[time-nuts] New (refurbished) LPRO-101 GPSDO
I just received my LPRO-101 with a GPSDO control on it, from TenMhz.com. After fiddling with getting a good placement for the GPS antenna, so that it doesn't keep losing the satellites, I have been attempting to discipline the oscillator for more than 24 hours. At this point, the LED has been toggling red / green for the past 24 hours which indicates solid GPS acquisition and 5e-8. But it isn't locked to NIST until it turns solid green which indicates 5e-11. Since this is a first deployment at my location, is it reasonable behavior for it to take longer than 24 hours to lock to NIST through GPS? Or do you think something may be wrong with the device. I already know by comparison to WWV that I'm within a few mHz of being aligned, but noise in the measurements, human impatience, and wander in the soundcard clock, prevents me knowing any better than this. So already I'm 5e-10. But that's about all I know until I see it lock. (If it ever does...) eh? Dr. David McClain Chief Technical Officer Refined Audiometrics Laboratory 4391 N. Camino Ferreo Tucson, AZ 85750 email: d...@refined-audiometrics.com phone: 1.520.390.3995 web: http://refined-audiometrics.com On Oct 15, 2010, at 16:00, Magnus Danielson wrote: On 10/16/2010 12:08 AM, Bob Camp wrote: Hi It's a crazy world when it comes to self signed certs. You have at least 5 OS's you need to consider (MS, Linux/FBSD, OS- X, I-OS, Android). You need to think about both browsers and mail clients. Each of those come from a half dozen sources on each platform. Then you have configuration options on each. That's a lot of combinations. Each combo seems to have a different idea of what not to do when they see a self signed cert. If you want to be able to handle all of them, even real certs may have issues. There are indeed several common combo's that are a major pain with a self signed cert. No, I didn't write any of the code with the problems in it. I also don't want to get into the details of what and where. This really isn't the forum for that sort of thing. I'm not out to bash any particular solution, only to point out that there are indeed issues. Do handle part of the mess, we have setup our local root cert at the computer club, and then sign our server certs to that. I did a major overhaul on the infrastructure for that. It is still not real safety routines, but ah well. We provide a cert download which quickly solves the cert issue with most browser. Seems to work for our myriad of server and client OSes and clients. There is various ways to get real root certs, but depending on degree of uhm... safety... it may be argued of their capabilities. There is efforts to build a chain of trust for a stable free root cert, but it is so far nog included in any major browsers. Essentially it's a mess. I'm only scratched the surface here. Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/ time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] New (refurbished) LPRO-101 GPSDO
Hi Straight out of the box, an LPRO should be within 2x10^-10 after an hour on power. That's with no disciplining and just normal luck in terms of it getting banged about in shipment. That also assumes it was set properly before it was shipped. As long as your antenna is outdoors with a good view of the sky to the south, the receiver should find enough sats to stay in timing mode all the time. In the horizontal plane the sky within +/- 30 degrees of due north is not very important for GPS. Vertically a view to within 20 degrees of the horizon is considered ok for this sort of thing. I'd give it a bit more time, but it sounds flaky to me. Bob On Oct 17, 2010, at 5:55 AM, David McClain wrote: I just received my LPRO-101 with a GPSDO control on it, from TenMhz.com. After fiddling with getting a good placement for the GPS antenna, so that it doesn't keep losing the satellites, I have been attempting to discipline the oscillator for more than 24 hours. At this point, the LED has been toggling red / green for the past 24 hours which indicates solid GPS acquisition and 5e-8. But it isn't locked to NIST until it turns solid green which indicates 5e-11. Since this is a first deployment at my location, is it reasonable behavior for it to take longer than 24 hours to lock to NIST through GPS? Or do you think something may be wrong with the device. I already know by comparison to WWV that I'm within a few mHz of being aligned, but noise in the measurements, human impatience, and wander in the soundcard clock, prevents me knowing any better than this. So already I'm 5e-10. But that's about all I know until I see it lock. (If it ever does...) eh? Dr. David McClain Chief Technical Officer Refined Audiometrics Laboratory 4391 N. Camino Ferreo Tucson, AZ 85750 email: d...