[time-nuts] Venus838LPx-T opinions?

I have implemented support for all of the relevant Venus binary messages. It's just that I don't have a Venus timing receiver to test the timing receiver specific messages (which are only three messages that control the self-survey / position hold modes). Oh, and besides the lack of a

Re: [time-nuts] Venus838LPx-T opinions?

Definitely the assembled "breakout board+". Maybe I'll wait til Lady Heather has a more complete communication set with this part... __ Clay Autery, KY5G MONTAC Enterprises (318) 518-1389 On 7/22/2016 10:08 PM, Mark Sims wrote: > I'd get the $80 assembled unit from Navspark

[time-nuts] Venus838LPx-T opinions?

I'd get the $80 assembled unit from Navspark first and see if it works for you. If not, you won't have wasted your time and money on doing a PC board. Lady Heather can now talk to Venus receivers in binary mode (also handles generic NMEA receivers). I don't have a Venus timing receiver so

Re: [time-nuts] Venus838LPx-T opinions?

Looks like a module I might want to start with... No way I'd want to start with the chip... __ Clay Autery, KY5G MONTAC Enterprises (318) 518-1389 On 7/22/2016 8:16 PM, Nick Sayer via time-nuts wrote: > Looks like the bare modules are available for $25 (FOB Taiwan) each MQ:4.

Re: [time-nuts] NIST UT1 NTP server results

> Le 23 juil. 2016 à 00:23, John Hawkinson a écrit : > > I have to wonder if it's really such a great idea to have this > as an open NTP server without huge red flags that it is not UTC. > One could imagine it leading to big problems if some people started > syncing to it without

Re: [time-nuts] Venus838LPx-T opinions?

Looks like the bare modules are available for $25 (FOB Taiwan) each MQ:4. Eminently reasonable. I am probably going to get 4 to start with and make an LGA breakout board for myself and do some experimenting with them. The tough part for me is going to be upgrading the controller to the

[time-nuts] Some interesting HP5071A design information

Hi, I've had this booklet for quite a few years and whenever someone posts about the HP5071A I think of sharing it. Finally got around to scanning it and Tom VanBaak was kind enough to host it on his website. It's at http://leapsecond.com/corby/5071comb.pdf Enjoy! Corby Dawson

[time-nuts] Venus838LPx-T opinions?

Navspark will sell you one in on a board for around $80. They claim 6 ns timing accuracy. Also 0.01 ppb on the 10 MHz output. I sent Navspark a couple of questions about their USB interface and they never responded... http://navspark.mybigcommerce.com/ns-t-precision-timing-gps-receiver/

Re: [time-nuts] NIST UT1 NTP server results

Hi There have been a number of “unusual” NTP servers running over the years. The whole “how do we handle leap seconds” thing resulted in a lot of variation. Simple answer is still the same: Only connect to servers that you have checked out. Bob > On Jul 22, 2016, at 6:23 PM, John Hawkinson

Re: [time-nuts] NCOCXO anyone?

Hal wrote: There are 2 markets for DACs and ADCs. I'll call them DC and RF, but the RF goes down to audio. In the DC market, the data sheet talks about linearity and usually covers temperature stability. * * * In the RF market, nobody cares about temperature drift. By far the

Re: [time-nuts] NIST UT1 NTP server results

On Fri, Jul 22, 2016 at 06:23:07PM -0400, John Hawkinson wrote: > With respect to interpolation and soforth, it seems like a lot of NTP > cares more about frequency than offset, and all this stepping presumably > wreaks havoc with the frequency? Maybe I'm wrong though... While fudging the

Re: [time-nuts] NIST UT1 NTP server results

I have to wonder if it's really such a great idea to have this as an open NTP server without huge red flags that it is not UTC. One could imagine it leading to big problems if some people started syncing to it without undersatnding that it was. Has there been thought to at least setting the

[time-nuts] Venus838LPx-T opinions?

