Re: [time-nuts] UBLOX LEA-5T Programming?
Hi It’s “happy” either way (as in, it will accept the pulse). The stability will be degraded due to hanging bridges if you don’t have sawtooth correction. Bob > On Oct 12, 2015, at 6:13 PM, Hal Murray wrote: > > > kb...@n1k.org said: >> A $25 Ref-0 with the same GPS and a (now) documented MCU will do the same >> thing as any other GPSDO. > > Does anybody know if the Ref-0 expects a clean PPS from the Ref-1 OCXO, or is > it happy with what comes out of a typical GPS unit? > > > > -- > These are my opinions. 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. ___ 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] UBLOX LEA-5T Programming?
Hi, The REF-0 will accept a PPS signal from a non-timing GPS. I use the u-blox NEO-6M for a lot of my testing. That module can be had in the $12 range online. I have also gotten the REF-0 to lock to a Venus GPS and an FE-5680B rubidium standard. Of course, using a less stable PPS signal will give you less performance out of the REF-0. I have some information about operating the REF-0 standalone documented on my blog: http://syncchannel.blogspot.com Dan > On Oct 12, 2015, at 6:13 PM, Hal Murray wrote: > > > kb...@n1k.org said: >> A $25 Ref-0 with the same GPS and a (now) documented MCU will do the same >> thing as any other GPSDO. > > Does anybody know if the Ref-0 expects a clean PPS from the Ref-1 OCXO, or is > it happy with what comes out of a typical GPS unit? > > > > -- > These are my opinions. 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. ___ 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] UBLOX LEA-5T Programming?
kb...@n1k.org said: > A $25 Ref-0 with the same GPS and a (now) documented MCU will do the same > thing as any other GPSDO. Does anybody know if the Ref-0 expects a clean PPS from the Ref-1 OCXO, or is it happy with what comes out of a typical GPS unit? -- These are my opinions. 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] UBLOX LEA-5T Programming?
I'd second that, sounds interesting and plenty of accuracy for the project I'm thinking of. On 10 Oct 2015 15:00, "Alex Pummer" wrote: > Hi Bert, > where could I get more inf on on that project? > 73 > KJ6UHN > Alex > > On 10/10/2015 4:23 AM, Bert Kehren via time-nuts wrote: > >> We did a GPS PLL using ublox M7 not for time nuts but for Hams no u >> processors, simple to build with readily available parts with >> performance of 1 >> E-10.. Hams still have get to gether and it would make sense to order the >> parts. Boards would be less than $ 2 in quantity 10. 5X5 cm board can >> also >> work with other VCXO's. >> Data is attached >> Bert Kehren >> >> >> >> >> ___ >> 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] UBLOX LEA-5T Programming?
Hi Bert, where could I get more inf on on that project? 73 KJ6UHN Alex On 10/10/2015 4:23 AM, Bert Kehren via time-nuts wrote: We did a GPS PLL using ublox M7 not for time nuts but for Hams no u processors, simple to build with readily available parts with performance of 1 E-10.. Hams still have get to gether and it would make sense to order the parts. Boards would be less than $ 2 in quantity 10. 5X5 cm board can also work with other VCXO's. Data is attached Bert Kehren ___ 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] UBLOX LEA-5T Programming?
We did a GPS PLL using ublox M7 not for time nuts but for Hams no u processors, simple to build with readily available parts with performance of 1 E-10.. Hams still have get to gether and it would make sense to order the parts. Boards would be less than $ 2 in quantity 10. 5X5 cm board can also work with other VCXO's. Data is attached Bert Kehren Morion_PLL_2-1.xls Description: Binary data ___ 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] UBLOX LEA-5T Programming?
