Re: [time-nuts] more of a time distribution question
Hal Murray wrote on Thu, 30 Mar 2017 at 13:43:34 -0700 in <20170330204334.18a8d406...@ip-64-139-1-69.sjc.megapath.net>: > That should work too. I don't know much about the Mac environment. If it's > running a normal-enough ntpd it is already a server and you don't have to do > anything. If not, you will have to build/install your own and/or poke holes > in the firewall rules. It is worth noting that the ntpd that Apple ships is kind of bizarre, and it does not actually adjust the clock on the Mac. (Instead it writes to the drift file -- or at least it is supposed to -- and an Apple process called "pacemaker(8)" readthe drift file and tries to maintain the systme clock. In my experience (only through Yosemite -- 10.10) this mechanism was horribly broken and did not maintain my laptop's system clock in any useful way.) This probably doesn't actually affect the intended use (as the goal is to keep machines in sync, not to keep them accurate), but anyone who messes with ntpd under OS X should be aware that it is "weird." Building the stock ntpd under OS X works just fine, and I recommend that for anyone who wants to tinker with ntp under OS X. --jh...@mit.edu John Hawkinson ___ 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] TAPR TICC boxed
A single or dual supply CMOS output comparator should suffice together with some diode clamps. Since the TICC only resolves a few tens of picosec the choice of comparator etc isnt critical. LTC6752 (~$US2) or similar perhaps? A single supply comparator should suffice unless you want to measure NECL or similar signals. Bruce > > On 31 March 2017 at 09:15 Mark Sims wrote: > > What did you do for input protection? > > I want to build an input system for the TICC that incorporates some input > protection, switchable terminator, possibly settable threshold and edge > selects, and a switchable PICDIV divider like the TADD-2 Mini. That would > allow inputs of <1 .. 100 (or maybe up to 1000) PPS and 1/5/10/15 MHz inputs. > > The main problem I'm having is coming up with an input squarer circuit > that is simple and cheap but can handle basically DC-15 MHz. Anybody got any > ideas? > > ___ > 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] GPS first LO need to be locked?
> > BTW a lot of GPS receivers don't have a "first LO".. they are more like a >> Tuned RF receiver - an input BPF for L1, L2, or L5, then direct sampling at >> around 30-40 MHz - something that makes the GPS signals alias down >> somewhere convenient (and always have positive frequency offset from zero, >> even at max negative Doppler) > > True. I've been wanting to try this with an FPGA transceiver; even the cheap ones go to 6 Gb/s now, but binary only. The newest transceivers support PAM-4, which would be great, but they're not affordable yet. Also that's a lot of gain at one frequency. Cheers, Peter ___ 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] TAPR TICC boxed
What did you do for input protection? I want to build an input system for the TICC that incorporates some input protection, switchable terminator, possibly settable threshold and edge selects, and a switchable PICDIV divider like the TADD-2 Mini. That would allow inputs of <1 .. 100 (or maybe up to 1000) PPS and 1/5/10/15 MHz inputs. The main problem I'm having is coming up with an input squarer circuit that is simple and cheap but can handle basically DC-15 MHz. Anybody got any ideas? ___ 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] GPS first LO need to be locked?
