Re: [time-nuts] Mac OS and iOS leap second handling
Eric, You might want to try this thread over on the LEAPSECS list [1]. Yes, there's a special list just for leap second nuts so that we don't have to discuss them here on time-nuts. You'll find the archives deep, fascinating, and often contentious. Practical real life examples like your low-cost high-reliability UTC station clock would be most welcome. /tvb [1] https://pairlist6.pair.net/mailman/listinfo/leapsecs On 10/22/2019 3:28 PM, Eric Scace wrote: Maybe someone on the list has a recent and authoritative answer to the following questions. I’ve been digging around in “civilian mode” (not an OS X or iOS developer) trying to determine if current Mac OS X and iOS releases handle leap seconds: no smearing proper display of 23:59:60, etc on the system clock & return of same to appropriate function calls. I have not been able to discover a well-documented answer to this question; e.g., video of an OS X/iOS system clock displaying a leap second, or Apple-sourced documentation stating leap second support. There are assertions that OS X was built around POSIX and suffers from the limitations of Unix epoch time decisions of long ago. Is that still the case? (In contrast, Microsoft docs claim Win 2018 Oct and Win Server 2019 now have leap second support.) Thanks, — Eric ___ time-nuts mailing list --time-nuts@lists.febo.com To unsubscribe, go tohttp://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] DC distribution
On 10/22/19 7:58 PM, Scott McGrath wrote: 4 pin xlr is also standard for pro audio/video. So you might want to use the same pin configuration as the ‘standard’ so you can use the large variety of accessories available. Content by Scott Typos by Siri On Oct 22, 2019, at 7:42 PM, "n...@lazygranch.com" wrote: Glad I read all the replies since I was also going to suggest Canon connectors. I have used the 3 pin canon because they are easy to find and I am not going to plug a microphone into a power supply. The breakout box is unique enough to not get it confused with anything else. (Not suitable for the general public!!!) That said, the 4 pin canon is a good idea. It is a power supply standard. You can find cables online. Mine is designed for battery use. I put reverse biased diodes across the supply and use a fuse. I never hooked it up backwards but you never know. 4 pin is pin 1 is gnd, pin 4 is +12V BTW there is a weird 4 pin configuration with 3 in a triangle and 1 pin in the middle. I've seen it in a catalog, but never in the wild. The 5 pin XLR is used for DMX lighting controllers, so you want to either be compatible pinout (i.e. not blow things up) or avoid it. Pin 1 is ground, don't recall how the rest is laid out, other than it's a pair The 6 pin XLR is a bit unusual, and the pins are significantly smaller, too. ___ 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] "Ancient 5065..."
Bob indeed with the comment from a friend, that sort of settled my desire for a patek down. Agree on the divide chain and drivers. Very easy to replace today. But not a concern since I won't be bidding for a clock with a maybe working something. Regards Paul WB8TSL On Tue, Oct 22, 2019 at 6:31 PM Bob kb8tq wrote: > Hi > > Indeed, while the clock *is* cool, I would strip it out of a 5065. The > nose is > one issue. The power consumed by the chain of boards (which also would > go) is (to me) at least as big a bother. > > Bob > > > On Oct 22, 2019, at 10:47 AM, paul swed wrote: > > > > The comment I would make is in the past there have been discussions on > > time-nuts about the patek clock movement. Maybe the units worth it for > that > > alone. But do agree the shipping will be quite an additional cost. > > I had actually wanted a clock. But a person filled me in on the clack > clack > > clack of the movement. Annoying was his comment. > > Regards > > Paul > > > > On Mon, Oct 21, 2019 at 11:07 PM Bob kb8tq wrote: > > > >> Hi > >> > >> I think that you never really know what’s what until *you* can poke at > it > >> and try to fire it up. > >> If the device (any device) was run for decades, parts probably were > >> swapped to keep it > >> running. > >> > >> Bob > >> > >>> On Oct 21, 2019, at 4:16 PM, Ulf Kylenfall via time-nuts < > >> time-nuts@lists.febo.com> wrote: > >>> > >>> Hmm... > >>> > >>> On one hand the seller claims ..."is fully functional" > >>> On the other hand the seller writes..."untested" > >>> Strange that it has the light brown type cover plates. > >>> My old s/n 848-00131 has the dark blue covers. > >>> for $333 I would have baught it untested but the shippingto Sweden is > >> another $209. It will be interseting to seehow much money it will go > for... > >>> > >>> > >>> /Ulf - SM6GXV > >>> ___ > >>> 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 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] DC distribution