(Long-term members of the list can skip this; you've seen it many times before. But it sounds like Clint is new, and could use some basic explanation. I was in his position once too). It sounds like you are assuming that the GPS receiver's internal oscillator is locked to GPS time. In most cases, it isn't - it's a free-running local oscillator. So its frequency isn't terribly accurate. The GPS receiver, as part of its operation, can determine what the local clock frequency is and compensate for it. For the 1 PPS output, the receiver can calculate which local clock edge is closest to being the correct location for the next 1 PPS pulse, and arranges to change the output state at that time. But the divisor between the internal clock and the 1 PPS output is not constant - it is adjusted as necessary to place the 1 PPS as close as possible to the correct time. For example, suppose the local oscillator is nominally 10 MHz, but it is actually 10 PPB fast. If it was simply divided by 1e7 to get the 1 PPS, the 1 PPS would also be 10 PPB fast. So the GPS receiver will arrange to (on average) divide by 10,000,000 for 9 seconds out of every 10, but divide by 10,000,001 every 10th second. This slows the PPS, on average, by one extra oscillator cycle in every 100 million, compensating for the long-term error. But now some "1 PPS" periods are actually 100 ns longer than others. The very best the GPS receiver can do at keeping the 1 PPS "on time" as well as "on frequency" is to always place the 1 PPS somewhere within 50 ns of the correct time. With this example, the error will drift from 50 ns late to 50 ns early over a span of 10 seconds, then abruptly jump to 50 ns late again due to the extra-cycle 1 PPS period. So the time error looks like a sawtooth when graphed. If you have a timing-grade GPS, the receiver will generally tell you the residual error of each 1 PPS pulse, and you can compensate for that when comparing an external oscillator to the 1 PPS output. Essentially, it gives you a timing reference with a somewhat-random error, but it tells you the amount of the error, so you can subtract it out of your calculations. That's easy if you're using a digital PLL to lock another oscillator to the (corrected) 1 PPS. Someone was even talking about designing a delay line to remove the sawtooth error from the 1 PPS in hardware. If you don't do one of these things, the 1 PPS output has a lot of jitter. (And it doesn't necessarily average out in 10 seconds, like in the example above. If the local oscillator is close to the correct frequency, you can get 1 PPS outputs that are on one side or the other of "correct" for hundreds or thousands of seconds. The phenomenon is called "hanging bridges" from the way they look on a graph). - Dave On 09/10/2015 10:16, Clint Jay wrote: I am still learning and want to understand, if the PPS is good then why is the programmable output bad, as I understand it thus far, the PPS is derived from the same clock source or have I got that badly wrong? ___ 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] UBLOX LEA-5T Programming?
Hi The PPS out of the GPS has a number of issues short term. Without sawtooth correction it likely is hopping and bopping 5 or 10 ns each second. Looked at as frequency, the 1 Hz is +/- many ppb. The “frequency” output inherits this problem and adds the issues associated with pulse drop frequency synthesis. More or less 10 MHz is a 16 MHz pulse train with 6 our of 16 edges dropped out. That does not give you a clean spectrum or a predictable signal. Combine these two things and you have a signal that most PLL chips will be a bit bothered by *and* a reference that is much less stable than the OCXO. The answer is to stretch out the comparison process to 100’s of seconds and to use sawtooth correction. Both of these things are easily done with a < $2 MCU. The gotcha is that you need code to go with it. A $25 Ref-0 with the same GPS and a (now) documented MCU will do the same thing as any other GPSDO. That sort of sets an upper limit on how much you probably should spend on this sort of thing. That’s not to say that similar logic *does* put an upper limit, as I’ve proven on a large number of projects I’ve done ….. Bob > On Oct 9, 2015, at 10:16 AM, Clint Jay wrote: > > I am still learning and want to understand, if the PPS is good then why is > the programmable output bad, as I understand it thus far, the PPS is > derived from the same clock source or have I got that badly wrong? > > On 9 October 2015 at 12:16, Bob Camp wrote: > >> Hi >> >> Doing a GPSDO by locking to the awful 10 MHz output from any of these GPS >> modules >> is not going to work very well. Given the very long time constants >> involved in a GPSDO >> control loop, doing it without code is going to be pretty difficult. >> >> A much easier approach: >> >> Grab the GPS PPS and a scope. Use it to set the Lucent boxes on frequency. >> Repeat the process >> once a week. The direct lock will flop around by (likely many) ppb. Your >> manual set will probably keep it >> under 1 ppb for a week. >> >> Bob >> >>> On Oct 9, 2015, at 1:39 AM, Perry Sandeen via time-nuts < >> time-nuts@febo.com> wrote: >>> >>> Hi, >>> I have six of the older style (anodized solid aluminum case) Lucent >> crystal oscillators that I’d like to turn into simple 10 MHZ output >> GPSDO’s. I have some salvaged HP cases so I can have a linear PS and all >> other stuff in one package. >>> I’ve found two different choices of GPS relatively low cost units on >> Ebay. >>> One is a LUCENT M12+ GPS Timing Receiver W/100 Hz output for $19.99 >> Item 171886538138. >>> The other is a UBLOX LEA-5T GPS module dev board 1PPS /USB/RS232/ntp ser >> with two 1 PPS outputs for $49.90. Item 251785217093. >>> IIRC, one output of a Ublox can be set to a 10 MHz. >>> Can this model be set to have a 10 MHz output and is it easily done from >> a PC? I have no coding ability. >>> For more money I’d get a simpler phase detector circuit, which is all >> I’m looking for. For less money I’d have to build more circuitry. >>> A factor I don’t know is if the ublox is that much better/newer to >> justify the price difference. >>> I already have packed away two Oncore units with either a 1 KHz or 10 >> KHz output. >>> Suggestions welcomed. >>> 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. >> > > > > -- > Clint. > > *No trees were harmed in the sending of this mail. However, a large number > of electrons were greatly inconvenienced.* > ___ > 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] UBLOX LEA-5T Programming?