Thanks everyone for your comments. It will be a GPSDP TBolt or Z3801 reference. I just wanted to eliminate some variables at this stage. Regards Paul WB8TSL On Thu, Mar 30, 2017 at 7:56 PM, Bob kb8tq wrote: > Hi > > > > On Mar 30, 2017, at 7:05 PM, jimlux wrote: > > > > On 3/30/17 10:32 AM, Bob Camp wrote: > >> Hi > >> > >> There is a limited tracking range for Doppler. You would need to stay > inside that. > >> > > > > Doppler is pretty big when the spacecraft is coming or going at the > horizon, about 5 kHz (out of 1.5 GHz, so 4-5 ppm). > > Relatively speaking, GPS satellites are moving slowly (a few km/s) > > > > So somewhere in the baseband processor code somebody said “we’ll handle > +/- 5 KHz”. If your LO is < (say) 500 Hz it’s still inside the likely > doppler handling range. > > If you want to do carrier phase then maybe you want to get a bit fancier …. > > Bob > > > > > in LEO you're buzzing along at 7km/s, which is about 20-25 ppm. That is > the usual limiting case for bandwidth/tracking loops; you might want to go > up to 11-12 km/s so you can get things moving at escape velocity. > > (there just aren't many people putting GPS on hypersonic projectiles - > if you've got the bucks to shoot something at Mach 45, you can probably > afford a custom GPS receiver) > > > > This is a bit tricky for older receivers because their tracking loop has > to acquire in the face of the Doppler uncertainty and the range (code > phase) uncertainty - there's a whole lore of optimum search strategies and > how to get the fastest time-to-first-fix. > > > > Does the first LO have to be locked to something? the signal you're > acquiring is MHz wide, so a 10ppm error in the LO frequency isn't a big > deal. Short term stability does help, while you're acquiring. > > > > But one of the things about GPS that made it attractive is that the > local clock can be pretty crummy. > > > >> Bob > >> > >> Sent from my iPhone > >> > >>> On Mar 30, 2017, at 9:46 AM, paul swed wrote: > >>> > >>> I am curious if the first local oscillator on a GPS receiver must > actually > >>> be locked or coherent to the reference oscillator in the GPS receiver > >>> typically running at some 10 MHz approximately. Or as long as the > first LO > >>> is quite stable it doesn't matter because the receiver can track the > code. > >>> This is a question for very classic receivers like Austrons, Odetics > etc. > >>> Discreet. Modern fully integrated receivers are not in question. > >>> Thank you for your insights. > >>> Regards > >>> Paul > >>> WB8TSL > >>> ___ > >>> 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. > > ___ > 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] GPS first LO need to be locked?
Hi > On Mar 30, 2017, at 7:05 PM, jimlux wrote: > > On 3/30/17 10:32 AM, Bob Camp wrote: >> Hi >> >> There is a limited tracking range for Doppler. You would need to stay inside >> that. >> > > Doppler is pretty big when the spacecraft is coming or going at the horizon, > about 5 kHz (out of 1.5 GHz, so 4-5 ppm). > Relatively speaking, GPS satellites are moving slowly (a few km/s) > So somewhere in the baseband processor code somebody said “we’ll handle +/- 5 KHz”. If your LO is < (say) 500 Hz it’s still inside the likely doppler handling range. If you want to do carrier phase then maybe you want to get a bit fancier …. Bob > > in LEO you're buzzing along at 7km/s, which is about 20-25 ppm. That is the > usual limiting case for bandwidth/tracking loops; you might want to go up to > 11-12 km/s so you can get things moving at escape velocity. > (there just aren't many people putting GPS on hypersonic projectiles - if > you've got the bucks to shoot something at Mach 45, you can probably afford a > custom GPS receiver) > > This is a bit tricky for older receivers because their tracking loop has to > acquire in the face of the Doppler uncertainty and the range (code phase) > uncertainty - there's a whole lore of optimum search strategies and how to > get the fastest time-to-first-fix. > > Does the first LO have to be locked to something? the signal you're > acquiring is MHz wide, so a 10ppm error in the LO frequency isn't a big deal. > Short term stability does help, while you're acquiring. > > But