4 pin xlr is also standard for pro audio/video. So you might want to use the same pin configuration as the ‘standard’ so you can use the large variety of accessories available. Content by Scott Typos by Siri On Oct 22, 2019, at 7:42 PM, "n...@lazygranch.com" wrote: Glad I read all the replies since I was also going to suggest Canon connectors. I have used the 3 pin canon because they are easy to find and I am not going to plug a microphone into a power supply. The breakout box is unique enough to not get it confused with anything else. (Not suitable for the general public!!!) That said, the 4 pin canon is a good idea. It is a power supply standard. You can find cables online. Mine is designed for battery use. I put reverse biased diodes across the supply and use a fuse. I never hooked it up backwards but you never know. If you need to make holes for the Canon jacks, those Harbor Freight multi-hole drills work fine. On Fri, 4 Oct 2019 13:32:12 +0100 "Paul Bicknell" wrote: > Hi I am standardising on 4 pin XLR connectors for 12 Volts as used in > the TV industry Perhaps you could use the 6 pin for 5 volts > I do not recommend the 2 pin as this is for 240 V ac > Or the 3 pin as you could take out a microphone > > I am going to be Using military connectors for 24 V DC and 400 Hz > > -Original Message- > From: time-nuts [mailto:time-nuts-boun...@lists.febo.com] On Behalf > Of John Ackermann. N8UR > Sent: 04 October 2019 12:40 > To: David Van Horn via time-nuts > Subject: Re: [time-nuts] DC distribution > > I use lots and lots of Anderson PowerPoles and (mostly) West Mountain > Radio distribution units. I have different color codes for different > voltages -- red/black for 12v, orange/black for 24v, green/black for > 5v, etc. Primary 12 and 24 volt sources are big AGM batteries across > float chargers. > > On Oct 4, 2019, 2:03 AM, at 2:03 AM, Bill Dailey > wrote: >> Setting up a new workbench and am wondering what wisdom people can >> offer. I am powering numerous synthesizers (5v), small receivers >> (5v), Upconverters (5v), larger receivers (12v), fury Gpsdo’s.. >> etc. anyone use something neat and not real expensive for >> distributing 5v and 12v. I am hoping for a long COTS pcb with fusing >> and maybe holes for plugs. >> >> >> Any insights? >> >> Bill >> >> Bill Dailey >> >> Negativity always wins the short game. But positivity wins the long >> game. - Gary Vaynerchuk >> >> Don’t be easy to understand, >> Be impossible to misunderstand >> - Steve Sims >> ___ >> 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. > > > - > No virus found in this message. > Checked by AVG - www.avg.com > Version: 2016.0.8048 / Virus Database: 4793/15886 - Release Date: > 08/14/18 Internal Virus Database is out of date. > > > ___ > 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] Mac OS and iOS leap second handling
Maybe someone on the list has a recent and authoritative answer to the following questions. I’ve been digging around in “civilian mode” (not an OS X or iOS developer) trying to determine if current Mac OS X and iOS releases handle leap seconds: no smearing proper display of 23:59:60, etc on the system clock & return of same to appropriate function calls. I have not been able to discover a well-documented answer to this question; e.g., video of an OS X/iOS system clock displaying a leap second, or Apple-sourced documentation stating leap second support. There are assertions that OS X was built around POSIX and suffers from the limitations of Unix epoch time decisions of long ago. Is that still the case? (In contrast, Microsoft docs claim Win 2018 Oct and Win Server 2019 now have leap second support.) Thanks, — Eric ___ 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] DC distribution
