[time-nuts] Galileo service currently degraded
It seems to more than a little "degradation". My F9T is seeing and tracking Galileo sats, but is not using the results for navigation... Lady Heather shows all Galileo sats in yellow. Selecting Galileo only, the receiver reports it is attempting to acquire satellites and not producing a navigation solution. Any reports of what kind of screw-up borked the whole Galileo system? ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Galileo service currently degraded
Looking at the data it seems that GPS is the best system among the four, correct? Luciano Da "time-nuts" time-nuts-boun...@lists.febo.com A "Discussion of precise time and frequency measurement" time-nuts@lists.febo.com Cc Data Fri, 12 Jul 2019 18:29:10 -0400 Oggetto Re: [time-nuts] Galileo service currently degraded I built this website as my senior design project last year, unfortunately there's no timing data (except for tdop) being logged but you can see the impact. Data is collected with four ublox m8n receivers, one per constellation. Galileo data from last 1 week: https://gnssperformancemonitor.com/viewdata.php?constellation=2×pan=1 Kevin On Fri, Jul 12, 2019, 4:06 PM Hal Murray wrote: > > > > Galileo service is currently degraded, see: https://www.gsc-europa.eu/ > > notice-advisory-to-galileo-users-nagu-2019025 > > Thanks. > > Is anybody monitoring a Galileo-only setup to see how far off the timing > drifts? > > > -- > These are my opinions. I hate spam. > > > > > ___ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. > ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] High accuracy temp controller ckt
Hi Ok, if it’s a “heat only” design, how about a dewar flask? They aren’t the most rugged items out there so some sort of padded enclosure would be needed. The real question is: Does a “single end” design impact your ability to use the resistor? Put another way - do you need to hit both ends of the device more or less directly? There are a variety of eBay sellers that will set you up with parts in a variety of shapes and sizes. As far as I can see, their designs would be reasonable for what you are trying to do. Back a while, the dewar was the enclosure of choice for a high grade OCXO. As people learned how to do ovens a bit better and the world decided they needed smaller parts, that approach fell by the wayside. It’s still a great way to get a reasonable oven that pulls pretty low power. Bob > On Jul 12, 2019, at 7:45 PM, Dr. David Kirkby > wrote: > > On Fri, 12 Jul 2019 at 22:02, Hal Murray wrote: > >> >> drkir...@kirkbymicrowave.co.uk said: >>> If it could run from a few NiMH cells for 48 hours, that would give the >>> option of shipping it. I don't know if that's going over the top, but it >>> would be an interesting exercise. >> >> Shipping a TEC cooler could get interesting. You need to get rid of the >> heat >> somehow. Cooling fins on a package would be interesting. > > > That is why I said that I would avoid a TEC. Running an oven should be less > problematic. > >> >> >> The airlines don't like dry ice. You could try an ice pack/gel. If it's >> well >> insulated, the TEC will be off. The heater won't take much power. It's >> just >> a matter of how much insulation you need. > > > I would not aim to ship by air, although at a push that might be possible. > > In the UK, in theory items can be shipped with batteries by Royal Mail > subject to some restrictions. Batteries inside equipment are okay up to > some capacity. Damaged cells or lose cells are not. In practice a lot of > staff in post office shops say no to batteries. > > I regularly get alkaline and NiMH batteries delivered from Farnel by UPS. > The packages are not marked. In contrast, even a coil cell comes in a box > saying it is batteries, not in transport if the package is damaged etc. So > Farnell follow all the rules. > > I contacted DHL once about a UK shipment of a battery powered item. That > was not a problem. > > If the box was much bigger than an OCXO, resistor oven, I don’t believe > heat would be a problem. > >> >> >> What's the hysteresis on a resistor? Is it really important to ship it >> powered up? > > > That I don’t know, but sometimes one does things as a challenge out of > interest, and to learn. It would be interesting to know if a resistor was > worth shipping powered up. > > Dave. > -- > Dr. David Kirkby, > ___ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] High accuracy temp controller ckt