one of the things about GPS that made it attractive is that the local > clock can be pretty crummy. > >> Bob >> >> Sent from my iPhone >> >>> On Mar 30, 2017, at 9:46 AM, paul swed wrote: >>> >>> I am curious if the first local oscillator on a GPS receiver must actually >>> be locked or coherent to the reference oscillator in the GPS receiver >>> typically running at some 10 MHz approximately. Or as long as the first LO >>> is quite stable it doesn't matter because the receiver can track the code. >>> This is a question for very classic receivers like Austrons, Odetics etc. >>> Discreet. Modern fully integrated receivers are not in question. >>> Thank you for your insights. >>> Regards >>> Paul >>> WB8TSL >>> ___ >>> 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. ___ 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] more of a time distribution question
On 3/30/17 1:11 PM, Majdi S. Abbas wrote: On Thu, Mar 30, 2017 at 09:37:50AM -0700, jimlux wrote: Running NTP (in some flavor) would be the obvious approach, but I'm in an environment where there's no "outside" connectivity.. Could I make one of the beaglebones be the NTP server, and the others be the clients? Disciplining them all to a specific free-running host would require the use of the LOCAL reference clock: http://doc.ntp.org/4.1.2/driver1.htm However, the LOCAL refclock is deprecated, and it is recommended that you use orphan mode instead, which is its intended replacement: https://www.eecis.udel.edu/~mills/ntp/html/orphan.html http://support.ntp.org/bin/view/Support/OrphanMode Orphan mode is designed for your use case, and allows for more redundancy than making them all clients of a single host. I'd go that route. That's exactly what I was looking for. Didn't think about googling for "orphan" (and really, this is a group of orphans) (I've seen some "add a GPS to a Rpi to make a NTP server" projects, and I could probably leverage that) You could do that, but you don't really have to -- you can keep them synchronized at least to each other reasonably well this way. I've also got a laptop (a mac, as it happens).. what's involved in making *that* be a NTP server (e.g. the Mac might get its time from a NTP server at some higher stratum, and then it propagates it down). OSX already runs ntpd; you should just need to tweak their default configuration. Yes, I got that figured out, although I need to figure out some network routing issues now (independent of NTP...), since it was bridging (via NAT) my pack of beagles to the outside world... I was going "from mac TO beagle" with ssh, but I've got a problem going "from beagle to mac, instead of big world" But that's straightfoward to solve. --msa ___ 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] GPS first LO need to be locked?
On 3/30/17 11:06 AM, Peter Monta wrote: I am curious if the first local oscillator on a GPS receiver must actually be locked or coherent to the reference oscillator in the GPS receiver typically running at some 10 MHz approximately. Or as long as the first LO is quite stable it doesn't matter because the receiver can track the code. It doesn't matter, so long as the first LO is in the ballpark so that the Doppler search is not needlessly large. I'm not so familiar with the early receivers, but I imagine a single reference oscillator serves for everything---there would seem to be no reason to have more than one unless the antenna/downconverter were physically separate from the rest of the receiver. If an older receiver used a physical source at 10.23 MHz, it would still need to be offset slightly for each satellite because of "code doppler", but this choice of frequency might slightly simplify the circuitry. Current receivers would use any convenient physical rate, then synthesize the code rates. BTW a lot of GPS receivers don't have a "first LO".. they are more like a Tuned RF receiver - an input BPF for L1, L2, or L5, then direct sampling at around 30-40 MHz - something that makes the GPS signals alias down somewhere convenient (and always have positive frequency offset from zero, even at max negative Doppler) ___ 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] GPS first LO need to be locked?