@refined-audiometrics.com phone: 1.520.390.3995 web: http://refined-audiometrics.com On Oct 15, 2010, at 16:00, Magnus Danielson wrote: On 10/16/2010 12:08 AM, Bob Camp wrote: Hi It's a crazy world when it comes to self signed certs. You have at least 5 OS's you need to consider (MS, Linux/FBSD, OS-X, I-OS, Android). You need to think about both browsers and mail clients. Each of those come from a half dozen sources on each platform. Then you have configuration options on each. That's a lot of combinations. Each combo seems to have a different idea of what not to do when they see a self signed cert. If you want to be able to handle all of them, even real certs may have issues. There are indeed several common combo's that are a major pain with a self signed cert. No, I didn't write any of the code with the problems in it. I also don't want to get into the details of what and where. This really isn't the forum for that sort of thing. I'm not out to bash any particular solution, only to point out that there are indeed issues. Do handle part of the mess, we have setup our local root cert at the computer club, and then sign our server certs to that. I did a major overhaul on the infrastructure for that. It is still not real safety routines, but ah well. We provide a cert download which quickly solves the cert issue with most browser. Seems to work for our myriad of server and client OSes and clients. There is various ways to get real root certs, but depending on degree of uhm... safety... it may be argued of their capabilities. There is efforts to build a chain of trust for a stable free root cert, but it is so far nog included in any major browsers. Essentially it's a mess. I'm only scratched the surface here. Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing 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] New (refurbished) LPRO-101 GPSDO
Le 17/10/2010 11:55, David McClain a écrit : I just received my LPRO-101 with a GPSDO control on it, from TenMhz.com. After fiddling with getting a good placement for the GPS antenna, so that it doesn't keep losing the satellites, I have been attempting to discipline the oscillator for more than 24 hours. At this point, the LED has been toggling red / green for the past 24 hours which indicates solid GPS acquisition and 5e-8. But it isn't locked to NIST until it turns solid green which indicates 5e-11. Since this is a first deployment at my location, is it reasonable behavior for it to take longer than 24 hours to lock to NIST through GPS? Or do you think something may be wrong with the device. I don't have this box or an LPRO, but if the manafacturer says 24hrs is OK, then I guess that should be enough. You may need to give them a call. However am wondering if you are getting reflected path GPS signals. You said that you had to fiddle with the antenna placement. Are you in an urban jungle? I have a situation where I can see satellites at all times, but once or twice a day I am getting strong reflected signal which is disturbing the GPS 1PPS. It is due to buidings opposite my north facing office where the antenna sits. The issue is seen with my TBOLT, Z3801A and independent Oncore GPS engines all of which are not the latest hardware. That would cause the PLL to be constantly chasing a moving target. I already know by comparison to WWV that I'm within a few mHz of being aligned, but noise in the measurements, human impatience, and wander in the soundcard clock, prevents me knowing any better than this. So already I'm 5e-10. But that's about all I know until I see it lock. (If it ever does...) eh? Dr. David McClain Chief Technical Officer Refined Audiometrics Laboratory 4391 N. Camino Ferreo Tucson, AZ 85750 email: d...@refined-audiometrics.com phone: 1.520.390.3995 web: http://refined-audiometrics.com On Oct 15, 2010, at 16:00, Magnus Danielson wrote: On 10/16/2010 12:08 AM, Bob Camp wrote: Hi It's a crazy world when it comes to self signed certs. You have at least 5 OS's you need to consider (MS, Linux/FBSD, OS-X, I-OS, Android). You need to think about both browsers and mail clients. Each of those come from a half dozen sources on each platform. Then you have configuration options on each. That's a lot of combinations. Each combo seems to have a different idea of what not to do when they see a self signed cert. If you want to be able to handle all of them, even real certs may have issues. There are indeed several common combo's that are a major pain with a self signed cert. No, I didn't write any of the code with the problems in it. I also don't want to get into the details of what and where. This really isn't the forum for that sort of thing. I'm not out to bash any particular solution, only to point out