On Fri, 12 Jul 2019 at 22:02, Hal Murray wrote: > > drkir...@kirkbymicrowave.co.uk said: > > If it could run from a few NiMH cells for 48 hours, that would give the > > option of shipping it. I don't know if that's going over the top, but it > > would be an interesting exercise. > > Shipping a TEC cooler could get interesting. You need to get rid of the > heat > somehow. Cooling fins on a package would be interesting. That is why I said that I would avoid a TEC. Running an oven should be less problematic. > > > The airlines don't like dry ice. You could try an ice pack/gel. If it's > well > insulated, the TEC will be off. The heater won't take much power. It's > just > a matter of how much insulation you need. I would not aim to ship by air, although at a push that might be possible. In the UK, in theory items can be shipped with batteries by Royal Mail subject to some restrictions. Batteries inside equipment are okay up to some capacity. Damaged cells or lose cells are not. In practice a lot of staff in post office shops say no to batteries. I regularly get alkaline and NiMH batteries delivered from Farnel by UPS. The packages are not marked. In contrast, even a coil cell comes in a box saying it is batteries, not in transport if the package is damaged etc. So Farnell follow all the rules. I contacted DHL once about a UK shipment of a battery powered item. That was not a problem. If the box was much bigger than an OCXO, resistor oven, I don’t believe heat would be a problem. > > > What's the hysteresis on a resistor? Is it really important to ship it > powered up? That I don’t know, but sometimes one does things as a challenge out of interest, and to learn. It would be interesting to know if a resistor was worth shipping powered up. Dave. -- Dr. David Kirkby, ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] High accuracy temp controller ckt
Hi The “thermoelectrc chamber” in that paper *is* the gizmo. There is / was a better paper diving into the unit in a bit more detail. Even that did not get down to issues like the controller, the driver, or the power consumption. Indeed one wonders if there is a giant heatsink and fan on the bottom of the unit ….. again, no real information. Bob > On Jul 12, 2019, at 7:11 PM, Bruce Griffiths > wrote: > > Figure 5 in http://www.wenzel.com/wp-content/uploads/Sub-pico-Multiplier.pdf > ?? > Bruce >> On 13 July 2019 at 05:23 Bob kb8tq wrote: >> >> >> Hi >> >> If you do go the TEC route, plan on a fairly big power source :). There is a >> Wenzel doc on doing a TEC based enclosure using a couple of die cast >> boxes. The pictures don’t show what they used to drive the beast so part of >> it would still be up to you. My search skills and their web site are not >> quite >> compatible so no link …. sorry !!! >> >> Bob >> >>> On Jul 12, 2019, at 12:12 PM, Javier Herrero wrote: >>> >>> Hello, >>> >>> A TEC is good if you want to maintain the resistors at 25ºC, that seems the >>> zero TC point for some precision low TCR resistors (for example, the Vishay >>> VFCP or VSMP series) >>> >>> Regards, >>> >>> Javier >>> >>> On 12/7/19 10:06, Dr. David Kirkby wrote: On Fri, 12 Jul 2019 at 08:07, Bernd Neubig wrote: > AXTAL has a miniature oven for heating precision resistors or other > components to a constant temperature. It is housed in a small DIP8 > package. > See attached AXR135 data sheet. > Optionally this device can be offered unsealed, ready for inserting the > component by yourself > > Regards > Bernd The resistors I am using are made by Caddock, are 1 M ohm & 10 M ohm, 0.01% tolerance and 5 ppm / deg C. They are much too large to fit in a DIP8 package. A quick check with a ruler indicates that the 10 M ohm is 38 x 12 mm and the 1 M ohm is 19 x 10 mm. A quick photograph shows this half finished project. Unfortunately, even before I have finished it, I am wishing I had done a better job. However, my original reason for doing this was to check the stability of a data acquisition unit before sending it to Keysight. I think this will be good enough for that, but I could certainly have done a job with some thought. The thermocouple is just meant to be a temperature sensor that dissipates no power. A thermistor or RTD buried in the polystyrene would have just got hot. The resistors should not get hot, as the power dissipated will be under 1 uW. I also intend putting in a 100 M ohm resistor, but the specification of that is much poorer (5%, 100 ppm/ deg C. ) I partially read the paper mentioned. I note that the authors used a thermo electric cooler (TEC) as they wanted get low temperatures. I assume that for crystals or resistors dissipating little heat, a TEC would be unnecessary, and just a resistor acting as a heater would be fine. But will read some of the references. Obviously for controlling a crystal oscillator, or my resistor, stability is most important, whereas for the authors of the paper, stability was not their major concern. > -- Dr. David Kirkby, ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there. >>> >>> -- >>> - >>> Javier Herrero >>> Chief Technology Officer EMAIL: >>> jherr...@hvsistemas.com >>> HV Sistemas S.L. PHONE: +34 949 >>> 336 806 >>> Teide 4, Núcleo 1 Of. 0.1 FAX: +34 949 >>> 336 792 >>> 28703 San Sebastián de los Reyes - Madrid - Spain WEB: >>> http://www.hvsistemas.com >>> >>> ___ >>> time-nuts mailing list -- time-nuts@lists.febo.com >>> To unsubscribe, go to >>> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com >>> and follow the instructions there. >> >> >> ___ >> time-nuts mailing list -- time-nuts@lists.febo.com >> To unsubscribe, go to >> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com >> and follow the instructions there. > > ___ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the