Glad I read all the replies since I was also going to suggest Canon connectors. I have used the 3 pin canon because they are easy to find and I am not going to plug a microphone into a power supply. The breakout box is unique enough to not get it confused with anything else. (Not suitable for the general public!!!) That said, the 4 pin canon is a good idea. It is a power supply standard. You can find cables online. Mine is designed for battery use. I put reverse biased diodes across the supply and use a fuse. I never hooked it up backwards but you never know. If you need to make holes for the Canon jacks, those Harbor Freight multi-hole drills work fine. On Fri, 4 Oct 2019 13:32:12 +0100 "Paul Bicknell" wrote: > Hi I am standardising on 4 pin XLR connectors for 12 Volts as used in > the TV industry Perhaps you could use the 6 pin for 5 volts > I do not recommend the 2 pin as this is for 240 V ac > Or the 3 pin as you could take out a microphone > > I am going to be Using military connectors for 24 V DC and 400 Hz > > -Original Message- > From: time-nuts [mailto:time-nuts-boun...@lists.febo.com] On Behalf > Of John Ackermann. N8UR > Sent: 04 October 2019 12:40 > To: David Van Horn via time-nuts > Subject: Re: [time-nuts] DC distribution > > I use lots and lots of Anderson PowerPoles and (mostly) West Mountain > Radio distribution units. I have different color codes for different > voltages -- red/black for 12v, orange/black for 24v, green/black for > 5v, etc. Primary 12 and 24 volt sources are big AGM batteries across > float chargers. > > On Oct 4, 2019, 2:03 AM, at 2:03 AM, Bill Dailey > wrote: > >Setting up a new workbench and am wondering what wisdom people can > >offer. I am powering numerous synthesizers (5v), small receivers > >(5v), Upconverters (5v), larger receivers (12v), fury Gpsdo’s.. > >etc. anyone use something neat and not real expensive for > >distributing 5v and 12v. I am hoping for a long COTS pcb with fusing > >and maybe holes for plugs. > > > > > >Any insights? > > > >Bill > > > >Bill Dailey > > > >Negativity always wins the short game. But positivity wins the long > >game. - Gary Vaynerchuk > > > >Don’t be easy to understand, > >Be impossible to misunderstand > >- Steve Sims > >___ > >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. > > > - > No virus found in this message. > Checked by AVG - www.avg.com > Version: 2016.0.8048 / Virus Database: 4793/15886 - Release Date: > 08/14/18 Internal Virus Database is out of date. > > > ___ > 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] "Deaf" receivers ?
I recently acquired a pair of Meinberg M600's (with GPS-CON downconverters). >From the usual auction site got a dual band antenna (for futureproofing), a 2nd hand mini-circuits ZN4PD1-63W-S+, several SMA BIAS-TEE to prevent DC issues, and an assortment of coax cables to connect everything up. To power the antenna I used a ublox M8Q series without a BIAS-TEE connected to the splitter, and then tested with another ublox (a NEO 7M) via a BIAS-TEE that it could also see satellites and that both could get a 3D fix. When I connected up each of the M600's, they eventually acquired positions and acheived sync, but while the ublox receivers rarely do not show a 3d fix, both of the M600's will show the a similar number of satellites in view as the ublox, and sometimes more than one "Good" satellite, but the "Selected Satellite Set:" never seems to change from "00 00 00 00". I presume that as its a timing device, that once it has surveyed its position, it only needs one satellite to solve for time, and the MRS status shows "Signal available, Is master, Is locked, Is accurate" with an offset that is usually within -50 to -120ns but I'm lost as to what the "Selected Satellite Set:" should be displaying. At the moment, one of the Meinbergs shows 10 in view and one good, and one of the ublox shows 12 in view and 8 used. I tried with one of the Meinberg's (via the GPS-CON) connected directly to the antenna with no improvement, and tried with a patch antenna directly connected, again with no improvement, and different ports on the splitter etc. The antenna location is by no means ideal (west facing window in fairly central London), but none of the ublox receivers (just basic Max8 and Neo7m, no timing ones yet) have had any trouble getting and keeping a 3D fix. >From my "naive" viewpoint, it looks as if the Meinbergs are a little "deaf", but I'm guessing that I'm missing something. Any suggestions gratefully received. Cheers Arne ___ 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] "Ancient 5065..."