> Le 9 oct. 2015 à 16:16, Clint Jay a écrit : > > I am still learning and want to understand, if the PPS is good then why is > the programmable output bad, as I understand it thus far, the PPS is > derived from the same clock source or have I got that badly wrong? Yes, the same clock, BUT the output signal rising edge is aligned with the nearest internal clock pulse leading edge, as is the 1PPS output, which gives rise to something called quantization error. If the configured frequency is an integral division of the cpu clock, then OK, but if it is not then this error is apparent. IIRC, the on board cpu oscillator is 48MHz, and so an 8MHz output will be OK, but 10MHz does not divide evenly into 48Mz so you get significant jitter. There is a nice Ublox doc « Timing_AppNote_(GPS.G6-X-11007).pdf » illustrating this. I don’t know if there was one issued for the 5T receiver, but the principle is the same. Google should find it. > > On 9 October 2015 at 12:16, Bob Camp wrote: > >> Hi >> >> Doing a GPSDO by locking to the awful 10 MHz output from any of these GPS >> modules >> is not going to work very well. Given the very long time constants >> involved in a GPSDO >> control loop, doing it without code is going to be pretty difficult. >> >> A much easier approach: >> >> Grab the GPS PPS and a scope. Use it to set the Lucent boxes on frequency. >> Repeat the process >> once a week. The direct lock will flop around by (likely many) ppb. Your >> manual set will probably keep it >> under 1 ppb for a week. >> >> Bob >> >>> On Oct 9, 2015, at 1:39 AM, Perry Sandeen via time-nuts < >> time-nuts@febo.com> wrote: >>> >>> Hi, >>> I have six of the older style (anodized solid aluminum case) Lucent >> crystal oscillators that I’d like to turn into simple 10 MHZ output >> GPSDO’s. I have some salvaged HP cases so I can have a linear PS and all >> other stuff in one package. >>> I’ve found two different choices of GPS relatively low cost units on >> Ebay. >>> One is a LUCENT M12+ GPS Timing Receiver W/100 Hz output for $19.99 >> Item 171886538138. >>> The other is a UBLOX LEA-5T GPS module dev board 1PPS /USB/RS232/ntp ser >> with two 1 PPS outputs for $49.90. Item 251785217093. >>> IIRC, one output of a Ublox can be set to a 10 MHz. >>> Can this model be set to have a 10 MHz output and is it easily done from >> a PC? I have no coding ability. >>> For more money I’d get a simpler phase detector circuit, which is all >> I’m looking for. For less money I’d have to build more circuitry. >>> A factor I don’t know is if the ublox is that much better/newer to >> justify the price difference. >>> I already have packed away two Oncore units with either a 1 KHz or 10 >> KHz output. >>> Suggestions welcomed. >>> 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. >> > > > > -- > Clint. > > *No trees were harmed in the sending of this mail. However, a large number > of electrons were greatly inconvenienced.* > ___ > 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. "The main function of a modern police force is filling in forms." ___ 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] UBLOX LEA-5T Programming?
