Re: [time-nuts] High-end GPSDO's
Bob Good pix for what its worth its the navsync Wi125 and information is available online. Its interesting thats most CASCs I have seen in one place. Regards Paul WB8TSL On Sat, Aug 18, 2018 at 4:54 PM, Bob Martin wrote: > I'm no expert on GPS receivers but here is a picture of a "GPSDO". > You can just make out the GPS receiver model number which may be helpful > to someone. I'm pretty sure I bought the receiver from Digikey. > > Best, > > Bob Martin > > > > > On 8/18/2018 12:56 PM, Attila Kinali wrote: > >> On Thu, 16 Aug 2018 17:14:55 -0400 >> Bob kb8tq wrote: >> >> It’s not at all clear what sort of GPS they have in these boxes. >>> >> >> The FS740 schematics say it's some Trimble chip/module, probably >> one of the Trimble SMT modules, which one, I do not know. >> >> Attila Kinali >> >> > ___ > 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] TNS-BUF update
We just got word that the new batch of TNS-BUF isolation amplifier boards have made it through customs and are on the way to the TAPR office. If you have one on order, it should be going out next week. We do have a few extra boards available if anyone needs one: https://tapr.org/kits_tns-buf John ___ 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] History Channel "In Search of" Time Travel
Bravo! How wonderful to read this. Thank you. You are truly living the dream imo. On Fri, Aug 17, 2018 at 17:09 Tom Van Baak wrote: > Check out History Channel tonight (Friday, August 17) for a new series > called "In Search Of" hosted by Zachary Quinto. Episode 5 is titled "Time > Travel". > > There's a chance this episode will include some bits with my car & cesium > clocks. Earlier this year I was invited by the producers to perform a > gravitational time dilation experiment like the ones I did in 2016 for a > Stephen Hawking TV show and the family clock trip up Mt Rainier in 2005. > > This time I selected Mt Palomar, CA which is conveniently located in the > greater LA area. You likely know of Palomar because of the famous 200 inch > Hale telescope up at the ~5500 foot summit. Our base was a beachfront hotel > in Seaside, CA. The elevation difference was about 1.6 km and the clocks > were separated for about 24 hr so 15 ns of time dilation is expected. > > Over two days they certainly took lots of footage of the clocks, the car, > and some conversations with me. I have no idea how many seconds of actual > screen time that might result in. None of it was scripted or rehearsed so I > hope I didn't do or say anything too stupid on camera. I'll have more info > by tomorrow and update the web page: > > http://leapsecond.com/great2018a/ > > /tvb > > > ___ > 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. > -- Dr. Geophysics http://dr.geophysics.googlepages.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] History Channel "In Search of" Time Travel
It can be watched on the History Channel's website if you have a TV provider that carries it and sign in. Tom, you made an excellent scientific presentation in the middle of others that were somewhat more "fanciful". Regards, Mark On Fri, Aug 17, 2018 at 2:07 PM, Tom Van Baak wrote: > Check out History Channel tonight (Friday, August 17) for a new series > called "In Search Of" hosted by Zachary Quinto. Episode 5 is titled "Time > Travel". > ___ 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] Choosing a GPS IC for carrier phase measurements
Hi, On 08/18/2018 10:01 PM, Bob kb8tq wrote: > Hi > > > >> On Aug 18, 2018, at 2:25 PM, Attila Kinali wrote: >> >> On Thu, 16 Aug 2018 17:45:30 +0200 >> Nicolas Braud-Santoni wrote: >> >>> The main issue I'm running into is that most timing GPS modules will >>> happily give you carrier phase measurements... for their internal >>> oscillator, and the few ICs I can find that would possibly do the job, like >>> ublox's UBX-M8030-KT-FT, do not have publicly-available datasheets & docs. >>> (I tried contacting ublox to ask, and never got an answer...) >> >> Yeah. u-blox isn't as nice as they used to be to small customers :-( >> There are two ways to proceede: >> >> 1) use the timing of the PPS to deduce what the phase relation between >> your clock and the internal oscillator of the LEA is. >> In principle, this is possible, but I have not worked out the math, >> so I cannot say for sure. >> >> 2) replace the internal oscillator with one phase locked to your OCXO. >> The internal clock of the LEA is derived from a single TCXO. You can >> easily unsolder it and feed your own signal in. It should be relatively >> easy to reverse engineer what you need. If you don't want to reverse >> engineer it and if you get hold of a u-blox representative, you can get >> the required information from them. I got the data from them a couple >> of years ago. Unfortunately, I was explicitly asked not to share this >> information :-( > > If you go this route, the close in phase noise of your signal needs to be in > the > “pretty good TCXO” range. There are indeed some sources out there that > are way to noisy …. Indeed. You want both pretty good wideband noise and close-in. Nowdays GPS-receiver TCXOs is their own class of TCXOs for a reason, and it's pretty impressive stuff for their size and cost. It's always good to keep an external ref input available to servo up the TCXO from. Cheers, Magnus ___ 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] History Channel "In Search of" Time Travel