Re: [time-nuts] High accuracy temp controller ckt
Figure 5 in http://www.wenzel.com/wp-content/uploads/Sub-pico-Multiplier.pdf ?? Bruce > On 13 July 2019 at 05:23 Bob kb8tq wrote: > > > Hi > > If you do go the TEC route, plan on a fairly big power source :). There is a > Wenzel doc on doing a TEC based enclosure using a couple of die cast > boxes. The pictures don’t show what they used to drive the beast so part of > it would still be up to you. My search skills and their web site are not quite > compatible so no link …. sorry !!! > > Bob > > > On Jul 12, 2019, at 12:12 PM, Javier Herrero wrote: > > > > Hello, > > > > A TEC is good if you want to maintain the resistors at 25ºC, that seems the > > zero TC point for some precision low TCR resistors (for example, the Vishay > > VFCP or VSMP series) > > > > Regards, > > > > Javier > > > > On 12/7/19 10:06, Dr. David Kirkby wrote: > >> On Fri, 12 Jul 2019 at 08:07, Bernd Neubig wrote: > >> > >>> AXTAL has a miniature oven for heating precision resistors or other > >>> components to a constant temperature. It is housed in a small DIP8 > >>> package. > >>> See attached AXR135 data sheet. > >>> Optionally this device can be offered unsealed, ready for inserting the > >>> component by yourself > >>> > >>> Regards > >>> Bernd > >> > >> The resistors I am using are made by Caddock, are 1 M ohm & 10 M ohm, 0.01% > >> tolerance and 5 ppm / deg C. They are much too large to fit in a DIP8 > >> package. A quick check with a ruler indicates that the 10 M ohm is 38 x 12 > >> mm and the 1 M ohm is 19 x 10 mm. > >> > >> A quick photograph shows this half finished project. Unfortunately, even > >> before I have finished it, I am wishing I had done a better job. However, > >> my original reason for doing this was to check the stability of a data > >> acquisition unit before sending it to Keysight. I think this will be good > >> enough for that, but I could certainly have done a job with some thought. > >> > >> The thermocouple is just meant to be a temperature sensor that dissipates > >> no power. A thermistor or RTD buried in the polystyrene would have just got > >> hot. The resistors should not get hot, as the power dissipated will be > >> under 1 uW. > >> > >> I also intend putting in a 100 M ohm resistor, but the specification of > >> that is much poorer (5%, 100 ppm/ deg C. ) > >> > >> I partially read the paper mentioned. I note that the authors used a thermo > >> electric cooler (TEC) as they wanted get low temperatures. I assume that > >> for crystals or resistors dissipating little heat, a TEC would be > >> unnecessary, and just a resistor acting as a heater would be fine. But will > >> read some of the references. Obviously for controlling a crystal > >> oscillator, or my resistor, stability is most important, whereas for the > >> authors of the paper, stability was not their major concern. > >> > >>> -- > >> Dr. David Kirkby, > >> > >> ___ > >> time-nuts mailing list -- time-nuts@lists.febo.com > >> To unsubscribe, go to > >> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > >> and follow the instructions there. > > > > -- > > - > > Javier Herrero > > Chief Technology Officer EMAIL: > > jherr...@hvsistemas.com > > HV Sistemas S.L. PHONE: +34 949 > > 336 806 > > Teide 4, Núcleo 1 Of. 0.1 FAX: +34 949 > > 336 792 > > 28703 San Sebastián de los Reyes - Madrid - Spain WEB: > > http://www.hvsistemas.com > > > > ___ > > time-nuts mailing list -- time-nuts@lists.febo.com > > To unsubscribe, go to > > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > > and follow the instructions there. > > > ___ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Galileo service currently degraded
I built this website as my senior design project last year, unfortunately there's no timing data (except for tdop) being logged but you can see the impact. Data is collected with four ublox m8n receivers, one per constellation. Galileo data from last 1 week: https://gnssperformancemonitor.com/viewdata.php?constellation=2=1 Kevin On Fri, Jul 12, 2019, 4:06 PM Hal Murray wrote: > > > > Galileo service is currently degraded, see: https://www.gsc-europa.eu/ > > notice-advisory-to-galileo-users-nagu-2019025 > > Thanks. > > Is anybody monitoring a Galileo-only setup to see how far off the timing > drifts? > > > -- > These are my opinions. I hate spam. > > > > > ___ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. > ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] High accuracy temp controller ckt
