven does.You can buy a pretty good OCXO for $20 or $25 How long? That depends on the required accuracy. You want 1Hz at 10GHz. That is 1E-10. Not super hard but no way will you have that 10 minutes after you apply power. If you need a portable standard look at those $40 rubidium nuts that are on eBay. It the 1E-10 level, after you calibrate it, if would stay on-frequency for days and not require much warm up. 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. -- __ 73, Ray Xu KF5LJO ___ 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. ___ 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] Racal-Dana 1991 w. Option 4C - what is that ?
On Fri, 20 Jan 2012 09:18:32 -0800, Larry McDavid wrote: One does occasionally find Racal 9462 ocxo offered on eBay. Also, one sometimes finds non-operational Racal instruments offered at low price but which to have Option 04E installed. I convinced one seller to remove the Option 04E module (the Racal 9462) and sell just that with much lower shipping cost. There is also what is evidently an older Racal frequency standard module similar in appearance to the 9462 but which has screws attaching the end plate rather than the soldered-can 9462; one of those is seen from time to time on eBay from the UK but I have avoided that. I have been looking for a Racal 9462 ocxo , for my Racal-Dana 1991 counter. I will prob. use my Tbolt anyway , and save the money. But i'm confused ... Is it a 5 Mhz or a 10 Mhz unit. I have found pictures of one claiming it's 5Mhz http://www.jbtech.de/parts/racal_dana/9462.html But i have also received a picture from jaap , with a racal 9492 , where it clearly says its a 10Mhz unit. Can anyone clarify ? I think there was an option that enabled the use of other ocxo values is that why a 5Mhz can be used , in some 1991's ? If i ever decide to get a OCXO , i would like to get the right one. Regards CFO ___ 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] HP5334B with 10544 OCXO
Hello. I recently bough an HP-5334B counter with option 010 from the big E. A Google search seems to indicate the OCXO should be a 10811 type OCXO but mine has a type 10544. Other than taking longer to warm up does anybody see any problems with this? Basic testing shows the unit seems to work OK. It is reading 1.7 Hz low compared to my Thunderbolt at 10 MHz - I have not tried adjusting the trimmer on the 10544 yet. Comments and thoughts appreciated. Regards. Mark. VE6NTP The service manual for the 5334B specifies the option 010 oscillator to be the 10811 variety. I suspect that a previous owner scavenged the original oscillator from your instrument and substituted the lower priced 10544 oscillator. The 10811 units can bring more money on the auction site than the 10544 units. Both will perform well in the counter, with somewhat longer warmup time for the 10544 oscillator. Pretty much the same performance for both units after warmup and stabilization. I recommend that you let your unit run continuously (standby is OK) for 30 days before making final adjustments to the oscillator. This is to allow the crystal and oscillator circuitry to stabilize after being turned off for an unknown period of time. Dave M A woman has the last word in any argument. Anything a man says after that is the beginning of a new argument. ___ 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] FE-.5680A trimming resolution
The Tbolt does not have any sawtooth error or corrections. Its' GPS receiver LO is generated from the 10 MHz oscillator. That's what makes it the best GPSDO out there. -- I'm also thinking of porting over much of the Lady Heather t-bolt monitoring stuff to the Arduino. One thing you can do with a uP based controller is look at the t-bolt's saw tooth error correction and remove a few nS of error. ___ 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] Racal-Dana 1991 w. Option 4C - what is that ?
On 1/30/2012 9:24 AM, cfo wrote: I have been looking for a Racal 9462 ocxo , for my Racal-Dana 1991 counter. I will prob. use my Tbolt anyway , and save the money. But i'm confused ... Is it a 5 Mhz or a 10 Mhz unit. It is a 5MHz oven but has a doubler board fitted to it, when fitted to the 1992. I would suggest that if you have a t'bolt then you should use that as an external reference. Dan ___ 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] Building a GPSDO trouble using Jupiter-T
On Mon, Jan 30, 2012 at 5:16 AM, Bob Camp li...@rtty.us wrote: Hi The GPS ops signal (or 10 KHz signal) you will be trying to track will be moving by 10's or 100's of ns per second. 10 ns per second is 10 ppb. 10 ppb at 10 GHz is 100 Hz. You need to smooth this out or your LO will be moving all over the place. Up at the top of this thread I said you need to have a long loop constant for exactly this reason. It does not matter of the GPS has a 1PPS 100PPS or 1000PPS the problem is GPS itself. GPS simply does not have good short term stability. In the short term the OCXO will be better. The reason we build GPSDOs is to combine the best of both, the short term characteristics of an OCXO and the long term characteristics of GPS. If you try and build a GPSDO using a very short loop filter time constant then you have a GPSDO with same characteristics of GPS averaged over your short time constant. In other words you select the time constant based of your frequency stability requirements. Look at the first blue line in the top graph. This is very much what a Jupiter GPS has. If you need 10E-10 you need a 100 second constant . The line is straight to for 10x better accuracy you need 10x longer time constant. I think using an analog PLL you can get to about the 1E-10 level. I think a non-expert could build a good 100 second RC filter. Doing better is going to require a longer time constant then is reasonable. a uP based PLL can do much better and likely with effort equal the performance of a Trimble Thuderbolt. But then you can simply buy a Thunderbolt for $150. I'm just starting work on a PLL that (I hope) can be built using just an Aduino as a controller and an 4046 chip (or the 74hct9046) as the phase detector. The Arduino costs more than a bare uP chip but I don't want to have to build a PCB. -- 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] Racal-Dana 1991 w. Option 4C - what is that ?
According to the manual (publication TH62B4 issue 4.10.91) options 04T, 04A, 04B are all 10MHz. No mention of 04c. I vaguely remember hearing that Racal were so satisfied with their 5MHz standards than rather than produce a 10MHz version they simply attached a frequency doubler. I have a 9421 with doubler board attached. John H. On 30 Jan 2012, at 17:24, cfo wrote: On Fri, 20 Jan 2012 09:18:32 -0800, Larry McDavid wrote: One does occasionally find Racal 9462 ocxo offered on eBay. Also, one sometimes finds non-operational Racal instruments offered at low price but which to have Option 04E installed. I convinced one seller to remove the Option 04E module (the Racal 9462) and sell just that with much lower shipping cost. There is also what is evidently an older Racal frequency standard module similar in appearance to the 9462 but which has screws attaching the end plate rather than the soldered-can 9462; one of those is seen from time to time on eBay from the UK but I have avoided that. I have been looking for a Racal 9462 ocxo , for my Racal-Dana 1991 counter. I will prob. use my Tbolt anyway , and save the money. But i'm confused ... Is it a 5 Mhz or a 10 Mhz unit. I have found pictures of one claiming it's 5Mhz http://www.jbtech.de/parts/racal_dana/9462.html But i have also received a picture from jaap , with a racal 9492 , where it clearly says its a 10Mhz unit. Can anyone clarify ? I think there was an option that enabled the use of other ocxo values is that why a 5Mhz can be used , in some 1991's ? If i ever decide to get a OCXO , i would like to get the right one. Regards CFO ___ 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] Racal-Dana 1991 w. Option 4C - what is that ?