that there are indeed issues. Do handle part of the mess, we have setup our local root cert at the computer club, and then sign our server certs to that. I did a major overhaul on the infrastructure for that. It is still not real safety routines, but ah well. We provide a cert download which quickly solves the cert issue with most browser. Seems to work for our myriad of server and client OSes and clients. There is various ways to get real root certs, but depending on degree of uhm... safety... it may be argued of their capabilities. There is efforts to build a chain of trust for a stable free root cert, but it is so far nog included in any major browsers. Essentially it's a mess. I'm only scratched the surface here. Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing 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] New (refurbished) LPRO-101 GPSDO
Well, not exactly an urban jungle here, but there could be multipath off the neighbor's home... Thanks for that suggestion. I will try moving the antenna about. When I first deployed it, the GPS would go solid reception for a while, and it actually claimed to lock, after only an hour or so. But it kept losing the birds and would go back into hunt mode after about 20 minutes of lock time. I wasn't sure that I could trust the lock indication after so short a time. And I didn't like the sporadic lock conditions. So I tried duct taping the antenna to the roof tiles that I could reach and got solid GPS reception, but no lock. The antenna is a little black hockey puck with a magnetic base. I wonder if it would do better affixed to a metal ground plane? First time user of a GPSDO and so I don't know what to expect. But I'm also beginning to understand better that a GSPDO probably is more than was warranted for the needs of a solid reference oscillator for radios. Now that I'm learning more about Rb and GPSDO's in general, I probably could have got by quite well with just a bare LPRO. And I am also beginning to understand that GPSDO's don't necessarily have internal Rb references -- looks like the T'Bird is just a really good OCXO with a GPS discipline. And everyone is raving about T'Birds... The LPRO has an internal Rb reference and an untamed VCXO. Thanks for all the advice! Dr. David McClain Chief Technical Officer Refined Audiometrics Laboratory 4391 N. Camino Ferreo Tucson, AZ 85750 email: d...@refined-audiometrics.com phone: 1.520.390.3995 web: http://refined-audiometrics.com On Oct 17, 2010, at 06:07, mike cook wrote: Le 17/10/2010 11:55, David McClain a écrit : I just received my LPRO-101 with a GPSDO control on it, from TenMhz.com. After fiddling with getting a good placement for the GPS antenna, so that it doesn't keep losing the satellites, I have been attempting to discipline the oscillator for more than 24 hours. At this point, the LED has been toggling red / green for the past 24 hours which indicates solid GPS acquisition and 5e-8. But it isn't locked to NIST until it turns solid green which indicates 5e-11. Since this is a first deployment at my location, is it reasonable behavior for it to take longer than 24 hours to lock to NIST through GPS? Or do you think something may be wrong with the device. I don't have this box or an LPRO, but if the manafacturer says 24hrs is OK, then I guess that should be enough. You may need to give them a call. However am wondering if you are getting reflected path GPS signals. You said that you had to fiddle with the antenna placement. Are you in an urban jungle? I have a situation where I can see satellites at all times, but once or twice a day I am getting strong reflected signal which is disturbing the GPS 1PPS. It is due to buidings opposite my north facing office where the antenna sits. The issue is seen with my TBOLT, Z3801A and independent Oncore GPS engines all of which are not the latest hardware. That would cause the PLL to be constantly chasing a moving target. I already know by comparison to WWV that I'm within a few mHz of being aligned, but noise in the measurements, human impatience, and wander in the soundcard clock, prevents me knowing any better than this. So already I'm 5e-10. But that's about all I know until I see it lock. (If it ever does...) eh? Dr. David McClain Chief Technical Officer Refined Audiometrics Laboratory 4391 N. Camino Ferreo Tucson, AZ 85750 email: d...