Hi Airlines tend to have issues with various battery types as well. Not clear what the rules are on “powered up in the hold” are. My guess is that ground transportation gets the nod pretty quickly. TEC’s are good for some limited temperature delta and then you need to go to cascaded “layers” of them. In cascade, the power requirements just go up and up. If your shipping container could be on a hot runway / parking lot or in an un-heated hold at 40,000 feet ….. the design could get really “interesting”. A whole other set of questions might reasonably be asked about pressure, humidity, shock and vibration. No idea about the answers on a precision resistor. On other devices they certainly *do* pop up. One traditional answer for things like running Cs standards was to have a “minder” (or two or three) accompany the device on it’s trip to the destination lab. It traveled as close to them as practical ( = in the passenger compartment) to minimize the issues. That also made hooking it to power while in transit a bit easier. Even with that level of pampering, the story seems to be that the trip was not always successful. Bob > On Jul 12, 2019, at 4:38 PM, Hal Murray wrote: > > > drkir...@kirkbymicrowave.co.uk said: >>> If you do go the TEC route, plan on a fairly big power source :). >> I'm particularly keen to avoid the requirement for high power, as I was >> thinking to make this in such a way it can be shipped and powered up all the >> time. If it could run from a few NiMH cells for 48 hours, that would give the >> option of shipping it. I don't know if that's going over the top, but it >> would be an interesting exercise. > > Shipping a TEC cooler could get interesting. You need to get rid of the heat > somehow. Cooling fins on a package would be interesting. > > The airlines don't like dry ice. You could try an ice pack/gel. If it's > well > insulated, the TEC will be off. The heater won't take much power. It's just > a matter of how much insulation you need. > > What's the hysteresis on a resistor? Is it really important to ship it > powered up? > > > -- > These are my opinions. I hate spam. > > > > > ___ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] High accuracy temp controller ckt
And if you are not in a well air conditioned room Gilles. Envoyé de mon iPad > Le 12 juil. 2019 à 18:12, Javier Herrero a écrit : > > Hello, > > A TEC is good if you want to maintain the resistors at 25ºC, that seems the > zero TC point for some precision low TCR resistors (for example, the Vishay > VFCP or VSMP series) > > Regards, > > Javier > >> On 12/7/19 10:06, Dr. David Kirkby wrote: >>> On Fri, 12 Jul 2019 at 08:07, Bernd Neubig wrote: >>> >>> AXTAL has a miniature oven for heating precision resistors or other >>> components to a constant temperature. It is housed in a small DIP8 package. >>> See attached AXR135 data sheet. >>> Optionally this device can be offered unsealed, ready for inserting the >>> component by yourself >>> >>> Regards >>> Bernd >> >> The resistors I am using are made by Caddock, are 1 M ohm & 10 M ohm, 0.01% >> tolerance and 5 ppm / deg C. They are much too large to fit in a DIP8 >> package. A quick check with a ruler indicates that the 10 M ohm is 38 x 12 >> mm and the 1 M ohm is 19 x 10 mm. >> >> A quick photograph shows this half finished project. Unfortunately, even >> before I have finished it, I am wishing I had done a better job. However, >> my original reason for doing this was to check the stability of a data >> acquisition unit before sending it to Keysight. I think this will be good >> enough for that, but I could certainly have done a job with some thought. >> >> The thermocouple is just meant to be a temperature sensor that dissipates >> no power. A thermistor or RTD buried in the polystyrene would have just got >> hot. The resistors should not get hot, as the power dissipated will be >> under 1 uW. >> >> I also intend putting in a 100 M ohm resistor, but the specification of >> that is much poorer (5%, 100 ppm/ deg C. ) >> >> I partially read the paper mentioned. I note that the authors used a thermo >> electric cooler (TEC) as they wanted get low temperatures. I assume that >> for crystals or resistors dissipating little heat, a TEC would be >> unnecessary, and just a resistor acting as a heater would be fine. But will >> read some of the references. Obviously for controlling a crystal >> oscillator, or my resistor, stability is most important, whereas for the >> authors of the paper, stability was not their major concern. >> >>> -- >> Dr. David Kirkby, >> >> ___ >> time-nuts mailing list -- time-nuts@lists.febo.com >> To unsubscribe, go to >> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com >> and follow the instructions there. > > -- > - > Javier Herrero > Chief Technology Officer EMAIL: > jherr...@hvsistemas.com > HV Sistemas S.L. PHONE: +34 949 336 > 806 > Teide 4, Núcleo 1 Of. 0.1 FAX: +34 949 336 > 792 > 28703 San Sebastián de los Reyes - Madrid - Spain WEB: > http://www.hvsistemas.com > > ___ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] High accuracy temp controller ckt