There is a lot of jitter on a GPS 1 PPS output. You need a big "flywheel" to smooth out the jitter errors. GPS modules only have room for small flywheels. --- Graham On Fri, Oct 9, 2015 at 9:16 AM, Clint Jay wrote: > I am still learning and want to understand, if the PPS is good then why is > the programmable output bad, as I understand it thus far, the PPS is > derived from the same clock source or have I got that badly wrong? > > On 9 October 2015 at 12:16, Bob Camp wrote: > > > Hi > > > > Doing a GPSDO by locking to the awful 10 MHz output from any of these GPS > > modules > > is not going to work very well. Given the very long time constants > > involved in a GPSDO > > control loop, doing it without code is going to be pretty difficult. > > > > A much easier approach: > > > > Grab the GPS PPS and a scope. Use it to set the Lucent boxes on > frequency. > > Repeat the process > > once a week. The direct lock will flop around by (likely many) ppb. Your > > manual set will probably keep it > > under 1 ppb for a week. > > > > Bob > > > > > On Oct 9, 2015, at 1:39 AM, Perry Sandeen via time-nuts < > > time-nuts@febo.com> wrote: > > > > > > Hi, > > > I have six of the older style (anodized solid aluminum case) Lucent > > crystal oscillators that I’d like to turn into simple 10 MHZ output > > GPSDO’s. I have some salvaged HP cases so I can have a linear PS and all > > other stuff in one package. > > > I’ve found two different choices of GPS relatively low cost units on > > Ebay. > > > One is a LUCENT M12+ GPS Timing Receiver W/100 Hz output for $19.99 > > Item 171886538138. > > > The other is a UBLOX LEA-5T GPS module dev board 1PPS /USB/RS232/ntp > ser > > with two 1 PPS outputs for $49.90. Item 251785217093. > > > IIRC, one output of a Ublox can be set to a 10 MHz. > > > Can this model be set to have a 10 MHz output and is it easily done > from > > a PC? I have no coding ability. > > > For more money I’d get a simpler phase detector circuit, which is all > > I’m looking for. For less money I’d have to build more circuitry. > > > A factor I don’t know is if the ublox is that much better/newer to > > justify the price difference. > > > I already have packed away two Oncore units with either a 1 KHz or 10 > > KHz output. > > > Suggestions welcomed. > > > 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. > > > > > > -- > Clint. > > *No trees were harmed in the sending of this mail. However, a large number > of electrons were greatly inconvenienced.* > ___ > 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] UBLOX LEA-5T Programming?
The 1 pps and the output frequencies are all derived from the same XO in the module. Up to 7 the difference in a T is that the saw tooth correction factor is brought out for correction purposes . 7 has a much higher XO frequency than the 5 so the saw tooth is smaller. So use a ublox 7 if you want to do a simple GPSPLL like James Miller described. If you use the cheaper M version you have to make sure you always have backup power since it does not have a flash memory like the more expensive N version to memorize the setting Also stay away from 10 MHz out better to use 200 or 400 KHz. We have done a GPSPLL with ublox7 and Morion and got very good results. I have a board if interested contact me off list. Bert Kehren In a message dated 10/9/2015 12:03:45 P.M. Eastern Daylight Time, cjaysh...@gmail.com writes: I am still learning and want to understand, if the PPS is good then why is the programmable output bad, as I understand it thus far, the PPS is derived from the same clock source or have I got that badly wrong? On 9 October 2015 at 12:16, Bob Camp wrote: > Hi > > Doing a GPSDO by locking to the awful 10 MHz output from any of these GPS > modules > is not going to work very well. Given the very long time constants > involved in a GPSDO > control loop, doing it without code is going to be pretty difficult. > > A much easier approach: > > Grab the GPS PPS and a scope. Use it to set the Lucent boxes on frequency. > Repeat the process > once a week. The direct lock will flop around by (likely many) ppb. Your > manual set will probably keep it > under 1 ppb for a week. > > Bob > > > On Oct 9, 2015, at 1:39 AM, Perry Sandeen via time-nuts < > time-nuts@febo.com> wrote: > > > > Hi, > > I have six of the older style (anodized solid aluminum case) Lucent > crystal oscillators that I’d like to turn into simple 10 MHZ output > GPSDO’s. I have some salvaged HP cases so I can have a linear PS and all > other stuff in one package. > > I’ve found two different choices of GPS relatively low cost units on > Ebay. > > One is a LUCENT M12+ GPS Timing Receiver W/100 Hz output for $19.99 > Item 171886538138. > > The other is a UBLOX LEA-5T GPS module dev board 1PPS /USB/RS232/ntp ser > with two 1 PPS outputs for $49.90. Item 251785217093. > > IIRC, one output of a Ublox can be set to a 10 MHz. > > Can this model be set to have a 10 MHz output and is it easily done from > a PC? I have no coding ability. > > For more money I’d get a simpler phase detector circuit, which is all > I’m looking for. For less money I’d have to build more circuitry. > > A factor I don’t know is if the ublox is that much better/newer to > justify the price difference. > > I already have packed away two Oncore units with either a 1 KHz or 10 > KHz output. > > Suggestions welcomed. > > 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. > -- Clint. *No trees were harmed in the sending of this mail. However, a large number of electrons were greatly inconvenienced.* ___ 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] UBLOX LEA-5T Programming?