I checked the documentations I have, the option 4C isn't mentionned, but all the (Internal Reference) options 04x (04A=OCXO, 04B=High Stability OCXO, 04T=TCXO, 04E=High Stability OCXO (?)) are 10 MHz. There is a Reference Frequency Multiplier (Option 10) which allows to use 1, 2, 5 or 10 MHz as an external reference. The parts numbers are: option 04A: 11-1710 (oscillator), assy=9444 option 04B: 11-1711 (oscillator), assy=9423 option 04E: 404386 option 04T: 11-1610 (plate assy) + 19-1208 (oscillator PCB) option 10: 19-1164 Hope that helps, Regards, Jean-Louis Le 30/01/2012 17:24, cfo a écrit : On Fri, 20 Jan 2012 09:18:32 -0800, Larry McDavid wrote: One does occasionally find Racal 9462 ocxo offered on eBay. Also, one sometimes finds non-operational Racal instruments offered at low price but which to have Option 04E installed. I convinced one seller to remove the Option 04E module (the Racal 9462) and sell just that with much lower shipping cost. There is also what is evidently an older Racal frequency standard module similar in appearance to the 9462 but which has screws attaching the end plate rather than the soldered-can 9462; one of those is seen from time to time on eBay from the UK but I have avoided that. I have been looking for a Racal 9462 ocxo , for my Racal-Dana 1991 counter. I will prob. use my Tbolt anyway , and save the money. But i'm confused ... Is it a 5 Mhz or a 10 Mhz unit. I have found pictures of one claiming it's 5Mhz http://www.jbtech.de/parts/racal_dana/9462.html But i have also received a picture from jaap , with a racal 9492 , where it clearly says its a 10Mhz unit. Can anyone clarify ? I think there was an option that enabled the use of other ocxo values is that why a 5Mhz can be used , in some 1991's ? If i ever decide to get a OCXO , i would like to get the right one. Regards CFO ___ 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. -- Jean-Louis Oneto OCA GeoAzur - Avenue Nicolas Copernic - 06130 Grasse - France email: jean-louis.on...@obs-azur.fr phone: (+33)[0]4.93.40.53.80 ___ 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] FE-.5680A trimming resolution
On Mon, Jan 30, 2012 at 9:47 AM, Mark Sims hol...@hotmail.com wrote: The Tbolt does not have any sawtooth error or corrections. Its' GPS receiver LO is generated from the 10 MHz oscillator. That's what makes it the best GPSDO out there. Inside Packet 0x8F-AC (supplemental timing packet) there are two data fields named PPSOset and 10MHZOset. Each is a 4-bit signed integer with units of nanoseconds for PPSOset and in pars per billion for 10MHZOset. They are used to report an estimate of the PPS and 10MHz signals offset from UTC. Typically the values reported are not constant and in the single digit range. (I'm reading from section A.10.31 of the Thunderbolt manual.) This is what I meant when I said sawtooth. Maybe the wrong term. But I think theses numbers can be used in a controller. 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] Building a GPSDO trouble using Jupiter-T
Using a $ 2 G/A (socket included) and a $ 2 PIC, four will fit on a mini board and there are 3 boards to the order that is $ 5.17 per board. Board is laid out, waiting for uP pin assignment and will be able to deliver in a week board and G/A. Bert Kehren In a message dated 1/30/2012 1:00:04 P.M. Eastern Standard Time, albertson.ch...@gmail.com writes: On Mon, Jan 30, 2012 at 5:16 AM, Bob Camp li...@rtty.us wrote: Hi The GPS ops signal (or 10 KHz signal) you will be trying to track will be moving by 10's or 100's of ns per second. 10 ns per second is 10 ppb. 10 ppb at 10 GHz is 100 Hz. You need to smooth this out or your LO will be moving all over the place. Up at the top of this thread I said you need to have a long loop constant for exactly this reason. It does not matter of the GPS has a 1PPS 100PPS or 1000PPS the problem is GPS itself. GPS simply does not have good short term stability. In the short term the OCXO will be better. The reason we build GPSDOs is to combine the best of both, the short term characteristics of an OCXO and the long term characteristics of GPS. If you try and build a GPSDO using a very short loop filter time constant then you have a GPSDO with same characteristics of GPS averaged over your short time constant. In other words you select the time constant based of your frequency stability requirements. Look at the first blue line in the top graph. This is very much what a Jupiter GPS has. If you need 10E-10 you need a 100 second constant . The line is straight to for 10x better accuracy you need 10x longer time constant. I think using an analog PLL you can get to about the 1E-10 level. I think a non-expert could build a good 100 second RC filter. Doing better is going to require a longer time constant then is reasonable. a uP based PLL can do much better and likely with effort equal the performance of a Trimble Thuderbolt. But then you can simply buy a Thunderbolt for $150. I'm just starting work on a PLL that (I hope) can be built using just an Aduino as a controller and an 4046 chip (or the 74hct9046) as the phase detector. The Arduino costs more than a bare uP chip but I don't want to have to build a PCB. -- Chris Albertson Redondo Beach, California ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts 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] Building a GPSDO trouble using Jupiter-T
On Mon, Jan 30, 2012 at 9:16 AM, ewkeh...@aol.com wrote: With a Rb we are talking loop time in excess of 20 minutes. Any thing other than digital is out of reach. To day I should get my second Rb and I will put it on aging test. My guess about why you don't see aging or so little of it is that maybe some engineer at FEI already did the test and added firmware in the FE5680 to correct the output for estimated aging. So what you are measuring is the difference between true aging and the unit's internal aging model. Trimble does something like this in holdover mode, the controller compensates for the OCXO's estimated aging Chris Albertson Redondo Beach, California ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] FE-.5680A trimming resolution
These are 4-BYTE single precision floating point numbers, not 4 bit integers. They are the values plotted in the Lady Heather PPS and OSC graphs (and used in the ADEV calculations and plots (not actually true ADEV values since they are not refereneced to an external reference, but still useful). From the plots, you can see that you would have a tough time using the OSC values in real time. They are very noisy and need heavy filtering. You might be able to do something useful with the PPS data, but it is also rather noisy. I think you would add just as much noise to the output as you would remove. A much better approach is to minimize the system errors with a GOOD antenna, accurate position survey, proper oscillator control parameters, and temperature stabilization (of both the receiver and power supply)... Lady Heather is willing to oblige on the last points. A good Tbolt implementation can get the PPS plot to under a few nanoseconds of error. -- Each is a 4-bit signed integer with units of nanoseconds for PPSOset and in pars per billion for 10MHZOset. ___ 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] Building a GPSDO trouble using Jupiter-T
What they do does not make any difference to us, what is important how often we have to change the tuning word to meet our requirements, and if we dither it will be an addition or subtraction from the center value. With out dither it would be 4 times a month on my unit. That will allow a very large filter TC. Bert Kehren In a message dated 1/30/2012 1:40:57 P.M. Eastern Standard Time, albertson.ch...@gmail.com writes: On Mon, Jan 30, 2012 at 9:16 AM, ewkeh...@aol.com wrote: With a Rb we are talking loop time in excess of 20 minutes. Any thing other than digital is out of reach. To day I should get my second Rb and I will put it on aging test. My guess about why you don't see aging or so little of it is that maybe some engineer at FEI already did the test and added firmware in the FE5680 to correct the output for estimated aging. So what you are measuring is the difference between true aging and the unit's internal aging model. Trimble does something like this in holdover mode, the controller compensates for the OCXO's estimated aging Chris Albertson Redondo Beach, California ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts 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] HP5334B with 10544 OCXO
I have had several HP-5370's with the 10544 oscillator. They consistently have much less long term frequency drift than the 10811's. If they have not been powered on for a long time, they do take a couple of months of power-on aging before they settle in. ___ 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] Racal-Dana 1991 w. Option 4C - what is that ?