drkir...@kirkbymicrowave.co.uk said: >> If you do go the TEC route, plan on a fairly big power source :). > I'm particularly keen to avoid the requirement for high power, as I was > thinking to make this in such a way it can be shipped and powered up all the > time. If it could run from a few NiMH cells for 48 hours, that would give the > option of shipping it. I don't know if that's going over the top, but it > would be an interesting exercise. Shipping a TEC cooler could get interesting. You need to get rid of the heat somehow. Cooling fins on a package would be interesting. The airlines don't like dry ice. You could try an ice pack/gel. If it's well insulated, the TEC will be off. The heater won't take much power. It's just a matter of how much insulation you need. What's the hysteresis on a resistor? Is it really important to ship it powered up? -- These are my opinions. I hate spam. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Galileo service currently degraded
> Galileo service is currently degraded, see: https://www.gsc-europa.eu/ > notice-advisory-to-galileo-users-nagu-2019025 Thanks. Is anybody monitoring a Galileo-only setup to see how far off the timing drifts? -- These are my opinions. I hate spam. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] High accuracy temp controller ckt
On Fri, 12 Jul 2019 at 20:02, Bob kb8tq wrote: > Hi > If you do go the TEC route, plan on a fairly big power source :). There is > a > Wenzel doc on doing a TEC based enclosure using a couple of die cast > boxes. The pictures don’t show what they used to drive the beast so part > of > it would still be up to you. My search skills and their web site are not > quite > compatible so no link …. sorry !!! > I'm particularly keen to avoid the requirement for high power, as I was thinking to make this in such a way it can be shipped and powered up all the time. If it could run from a few NiMH cells for 48 hours, that would give the option of shipping it. I don't know if that's going over the top, but it would be an interesting exercise. -- Dr David Kirkby Ph.D C.Eng MIET Kirkby Microwave Ltd Registered office: Stokes Hall Lodge, Burnham Rd, Althorne, CHELMSFORD, Essex, CM3 6DT, United Kingdom. Registered in England and Wales as company number 08914892 https://www.kirkbymicrowave.co.uk/ Tel 01621-680100 / +44 1621-680100 ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] High accuracy temp controller ckt
Hi If you do go the TEC route, plan on a fairly big power source :). There is a Wenzel doc on doing a TEC based enclosure using a couple of die cast boxes. The pictures don’t show what they used to drive the beast so part of it would still be up to you. My search skills and their web site are not quite compatible so no link …. sorry !!! Bob > On Jul 12, 2019, at 12:12 PM, Javier Herrero wrote: > > Hello, > > A TEC is good if you want to maintain the resistors at 25ºC, that seems the > zero TC point for some precision low TCR resistors (for example, the Vishay > VFCP or VSMP series) > > Regards, > > Javier > > On 12/7/19 10:06, Dr. David Kirkby wrote: >> On Fri, 12 Jul 2019 at 08:07, Bernd Neubig wrote: >> >>> AXTAL has a miniature oven for heating precision resistors or other >>> components to a constant temperature. It is housed in a small DIP8 package. >>> See attached AXR135 data sheet. >>> Optionally this device can be offered unsealed, ready for inserting the >>> component by yourself >>> >>> Regards >>> Bernd >> >> The resistors I am using are made by Caddock, are 1 M ohm & 10 M ohm, 0.01% >> tolerance and 5 ppm / deg C. They are much too large to fit in a DIP8 >> package. A quick check with a ruler indicates that the 10 M ohm is 38 x 12 >> mm and the 1 M ohm is 19 x 10 mm. >> >> A quick photograph shows this half finished project. Unfortunately, even >> before I have finished it, I am wishing I had done a better job. However, >> my original reason for doing this was to check the stability of a data >> acquisition unit before sending it to Keysight. I think this will be good >> enough for that, but I could certainly have done a job with some thought. >> >> The thermocouple is just meant to be a temperature sensor that dissipates >> no power. A thermistor or RTD buried in the polystyrene would have just got >> hot. The resistors should not get hot, as the power dissipated will be >> under 1 uW. >> >> I also intend putting in a 100 M ohm resistor, but the specification of >> that is much poorer (5%, 100 ppm/ deg C. ) >> >> I partially read the paper mentioned. I note that the authors used a thermo >> electric cooler (TEC) as they wanted get low temperatures. I assume that >> for crystals or resistors dissipating little heat, a TEC would be >> unnecessary, and just a resistor acting as a heater would be fine. But will >> read some of the references. Obviously for controlling a crystal >> oscillator, or my resistor, stability is most important, whereas for the >> authors of the paper, stability was not their major concern. >> >>> -- >> Dr. David Kirkby, >> >> ___ >> time-nuts mailing list -- time-nuts@lists.febo.com >> To unsubscribe, go to >> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com >> and follow the instructions there. > > -- > - > Javier Herrero > Chief Technology Officer EMAIL: > jherr...@hvsistemas.com > HV Sistemas S.L. PHONE: +34 949 336 > 806 > Teide 4, Núcleo 1 Of. 0.1 FAX: +34 949 336 > 792 > 28703 San Sebastián de los Reyes - Madrid - Spain WEB: > http://www.hvsistemas.com > > ___ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] High accuracy temp controller ckt