Hi Indeed, while the clock *is* cool, I would strip it out of a 5065. The nose is one issue. The power consumed by the chain of boards (which also would go) is (to me) at least as big a bother. Bob > On Oct 22, 2019, at 10:47 AM, paul swed wrote: > > The comment I would make is in the past there have been discussions on > time-nuts about the patek clock movement. Maybe the units worth it for that > alone. But do agree the shipping will be quite an additional cost. > I had actually wanted a clock. But a person filled me in on the clack clack > clack of the movement. Annoying was his comment. > Regards > Paul > > On Mon, Oct 21, 2019 at 11:07 PM Bob kb8tq wrote: > >> Hi >> >> I think that you never really know what’s what until *you* can poke at it >> and try to fire it up. >> If the device (any device) was run for decades, parts probably were >> swapped to keep it >> running. >> >> Bob >> >>> On Oct 21, 2019, at 4:16 PM, Ulf Kylenfall via time-nuts < >> time-nuts@lists.febo.com> wrote: >>> >>> Hmm... >>> >>> On one hand the seller claims ..."is fully functional" >>> On the other hand the seller writes..."untested" >>> Strange that it has the light brown type cover plates. >>> My old s/n 848-00131 has the dark blue covers. >>> for $333 I would have baught it untested but the shippingto Sweden is >> another $209. It will be interseting to seehow much money it will go for... >>> >>> >>> /Ulf - SM6GXV >>> ___ >>> 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 instructions there.
Re: [time-nuts] Do ordinary clouds adversely affect GPS reception?
Hi jimlux -- unfortunately my domain expertise is in the digital domain (computer science) and I'm having a hard time in following this paper. I do understand that "space weather", i.e. CMEs (coronal mass ejections) will significantly impact GPS/GLONASS operations when the charged particles reach earth. One question I would have for you is on the ionospheric delays due to weather conditions like moderate or heavy rain, thunderstorms and more severe weather fronts. My understanding of it is that when it comes to GPS usage for positioning purposes, the use of DGPS or some kind of augmentation system like WAAS provides "good enough" corrections to compensate for ionospheric perturbations. Whereas for timing applications, using stationary mode (i.e. either manually programming station coordinates into the GPS receiver or having the GPS receiver compute them over several hours by averaging out positioning data) is enough for "good" enough timing measurements. How much is "good enough" is not quite clear to me. What would be the magnitude of timing errors with GPS in stationary mode, assuming my understanding of stationary mode is correct? My current Oscilloquartz DGPS, BG7TBL DGPS and GPS + Symmetricom BCP 635 timing board setups gives me an estimated best time accuracy in the order of 5 to 50 microseconds (my own estimate -- unfortunately I don't have access to a lab with calibrated reference cesium oscillators), which is enough for my "time-nuts" hobby. I wonder if I would be able to measure ionospheric delays -- perhaps I could measure them by comparing the difference of my "well known" GPS coordinates once Oscilloquartz DGPS locks in stationary mode versus the GPS coordinates I receive with a UBLOX-7 vanilla receiver? Apologies for the many questions. -- Fio Cattaneo Universal AC, can Entropy be reversed? -- "THERE IS AS YET INSUFFICIENT DATA FOR A MEANINGFUL ANSWER." On Tue, Oct 22, 2019 at 6:06 AM jimlux wrote: > > On 10/22/19 1:13 AM, Poul-Henning Kamp wrote: > > > > In message > > , > > Fiorenzo Cattaneo writes: > > > >> Any kind of atmospheric disturbance has a measurable effect on GPS > >> space and time precision, [...] > > > > Actually, it's even simpler than that: > > > > Any electrical charge in the freshnell-zone between the two antennas > > delays the signal. > > > > In practice that means "any ion ..." > > > > Rain clouds harbour significant ionization, long before they become > > thunderstorms. > > > That's still a pretty small effect for RF propagation at L-band > > and here's a paper discussing just such effects > https://iopscience.iop.org/article/10.1088/1742-6596/1112/1/012021/pdf > > what happens here is that charge in a large thunderstorm affects the ion > density in the ionosphere. > > However, I don't think that's "cloudy day vs sunny day" > > > > > > > > Apart from that, the lower atmosphere is pretty predictable with > > respect to ionization. > > > > > ___ > 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] can of worms: time-of-day in a community radio station