Thank you everyone. It makes sense now , that Racal might use a 5Mhz w. a freq-doubler. I'll use my Tbolt as a ref , or the FEI-5680A i just got. And keep an eye on E... , for a cheap Opt 4e :-) CFO ___ 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] Racal Dana 9466 5 MHz Oscillator
Anyone know which equipment used the Racal Dana 9466 5 MHz oscillator? Thanks. Jim Robbins, N1JR ___ 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] HP5334B with 10544 OCXO
10544 is cool - earlier version than the 10811. Just make sure that the unit is getting warm - some of them have had oven controller problems - but haven't we all??!! Regards, Bill Riches WA2DVU -. Hello. I recently bough an HP-5334B counter with option 010 from the big E. A Google search seems to indicate the OCXO should be a 10811 type OCXO but mine has a type 10544. Other than taking longer to warm up does anybody see any problems with this? Basic testing shows the unit seems to work OK. It is reading 1.7 Hz low compared to my Thunderbolt at 10 MHz - I have not tried adjusting the trimmer on the 10544 yet. Comments and thoughts appreciated. Regards. Mark. VE6NTP . ___ 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] Prologix GPIB-ETH - Linux examples ?
I just got my Prologix GPIB-ETH I am 90% Linux Ubuntu based , and would like to get 99% based. So i am looking for some C code examples, implementing the linux networking part. I have sen the Prologix example C/C+ , but it's WINSOCK. I was thinking ... There must be someone out there using a Prologix GPIB- ETH with linux , that might want to share some code/lib. I saw a ref. for some Prologix stuff in the TimeLab source (win32 i think) , but i can't seem to find the source. CFO ___ 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] FE-.5680A trimming resolution
On Mon, Jan 30, 2012 at 10:43 AM, Mark Sims hol...@hotmail.com wrote: These are 4-BYTE single precision floating point numbers, not 4 bit integers. They are the values plotted in the Lady Heather PPS and OSC graphs Sorry I type faster than I think. You are right they can't be four bits. I work in rocket telemetry, you'd think I'd get this straight. I write software to unpack this kind of stuff. A much better approach is to minimize the system errors with a GOOD antenna, accurate position survey, proper oscillator control parameters, and temperature stabilization (of both the receiver and power supply)... Lady Heather is willing to oblige on the last points. A good Tbolt implementation can get the PPS plot to under a few nanoseconds of error. I've done this. I see values in the single digit nanoseconds. I have a timing antana on a mast on the roof. Perhaps I could get a better timing antenna and low loss coax lead. LH reports the signal at 40dB, +-2dB. Is that good enough? I've seen adev plots from an Oncore MT12 (www.leapsecond.com/pages/m12-adev/) where these error estimates are added in or not and they get maybe 20% better with the corrects applied.the MT12 produces error estimates about that same size as a T-bolt. The data looks noisy on LH's graph because of the scale of the graph. Compared to the 1PPS it is a smooth function. 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] Prologix GPIB-ETH - Linux examples ?
In message jg6qmu$itq$3...@dough.gmane.org, cfo writes: I just got my Prologix GPIB-ETH I am 90% Linux Ubuntu based , and would like to get 99% based. So i am looking for some C code examples, implementing the linux networking part. Look at this stuff: https://github.com/bsdphk/pylt As far as I know the GPIB-ETH is just like the GPIB-USB, except you open a socket in stead of as (usb-) serial port. I switched from C to python for stuff like this. -- 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] Racal-Dana 1991 w. Option 4C - what is that ?
The Racal 9462 ocxo uses a temperature-controlled 5 MHz crystal oscillator inside a sealed can. On the outside end of the can is a small circuit board that doubles the output frequency to 10 MHz. The ocxo cable comes from this circuit board so the output to the counter is 10 MHz. The Racal 9462 operates on 5 vdc and the cable has only three wires, two of which are provided by a shielded cable for the 10 MHz signal. Depending on the age of the ocxo, this doubler circuit board can be either PTH design or (on later units) SMT design. My understanding is that a 5 MHz crystal is inherently more stable than a 10 MHz crystal so better overall performance is achieved by using a 5 MHz crystal and doubling the output to get 10 MHz. I have pictures of these OCXO if you are interested. The Racal Option 04C is a really, really simple 10 MHz oscillator whose performance is terrible! It is not described in any Racal publication I have found and I think it was offered to customers who bought many counters for use in applications where an external precision 10 MHz source was to be used; the Option 04C allows the counter to operate poorly until connected to an external precision 10 MHz source. Option 04E provides the Racal 9462 and there are other ocxo versions, such as Option 04A, that offer better performance than 04C but not so good as Option 04E. Larry On 1/30/2012 9:24 AM, cfo wrote: On Fri, 20 Jan 2012 09:18:32 -0800, Larry McDavid wrote: One does occasionally find Racal 9462 ocxo offered on eBay. Also, one sometimes finds non-operational Racal instruments offered at low price but which to have Option 04E installed. I convinced one seller to remove the Option 04E module (the Racal 9462) and sell just that with much lower shipping cost. There is also what is evidently an older Racal frequency standard module similar in appearance to the 9462 but which has screws attaching the end plate rather than the soldered-can 9462; one of those is seen from time to time on eBay from the UK but I have avoided that. I have been looking for a Racal 9462 ocxo , for my Racal-Dana 1991 counter. I will prob. use my Tbolt anyway , and save the money. But i'm confused ... Is it a 5 Mhz or a 10 Mhz unit. I have found pictures of one claiming it's 5Mhz http://www.jbtech.de/parts/racal_dana/9462.html But i have also received a picture from jaap , with a racal 9492 , where it clearly says its a 10Mhz unit. Can anyone clarify ? I think there was an option that enabled the use of other ocxo values is that why a 5Mhz can be used , in some 1991's ? If i ever decide to get a OCXO , i would like to get the right one. Regards CFO ___ 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. -- Best wishes, Larry McDavid W6FUB Anaheim, CA (20 miles southeast of Los Angeles, near Disneyland) ___ 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] Prologix GPIB-ETH - Linux examples ?