Hello, A TEC is good if you want to maintain the resistors at 25ºC, that seems the zero TC point for some precision low TCR resistors (for example, the Vishay VFCP or VSMP series) Regards, Javier On 12/7/19 10:06, Dr. David Kirkby wrote: On Fri, 12 Jul 2019 at 08:07, Bernd Neubig wrote: AXTAL has a miniature oven for heating precision resistors or other components to a constant temperature. It is housed in a small DIP8 package. See attached AXR135 data sheet. Optionally this device can be offered unsealed, ready for inserting the component by yourself Regards Bernd The resistors I am using are made by Caddock, are 1 M ohm & 10 M ohm, 0.01% tolerance and 5 ppm / deg C. They are much too large to fit in a DIP8 package. A quick check with a ruler indicates that the 10 M ohm is 38 x 12 mm and the 1 M ohm is 19 x 10 mm. A quick photograph shows this half finished project. Unfortunately, even before I have finished it, I am wishing I had done a better job. However, my original reason for doing this was to check the stability of a data acquisition unit before sending it to Keysight. I think this will be good enough for that, but I could certainly have done a job with some thought. The thermocouple is just meant to be a temperature sensor that dissipates no power. A thermistor or RTD buried in the polystyrene would have just got hot. The resistors should not get hot, as the power dissipated will be under 1 uW. I also intend putting in a 100 M ohm resistor, but the specification of that is much poorer (5%, 100 ppm/ deg C. ) I partially read the paper mentioned. I note that the authors used a thermo electric cooler (TEC) as they wanted get low temperatures. I assume that for crystals or resistors dissipating little heat, a TEC would be unnecessary, and just a resistor acting as a heater would be fine. But will read some of the references. Obviously for controlling a crystal oscillator, or my resistor, stability is most important, whereas for the authors of the paper, stability was not their major concern. -- Dr. David Kirkby, ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there. -- - Javier Herrero Chief Technology Officer EMAIL: jherr...@hvsistemas.com HV Sistemas S.L. PHONE: +34 949 336 806 Teide 4, Núcleo 1 Of. 0.1 FAX: +34 949 336 792 28703 San Sebastián de los Reyes - Madrid - Spain WEB: http://www.hvsistemas.com ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] time-nuts Digest, Vol 180, Issue 22
Hi Here’s the gotcha with what they are talking about. The SC when done as a *fundamental* crystal has a higher Q than the AT. You don’t use fundamental mode SC’s in a normal OCXO. The issue with Q relates very specifically to the sort of HC-40 package AT resonators you *would* use for maximum Q in a 5 or 10 MHz OCXO. Practical package size for the resonators is as much a part of it as anything else. ( = that’s about as big a package as anybody is tooled to do an OCXO crystal in ) Bob > On Jul 12, 2019, at 4:24 AM, Leo Bodnar wrote: > > From: Bob kb8tq > - high-Q crystals require SC-cut ... An SC has a lower Q than an AT of similar size and design up to the point acoustic Q losses completely take over. If you are talking about sub 20 MHz OCXO?s with ?doable? crystal package sizes, the AT will have the higher Q by a significant margin. >>> >>> Could you please back up this claim with verifiable facts? >> >> Order up a few 5 MHz 3rd overtones in HC-40 packages and see what you get. >> You also could send in an RFQ for a batch of each to any of the people who >> make them >> and see what comes back. >> Bob > > Here is a random selection of links to back my point of view that, if you > have noticed, contradicts Bob's. > If anybody is interested they will find information themselves without much > effort. I suggest printed books if you don't trust Internet at large. > > http://www.crovencrystals.com/croven_pdf/Old%20Spec%20Sheets/croven_catalogue.pdf > (Croven Crystals is Wenzel company) > The main advantages of these resonators, and in particular the SC-cut type > are: > higher Q-factor (typically 10 - 15% better than equivalent AT-cut resonators) > > https://www.tfc.co.uk/pdfs/SC_cut_crystals_article_TFC.pdf > SC cut family of quartz crystals: > Other key characteristics include Higher Q factor > > https://www.rfwireless-world.com/Terminology/AT-cut-vs-SC-cut-quartz-crystal.html > Specification:Q factor > AT cut: lower > SC cut: higher (it will achieve low phase noise) > > http://members.femto-st.fr/sites/femto-st.fr.patrice-salzenstein/files/content/Peer-review-journal/smdo160017.pdf > SC-cut > It has faster higher Q, warm-up speed and better phase noise close to the > carrier. > > http://www.resonal.com/Downloads/John%20R.