Yes, please. PS: VLC media player will also play .mkv files. John K1AE Bolton, MA -Original Message- From: time-nuts [mailto:time-nuts-boun...@lists.febo.com] On Behalf Of Dan Rae Sent: Saturday, August 18, 2018 3:23 PM To: time-nuts@lists.febo.com Subject: Re: [time-nuts] History Channel "In Search of" Time Travel If anyone wants to see this I could upload a .mkv copy to Wetransfer for download. Dan ___ 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. --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus ___ 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] Choosing a GPS IC for carrier phase measurements
Hi > On Aug 18, 2018, at 2:25 PM, Attila Kinali wrote: > > On Thu, 16 Aug 2018 17:45:30 +0200 > Nicolas Braud-Santoni wrote: > >> The main issue I'm running into is that most timing GPS modules will >> happily give you carrier phase measurements... for their internal >> oscillator, and the few ICs I can find that would possibly do the job, like >> ublox's UBX-M8030-KT-FT, do not have publicly-available datasheets & docs. >> (I tried contacting ublox to ask, and never got an answer...) > > Yeah. u-blox isn't as nice as they used to be to small customers :-( > There are two ways to proceede: > > 1) use the timing of the PPS to deduce what the phase relation between > your clock and the internal oscillator of the LEA is. > In principle, this is possible, but I have not worked out the math, > so I cannot say for sure. > > 2) replace the internal oscillator with one phase locked to your OCXO. > The internal clock of the LEA is derived from a single TCXO. You can > easily unsolder it and feed your own signal in. It should be relatively > easy to reverse engineer what you need. If you don't want to reverse > engineer it and if you get hold of a u-blox representative, you can get > the required information from them. I got the data from them a couple > of years ago. Unfortunately, I was explicitly asked not to share this > information :-( If you go this route, the close in phase noise of your signal needs to be in the “pretty good TCXO” range. There are indeed some sources out there that are way to noisy …. Bob > > >> So, what are people around here using for that purpose? Bonus points if the >> chip can work with a differential-signal clock. :) > > The alternative is to build your own GPS receiver. If you only want > GPS L1 C/A, then you can use the design of The Witch Navigator[1] > with one of the VHDL/Verilog projects out there (e.g. cu-hw-gps [2]) > > If you want to go for L2C, L5 or Galileo, you have to do your own coding :-) > > Attila Kinali > > > [1] http://www.witchnav.cz > The website seems to be down at the moment so use archive.org for now: > https://web.archive.org/web/20161122121726/http://www.witchnav.cz/doku.php > > [2] https://github.com/perfaram/cu-hw-gps > > -- > The bad part of Zurich is where the degenerates >throw DARK chocolate at you. > > ___ > 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] History Channel "In Search of" Time Travel
I would appreciate it, thanks. Bob LaJeunesse > Sent: Saturday, August 18, 2018 at 3:22 PM > From: "Dan Rae" > To: time-nuts@lists.febo.com > Subject: Re: [time-nuts] History Channel "In Search of" Time Travel > > If anyone wants to see this I could upload a .mkv copy to Wetransfer for > download. > Dan > > ___ > 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] History Channel "In Search of" Time Travel
If anyone wants to see this I could upload a .mkv copy to Wetransfer for download. Dan ___ 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] History Channel "In Search of" Time Travel
To: Tom Van Baak ; Discussion of precise time and frequency measurement Check out History Channel tonight (Friday, August 17) for a new series called "In Search Of" hosted by Zachary Quinto. Episode 5 is titled "Time Travel". = It would be most interesting if this were also downloadable - YouTube or whatever. Cheers, David -- SatSignal Software - Quality software for you Web: http://www.satsignal.eu Email: david-tay...@blueyonder.co.uk Twitter: @gm8arv ___ 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.