On Mon, Jan 30, 2012 at 11:23 AM, cfo xne...@luna.kyed.com wrote: I just got my Prologix GPIB-ETH I am 90% Linux Ubuntu based , and would like to get 99% based. So i am looking for some C code examples, implementing the linux networking part. I have sen the Prologix example C/C+ , but it's WINSOCK. There's hardly any difference between Linux sockets and WINSOCK as far as that example code goes. Remove the WSAStartup/WSACleanup calls, change sprintf_s to sprintf, WSAGetLastError() to errno, SOCKET to int and you should be done. That's the easy part. The hard part is handling timeouts as the Prologix doesn't give any indication if a ++read timed out. Orin. ___ 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] HP5334B with 10544 OCXO
Could it be that since they are much older (on average) than the 10811s, that (if they've been running) they would have much more accumulated time, so in a more stable part of the long term drift curve? Ed Mark Sims wrote Mon Jan 30 18:50:36 UTC 2012 I have had several HP-5370's with the 10544 oscillator. They consistently have much less long term frequency drift than the 10811's. If they have not been powered on for a long time, they do take a couple of months of power-on aging before they settle in. ___ 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] Prologix GPIB-ETH - Linux examples ?
Interesting, I've downloaded and taken a look at the example and noted how the Prologix doesn't use the Remote Procedure Call (RPC) method but a simple telnet-like connection. Follow Orin's directions to convert from WINSOCK to Linux-style socket calls. Maybe you should first take a look how to open a simple TCP connection under Linux and you'll find the system calls pointed out by Orin. On Mon, Jan 30, 2012 at 9:28 PM, Orin Eman orin.e...@gmail.com wrote: On Mon, Jan 30, 2012 at 11:23 AM, cfo xne...@luna.kyed.com wrote: I just got my Prologix GPIB-ETH I am 90% Linux Ubuntu based , and would like to get 99% based. So i am looking for some C code examples, implementing the linux networking part. I have sen the Prologix example C/C+ , but it's WINSOCK. There's hardly any difference between Linux sockets and WINSOCK as far as that example code goes. Remove the WSAStartup/WSACleanup calls, change sprintf_s to sprintf, WSAGetLastError() to errno, SOCKET to int and you should be done. That's the easy part. The hard part is handling timeouts as the Prologix doesn't give any indication if a ++read timed out. Orin. ___ 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] FE-.5680A trimming resolution ( TBolt)
Chris asked: LH reports the signal at 40dB, +-2dB. Is that good enough? Good enough for what? The TBolt can be setup to work with that, but it could certainly be much better. With a good Tbolt antenna setup you should see about 50 db for overhead birds and in the high 40's for the lower ones. With an indoor puck antenna I see mostly in the low 40's, and it still works OK, IF the Tbolt is set up for the lower signal level. More important is the Antenna signal strength variations plotted over the whole sky which LH can do. Look for low signal areas due to obstructions in the SAS plot and small delta signal strength blips in the SAD plot due to multipath cancellations. ws * - Original Message - From: Chris Albertson albertson.ch...@gmail.com To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Monday, January 30, 2012 11:52 AM Subject: Re: [time-nuts] FE-.5680A trimming resolution On Mon, Jan 30, 2012 at 10:43 AM, Mark Sims hol...@hotmail.com wrote: These are 4-BYTE single precision floating point numbers, not 4 bit integers. They are the values plotted in the Lady Heather PPS and OSC graphs Sorry I type faster than I think. You are right they can't be four bits. I work in rocket telemetry, you'd think I'd get this straight. I write software to unpack this kind of stuff. A much better approach is to minimize the system errors with a GOOD antenna, accurate position survey, proper oscillator control parameters, and temperature stabilization (of both the receiver and power supply)... Lady Heather is willing to oblige on the last points. A good Tbolt implementation can get the PPS plot to under a few nanoseconds of error. I've done this. I see values in the single digit nanoseconds. I have a timing antana on a mast on the roof. Perhaps I could get a better timing antenna and low loss coax lead. LH reports the signal at 40dB, +-2dB. Is that good enough? I've seen adev plots from an Oncore MT12 (www.leapsecond.com/pages/m12-adev/) where these error estimates are added in or not and they get maybe 20% better with the corrects applied.the MT12 produces error estimates about that same size as a T-bolt. The data looks noisy on LH's graph because of the scale of the graph. Compared to the 1PPS it is a smooth function. 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] Thank you Tom and Rick MUST READ
Hi Bert, On 30/01/12 12:02, ewkeh...@aol.com wrote: Having been on the list for only three years somehow tow-time 2009 had escaped me. Thank you Tom and Rick for putting together such an informative document. Probably one of the best contributions. Every member of the list should have a copy and I strongly urge those having joined more recently like my self download this. Thanks again Bert Kehren http://gpstime.com/files/tow-time2009.pdf It's a good read, but it also made me realize just how much I have picked up over the time I've spent on this list, reading it actively. I hope I contribute back to the list. Best Regards, 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] Building a GPSDO trouble using Jupiter-T
So would I Don Latham ewkeh...@aol.com I take 2 Bert Kehren In a message dated 1/30/2012 11:52:07 A.M. Eastern Standard Time, att...@kinali.ch writes: On Mon, 30 Jan 2012 07:37:41 -0500 (EST) ewkeh...@aol.com wrote: Maybe we should consider a group buy. With all the FE 5680A purchases it would make sense to combine them with a good GPS receiver and a digital loop. Since there a uP's out there that have timing functions that will be a low cost simple solution with only a few external components. A $ 2 PIC or some other uP along with a $ 1 G/A will also do. Rb GPS digital loop all for $ 100!!! I do not think we can do better than that. I could handle such a group buy. How many people would be interested? The price breaks u-blox has are IIRC 1-50, 50-100,... Attila Kinali -- Why does it take years to find the answers to the questions one should have asked long ago? ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. -- Neither the voice of authority nor the weight of reason and argument are as significant as experiment, for thence comes quiet to the mind. R. Bacon If you don't know what it is, don't poke it. Ghost in the Shell Dr. Don Latham AJ7LL Six Mile Systems LLP 17850 Six Mile Road POB 134 Huson, MT, 59846 VOX 406-626-4304 www.lightningforensics.com www.sixmilesystems.com ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] Building a GPSDO trouble using Jupiter-T
I would buy some. I´m in Brazil, but I can pay with Paypal... Daniel - I could handle such a group buy. How many people would be interested? The price breaks u-blox has are IIRC 1-50, 50-100,... Attila Kinali -- Why does it take years to find the answers to the questions one should have asked long ago? ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] HP5334B with 10544 OCXO