Anybody played with one of these? http://www.skytraq.com.tw/products/products-Timing%20Module.html It looks promising for GPSDO designers. It has a survey mode (looks to be automatic) and one of the NMEA messages reports quantization error. The downsides I’ve identified so far are that it’s an

Re: [time-nuts] NIST UT1 NTP server results

Hi Mike, A direct reply from Judah to the list: > > Hello, > Following a discussion with Felicitas Arias and a number of others, > I have removed the registration requirement for the ut1 time server. It > is now open access. Enjoy. Note the usual limitation -- no more than 3 > requests in

Re: [time-nuts] NCOCXO anyone?

On Fri, July 22, 2016 2:15 pm, Hal Murray wrote: > Has anybody put the DAC and all of the analog stuff inside the oven? I ran across some OCXO's with a DAC inside the oven a few years back. They were 5MHz instead of the 10MHz I was looking for so I didn't buy them at the time. I have forgotten

Re: [time-nuts] LSEM (Leap Second Every Month)

Hi Brooke, About sundials, timezones and "precise" timekeeping ... There's a wonderful map by Stefano Maggiolo that everyone should look at: http://blog.poormansmath.net/images/SolarTimeVsStandardTime.png "How much is time wrong around the world?"

[time-nuts] NIST UT1 NTP server results

I have started a new thread for this just in case anyone wants to comment and added a link to the stats plot as the png got removed from the first post. This really has more to do with timescale distribution rather than leap seconds but the fact that NIST put together a UT1 NTP server in the

Re: [time-nuts] [LEAPSECS] NIST UT1 NTP server results

"Mike" wrote on Fri, 22 Jul 2016 at 22:21:08 +0200 in : > You will also note from the NIST document and the NIST time server > address links, that the UT1 NTP service will not respond to > unregistered

Re: [time-nuts] [LEAPSECS] Leap second to be introduced at midnight UTC December 31 this year

Am 22.07.2016 um 10:44 schrieb Martin Burnicki: > Tom Van Baak wrote: >> Time to mention this again... >> >> If we adopted the LSEM (Leap Second Every Month) model then none of >> this would be a problem. The idea is not to decide *if* there will be >> leap second, but to force every month to

Re: [time-nuts] [LEAPSECS] Leap second to be introduced at midnight UTC December 31 this year

Hi The practical problem with any change to leap seconds is transition from what we have to the “new system”. Anything other than dropping them altogether involves a *lot* of coordination. You pretty much have to pick a date and bring everything onto the new standard then. For testing

Re: [time-nuts] NCOCXO anyone?

att...@kinali.ch said: > You can already get 24bit DAC's off the shelf from TI (DAC1282). I do not > know how stable they are in reality. ... There are 2 markets for DACs and ADCs. I'll call them DC and RF, but the RF goes down to audio. In the DC market, the data sheet talks about linearity

Re: [time-nuts] NCOCXO anyone?

rich...@karlquist.com said: > That's what we tried to do with the E1938A. A multiplying DAC is used based > on a reference that is ovenized instead the crystal oven. That certainly > eliminated the tempco issue with the reference, but then we discovered 1/f > noise on the reference. We had to

Re: [time-nuts] NCOCXO anyone?

In message <20160722113312.f1f292c42ba086aafd6d4...@kinali.ch>, Attila Kinali w rites: >You can already get 24bit DAC's off the shelf from TI (DAC1282). Precisely(!) as stable as the voltage reference you feed them. These are oversampling designs which *by definition* cannot attenuate

Re: [time-nuts] LSEM (Leap Second Every Month)

Hi Tom: One of my interests is in Sun dials, so I like the idea of civil time corresponding as close as possible to the Sun's position. Heliochronometers can be accurate to some seconds. The Dent Dipleidoscope was used to

Re: [time-nuts] NCOCXO anyone?