> > > With this setup you have no single point of failure, and even if the > > connection to internet fails, they can still provide time as they are > > peering > > and synchronizing with each other. > No, it doesn't work that way. You need connectivity to at least one stratum 1 > server. > There is an option to elect one, orphan mode, if you get disconnected from the > net. That keeps all the local clocks close together. They will all drift > along with the chosen leader. My understanding is that it would work moderately well even without a stratum-1 server, at least be able to operate within a few tens of milliseconds for several hours. Although I confess I haven't used peering in a very long time. In my workplace we added stratum-1 GPS symmetricom NTP servers about 6 months after the above mentioned setup. > > > > You can use this list to pick stratum 1 servers: > > http://www.advtimesync.com/docs/manual/ > > stratum1.html > > There is no date on that list. At a quick glance, a few systems I'm familiar > with are way out of date. I wouldn't trust any of the details. Same for > other lists of stratum 1 servers. They might be a good starting point. In > particular, many servers that say "open access" on lists like that have > changed their rules, often going off the air. My apologies, I just did a quick googling because I was on the phone and didn't have access to my desktop bookmarks. This is the list I normally use http://support.ntp.org/bin/view/Servers/StratumOneTimeServers > > > > server time.nist.gov > > That's a bad example. NIST has servers at several locations. That name > rotates across them. You might get a good one, or you might get one on the > other side of the country. If it works well today, it may not after you > reboot and pick a different server. > https://tf.nist.gov/tf-cgi/servers.cgi 100% agree on this.. DNS roundrobin is good enough for 10s of milliseconds, but for best results you should always pick nearby servers. The worst thing of DNS round robin is that it gives unpredictable results. > > > > just a cheap GPS receiver (serial is best, but USB should be OK > > There are 3 levels of GPS receiver. GPSDO is best. GPS with PPS is second - > serial prefered, but USB works. Low cost GPS (without PPS) on USB is last. > > USB is polled -- no interrupts. That adds a millisecond of jitter. That's > probably not an issue if your goal is 100 ms. (If you are a geek, be sure > you understand hanging bridges.) > > The timing on the serial port from low cost GPS receivers is often crappy. > This is a horrible example: > http://users.megapathdsl.net/~hmurray/ntp/GPSSiRF-off.gif > Anyway, you need to check the device you select. (Or get suggestions from > people who are using them for NTP.) Ouch, that looks pretty awful. > > The PPS signal will fix that. > > The GPSDO will continue providing decent time if your GPS stops working. > Holdover is the buzzword. Currently my stratum-1 servers are as follows, in decreasing order of accuracy: * amd64 PC with Symmetricom/Microsemi BCP635 timing board, fed with the 1 PPS signal from a UBLOX-7 receiver. * amd64 PCENGINES with GPSDO with PPS fed to serial port. I very recently got two GPSDO, a BG7TBL and a Oscilloquartz STAR 4 receiver. The latter is very nice as it also provides the receiver state (calculating stationary mode, stationary mode, GPS lock info and holdover info). * amd64 PCENGINES with vanilla UBLOX-7 receiver with PPS fed to serial port. Thus far I have been playing with PPS on the serial port. I just modified the serial port driver to support PPS_ECHOASSERT and PPS_ECHOCLEAR so that I can use the oscilloscope to get a quantitative understanding of what the interrupt latency and jitter is. Perhaps I should experiment with PPS on the parallel port as well. RS232 is far from ideal, mainly due to the fact that the rise time of the PPS edge on a 12 volt signal is very high. The UBLOX-7 PPS has a TTL output and the RS232 port I use is TTL compatible so I'm hoping this ameliorates the issue with the rising edge on the RS232, but I'll only know for once I get the measurements with the oscilloscope. I keep comparing the time between these three servers, and I've observed an absolute lock offset of approximately 10 to 20 microseconds between the timing board server and the PPS on RS232 servers. That is what I would expect by RS232 timings. Once I have the oscilloscope measurements I should be able to adjust and correct for the average interrupt latency, although I won't be able to do anything for the jitter. > > > -- > 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
Re: [time-nuts] "Ancient 5065..."