ed breya wrote: Could it be that since they are much older (on average) than the 10811s, that (if they've been running) they would have much more accumulated time, so in a more stable part of the long term drift curve? Ed This argument is frequently advanced, however there is no guarantee that the aging continues to improve with age. Also some 10811's now go back 30 years, so its not like they are a lot newer than 10544's. It could be just as important what year the oscillator was made, since the quality varied over time. It gradually improved for a while, then went downhill when the experts retired. Rick ___ 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] HP5334B with 10544 OCXO
Other than taking longer to warm up does anybody see any problems with this? Basic testing shows the unit seems to work OK. It is reading 1.7 Hz low compared to my Thunderbolt at 10 MHz - I have not tried adjusting the trimmer on the 10544 yet. Comments and thoughts appreciated. Regards. Mark. VE6NTP At http://home.teleport.com/~oldaker/10mhz_construction.htm which has TAPR info, I found this description of the differences. If you have a Thunderbolt or rubidium to feed in to replace the internal oscillator, or you're not concerned about leaving the oven energized 24/7, it probably doesn't make much difference as Rick Karlquist said. The HP 10811A/B, using an SC-cut resonator, is very similar physically to the HP 10544 that used a AT-cut resonator. The SC-cut crystal has several advantages compared to the AT cut. It has a much smaller temperature coefficient, the resonator can be operated at a higher drive level, which improves the signal-to-noise ratio and short-term frequency stability without degrading the aging rate; it has faster warm up with less frequency overshoot. The SC cut is a doubly rotated resonator and requires much tighter angular tolerances when the crystal is cut from the quartz bar. The SC-cut resonator came into commercial production around 1980. The use of SC-cut resonators in oscillators immediately improved their performance of the stand alone HP 10811 series OCXO installed in their test equipment. In our use we are able to improve on the HP frequency stability specs by a factor of 100 to 1000 depending on conditions. ___ 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] HP5334B with 10544 OCXO
Mark By chance I have just today installed a recently acquired 10554 OCXO into my HP 5334B Counter. Its has been running for 5 hours and is yet to stabilize - my Manual suggest that 24 hours is the required time. Despite reading the manual, I cannot see any reference to the change over from the low grade inbuilt oscillator - is this automatic or does it require a jumper alteration. I seem to recall that Rick Karlquist referred to a voltage droop in the PSU occurring, due to the additional load of the oven as a consequence of fitting the OCXO to the 5334B. I assume that this is when the oven is taking maximum current - perhaps he will offer some help (again) as I cannot find his earlier comments ? I note that the rear simple oscillators trimmer is still operative - should this be so ?, or is it indicative to a need to disconnect it ? Again, any comments would be appreciated. Regards Roy -- From: Allwright, Mark mark_allwri...@kindermorgan.com Sent: Monday, January 30, 2012 4:02 PM To: time-nuts@febo.com Subject: [time-nuts] HP5334B with 10544 OCXO Hello. I recently bough an HP-5334B counter with option 010 from the big E. A Google search seems to indicate the OCXO should be a 10811 type OCXO but mine has a type 10544. Other than taking longer to warm up does anybody see any problems with this? Basic testing shows the unit seems to work OK. It is reading 1.7 Hz low compared to my Thunderbolt at 10 MHz - I have not tried adjusting the trimmer on the 10544 yet. Comments and thoughts appreciated. Regards. Mark. VE6NTP -- Mark Allwright ___ 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] HP5334B with 10544 OCXO
There is a section in the HP5334 Service manual on changes needed. The oscillator uses either the internal crystal (The trimmer is connected to) or the 10811. Basically you change a capacitor feeding from one to the other. I could scan the appropriate pages if you need (Contact me off list). Regards Randall Prentice Stokes Valley Lower Hutt5019 New Zealand ZL2RJP -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Roy Phillips Sent: Tuesday, 31 January 2012 10:40 a.m. To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] HP5334B with 10544 OCXO Mark By chance I have just today installed a recently acquired 10554 OCXO into my HP 5334B Counter. Its has been running for 5 hours and is yet to stabilize - my Manual suggest that 24 hours is the required time. Despite reading the manual, I cannot see any reference to the change over from the low grade inbuilt oscillator - is this automatic or does it require a jumper alteration. I seem to recall that Rick Karlquist referred to a voltage droop in the PSU occurring, due to the additional load of the oven as a consequence of fitting the OCXO to the 5334B. I assume that this is when the oven is taking maximum current - perhaps he will offer some help (again) as I cannot find his earlier comments ? I note that the rear simple oscillators trimmer is still operative - should this be so ?, or is it indicative to a need to disconnect it ? Again, any comments would be appreciated. Regards Roy -- From: Allwright, Mark mark_allwri...@kindermorgan.com Sent: Monday, January 30, 2012 4:02 PM To: time-nuts@febo.com Subject: [time-nuts] HP5334B with 10544 OCXO Hello. I recently bough an HP-5334B counter with option 010 from the big E. A Google search seems to indicate the OCXO should be a 10811 type OCXO but mine has a type 10544. Other than taking longer to warm up does anybody see any problems with this? Basic testing shows the unit seems to work OK. It is reading 1.7 Hz low compared to my Thunderbolt at 10 MHz - I have not tried adjusting the trimmer on the 10544 yet. Comments and thoughts appreciated. Regards. Mark. VE6NTP -- Mark Allwright ___ 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] Racal-Dana 1991 w. Option 4C - what is that ?
lmcda...@lmceng.com said: My understanding is that a 5 MHz crystal is inherently more stable than a 10 MHz crystal so better overall performance is achieved by using a 5 MHz crystal and doubling the output to get 10 MHz. What makes 5 MHz more stable than 10 MHz? Why not 2.5 MHz and double twice? Or 1.25 MHz and three doublers? -- These are my opinions, not necessarily my employer's. I hate spam. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Thank you Tom and Rick MUST READ
Magnus I fully agree, regardless of the subject if it comes from you I read it and save it.. How ever we have clearly some new bees and this one write up is a nice introduction. Covers a lot of basic territory. Bert Kehren In a message dated 1/30/2012 4:18:27 P.M. Eastern Standard Time, mag...@rubidium.dyndns.org writes: Hi Bert, On 30/01/12 12:02, ewkeh...@aol.com wrote: Having been on the list for only three years somehow tow-time 2009 had escaped me. Thank you Tom and Rick for putting together such an informative document. Probably one of the best contributions. Every member of the list should have a copy and I strongly urge those having joined more recently like my self download this. Thanks again Bert Kehren http://gpstime.com/files/tow-time2009.pdf It's a good read, but it also made me realize just how much I have picked up over the time I've spent on this list, reading it actively. I hope I contribute back to the list. Best Regards, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts 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] Prologix GPIB-ETH - Linux examples ?