@refined-audiometrics.com phone: 1.520.390.3995 web: http://refined-audiometrics.com On Oct 15, 2010, at 16:00, Magnus Danielson wrote: On 10/16/2010 12:08 AM, Bob Camp wrote: Hi It's a crazy world when it comes to self signed certs. You have at least 5 OS's you need to consider (MS, Linux/FBSD, OS-X, I-OS, Android). You need to think about both browsers and mail clients. Each of those come from a half dozen sources on each platform. Then you have configuration options on each. That's a lot of combinations. Each combo seems to have a different idea of what not to do when they see a self signed cert. If you want to be able to handle all of them, even real certs may have issues. There are indeed several common combo's that are a major pain with a self signed cert. No, I didn't write any of the code with the problems in it. I also don't want to get into the details of what and where. This really isn't the forum for that sort of thing. I'm not out to bash any particular solution, only to point out that there are indeed issues. Do handle part of the mess, we have setup our local root cert at the computer club, and then sign our server certs to that. I did a major overhaul on the infrastructure for that. It is still not real safety routines, but ah well. We provide a cert download which quickly solves the cert issue with
Re: [time-nuts] New (refurbished) LPRO-101 GPSDO
Hi The antenna should do fine just sitting on the roof. It will do better sitting over a ground plane. Does the antenna have a clear view of the sky to the south? Bob On Oct 17, 2010, at 10:15 AM, David McClain wrote: Well, not exactly an urban jungle here, but there could be multipath off the neighbor's home... Thanks for that suggestion. I will try moving the antenna about. When I first deployed it, the GPS would go solid reception for a while, and it actually claimed to lock, after only an hour or so. But it kept losing the birds and would go back into hunt mode after about 20 minutes of lock time. I wasn't sure that I could trust the lock indication after so short a time. And I didn't like the sporadic lock conditions. So I tried duct taping the antenna to the roof tiles that I could reach and got solid GPS reception, but no lock. The antenna is a little black hockey puck with a magnetic base. I wonder if it would do better affixed to a metal ground plane? First time user of a GPSDO and so I don't know what to expect. But I'm also beginning to understand better that a GSPDO probably is more than was warranted for the needs of a solid reference oscillator for radios. Now that I'm learning more about Rb and GPSDO's in general, I probably could have got by quite well with just a bare LPRO. And I am also beginning to understand that GPSDO's don't necessarily have internal Rb references -- looks like the T'Bird is just a really good OCXO with a GPS discipline. And everyone is raving about T'Birds... The LPRO has an internal Rb reference and an untamed VCXO. Thanks for all the advice! Dr. David McClain Chief Technical Officer Refined Audiometrics Laboratory 4391 N. Camino Ferreo Tucson, AZ 85750 email: d...@refined-audiometrics.com phone: 1.520.390.3995 web: http://refined-audiometrics.com On Oct 17, 2010, at 06:07, mike cook wrote: Le 17/10/2010 11:55, David McClain a écrit : I just received my LPRO-101 with a GPSDO control on it, from TenMhz.com. After fiddling with getting a good placement for the GPS antenna, so that it doesn't keep losing the satellites, I have been attempting to discipline the oscillator for more than 24 hours. At this point, the LED has been toggling red / green for the past 24 hours which indicates solid GPS acquisition and 5e-8. But it isn't locked to NIST until it turns solid green which indicates 5e-11. Since this is a first deployment at my location, is it reasonable behavior for it to take longer than 24 hours to lock to NIST through GPS? Or do you think something may be wrong with the device. I don't have this box or an LPRO, but if the manafacturer says 24hrs is OK, then I guess that should be enough. You may need to give them a call. However am wondering if you are getting reflected path GPS signals. You said that you had to fiddle with the antenna placement. Are you in an urban jungle? I have a situation where I can see satellites at all times, but once or twice a day I am getting strong reflected signal which is disturbing the GPS 1PPS. It is due to buidings opposite my north facing office where the antenna sits. The issue is seen with my TBOLT, Z3801A and independent Oncore GPS engines all of which are not the latest hardware. That would cause the PLL to be constantly chasing a moving target. I already know by comparison to WWV that I'm within a few mHz of being aligned, but noise in the measurements, human impatience, and wander in the soundcard clock, prevents me knowing any better than this. So already I'm 5e-10. But that's about all I know until I see it lock. (If it ever does...) eh? Dr. David McClain Chief Technical Officer Refined Audiometrics Laboratory 4391 N. Camino Ferreo Tucson, AZ 85750 email: d...