On 3/30/17 10:32 AM, Bob Camp wrote: Hi There is a limited tracking range for Doppler. You would need to stay inside that. Doppler is pretty big when the spacecraft is coming or going at the horizon, about 5 kHz (out of 1.5 GHz, so 4-5 ppm). Relatively speaking, GPS satellites are moving slowly (a few km/s) in LEO you're buzzing along at 7km/s, which is about 20-25 ppm. That is the usual limiting case for bandwidth/tracking loops; you might want to go up to 11-12 km/s so you can get things moving at escape velocity. (there just aren't many people putting GPS on hypersonic projectiles - if you've got the bucks to shoot something at Mach 45, you can probably afford a custom GPS receiver) This is a bit tricky for older receivers because their tracking loop has to acquire in the face of the Doppler uncertainty and the range (code phase) uncertainty - there's a whole lore of optimum search strategies and how to get the fastest time-to-first-fix. Does the first LO have to be locked to something? the signal you're acquiring is MHz wide, so a 10ppm error in the LO frequency isn't a big deal. Short term stability does help, while you're acquiring. But one of the things about GPS that made it attractive is that the local clock can be pretty crummy. Bob Sent from my iPhone On Mar 30, 2017, at 9:46 AM, paul swed wrote: I am curious if the first local oscillator on a GPS receiver must actually be locked or coherent to the reference oscillator in the GPS receiver typically running at some 10 MHz approximately. Or as long as the first LO is quite stable it doesn't matter because the receiver can track the code. This is a question for very classic receivers like Austrons, Odetics etc. Discreet. Modern fully integrated receivers are not in question. Thank you for your insights. Regards Paul WB8TSL ___ 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] more of a time distribution question
jim...@earthlink.net said: > I've got a bunch (a pack?) of beaglebones that are connected via ethernet > (wired) and I want them to be (roughly) synchronized. How rough? > Running NTP (in some flavor) would be the obvious approach, but I'm in an > environment where there's no "outside" connectivity.. Could I make one of > the beaglebones be the NTP server, and the others be the clients? Yes. Search for orphan mode. I've never tried it. Let e know if you can't figure out how to make it work and I'll use that as an excuse to learn more. > (I've seen some "add a GPS to a Rpi to make a NTP server" projects, and I > could probably leverage that) That should work. I haven't found a GPS with PPS for the beaglebone. What level of accuracy do you want? If you only need 100 ms or so, then a normal junk GPS (no PPS) on USB should work. There is at least one GPS+PPS over USB. The GPS breakout board plus FTDI USB 2.0 breakout with a few wires gives you PPS with improved accuracy. (Not great, just 8x better than PPS over old/slow USB.) I got mine from Sparkfun. > I've also got a laptop (a mac, as it happens).. what's involved in making > *that* be a NTP server (e.g. the Mac might get its time from a NTP server > at some higher stratum, and then it propagates it down). That should work too. I don't know much about the Mac environment. If it's running a normal-enough ntpd it is already a server and you don't have to do anything. If not, you will have to build/install your own and/or poke holes in the firewall rules. -- 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] more of a time distribution question
https://www.eecis.udel.edu/~mills/ntp/html/orphan.html On Thu, Mar 30, 2017 at 12:37 PM, jimlux wrote: > > Pointers to documentation would be appreciated. > ___ 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] more of a time distribution question