I am still learning and want to understand, if the PPS is good then why is the programmable output bad, as I understand it thus far, the PPS is derived from the same clock source or have I got that badly wrong? On 9 October 2015 at 12:16, Bob Camp wrote: > Hi > > Doing a GPSDO by locking to the awful 10 MHz output from any of these GPS > modules > is not going to work very well. Given the very long time constants > involved in a GPSDO > control loop, doing it without code is going to be pretty difficult. > > A much easier approach: > > Grab the GPS PPS and a scope. Use it to set the Lucent boxes on frequency. > Repeat the process > once a week. The direct lock will flop around by (likely many) ppb. Your > manual set will probably keep it > under 1 ppb for a week. > > Bob > > > On Oct 9, 2015, at 1:39 AM, Perry Sandeen via time-nuts < > time-nuts@febo.com> wrote: > > > > Hi, > > I have six of the older style (anodized solid aluminum case) Lucent > crystal oscillators that I’d like to turn into simple 10 MHZ output > GPSDO’s. I have some salvaged HP cases so I can have a linear PS and all > other stuff in one package. > > I’ve found two different choices of GPS relatively low cost units on > Ebay. > > One is a LUCENT M12+ GPS Timing Receiver W/100 Hz output for $19.99 > Item 171886538138. > > The other is a UBLOX LEA-5T GPS module dev board 1PPS /USB/RS232/ntp ser > with two 1 PPS outputs for $49.90. Item 251785217093. > > IIRC, one output of a Ublox can be set to a 10 MHz. > > Can this model be set to have a 10 MHz output and is it easily done from > a PC? I have no coding ability. > > For more money I’d get a simpler phase detector circuit, which is all > I’m looking for. For less money I’d have to build more circuitry. > > A factor I don’t know is if the ublox is that much better/newer to > justify the price difference. > > I already have packed away two Oncore units with either a 1 KHz or 10 > KHz output. > > Suggestions welcomed. > > 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. > -- Clint. *No trees were harmed in the sending of this mail. However, a large number of electrons were greatly inconvenienced.* ___ 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] UBLOX LEA-5T Programming?
Hi Doing a GPSDO by locking to the awful 10 MHz output from any of these GPS modules is not going to work very well. Given the very long time constants involved in a GPSDO control loop, doing it without code is going to be pretty difficult. A much easier approach: Grab the GPS PPS and a scope. Use it to set the Lucent boxes on frequency. Repeat the process once a week. The direct lock will flop around by (likely many) ppb. Your manual set will probably keep it under 1 ppb for a week. Bob > On Oct 9, 2015, at 1:39 AM, Perry Sandeen via time-nuts > wrote: > > Hi, > I have six of the older style (anodized solid aluminum case) Lucent crystal > oscillators that I’d like to turn into simple 10 MHZ output GPSDO’s. I have > some salvaged HP cases so I can have a linear PS and all other stuff in one > package. > I’ve found two different choices of GPS relatively low cost units on Ebay. > One is a LUCENT M12+ GPS Timing Receiver W/100 Hz output for $19.99 Item > 171886538138. > The other is a UBLOX LEA-5T GPS module dev board 1PPS /USB/RS232/ntp ser with > two 1 PPS outputs for $49.90. Item 251785217093. > IIRC, one output of a Ublox can be set to a 10 MHz. > Can this model be set to have a 10 MHz output and is it easily done from a > PC? I have no coding ability. > For more money I’d get a simpler phase detector circuit, which is all I’m > looking for. For less money I’d have to build more circuitry. > A factor I don’t know is if the ublox is that much better/newer to justify > the price difference. > I already have packed away two Oncore units with either a 1 KHz or 10 KHz > output. > Suggestions welcomed. > 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] UBLOX LEA-5T Programming?
Hi, I have six of the older style (anodized solid aluminum case) Lucent crystal oscillators that I’d like to turn into simple 10 MHZ output GPSDO’s. I have some salvaged HP cases so I can have a linear PS and all other stuff in one package. I’ve found two different choices of GPS relatively low cost units on Ebay. One is a LUCENT M12+ GPS Timing Receiver W/100 Hz output for $19.99 Item 171886538138. The other is a UBLOX LEA-5T GPS module dev board 1PPS /USB/RS232/ntp ser with two 1 PPS outputs for $49.90. Item 251785217093. IIRC, one output of a Ublox can be set to a 10 MHz. Can this model be set to have a 10 MHz output and is it easily done from a PC? I have no coding ability. For more money I’d get a simpler phase detector circuit, which is all I’m looking for. For less money I’d have to build more circuitry. A factor I don’t know is if the ublox is that much better/newer to justify the price difference. I already have packed away two Oncore units with either a 1 KHz or 10 KHz output. Suggestions welcomed. 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.