@refined-audiometrics.com phone: 1.520.390.3995 web: http://refined-audiometrics.com On Oct 15, 2010, at 16:00, Magnus Danielson wrote: On 10/16/2010 12:08 AM, Bob Camp wrote: Hi It's a crazy world when it comes to self signed certs. You have at least 5 OS's you need to consider (MS, Linux/FBSD, OS-X, I-OS, Android). You need to think about both browsers and mail clients. Each of those come from a half dozen sources on each platform. Then you have configuration options on each. That's a lot of combinations. Each combo seems to have a different idea of what not to do when they see a self signed cert. If you want to be able to handle all of them, even real certs may have issues. There are indeed several common combo's that are a major pain with a self signed cert. No, I didn't write any of the code with the problems in it. I also don't want to get into the details of what and where. This really isn't the forum for that sort of thing. I'm not out to bash any particular solution, only to point out that there are indeed issues. Do handle part of the mess, we have setup our
Re: [time-nuts] New (refurbished) LPRO-101 GPSDO
Also Regards, David Partridge -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Bob Camp Sent: 17 October 2010 16:09 To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] New (refurbished) LPRO-101 GPSDO Hi The antenna should do fine just sitting on the roof. It will do better sitting over a ground plane. Does the antenna have a clear view of the sky to the south? Bob On Oct 17, 2010, at 10:15 AM, David McClain wrote: Well, not exactly an urban jungle here, but there could be multipath off the neighbor's home... Thanks for that suggestion. I will try moving the antenna about. When I first deployed it, the GPS would go solid reception for a while, and it actually claimed to lock, after only an hour or so. But it kept losing the birds and would go back into hunt mode after about 20 minutes of lock time. I wasn't sure that I could trust the lock indication after so short a time. And I didn't like the sporadic lock conditions. So I tried duct taping the antenna to the roof tiles that I could reach and got solid GPS reception, but no lock. The antenna is a little black hockey puck with a magnetic base. I wonder if it would do better affixed to a metal ground plane? First time user of a GPSDO and so I don't know what to expect. But I'm also beginning to understand better that a GSPDO probably is more than was warranted for the needs of a solid reference oscillator for radios. Now that I'm learning more about Rb and GPSDO's in general, I probably could have got by quite well with just a bare LPRO. And I am also beginning to understand that GPSDO's don't necessarily have internal Rb references -- looks like the T'Bird is just a really good OCXO with a GPS discipline. And everyone is raving about T'Birds... The LPRO has an internal Rb reference and an untamed VCXO. Thanks for all the advice! Dr. David McClain Chief Technical Officer Refined Audiometrics Laboratory 4391 N. Camino Ferreo Tucson, AZ 85750 email: d...@refined-audiometrics.com phone: 1.520.390.3995 web: http://refined-audiometrics.com On Oct 17, 2010, at 06:07, mike cook wrote: Le 17/10/2010 11:55, David McClain a écrit : I just received my LPRO-101 with a GPSDO control on it, from TenMhz.com. After fiddling with getting a good placement for the GPS antenna, so that it doesn't keep losing the satellites, I have been attempting to discipline the oscillator for more than 24 hours. At this point, the LED has been toggling red / green for the past 24 hours which indicates solid GPS acquisition and 5e-8. But it isn't locked to NIST until it turns solid green which indicates 5e-11. Since this is a first deployment at my location, is it reasonable behavior for it to take longer than 24 hours to lock to NIST through GPS? Or do you think something may be wrong with the device. I don't have this box or an LPRO, but if the manafacturer says 24hrs is OK, then I guess that should be enough. You may need to give them a call. However am wondering if you are getting reflected path GPS signals. You said that you had to fiddle with the antenna placement. Are you in an urban jungle? I have a situation where I can see satellites at all times, but once or twice a day I am getting strong reflected signal which is disturbing the GPS 1PPS. It is due to buidings opposite my north facing office where the antenna sits. The issue is seen with my TBOLT, Z3801A and independent Oncore GPS engines all of which are not the latest hardware. That would cause the PLL to be constantly chasing a moving target. I already know by comparison to WWV that I'm within a few mHz of being aligned, but noise in the measurements, human impatience, and wander in the soundcard clock, prevents me knowing any better than this. So already I'm 5e-10. But that's about all I know until I see it lock. (If it ever does...) eh? Dr. David McClain Chief Technical Officer Refined Audiometrics Laboratory 4391 N. Camino Ferreo Tucson, AZ 85750 email: d...