On Thu, Mar 30, 2017 at 09:37:50AM -0700, jimlux wrote: > Running NTP (in some flavor) would be the obvious approach, but I'm in an > environment where there's no "outside" connectivity.. Could I make one of > the beaglebones be the NTP server, and the others be the clients? Disciplining them all to a specific free-running host would require the use of the LOCAL reference clock: http://doc.ntp.org/4.1.2/driver1.htm However, the LOCAL refclock is deprecated, and it is recommended that you use orphan mode instead, which is its intended replacement: https://www.eecis.udel.edu/~mills/ntp/html/orphan.html http://support.ntp.org/bin/view/Support/OrphanMode Orphan mode is designed for your use case, and allows for more redundancy than making them all clients of a single host. I'd go that route. > (I've seen some "add a GPS to a Rpi to make a NTP server" projects, and I > could probably leverage that) You could do that, but you don't really have to -- you can keep them synchronized at least to each other reasonably well this way. > I've also got a laptop (a mac, as it happens).. what's involved in making > *that* be a NTP server (e.g. the Mac might get its time from a NTP server at > some higher stratum, and then it propagates it down). OSX already runs ntpd; you should just need to tweak their default configuration. --msa ___ 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] more of a time distribution question
On Thu, 30 Mar 2017 09:37:50 -0700 jimlux wrote: > Running NTP (in some flavor) would be the obvious approach, but I'm in > an environment where there's no "outside" connectivity.. Could I make > one of the beaglebones be the NTP server, and the others be the clients? Yes, you can tell ntpd to use the system clock as reference. I have in my ntpd.conf: ---schnipp--- # use hw clock in case no servers available server 127.127.1.0 # local clock fudge 127.127.1.0 stratum 10 ---schnapp--- That makes the system clock a valid source. The fudge line is there to prevent ntpd from using the local system clock as reference unless it's the only source available. Attila Kinali -- You know, the very powerful and the very stupid have one thing in common. They don't alters their views to fit the facts, they alter the facts to fit the views, which can be uncomfortable if you happen to be one of the facts that needs altering. -- The Doctor ___ 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] HP5061B Ion Current
https://www.febo.com/pipermail/time-nuts/2017-March/104374.html I posted another HP cesium beam tube patent at http://gonascent.com/papers/hp/hp5061/US3387130.pdf . It covers the formation of the cesium beam and should be of interest. We now have over a month of operation on our first HP5061B at ion currents over 50 μA with no lock problems. The uon pump voltage is 2,338 V at that current. We are still working for lock on our second HP5061B. Both of the HV power supplies had to be repaired and other problems remain. Anyone having supposedly unusable beam tubes with high ion current should contact me at trojancowboy at gmail .com. πθ°μΩω±√·Γλ WB0KVV ___ 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] more of a time distribution question
I've got a bunch (a pack?) of beaglebones that are connected via ethernet (wired) and I want them to be (roughly) synchronized. Running NTP (in some flavor) would be the obvious approach, but I'm in an environment where there's no "outside" connectivity.. Could I make one of the beaglebones be the NTP server, and the others be the clients? (I've seen some "add a GPS to a Rpi to make a NTP server" projects, and I could probably leverage that) I've also got a laptop (a mac, as it happens).. what's involved in making *that* be a NTP server (e.g. the Mac might get its time from a NTP server at some higher stratum, and then it propagates it down). Pointers to documentation would be appreciated. ___ 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] GPS first LO need to be locked?
Hi There is a limited tracking range for Doppler. You would need to stay inside that. Bob Sent from my iPhone > On Mar 30, 2017, at 9:46 AM, paul swed wrote: > > I am curious if the first local oscillator on a GPS receiver must actually > be locked or coherent to the reference oscillator in the GPS receiver > typically running at some 10 MHz approximately. Or as long as the first LO > is quite stable it doesn't matter because the receiver can track the code. > This is a question for very classic receivers like Austrons, Odetics etc. > Discreet. Modern fully integrated receivers are not in question. > Thank you for your insights. > Regards > Paul > WB8TSL > ___ > 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] GPS first LO need to be locked?