The comment I would make is in the past there have been discussions on time-nuts about the patek clock movement. Maybe the units worth it for that alone. But do agree the shipping will be quite an additional cost. I had actually wanted a clock. But a person filled me in on the clack clack clack of the movement. Annoying was his comment. Regards Paul On Mon, Oct 21, 2019 at 11:07 PM Bob kb8tq wrote: > Hi > > I think that you never really know what’s what until *you* can poke at it > and try to fire it up. > If the device (any device) was run for decades, parts probably were > swapped to keep it > running. > > Bob > > > On Oct 21, 2019, at 4:16 PM, Ulf Kylenfall via time-nuts < > time-nuts@lists.febo.com> wrote: > > > > Hmm... > > > > On one hand the seller claims ..."is fully functional" > > On the other hand the seller writes..."untested" > > Strange that it has the light brown type cover plates. > > My old s/n 848-00131 has the dark blue covers. > > for $333 I would have baught it untested but the shippingto Sweden is > another $209. It will be interseting to seehow much money it will go for... > > > > > > /Ulf - SM6GXV > > ___ > > 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] Flash!!! FA2 works on Arduino Tablets !!!
How does https://www.startech.com/Cards-Adapters/Serial-Cards-Adapters/micro-usb-serial-adapter-android~ICUSBANDR232 do it? Once every thing else works I may buy one. Bert Kehren In a message dated 10/22/2019 9:06:15 AM Eastern Standard Time, shali...@gmail.com writes: The tablet will not accept charging current when in the OTG mode, which is required to make the tablet a master (USB is asymmetrical system, there is always a master and a slave). It is not a function of the type of hub plugged into it. When you plug the tablet into a PC, the PC is the master and the tablet will charge from the PC. When you plug an accessory into the tablet, it becomes the master and it delivers power to whatever is connected to it. On Mon, Oct 21, 2019 at 9:06 AM Paul Moore wrote: > On Mon, Oct 21, 2019 at 12:01 AM Didier Juges wrote: > > One issue: once the tablet is connected to the FA2, there will be no way > to > > charge the tablet, so start with a fresh battery... > > I would think that if you connected both the FA2 and the tablet to a > USB hub you should be able to talk to the FA2 as well as maintain the > tablet's battery. Of course this requires that you select a USB hub > which can deliver enough power to the tablet, but that shouldn't be > too difficult. > > -- > paul moore > www.paul-moore.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] Flash!!! FA2 works on Arduino Tablets !!!
The tablet will not accept charging current when in the OTG mode, which is required to make the tablet a master (USB is asymmetrical system, there is always a master and a slave). It is not a function of the type of hub plugged into it. When you plug the tablet into a PC, the PC is the master and the tablet will charge from the PC. When you plug an accessory into the tablet, it becomes the master and it delivers power to whatever is connected to it. On Mon, Oct 21, 2019 at 9:06 AM Paul Moore wrote: > On Mon, Oct 21, 2019 at 12:01 AM Didier Juges wrote: > > One issue: once the tablet is connected to the FA2, there will be no way > to > > charge the tablet, so start with a fresh battery... > > I would think that if you connected both the FA2 and the tablet to a > USB hub you should be able to talk to the FA2 as well as maintain the > tablet's battery. Of course this requires that you select a USB hub > which can deliver enough power to the tablet, but that shouldn't be > too difficult. > > -- > paul moore > www.paul-moore.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] Do ordinary clouds adversely affect GPS reception?