@refined-audiometrics.com phone: 1.520.390.3995 web: http://refined-audiometrics.com On Oct 15, 2010, at 16:00, Magnus Danielson wrote: On 10/16/2010 12:08 AM, Bob Camp wrote: Hi It's a crazy world when it comes to self signed certs. You have at least 5 OS's you need to consider (MS, Linux/FBSD, OS-X, I-OS, Android). You need to think about both browsers and mail clients. Each of those come from a half dozen sources on each platform. Then you have configuration options on each. That's a lot of combinations. Each combo seems to have a different idea of what not to do when they see a self signed cert. If you want to be able to handle all of them, even real certs may have issues. There are indeed several common combo's that are a major pain with a self signed cert. No, I didn't write
Re: [time-nuts] New (refurbished) LPRO-101 GPSDO
Hi Bob, Well,... sort of... I live in a rather cramped housing development, where the neighbors wall is about 20 feet from my window, and his wall is about 12 feet high. So that seems rather marginal for a southern view from the windowpane of my lab. As it happens, I moved the antenna about 4 feet lower, to a slightly more restricted view of the sky, and the LPRO pretty quickly locked to its best state. Then after fiddling some more with the antenna it must have lost the birds, but still remained in its second-best state. Now after more fiddling, the sats were reacquired and the LPRO is back to its best locked state. What a huge difference this makes. Incidentally, the antenna was originally located about 1 foot from a Comcast coax line running around the house, just below the eaves. I have had no end of frustration with Comcast equipment, and so I wonder if that was the culprit. Right now the antenna is sitting slightly higher for a better view of the south, but careful to keep at least 3-4 feet from the Comcast coax line. Everything is working great at the moment. Very happy camper. Thanks so much for all your input. I'll give the groundplane idea a try with one of my wife's cookie sheets... Cheers, Dr. David McClain Chief Technical Officer Refined Audiometrics Laboratory 4391 N. Camino Ferreo Tucson, AZ 85750 email: d...@refined-audiometrics.com phone: 1.520.390.3995 web: http://refined-audiometrics.com On Oct 17, 2010, at 08:09, Bob Camp wrote: Hi The antenna should do fine just sitting on the roof. It will do better sitting over a ground plane. Does the antenna have a clear view of the sky to the south? Bob On Oct 17, 2010, at 10:15 AM, David McClain wrote: Well, not exactly an urban jungle here, but there could be multipath off the neighbor's home... Thanks for that suggestion. I will try moving the antenna about. When I first deployed it, the GPS would go solid reception for a while, and it actually claimed to lock, after only an hour or so. But it kept losing the birds and would go back into hunt mode after about 20 minutes of lock time. I wasn't sure that I could trust the lock indication after so short a time. And I didn't like the sporadic lock conditions. So I tried duct taping the antenna to the roof tiles that I could reach and got solid GPS reception, but no lock. The antenna is a little black hockey puck with a magnetic base. I wonder if it would do better affixed to a metal ground plane? First time user of a GPSDO and so I don't know what to expect. But I'm also beginning to understand better that a GSPDO probably is more than was warranted for the needs of a solid reference oscillator for radios. Now that I'm learning more about Rb and GPSDO's in general, I probably could have got by quite well with just a bare LPRO. And I am also beginning to understand that GPSDO's don't necessarily have internal Rb references -- looks like the T'Bird is just a really good OCXO with a GPS discipline. And everyone is raving about T'Birds... The LPRO has an internal Rb reference and an untamed VCXO. Thanks for all the advice! Dr. David McClain Chief Technical Officer Refined Audiometrics Laboratory 4391 N. Camino Ferreo Tucson, AZ 85750 email: d...