> I am curious if the first local oscillator on a GPS receiver must actually > be locked or coherent to the reference oscillator in the GPS receiver > typically running at some 10 MHz approximately. Or as long as the first LO > is quite stable it doesn't matter because the receiver can track the code. > It doesn't matter, so long as the first LO is in the ballpark so that the Doppler search is not needlessly large. I'm not so familiar with the early receivers, but I imagine a single reference oscillator serves for everything---there would seem to be no reason to have more than one unless the antenna/downconverter were physically separate from the rest of the receiver. If an older receiver used a physical source at 10.23 MHz, it would still need to be offset slightly for each satellite because of "code doppler", but this choice of frequency might slightly simplify the circuitry. Current receivers would use any convenient physical rate, then synthesize the code rates. Cheers, Peter ___ 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] TAPR Oncore M12+ kit
Bob, Couldn't find a part number on the .jpg of the gps rx to to cross reference. Have a few +T's. Don't need another timing rx. Would take a few positioning rx's as the M12+ units are good for balloon launches. Reads out >65535ft. See top comment. Norm n3ykf On Thu, Mar 30, 2017 at 7:33 AM, Bob kb8tq wrote: > Hi > > At least from a quick read of the TAPR page it’s not real clear if the GPS > modules are M12+T or just M12+ boards. I believe that if they don’t have the > T on the end, they don’t have sawtooth / PPS (?). > > Bob > >> On Mar 30, 2017, at 2:11 AM, Mike Cook wrote: >> >> I would like to add mention of the M12+ interface board that Tom Wimmenhove >> offered on this list. I am using them to lock PRS10s. Very happy with it. >> Here is a link to some of his performance measurements. < >> http://tomwimmenhove.com/otherstuff/Oncore/ > >> >>> Le 28 mars 2017 à 20:47, Gregory Beat a écrit : >>> >>> Larry - >>> >>> Interface Boards for Motorola (and Garmin) receivers have been discussed >>> (and sold) by TAPR since late 1990s. TAPR archives all of this >>> documentation, for discontinued GPS kits, can be seen on the left margin. >>> https://www.tapr.org/gps_exp-kit.html >>> >>> Tom Clark, W3IWI Total Accurate Clock (TAC) project (1996) covers the >>> entire topic. >>> https://www.tapr.org/kits_tac2.html >>> >>> Simple interface board schematics (Serial Level converters, and voltage >>> adjustments for external antennas/ 3.3 or 5 V) can be found throughout the >>> Internet since mid-1990s. >>> Numerous radio amateurs DIY their own (breadboard) or sold small interfaces >>> at hamfests (1996-2006), until newer GPS solutions became surplus (and >>> smartphones with built-in GPS appeared after 2007). >>> >>> Doug McKinney, KC3RL (SK, December 2006) offered interface boards for the >>> Garmin (GPS-25) and Motorola receivers until about 2005. I have one of >>> Doug's boards in my GPS parts box. These were sold by TAPR until their >>> inventory was exhausted. >>> -- >>> Garmin >>> https://www.tapr.org/gps_garminib.html >>> Motorola >>> https://www.tapr.org/gps_vpib.html >>> >>> Synergy M12-MB board (web link to photo [jpg] below) >>> IF you look closely at the Synergy Board, you see the board outline and 2x5 >>> (10-pin) header for the earlier 8-channel Motorola receivers >>> https://www.tapr.org/images/M12-MB.jpg >>> >>> greg >>> w9gb >>> >>> Sent from iPad Air >>> On Mar 28, 2017, at 12:18 PM, Larry McDavid wrote: What "OEM supplier?" Do you mean from Synergy Systems? Or, is there an enclosure supplier to Synergy? Do you know if there is a schematic of the Synergy interface board available? Larry W6FUB > On 3/27/2017 9:31 AM, Gregory Beat wrote: > The TAPR offering is a "partial kit" from the Synergy's SynPaQ/E product. > Here is that data sheet: > http://www.synergy-gps.com/images/stories/pdf/synpaq%20product%20data%20sheet%20040110.pdf > Blank aluminum end-plates can be fabricated, or purchased from the OEM > supplier. > > w9gb -- Best wishes, Larry McDavid W6FUB Anaheim, California (SE of Los Angeles, near Disneyland) >>> ___ >>> 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 power of accurate observation is commonly called cynicism by those who >> have not got it. » >> George Bernard Shaw >> >> ___ >> 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.
[time-nuts] GPS first LO need to be locked?