On 10/22/19 1:13 AM, Poul-Henning Kamp wrote: In message , Fiorenzo Cattaneo writes: Any kind of atmospheric disturbance has a measurable effect on GPS space and time precision, [...] Actually, it's even simpler than that: Any electrical charge in the freshnell-zone between the two antennas delays the signal. In practice that means "any ion ..." Rain clouds harbour significant ionization, long before they become thunderstorms. That's still a pretty small effect for RF propagation at L-band and here's a paper discussing just such effects https://iopscience.iop.org/article/10.1088/1742-6596/1112/1/012021/pdf what happens here is that charge in a large thunderstorm affects the ion density in the ionosphere. However, I don't think that's "cloudy day vs sunny day" Apart from that, the lower atmosphere is pretty predictable with respect to ionization. ___ 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] Do ordinary clouds adversely affect GPS reception?
On 10/22/19 2:23 AM, Jim Palfreyman wrote: I see no attenuation at 1376 MHz (close to GPS frequency) when observing pulsars with a radio telescope. Even the brightest pulsar (Vela) is so much fainter than a GPS signal which boom in when they happen to pass into the telescope's beam. It definitely happens at higher frequencies though. Up around 20 GHz it's a different story. On a sensitive receiver I operated at 13.402 GHz in New Mexico, I could easily tell when it was overcast or not by the noise temperature. There was some discussion about whether we were seeing the physical temperature of the clouds, or we were seeing a reflection of the earth off the water particles in the clouds. We didn't go any further, since our project was to measure a radar signal, but it was interesting. ___ 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] Do ordinary clouds adversely affect GPS reception?
On 10/21/19 10:06 PM, Dana Whitlow wrote: A friend of mine living in SE lower Michigan recently bought a Geppetto GPS clock, and swears that it tends to lose satellite lock on cloudy days but does OK on sunny days. He is admittedly using a very poorly-sited antenna, placed in a window because his house has aluminum siding. He reports that his Garmin handheld GPS has much less trouble acquiring and maintaining lock on cloudy days than does the Geppetto, but still tends to show higher levels of probable position error on cloudy days. I don't yet know if he takes the Garmin outside for these comparisons. Is this a real phenomenon, or is my friend just imagining things? Clpuds and even light rain won't change the received SNR very much at L band. I'm going to guess that there's something that is cloud correlated - open and closing ventilation shutters? Soil or ground cover moisture changes, which changes the strength of a multipath signal. Some sort of thermal expansion effects changing the spacing of siding panels when the sun shines on them vs no. Meanwhile I think I have finally persuaded him to install the antenna outside on the roof. Dana(K8YUM) ___ 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] Do ordinary clouds adversely affect GPS reception?
In message , Fiorenzo Cattaneo writes: >Any kind of atmospheric disturbance has a measurable effect on GPS >space and time precision, [...] Actually, it's even simpler than that: Any electrical charge in the freshnell-zone between the two antennas delays the signal. In practice that means "any ion ..." Rain clouds harbour significant ionization, long before they become thunderstorms. Apart from that, the lower atmosphere is pretty predictable with respect to ionization. -- 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] Do ordinary clouds adversely affect GPS reception?
I see no attenuation at 1376 MHz (close to GPS frequency) when observing pulsars with a radio telescope. Even the brightest pulsar (Vela) is so much fainter than a GPS signal which boom in when they happen to pass into the telescope's beam. It definitely happens at higher frequencies though. Up around 20 GHz it's a different story. On Tue, 22 Oct 2019 at 17:01, Dana Whitlow wrote: > A friend of mine living in SE lower Michigan recently bought > a Geppetto GPS clock, and swears that it tends to lose > satellite lock on cloudy days but does OK on sunny days. > > He is admittedly using a very poorly-sited antenna, > placed in a window because his house has aluminum > siding. He reports that his Garmin handheld GPS > has much less trouble acquiring and maintaining lock > on cloudy days than does the Geppetto, but still tends > to show higher levels of probable position error on > cloudy days. I don't yet know if he takes the Garmin > outside for these comparisons. > > Is this a real phenomenon, or is my friend just imagining > things? > > Meanwhile I think I have finally persuaded him to install > the antenna outside on the roof. > > Dana(K8YUM) > ___ > 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] Ancient HP 5065A on ebay
It must be very old, had I ever seen an HP5065A with three positions of the Function Switch (Adj Mag Field) Luciano Da "time-nuts" time-nuts-boun...@lists.febo.com A time-nuts@lists.febo.com Cc Data Mon, 21 Oct 2019 08:59:34 -0700 Oggetto [time-nuts] Ancient HP 5065A on ebay There is an 5065A on Ebay that has the earliest SN I have ever seen. 808-00031 or maybe 00051? Maybe the first one sold? If the lamp oven has not fried it might be a fun project. It has the Patek analog clock. Cheers, Corby ___ 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] Do ordinary clouds adversely affect GPS reception?