%20Vig%20-%20tutorial%20on%20Quartz%20Crystals%20and%20Oscillators.pdf > Advantages of the SC-cut: > Higher Q for fundamental mode resonators of similar geometry > > http://www.mtronpti.com/sites/default/files/files/crystal-resonator-terminology.pdf > A typical 10 MHz, 3rdovertone SC may have a Q of 1.0 to 1.3 million; > a 100 MHz, 5th overtone AT may have a Q of 80 to 100 thousand, > while a 100 MHz AT fundamental would be much lower, in the range of 20 to 50 > thousand. > > https://www.eetimes.com/document.asp?doc_id=1290592# (MptronPTI) > Since SC-cuts have a much higher Q-factor than AT-cuts, SC-based OCXOs offer > better noise performance from 1-Hz offset to 1,000-Hz offset. > > Worryingly, I have started receiving unpleasant personal emails from list > members suggesting that I do not question factual correctness of other's > opinions. > This will explain why I am going off the list for the sake of everyone's good. > > Leo Bodnar > ___ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] time-nuts Digest, Vol 180, Issue 22
The HP Journal article (page 20 March 1981 issue) on the 10811A agrees with Bob. It also points out that the lack of activity dips due to coupled modes and a much smaller dependence of the frequency on the signal level are advantages of the SC cut compared to the AT and BT cuts. Bruce > On 13 July 2019 at 00:06 Poul-Henning Kamp wrote: > > > > In message <2573d544-e3c9-4810-95c9-9e3a468ed...@leobodnar.com>, Leo Bodnar > wri > tes: > > >Here is a random selection of links to back my point of view that, > >if you have noticed, contradicts Bob's. > > Given that quartz resonators is still both science and art, I put > my money on the guy who spent a whole career on quartz resonators > over the guy who just walked out of the library :-) > > -- > 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@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] time-nuts Digest, Vol 180, Issue 22
In message <2573d544-e3c9-4810-95c9-9e3a468ed...@leobodnar.com>, Leo Bodnar wri tes: >Here is a random selection of links to back my point of view that, >if you have noticed, contradicts Bob's. Given that quartz resonators is still both science and art, I put my money on the guy who spent a whole career on quartz resonators over the guy who just walked out of the library :-) -- 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@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] High accuracy temp controller ckt
In message , "Dr. David Kirkby" writes: >I partially read the paper mentioned. I note that the authors used a thermo >electric cooler (TEC) as they wanted get low temperatures. Cooling GigaOhm resistors makes sense, Johnson/Nyquist noise is proportional to the product of absolute temperature and resistance. -- 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@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Galileo service currently degraded
Galileo service is currently degraded, see: https://www.gsc-europa.eu/notice-advisory-to-galileo-users-nagu-2019025 Martin ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Thunderbolt E
Hi John, That repair cost is enough to steer me away from buying one. I have a mediocre view of the sky with my current antenna setup. I'll continue on and research some additional possibilities for a GPSDO unit. Thanks for sharing your experience with the Thunderbolt E unit. Chris On 07/12/19 04:00:39, Jon “KF5TFJ” Noxon wrote: Chris, i have one which I bought new several years ago. It had a failure under warranty where in the serial chip stopped doing its thing. The unit continued to lock to SVs and delivered 10MHz and the PPS. Took almost two months to be returned, where it worked fine until very recently. Same issue with the serial chip. Trimble quoted a price of $650 for repairs. Ouch. As they say "Other than that Mrs Lincoln, how did you enjoy the play...”, it played fine as long as you could talk to it. Antenna location is very important as is true for all timing GPS units. The fit is supplied with a good length of 75 Ohn coax, power supply, antenna, and some coas adapters. So the question is how much do you intend to spend? Lady Heather works great when the serial chip was still good. Jon KF5TFJ Re: Date: Thu, 11 Jul 2019 14:22:51 -0500 From: Chris Burford To: Time Nuts Listings Subject: [time-nuts] Thunderbolt E Message-ID: <9165f782-88f7-d015-6a82-6102a4258...@austin.rr.com> Content-Type: text/plain; charset=utf-8; format=flowed I'm on the fence on purchasing a new Thunderbolt E from Trimble and wanted to hear from current or past owners. I have a couple of the eBay x-telecom patchwork quilt GPSDO units which seem to do an OK job. Is there anything else besides a warranty and better performance specs that the Thunderbolt offers? My intention is to use the Thunderbolt as a backup reference to my PRS10. Thanks. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] time-nuts Digest, Vol 180, Issue 22