@refined-audiometrics.com phone: 1.520.390.3995 web: http://refined-audiometrics.com On Oct 17, 2010, at 06:07, mike cook wrote: Le 17/10/2010 11:55, David McClain a écrit : I just received my LPRO-101 with a GPSDO control on it, from TenMhz.com. After fiddling with getting a good placement for the GPS antenna, so that it doesn't keep losing the satellites, I have been attempting to discipline the oscillator for more than 24 hours. At this point, the LED has been toggling red / green for the past 24 hours which indicates solid GPS acquisition and 5e-8. But it isn't locked to NIST until it turns solid green which indicates 5e-11. Since this is a first deployment at my location, is it reasonable behavior for it to take longer than 24 hours to lock to NIST through GPS? Or do you think something may be wrong with the device. I don't have this box or an LPRO, but if the manafacturer says 24hrs is OK, then I guess that should be enough. You may need to give them a call. However am wondering if you are getting reflected path GPS signals. You said that you had to fiddle with the antenna placement. Are you in an urban jungle? I have a situation where I can see satellites at all times, but once or twice a day I am getting strong reflected signal which is disturbing the GPS 1PPS. It is due to buidings opposite my north facing office where the antenna sits. The issue is seen with my TBOLT, Z3801A and independent Oncore GPS engines all of which are not the latest hardware. That would cause the PLL to be constantly chasing a moving target. I already know by comparison to WWV that I'm within a few mHz of
[time-nuts] Subject: Neat TCXO
Gents, Ernie said Have a look on ebay.280567398921. quite good TCXO. Great find! Thanks for sharing. If you didn’t know it, Motorola has been in the crystal manufacturing business for over 60 years. They usually just make them for their own products. Their reputation is excellent. If one wants or needs an oven controlled VCXO item number: 270547849874 is an EFRATOM 105243-003 10MHz Crystal Oscillator. This the one that is used in the Lucent GPS and Xtal oscillator units. $10 plus $25 for shipping. Usual Disclaimer Etc. Regards, Perrier ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] New (refurbished) LPRO-101 GPSDO
Hi Depending on your local antenna restrictions, you may or may not be able to put up a proper outdoor antenna. If you can, it's well worth it. They are available for $40 on the e-place. The normal ones mount on the end of a piece of iron pipe, so setting up a mound is normally pretty easy. I just use a flange and screw it into an available chunk of wood on the outside of the house. The mounts I use are rarely more than 18 tall, a little Krylon on the pipe pretty much makes it disappear. Total cost (assuming you don't fall off a ladder) - under $50. Bob On Oct 17, 2010, at 12:32 PM, David McClain wrote: Hi Bob, Well,... sort of... I live in a rather cramped housing development, where the neighbors wall is about 20 feet from my window, and his wall is about 12 feet high. So that seems rather marginal for a southern view from the windowpane of my lab. As it happens, I moved the antenna about 4 feet lower, to a slightly more restricted view of the sky, and the LPRO pretty quickly locked to its best state. Then after fiddling some more with the antenna it must have lost the birds, but still remained in its second-best state. Now after more fiddling, the sats were reacquired and the LPRO is back to its best locked state. What a huge difference this makes. Incidentally, the antenna was originally located about 1 foot from a Comcast coax line running around the house, just below the eaves. I have had no end of frustration with Comcast equipment, and so I wonder if that was the culprit. Right now the antenna is sitting slightly higher for a better view of the south, but careful to keep at least 3-4 feet from the Comcast coax line. Everything is working great at the moment. Very happy camper. Thanks so much for all your input. I'll give the groundplane idea a try with one of my wife's cookie sheets... Cheers, Dr. David McClain Chief Technical Officer Refined Audiometrics Laboratory 4391 N. Camino Ferreo Tucson, AZ 85750 email: d...@refined-audiometrics.com phone: 1.520.390.3995 web: http://refined-audiometrics.com On Oct 17, 2010, at 08:09, Bob Camp wrote: Hi The antenna should do fine just sitting on the roof. It will do better sitting over a ground plane. Does the antenna have a clear view of the sky to the south? Bob On Oct 17, 2010, at 10:15 AM, David McClain wrote: Well, not exactly an urban jungle here, but there could be multipath off the neighbor's home... Thanks for that suggestion. I will try moving the antenna about. When I first deployed it, the GPS would go solid reception for a while, and it actually claimed to lock, after only an hour or so. But it kept losing the birds and would go back into hunt mode after about 20 minutes of lock time. I wasn't sure that I could trust the lock indication after so short a time. And I didn't like the sporadic lock conditions. So I tried duct taping the antenna to the roof tiles that I could reach and got solid GPS reception, but no lock. The antenna is a little black hockey puck with a magnetic base. I