Any kind of atmospheric disturbance has a measurable effect on GPS space and time precision, the question is more about how much the impact is. Presuming that the GPS receiver is stationary, the antenna has a clear visibility of the sky, then "ordinary weather" like clouds, moderate rain or snow, should not have a large effect. The GPS signal will be attenuated by rain and snow, but precision should not be impacted provided that the GPS receiver is operating in stationary mode (I'm referring to stationary mode as I presume the goal here is to get precise GPS or UTC time, not position). The signal quality will definitely be very poor if keeping the antenna window mounted, especially if there are nearby metal surfaces. I see a significant difference in quality between an antenna by the window in my basement (up to and including complete periodic loss of GPS lock) versus keeping the antenna in the attic (composition roof in my case). In the basement there is only 1/4 sky direct view as opposed to the attic which has essentially unobstructed view. The antenna in the attic never gave me trouble. I have not compared the difference in signal quality between an attic mounted antenna versus an externally mounted antenna so I don't know about that. I haven't seen loss of GPS lock under light to moderate rain, let alone simple clouds. Heavy rain doesn't seem to be a big problem either. Your friend's experience of losing GPS lock on cloudy days seems very, very strange to me. Barring malfunctioning receiver or a defective antenna, I would first make sure to have the antenna externally mounted, or at least in the attic if the roof is composition or wood shingles. Your friend could collect NMEA data on PDOP, HDOP, satellites view with signal strengths and how many satellites are tracked and part of the GPS solution. I definitely see better signal quality with the BG7TBL GPSDO as opposed to a Garmin 18x with serial output and PPS. The Oscilloquartz Star IV GPSDO seems to give even better results than the BG7TBL, although having just recently bought them, I don't have enough statistical data. Another thing to try would be setting the minimum elevation threshold for a satellite to be included in the position and time solution to make sure to avoid surrounding hills or mountains, if any. Both the Oscilloquartz Star IV GPSDO as well as the plain old UBLOX-7 GPS receiver with PPS allow you to set the minimum elevation threshold. The BG7TBL GPSDO does not allow you to do that. You should look at the specifications of the two GPS receivers. At the very high end of measurements, there are observable effects during weather fronts -- which are of course much more severe than simply ordinary clouds or light rain. This article is rather dated but very interesting. With dual frequency receivers (L1 and L2 bands) they can observe precision errors down to the order of about 3 - 10 centimeters : http://geodesy.unr.edu/publications/gpsworld.may98.pdf -- Fio Cattaneo Universal AC, can Entropy be reversed? -- "THERE IS AS YET INSUFFICIENT DATA FOR A MEANINGFUL ANSWER." On Mon, Oct 21, 2019 at 11:01 PM Dana Whitlow wrote: > > A friend of mine living in SE lower Michigan recently bought > a Geppetto GPS clock, and swears that it tends to lose > satellite lock on cloudy days but does OK on sunny days. > > He is admittedly using a very poorly-sited antenna, > placed in a window because his house has aluminum > siding. He reports that his Garmin handheld GPS > has much less trouble acquiring and maintaining lock > on cloudy days than does the Geppetto, but still tends > to show higher levels of probable position error on > cloudy days. I don't yet know if he takes the Garmin > outside for these comparisons. > > Is this a real phenomenon, or is my friend just imagining > things? > > Meanwhile I think I have finally persuaded him to install > the antenna outside on the roof. > > Dana(K8YUM) > ___ > 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.