From: Bob kb8tq - high-Q crystals require SC-cut >>> ... An SC has a lower Q than an AT of similar size >>> and design up to the point acoustic Q losses completely take over. >>> If you are talking about sub 20 MHz OCXO?s with ?doable? crystal >>> package sizes, the AT will have the higher Q by a significant margin. >> >> Could you please back up this claim with verifiable facts? > > Order up a few 5 MHz 3rd overtones in HC-40 packages and see what you get. > You also could send in an RFQ for a batch of each to any of the people who > make them > and see what comes back. > Bob Here is a random selection of links to back my point of view that, if you have noticed, contradicts Bob's. If anybody is interested they will find information themselves without much effort. I suggest printed books if you don't trust Internet at large. http://www.crovencrystals.com/croven_pdf/Old%20Spec%20Sheets/croven_catalogue.pdf (Croven Crystals is Wenzel company) The main advantages of these resonators, and in particular the SC-cut type are: higher Q-factor (typically 10 - 15% better than equivalent AT-cut resonators) https://www.tfc.co.uk/pdfs/SC_cut_crystals_article_TFC.pdf SC cut family of quartz crystals: Other key characteristics include Higher Q factor https://www.rfwireless-world.com/Terminology/AT-cut-vs-SC-cut-quartz-crystal.html Specification:Q factor AT cut: lower SC cut: higher (it will achieve low phase noise) http://members.femto-st.fr/sites/femto-st.fr.patrice-salzenstein/files/content/Peer-review-journal/smdo160017.pdf SC-cut It has faster higher Q, warm-up speed and better phase noise close to the carrier. http://www.resonal.com/Downloads/John%20R.%20Vig%20-%20tutorial%20on%20Quartz%20Crystals%20and%20Oscillators.pdf Advantages of the SC-cut: Higher Q for fundamental mode resonators of similar geometry http://www.mtronpti.com/sites/default/files/files/crystal-resonator-terminology.pdf A typical 10 MHz, 3rdovertone SC may have a Q of 1.0 to 1.3 million; a 100 MHz, 5th overtone AT may have a Q of 80 to 100 thousand, while a 100 MHz AT fundamental would be much lower, in the range of 20 to 50 thousand. https://www.eetimes.com/document.asp?doc_id=1290592# (MptronPTI) Since SC-cuts have a much higher Q-factor than AT-cuts, SC-based OCXOs offer better noise performance from 1-Hz offset to 1,000-Hz offset. Worryingly, I have started receiving unpleasant personal emails from list members suggesting that I do not question factual correctness of other's opinions. This will explain why I am going off the list for the sake of everyone's good. Leo Bodnar ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Thunderbolt E
Chris, i have one which I bought new several years ago. It had a failure under warranty where in the serial chip stopped doing its thing. The unit continued to lock to SVs and delivered 10MHz and the PPS. Took almost two months to be returned, where it worked fine until very recently. Same issue with the serial chip. Trimble quoted a price of $650 for repairs. Ouch. As they say "Other than that Mrs Lincoln, how did you enjoy the play...”, it played fine as long as you could talk to it. Antenna location is very important as is true for all timing GPS units. The fit is supplied with a good length of 75 Ohn coax, power supply, antenna, and some coas adapters. So the question is how much do you intend to spend? Lady Heather works great when the serial chip was still good. Jon KF5TFJ Re: Date: Thu, 11 Jul 2019 14:22:51 -0500 From: Chris Burford To: Time Nuts Listings Subject: [time-nuts] Thunderbolt E Message-ID: <9165f782-88f7-d015-6a82-6102a4258...@austin.rr.com> Content-Type: text/plain; charset=utf-8; format=flowed I'm on the fence on purchasing a new Thunderbolt E from Trimble and wanted to hear from current or past owners. I have a couple of the eBay x-telecom patchwork quilt GPSDO units which seem to do an OK job. Is there anything else besides a warranty and better performance specs that the Thunderbolt offers? My intention is to use the Thunderbolt as a backup reference to my PRS10. Thanks. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Used Hydrogen Maser, and Mercury Stored-Ion Clocks
In message <009b66fe-c0b0-4f80-8a79-4a487dcb0...@yahoo.com>, Demetrios Matsakis via time-nuts writes: > Demetrios Matsakis, as of this Saturday a USNO retiree, and as of August 1 a > consultant for Masterclock. Do Time Lords get to keep their TARDIS in retirement ? Best wishes for the "3rd age"! Poul-Henning -- 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@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] High accuracy temp controller ckt
Dave wrote: >I have recently assembled some reasonably low temperature coefficient (5 ppm/deg C) resistors in a reasonably well insulated box to try to make a resistor that should be stable over short time periods to allow it to be used as a transfer standard. But I am seriously >considering having another attempt at this, but putting the resistor in an oven. AXTAL has a miniature oven for heating precision resistors or other components to a constant temperature. It is housed in a small DIP8 package. See attached AXR135 data sheet. Optionally this device can be offered unsealed, ready for inserting the component by yourself Regards Bernd AXR135_Rev.2_D1.pdf Description: Adobe PDF document ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