wonder if it would do better affixed to a metal ground plane? First time user of a GPSDO and so I don't know what to expect. But I'm also beginning to understand better that a GSPDO probably is more than was warranted for the needs of a solid reference oscillator for radios. Now that I'm learning more about Rb and GPSDO's in general, I probably could have got by quite well with just a bare LPRO. And I am also beginning to understand that GPSDO's don't necessarily have internal Rb references -- looks like the T'Bird is just a really good OCXO with a GPS discipline. And everyone is raving about T'Birds... The LPRO has an internal Rb reference and an untamed VCXO. Thanks for all the advice! Dr. David McClain Chief Technical Officer Refined Audiometrics Laboratory 4391 N. Camino Ferreo Tucson, AZ 85750 email: d...@refined-audiometrics.com phone: 1.520.390.3995 web: http://refined-audiometrics.com On Oct 17, 2010, at 06:07, mike cook wrote: Le 17/10/2010 11:55, David McClain a écrit : I just received my LPRO-101 with a GPSDO control on it, from TenMhz.com. After fiddling with getting a good placement for the GPS antenna, so that it doesn't keep losing the satellites, I have been attempting to discipline the oscillator for more than 24 hours. At this point, the LED has been toggling red / green for the past 24 hours which indicates solid GPS acquisition and 5e-8. But it isn't locked to NIST until it turns solid green which indicates 5e-11. Since this is a first deployment at my location, is it reasonable behavior for it to take longer than 24 hours to lock to NIST through GPS? Or do you think something may be wrong with the device. I don't have this box or an LPRO, but if the manafacturer says 24hrs is OK, then I guess that should be enough. You may need to give them a
Re: [time-nuts] Subject: Neat TCXO
Hi To be a bit more precise: Motorola set up the US crystal industry as we know it today during WWII. Up until the 1960's they bought rather than built the vast majority of their crystals. By the 1970's they were making more precision TCXO's than anybody else anywhere. That all has changed quite a bit. For the most part they got out of the crystal business in the 1990's. Part of their operation became Champion and another part spun off to CTS. Bob On Oct 17, 2010, at 4:17 PM, Perry Sandeen wrote: Gents, Ernie said Have a look on ebay.280567398921. quite good TCXO. Great find! Thanks for sharing. If you didn’t know it, Motorola has been in the crystal manufacturing business for over 60 years. They usually just make them for their own products. Their reputation is excellent. If one wants or needs an oven controlled VCXO item number: 270547849874 is an EFRATOM 105243-003 10MHz Crystal Oscillator. This the one that is used in the Lucent GPS and Xtal oscillator units. $10 plus $25 for shipping. Usual Disclaimer Etc. Regards, Perrier ___ time-nuts mailing 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] Neat TCXO
I'll see your OCXO, and raise you a DOCXO. Ebay item 180401766962. These things are amazingly stable over time. I install them in Tek DC5010 counters. They can hold to the last digit for over a year. ___ time-nuts mailing 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] Subject: Neat TCXO
There's another efratom for $20 free shipping. The $25 shipping is for UPS, HK post is considerably cheaper. Lots of the ocxo's in the 20-50 buck range could be opened up carefully, and the oven control pot or adjustment voltage brought out for remote control. Might be fun, except there are currently a bunch of HP ocxo's around $125. Don Perry Sandeen Gents, Ernie said Have a look on ebay.280567398921. quite good TCXO. Great find! Thanks for sharing. If you didnât know it, Motorola has been in the crystal manufacturing business for over 60 years. They usually just make them for their own products. Their reputation is excellent. If one wants or needs an oven controlled VCXO item number: 270547849874 is an EFRATOM 105243-003 10MHz Crystal Oscillator. This the one that is used in the Lucent GPS and Xtal oscillator units. $10 plus $25 for shipping. Usual Disclaimer Etc. Regards, Perrier ___ time-nuts mailing 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 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.
Re: [time-nuts] Febo.com SSL certificate expired
I used these guys for $9: http://www.cheapssls.com/comodo-ssl-certificates/positivessl.html It was worth it to not have to walk people through accepting a self-signed cert. On 10/15/2010 2:36 AM, David C. Partridge wrote: Subject says all Dave ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. -- mailto:o...@ozindfw.net Oz POB 93167 Southlake, TX 76092 (Near DFW Airport) ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