I am curious if the first local oscillator on a GPS receiver must actually be locked or coherent to the reference oscillator in the GPS receiver typically running at some 10 MHz approximately. Or as long as the first LO is quite stable it doesn't matter because the receiver can track the code. This is a question for very classic receivers like Austrons, Odetics etc. Discreet. Modern fully integrated receivers are not in question. Thank you for your insights. Regards Paul WB8TSL ___ 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] TAPR Oncore M12+ kit
Hi At least from a quick read of the TAPR page it’s not real clear if the GPS modules are M12+T or just M12+ boards. I believe that if they don’t have the T on the end, they don’t have sawtooth / PPS (?). Bob > On Mar 30, 2017, at 2:11 AM, Mike Cook wrote: > > I would like to add mention of the M12+ interface board that Tom Wimmenhove > offered on this list. I am using them to lock PRS10s. Very happy with it. > Here is a link to some of his performance measurements. < > http://tomwimmenhove.com/otherstuff/Oncore/ > > >> Le 28 mars 2017 à 20:47, Gregory Beat a écrit : >> >> Larry - >> >> Interface Boards for Motorola (and Garmin) receivers have been discussed >> (and sold) by TAPR since late 1990s. TAPR archives all of this >> documentation, for discontinued GPS kits, can be seen on the left margin. >> https://www.tapr.org/gps_exp-kit.html >> >> Tom Clark, W3IWI Total Accurate Clock (TAC) project (1996) covers the entire >> topic. >> https://www.tapr.org/kits_tac2.html >> >> Simple interface board schematics (Serial Level converters, and voltage >> adjustments for external antennas/ 3.3 or 5 V) can be found throughout the >> Internet since mid-1990s. >> Numerous radio amateurs DIY their own (breadboard) or sold small interfaces >> at hamfests (1996-2006), until newer GPS solutions became surplus (and >> smartphones with built-in GPS appeared after 2007). >> >> Doug McKinney, KC3RL (SK, December 2006) offered interface boards for the >> Garmin (GPS-25) and Motorola receivers until about 2005. I have one of >> Doug's boards in my GPS parts box. These were sold by TAPR until their >> inventory was exhausted. >> -- >> Garmin >> https://www.tapr.org/gps_garminib.html >> Motorola >> https://www.tapr.org/gps_vpib.html >> >> Synergy M12-MB board (web link to photo [jpg] below) >> IF you look closely at the Synergy Board, you see the board outline and 2x5 >> (10-pin) header for the earlier 8-channel Motorola receivers >> https://www.tapr.org/images/M12-MB.jpg >> >> greg >> w9gb >> >> Sent from iPad Air >> >>> On Mar 28, 2017, at 12:18 PM, Larry McDavid wrote: >>> >>> What "OEM supplier?" Do you mean from Synergy Systems? Or, is there an >>> enclosure supplier to Synergy? >>> >>> Do you know if there is a schematic of the Synergy interface board >>> available? >>> >>> Larry W6FUB >>> On 3/27/2017 9:31 AM, Gregory Beat wrote: The TAPR offering is a "partial kit" from the Synergy's SynPaQ/E product. Here is that data sheet: http://www.synergy-gps.com/images/stories/pdf/synpaq%20product%20data%20sheet%20040110.pdf Blank aluminum end-plates can be fabricated, or purchased from the OEM supplier. w9gb >>> -- >>> Best wishes, >>> >>> Larry McDavid W6FUB >>> Anaheim, California (SE of Los Angeles, near Disneyland) >> ___ >> 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 power of accurate observation is commonly called cynicism by those who > have not got it. » > George Bernard Shaw > > ___ > 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] HP5061B Cesium Oven Properties
Donald some great work you are doing and since many of us have 5061s that are on fumes this is a great way to further extend the life while operating. The run time may be different for various ovens. If its 83c then it was a high flux tube. They burned up the Cs at a fasterate to give a better signal to noise. These are typically option 004 units. Frankenstein has the fewest Cs and would be an ideal candidate for a cycled oven since currently it uses a home brew DC oven controller and is quite easily modified. Funny this is like restoring an old 1960s class car. The tricks that are needed. Regards Paul WB8TSL On Wed, Mar 29, 2017 at 11:02 PM, Donald E. Pauly wrote: > https://www.febo.com/pipermail/time-nuts/2017-March/104374.html > > The