I was thinking ... There must be someone out there using a Prologix GPIB- ETH with linux , that might want to share some code/lib. I saw a ref. for some Prologix stuff in the TimeLab source (win32 i think) , but i can't seem to find the source. Sorry, I should've been more specific -- when you run the (Windows) setup from http://www.miles.io/timelab/readme.htm it will give you a near-complete copy of my development directory at the time that version was built. By default, most of the program's .cpp/.h source code ends up in c:\program files\miles design\timelab alongside the 32-bit and 64-bit executables, and in various directories underneath it. This includes all of the data importers and TIC/frequency counter drivers, as well as the TSC 5115/5120/5125 drivers... basically everything is there but the TimePod driver source. For GPIB-LAN example code, you could look at the TCPBLOCK class in drivers\shared\comblock.cpp, as well as the module that abstracts the various GPIB providers (gpibport.cpp). . As Orin says the differences between Winsock and *nix/BSD sockets are not large, at least for trivial applications like this one. Higher-performance code will tend to use more OS-specific calls to set up overlapped I/O operations and such, but there's no need for that here. TCPBLOCK is a rather low-performance chunk of code, being structured to read one byte at a time. It's fine for GPIB work but you wouldn't want to write a browser with it. -- 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] HP5334B with 10544 OCXO
Roy Phillips wrote: Mark By chance I have just today installed a recently acquired 10554 OCXO into my HP 5334B Counter. Its has been running for 5 hours and is yet to stabilize - my Manual suggest that 24 hours is the required time. Despite reading the manual, I cannot see any reference to the change over from the low grade inbuilt oscillator - is this automatic or does it require a jumper alteration. I seem to recall that Rick Karlquist referred to a voltage droop in the PSU occurring, due to the additional load of the oven as a consequence of fitting the OCXO to the 5334B. I assume that this is when the oven is taking maximum current - perhaps he will offer some help (again) as I cannot find his earlier comments ? I note that the rear simple oscillators trimmer is still operative - should this be so ?, or is it indicative to a need to disconnect it ? Again, any comments would be appreciated. Regards Roy I inherited the built in oscillator from the 5334A; it is a poor design based on a 10116 ECL line receiver (HP part no 1820-0810, near the rear panel switch that selects the external reference). I believe that spare gates in the package are used to select the 10811 vs built in vs external ref. I don't remember, but I suspect plugging in the 10811 is detected somehow by the 10116. I wouldn't normally allow a design where it wasn't automatic. When you say the rear panel trimmer is still operative, do you mean it affects the frequency? Is so, you are not running on the 10544. The design should be obvious from the schematic, however I don't have one and can't remember every detail from 25 years ago. Rick ___ 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] Quick tutorial on jitter
Fellow time-nuts, In a private discussion, I got somewhat inspired, so I wrote this relating to what jitter is. It's the pre-breakfast, won't get out of bed version. Since it was enjoyed by a fellow time-nut, I share it with a little larger audience. Jitter as such is the part of the phase deviations being fast while wander is part of the phase deviations being slow. Jitter and Wander is measured in seconds, degrees or Unit Interval depending on the application. Jitter is reported in RMS or peak-to-peak values depending on where it is being used, but since jitter has a underlying Gaussian distribution, the longer you measure the higher peak-to-peak value gets and you don't get very smarter. For gaussian distribition the RMS value is much better. However... jitter can have other additive components than gaussian jitter, so over the last 10-15 years or so it has become increasingly popular to use software tools to separate Random Jitter (with Gaussian distribtion) from Deterministic Jitter (which has stable peak-to-peak values, such as an added sine-modulation). Then this can be broken down further to include intersymbolic interference, crosstalk etc. This is the market that Wavecrest was pursuing with their counters, a market which has the needs. Today Tektronix, Agilent and LeCroy have this processing as a software option into their scopes. Jitter for a signal is measured with a PLL clock recovery, and the output of the mixer is tapped and then filtering is done to measure different standard values. Then a RMS value of the aggregate is reported. By using this method, a cheap compliance testing can be done, and the filter frequencies is standardised. They also relate to the sinus jitter tolerance curves, which also relate to the MTIE tolerance curves. These tolerance curves work in two ways, the output tolerance must be below the curve while the input tolerance must be above, when they are the output will always be tolerated by the input. For telecom use, aggregate numbers for jitter and wander is reported in UI after filtering. A UI is a scaled unit of time, where 1 UI is the time of the shortest symboltime (or symbol time quanta). For simple compliance getting the aggregate readings suffice, but for detailed analysis the data is processed according to TDEV and MTIE numbers. TDEV addresses the random properties of the signal noise, while MTIE covers the systematic properties of the signal noise. The neat thing is that MTIE numbers in their UI scale provides very good hints about jitter compensation buffer size. It correlate nicely. Also, the corner frequencies correlate well with the bandwidth of the jitter damping PLL being in parallel with the jitter compensation buffer. With the plots in the standards you can read out all the key parameter for your design! The separation between jitter and wander now becomes a little easier to explain. They relate to different sources, so in telecom the separation is being said to occur at 10 Hz, but to be honest, this is a separation only meaning full in the context of PDH, SONET and SDH systems. It's not meaningful in the context of other signals or systems, not by any form of automagic anyway. Looking at the aggregate signals and how they best are measured and characterized the separation makes sense. Jitter uses the sinusoidal tolerance curves while wander used TDEV and MTIE. I like to compare jitter and wander to wow and flutter. Wow is the low frequency modulation that typically occur when the record slips a little in angle compared to the record player disc. This causes a low frequency modulation causing a Wooow sound on voices. This is clearly the wander of the record player industry. Flutter comes as a result of the drive mechanism, steps in the motors, gears and lack of damping through rubber band and heavy turntable disc. Actually jitter (shaking) and wander (walking around) is just colloquial terms just was wow and flutter, but they all relate to particular phase modulation aspects. So the question is, how does one relate ADEV or TDEV or phase or phase noise to a 1PPS jitter number? Or, is it safe to say for TF use, that TDEV at tau 1 s is a more useful measure of 1PPS jitter anyway? Now, if your jitter (and wander) is dominated by gaussian jitter, then yes, your ADEV and TDEV correlate at 1 s to the jitter (do notice the sqrt(3) between these measures). The reason is that ADEV as such is scaled to match the white noise readings. If your jitter has sufficiently strong components of non-gaussian character, you will need to measure them separately and join them after proper scaling. Consider that you have a bit error rate (BER) requirement of 10-12. This is very common number, so it provides the basis of the rule of thumb. You get a bit error when you sample the wrong bit value, so in a simplified model you would get a bit error when you sample 1 UI away from your average
Re: [time-nuts] HP5334B with 10544 OCXO