On 7/22/2016 10:15 AM, David wrote: It is too bad voltage control of an oscillator cannot be made ratiometric. Or can it? I have never heard of such a thing. That would remove some of the demands on a low drift reference. That's what we tried to do with the E1938A. A multiplying DAC

Re: [time-nuts] Leap second to be introduced at midnight UTC December 31 this year

> Le 21 juil. 2016 à 19:27, Tom Van Baak a écrit : > > Time to mention this again... > > If we adopted the LSEM (Leap Second Every Month) model then none of this > would be a problem. The idea is not to decide *if* there will be leap second, > but to force every month to

Re: [time-nuts] LSEM (Leap Second Every Month)

Hi Tom, Thanks for your insights on days past, and great website. I haven't convinced myself that you can always guarantee | DUT1 | <= 1 if you force a leap second at the end of each month. Certainly would aid in combating sketchy code. I tried it on a very rudimentary model to visualize it. On

Re: [time-nuts] NCOCXO anyone?

On Fri, 22 Jul 2016 11:33:12 +0200, you wrote: >On Thu, 21 Jul 2016 22:22:14 -0500 >David wrote: > >> Increased integration has only helped insofar as you can attempt >> designs which would have been prohibitive before. >> >> I keep trying to come up with a charge

Re: [time-nuts] Leap second to be introduced at midnight UTC December 31 this year

Follow up: Spectracom has released an official document which broadens the known impact to include their Accutime GG antenna: http://support.spectracom.com/articles/FAQ/Why-is-there-a-1-second-time-error-from-my-GPS-reference > On Jul 21, 2016, at 12:02 PM, Noah

Re: [time-nuts] NCOCXO anyone?

Capacitor matching (Moore's law) has improved for switch-cap designs. Also depends on the tuning gain, 10 ppm/V would be very demanding versus 10 ppb/V. On Thu, Jul 21, 2016 at 9:47 PM, Richard (Rick) Karlquist < rich...@karlquist.com> wrote: > > > On 7/21/2016 4:56 PM, Nick Sayer via time-nuts

Re: [time-nuts] NCOCXO anyone?

SpectraDynamics HROG 5/10 http://www.spectradynamics.com/products/hrog-10-high-resolution-phase-and-frequency-offset-generator/ On 22. jul. 2016, at 09.49, Anders Wallin wrote: >> rich...@karlquist.com said: >>> Also in 1996, phase microsteppers were already legacy

Re: [time-nuts] NCOCXO anyone?

On 7/22/2016 2:22 AM, Attila Kinali wrote: Hoi Rick, On Thu, 21 Jul 2016 18:47:24 -0700 "Richard (Rick) Karlquist" wrote: Also in 1996, phase microsteppers were already legacy technology and didn't have a good reputation for spectral purity. Another non-panacea. If

Re: [time-nuts] NCOCXO anyone?

On Thu, 21 Jul 2016 22:22:14 -0500 David wrote: > Increased integration has only helped insofar as you can attempt > designs which would have been prohibitive before. > > I keep trying to come up with a charge balancing design but what about > Linear Technology's solution

Re: [time-nuts] [LEAPSECS] Leap second to be introduced at midnight UTC December 31 this year

Tom Van Baak wrote: > Time to mention this again... > > If we adopted the LSEM (Leap Second Every Month) model then none of > this would be a problem. The idea is not to decide *if* there will be > leap second, but to force every month to have a leap second. The IERS > decision is then what the

Re: [time-nuts] NCOCXO anyone?

No, the first one merely uses a pair of cascaded heterodyne PLLs as shown on p3 of the manual.A diophantine setup may be useful here if one wished to construct something similar. Bruce From: Anders Wallin To: Discussion of precise time and frequency

Re: [time-nuts] NCOCXO anyone?

> rich...@karlquist.com said: > > Also in 1996, phase microsteppers were already legacy technology and > didn't > > have a good reputation for spectral purity. Another non-panacea. > > What is a phase microstepper and/or how does it compare to a DDS? > > (Google gets lots of hits, but they all