cesium oven acts as an evaporator for liquid cesium which melts at > 28.5° C. One of our beam tubes has 83°C for its operating > temperature. It also calls for a A11R11 and A11R12 of 3.83 K and > 42.2K which is 3.51K. Oven power is specified at 2.2V and 0.9A or > 1.98 W. Being in a vacuum allows less heater power. Oven temperature > is very critical to provide enough cesium in the beam but at the same > time not wasting it. A switching power supply runs the oven as well > as providing 1.2V at 3.4A to the hot wire ionizer which is 4.08 Watts. > > It took 10 minutes from a cold start for the cesium oven current to > drop from being pegged to its final value. After stabilizing, we > connected a 470 Ω across the thermistor from the beam tube to shut off > the heater. Here is the beam current versus time in minutes as the > oven cooled off. Note that it took 17 minutes for the beam current to > drop to half value. Continuous lock was maintained. > > time beam > 0 20 > 3 18 > 5 17 > 8 16 > 9 15 > 1114 > 1412 > 1711 > > We then reapplied oven power and watched the beam current increase and > oven current decrease. > > time beam oven > 0 16 over 50 > 3 20missed > 5 22missed > 6 2115 > 8 20 15 > 10 20 14 > > Finally we applied oven power from a 35 minute cooldown and waited for > lock. If the oscillator oven is stable, the cesium oven will achieve > lock in only two minutes. There is no need to waste cesium if you do > not need the instrument to be locked. > > time beam status > 0 8 unlock > 2 10 lock > 3 12lock > 4 18lock > > πθ°μΩω±√·Γλ > WB0KVV > ___ > 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] TAPR Oncore M12+ kit
I would like to add mention of the M12+ interface board that Tom Wimmenhove offered on this list. I am using them to lock PRS10s. Very happy with it. Here is a link to some of his performance measurements. < http://tomwimmenhove.com/otherstuff/Oncore/ > > Le 28 mars 2017 à 20:47, Gregory Beat a écrit : > > Larry - > > Interface Boards for Motorola (and Garmin) receivers have been discussed (and > sold) by TAPR since late 1990s. TAPR archives all of this documentation, for > discontinued GPS kits, can be seen on the left margin. > https://www.tapr.org/gps_exp-kit.html > > Tom Clark, W3IWI Total Accurate Clock (TAC) project (1996) covers the entire > topic. > https://www.tapr.org/kits_tac2.html > > Simple interface board schematics (Serial Level converters, and voltage > adjustments for external antennas/ 3.3 or 5 V) can be found throughout the > Internet since mid-1990s. > Numerous radio amateurs DIY their own (breadboard) or sold small interfaces > at hamfests (1996-2006), until newer GPS solutions became surplus (and > smartphones with built-in GPS appeared after 2007). > > Doug McKinney, KC3RL (SK, December 2006) offered interface boards for the > Garmin (GPS-25) and Motorola receivers until about 2005. I have one of > Doug's boards in my GPS parts box. These were sold by TAPR until their > inventory was exhausted. > -- > Garmin > https://www.tapr.org/gps_garminib.html > Motorola > https://www.tapr.org/gps_vpib.html > > Synergy M12-MB board (web link to photo [jpg] below) > IF you look closely at the Synergy Board, you see the board outline and 2x5 > (10-pin) header for the earlier 8-channel Motorola receivers > https://www.tapr.org/images/M12-MB.jpg > > greg > w9gb > > Sent from iPad Air > >> On Mar 28, 2017, at 12:18 PM, Larry McDavid wrote: >> >> What "OEM supplier?" Do you mean from Synergy Systems? Or, is there an >> enclosure supplier to Synergy? >> >> Do you know if there is a schematic of the Synergy interface board available? >> >> Larry W6FUB >> >>> On 3/27/2017 9:31 AM, Gregory Beat wrote: >>> The TAPR offering is a "partial kit" from the Synergy's SynPaQ/E product. >>> Here is that data sheet: >>> http://www.synergy-gps.com/images/stories/pdf/synpaq%20product%20data%20sheet%20040110.pdf >>> Blank aluminum end-plates can be fabricated, or purchased from the OEM >>> supplier. >>> >>> w9gb >> -- >> Best wishes, >> >> Larry McDavid W6FUB >> Anaheim, California (SE of Los Angeles, near Disneyland) > ___ > 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 power of accurate observation is commonly called cynicism by those who have not got it. » George Bernard Shaw ___ 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.