Arthur Dent wrote: At http://home.teleport.com/~oldaker/10mhz_construction.htm which has TAPR info, I found this description of the differences. If you have a Thunderbolt or rubidium to feed in to replace the internal oscillator, or you're not concerned about leaving the oven energized 24/7, it probably doesn't make much difference as Rick Karlquist said. The HP 10811A/B, using an SC-cut resonator, is very similar physically to the HP 10544 that used a AT-cut resonator. The SC-cut crystal has several advantages compared to the AT cut. It has a much smaller temperature coefficient, the resonator can be operated at a higher drive level, which improves the signal-to-noise ratio and short-term frequency stability without degrading the aging rate; it has faster warm up with less frequency overshoot. The SC cut is a doubly rotated resonator and requires much tighter angular tolerances when the crystal is cut from the quartz bar. The SC-cut resonator came into commercial production around 1980. The use of SC-cut resonators in oscillators immediately improved their performance of the stand alone HP 10811 series OCXO installed in their test equipment. In our use we are able to improve on the HP frequency stability specs by a factor of 100 to 1000 depending on conditions. A mix of facts and folklore. I would especially challenge the last sentence. Rick ___ 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] GHz output from fe5680a
hello everyone, I'm just wondering if its possible to tap into the GHz output from the rubidium in the fe5680a. many thanks Chris ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Thank you Tom and Rick MUST READ
Hi Bert, On 30/01/12 23:01, ewkeh...@aol.com wrote: Magnus I fully agree, regardless of the subject if it comes from you I read it and save it.. How ever we have clearly some new bees and this one write up is a nice introduction. Covers a lot of basic territory. Indeed it does. One has to recall that this is from a presentation, so a lot is missing which would aid in the understanding, but most will catch on to the basic story. Now, if I only had a few H-masers standing around... I had 5 of those newer 5680As hit my lab-bench today. Will be fun to catch up with you guys. I have one of the older 5680As as well, with the DDS option. (Yes Bert, I'm spending more time in the lab again!) 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] ANN: UK - Notification of GPS Jamming - 2012 April 9-20
On 30/01/12 12:10, David J Taylor wrote: Folks, I have received the following: NOTIFICATION OF GPS JAMMING EXERCISES RAF SPADEADAM, CUMBRIA, 9TH APRIL 2012 Dates: Between 9th and 20th April 2012 inclusive (weekdays only). Times: 0700 - 1800 GMT. Location of MULTIPLE jammers: Land based within 5km of N55° 04.000' W002° 34.000'. Frequency: A 24 MHz band centred around 1575.42MHz (GPS L1). Total Power: Up to 10 Watts EIRP. It is stressed that, as in previous exercises, Safety of Life operations will at all times take precedence over exercise activities. Anyone taking a recording of jamming events like that? Always nice to see what they throw at the receivers :) 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] HP5334B with 10544 OCXO
There is a section in the HP5334 Service manual on changes needed. The oscillator uses either the internal crystal (The trimmer is connected to) or the 10811. Basically you change a capacitor feeding from one to the other. I could scan the appropriate pages if you need (Contact me off list). Regards Randall Prentice Stokes Valley Lower Hutt5019 New Zealand ZL2RJP -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Roy Phillips Sent: Tuesday, 31 January 2012 10:40 a.m. To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] HP5334B with 10544 OCXO Mark By chance I have just today installed a recently acquired 10554 OCXO into my HP 5334B Counter. Its has been running for 5 hours and is yet to stabilize - my Manual suggest that 24 hours is the required time. Despite reading the manual, I cannot see any reference to the change over from the low grade inbuilt oscillator - is this automatic or does it require a jumper alteration. I seem to recall that Rick Karlquist referred to a voltage droop in the PSU occurring, due to the additional load of the oven as a consequence of fitting the OCXO to the 5334B. I assume that this is when the oven is taking maximum current - perhaps he will offer some help (again) as I cannot find his earlier comments ? I note that the rear simple oscillators trimmer is still operative - should this be so ?, or is it indicative to a need to disconnect it ? Again, any comments would be appreciated. Regards Roy Installation of Option 010 is basically removing capacitor C8 and reinstalling it into the holes designated for C100. Install the 10544 oscillator into the receptacle, secure with appropriate screws and you're all set. C8 and C100 are located very close to the standard (low-stability) crystal at the rear of the main board. Dave M A woman has the last word in any argument. Anything a man says after that is the beginning of a new argument. ___ 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] GHz output from fe5680a
Hi Chris, The short answer is NO ! BillWB6BNQ chris 0 wrote: hello everyone, I'm just wondering if its possible to tap into the GHz output from the rubidium in the fe5680a. many thanks Chris ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ 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] GHz output from fe5680a
What would you intend to do with the signal? I'm not a microwave expert, but I believe the only microwave signals in the FE-5680A are the output of the step-recovery diode that multiplies the 60 MHz VCXO signal up to the 114th harmonic, plus that mixed with the 5.313 MHz DDS output to reach the Rb frequency. ( 114 * 60 Mhz - 5.313 Mhz - 6.835 Ghz) The SRD output would be just a mix of a lot of harmonics, not any sort of clean signal; I suspect the only real filter is the resonant cavity which is occupied by the Rb bulb. I suppose a small enough probe into that cavity might not detune it too much, but you'd probably need an additional amplifier to do anything with that signal. Iin this device the Rb vapor itself does not generate microwaves (like an active H maser), it just absorbs them, and it changes optically if the signal happens to be at the resonance frequency around 6.8 GHz. ---Original Message--- From: chris 0 viscousplac...@gmail.com Subject: [time-nuts] GHz output from fe5680a I'm just wondering if its possible to tap into the GHz output from the rubidium in the fe5680a. ___ 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] Thank you Tom and Rick MUST READ
did a quick scan looked good so will go back and read later. Thanks On Mon, Jan 30, 2012 at 6:27 PM, Magnus Danielson mag...@rubidium.dyndns.org wrote: Hi Bert, On 30/01/12 23:01, ewkeh...@aol.com wrote: Magnus I fully agree, regardless of the subject if it comes from you I read it and save it.. How ever we have clearly some new bees and this one write up is a nice introduction. Covers a lot of basic territory. Indeed it does. One has to recall that this is from a presentation, so a lot is missing which would aid in the understanding, but most will catch on to the basic story. Now, if I only had a few H-masers standing around... I had 5 of those newer 5680As hit my lab-bench today. Will be fun to catch up with you guys. I have one of the older 5680As as well, with the DDS option. (Yes Bert, I'm spending more time in the lab again!) Cheers, Magnus __**_ 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] GHz output from fe5680a
Hi Simple answer is don't bother. More complex answer - of course you can. You will get a forest of spikes (every 5, MHz or so ). Bob On Jan 30, 2012, at 6:26 PM, chris 0 viscousplac...@gmail.com wrote: hello everyone, I'm just wondering if its possible to tap into the GHz output from the rubidium in the fe5680a. many thanks Chris ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ 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] Building a GPSDO trouble using Jupiter-T
Hi Aging tends to be bidirectional ( equal probability positive or negative within a group of Rb's ). That would make it tough to pre-estimate. Bob On Jan 30, 2012, at 1:40 PM, Chris Albertson albertson.ch...@gmail.com wrote: On Mon, Jan 30, 2012 at 9:16 AM, ewkeh...@aol.com wrote: With a Rb we are talking loop time in excess of 20 minutes. Any thing other than digital is out of reach. To day I should get my second Rb and I will put it on aging test. My guess about why you don't see aging or so little of it is that maybe some engineer at FEI already did the test and added firmware in the FE5680 to correct the output for estimated aging. So what you are measuring is the difference between true aging and the unit's internal aging model. Trimble does something like this in holdover mode, the controller compensates for the OCXO's estimated aging Chris Albertson Redondo Beach, California ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts 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] FE-.5680A trimming resolution
Mark, If you feel adventurous, my GPSMonitor (written in C for the 8051) source code is available. Development tools including C compiler are free. Didier KO4BB On Mon, Jan 30, 2012 at 11:47 AM, Mark Sims hol...@hotmail.com wrote: The Tbolt does not have any sawtooth error or corrections. Its' GPS receiver LO is generated from the 10 MHz oscillator. That's what makes it the best GPSDO out there. -- I'm also thinking of porting over much of the Lady Heather t-bolt monitoring stuff to the Arduino. One thing you can do with a uP based controller is look at the t-bolt's saw tooth error correction and remove a few nS of error. ___ 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] GHz output from fe5680a
On 31/01/12 02:20, Bob Camp wrote: Hi Simple answer is don't bother. More complex answer - of course you can. You will get a forest of spikes (every 5, MHz or so ). Also, since the 5,3 MHz is modulated, 1,4 kHz apart is the two signals, and then a skirt of side-bands as the frequency modulation is relatively quick. It's not clean. BTW. A fun hack would be to hook up the 63,8976 MHz OCXO in replacement of the 60 MHz and then re-adjusting the DDS to 2.35645 MHz, as the 107s overtone of the OCXO minus the new DDS frequency hits the Rb resonance. 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] Building a GPSDO trouble using Jupiter-T
You have to spend good money to get a GPS receiver capable of calculating it's time and/or position more than once per second. I am not aware of that being done for timing applications, but it is available for navigation GPS receivers, such as those used to track race cars (for a race car, one second is an eternity). I have seen navigation receivers capable of 10 fixes/second, I am sure there are better ones yet. They cost a lot of money. Didier KO4BB On Mon, Jan 30, 2012 at 4:31 AM, Azelio Boriani azelio.bori...@screen.itwrote: OK, now I know and wonder if other GPS receivers that have frequency outputs behave in this manner. For example the Motorola 100PPS output, the uBlox 800Hz, the Navsync variable frequency output and so on. It is possible to compute solutions from GPS satellite at greater than 1 second rate so the phase of these signals should be adjustable at a rate that could minimize the phase jump... this is only my opinion, not the real possibility. On Mon, Jan 30, 2012 at 11:15 AM, Bruce Griffiths bruce.griffi...@xtra.co.nz wrote: The 10kHz is continuous but its phase jerked on the second. The new phase is held until the next jerk. Bruce Azelio Boriani wrote: Ah, is it a burst of 10KHz once a second? I don't have a Jupiter-T and I'm a PPS-type discplining fan but I thought it was a continuous 10KHz. On Mon, Jan 30, 2012 at 10:33 AM, Attila Kinaliatt...@kinali.ch wrote: On Sun, 29 Jan 2012 00:50:35 -0600 Ray Xurayxu...@gmail.com wrote: For those who have experience using the Jupiter T GPS: I have bought this http://www.ebay.com/itm/**Navman-jupiter-T-Tu60-GPS-Kit-** 1pps-10khz-GPS-Module-/**260790984470 http://www.ebay.com/itm/Navman-jupiter-T-Tu60-GPS-Kit-1pps-10khz-GPS-Module-/260790984470 Ouch... For that price you get already a new LEA-6T, which is a state of the art timing GPS receiver. Beside having the better sensitivity (more satelites in difficult conditions) it features also an frequency output that can go up to 10MHz (or 8MHz if you want low jitter). 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 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 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 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] GHz output from fe5680a
That approximate frequency exists in Rb oscillators, but it is only one of many harmonics, and very small in amplitude. The Rb system doesn't (can't) count it - it sees only the difference between a certain harmonic and the natural resonance, and a phase locked loop adjusts it. Ed ___ 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] GHz output from fe5680a
hello everyone, I'm just wondering if its possible to tap into the GHz output from the rubidium in the fe5680a. many thanks Chris If I understand your question right... Most rubidium frequency standards (and cesium for that matter) do not actually output that frequency. I know in the popular press they talk about the precise vibrations of the cesium atom or the precise frequency that they emit but that's a metaphor and not how they actually work. The atoms don't vibrate, they don't emit a GHz frequency, and you don't count 9,192,631,770 of them to make one second. What typically happens is that electronics synthesizes an RF (microwave) signal and continuously sweeps across a narrow range of frequencies; the element (Rb or Cs or H) will respond more or less depending on how correct the probe frequency is. A servo then tries to keep the probe frequency centered on the peak. These are all called passive standards. The rare exception is the active hydrogen maser; where there really is a live signal (1420+ MHz) coming out of the apparatus. You may find these two papers helpful: Introduction to time and frequency metrology http://tf.nist.gov/general/pdf/1288.pdf Fundamentals of Time and Frequency http://tf.nist.gov/general/pdf/1498.pdf /tvb ___ 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] Racal-Dana 1991 w. Option 4C - what is that ?
What makes 5 MHz more stable than 10 MHz? Why not 2.5 MHz and double twice? Or 1.25 MHz and three doublers? Apparently 2.5 MHz is the most stable of all for reasons not fully understood, but accepted. That's why the early Sulzer oscillators were 2.5 Mc. They doubled them to get 5 MHz. I don't have a reference handy but there are charts and curves in old papers on quartz technology that show a peak in performance (Q?) around 2.5 MHz. Doubling, tripling, or quadupling works too but you get noise at every stage so this is not always a solution. The 2.5 MHz blanks are very large and expensive; I heard that's why the industry moved to 5 and then 10 MHz crystals. Perhaps one of the xtal experts on the list can clarify this for us. See also: Brief History of the Development of Ultra-Precise Oscillators http://www.ieee-uffc.org/main/history.asp?file=norton Fifty Years of Progress in Quartz Crystal Frequency Standards http://www.ieee-uffc.org/main/history.asp?file=frerking /tvb ___ 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] HP5334B with 10544 OCXO
I think the 10811 was the newer improved replacement for the 10544, with the same connections and external signals, and a little better performance. In that era of equipment you may see either one. They should be interchangeable, and the manuals and specs for both are readily available. Ed Not quite same connections. Although the 10811 was designed to be a plug-in replacement for the 10544 the converse is not true. The 10544A requires additional connections (pins 8 and 9) for oven controller power and it is not always a valid replacement for a 10811, depending on the instrument in which it is installed. The symptom is the 10544A never warms up. The 10544B does not have this problem. See datasheets at: http://www.leapsecond.com/museum/10544/ /tvb ___ 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] GHz output from fe5680a
El 31/01/2012 02:52, Magnus Danielson escribió: On 31/01/12 02:20, Bob Camp wrote: Hi Simple answer is don't bother. More complex answer - of course you can. You will get a forest of spikes (every 5, MHz or so ). Also, since the 5,3 MHz is modulated, 1,4 kHz apart is the two signals, and then a skirt of side-bands as the frequency modulation is relatively quick. It's not clean. BTW. A fun hack would be to hook up the 63,8976 MHz OCXO in replacement of the 60 MHz and then re-adjusting the DDS to 2.35645 MHz, as the 107s overtone of the OCXO minus the new DDS frequency hits the Rb resonance. Cheers, Magnus And then we will have a not less fun 10.6469MHz and 0.939Hz outputs :) However, if the DDS can easily be reprogrammed to large offsets (and the output filter is a simple lowpass...), that idea is very useful if you need an strange frequency and have an OCXO at 6x that extrange frequency ;) Regards, Javier ___ 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] FE-5680A decoded - another piece of the puzzle
On 1/29/2012 8:22 PM, Skip Withrow wrote: I recall someone implementing C-field control on a FE-5680A with the pot disabled, but cannot find it now. If someone can point me to that post I sure would appreciate it. I added that post to the FE-5680A FAQ, and added my own photo also to help locate the part. Note, I have not actually tried this modification myself. http://www.ko4bb.com/dokuwiki/doku.php?id=precision_timing:fe5680a_faq#adding_an_analog_adjustment_pot Original post was by Bill Riches, Thu, 22 Dec 2011 14:01:18 -0800 ___ 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.
