Re: [time-nuts] ISS NTP operation problems.

Magnus, Warren, ITAR are US rules for US products. Thus ITAR don’t apply for non US products. Has that changed? The original COCOM rule was “don’t do altitude above 18000m and speed exceeding 1000 knots. “ COCOM was then replaced by the Wassenaar agreement. I would have expected it the

Re: [time-nuts] ISS NTP operation problems.

Responses to several comments. Opportunities to collect critical NTP debugging data on the ISS will be limited. Specific suggestions sent to me off-list would be appreciated. Earth station to ISS delays: I inferred the 600-700 msec RTT using the reported root distance [I've seen much higher

Re: [time-nuts] ISS NTP operation problems.

On 1/8/21 2:15 PM, Warren Kumari wrote: This is a propagation path that I suspect NTP is just not designed to deal with. Well, I wonder if NTP over that path is even the best solution. Taking time off a GPS/GNSS receiver onboard the ISS would be a significant improvement. Just having the PPS

Re: [time-nuts] ISS NTP operation problems.

Warren, On 2021-01-08 23:15, Warren Kumari wrote: > On Fri, Jan 8, 2021 at 11:40 AM Lux, Jim wrote: >> On 1/8/21 6:59 AM, Magnus Danielson wrote: >> That is probably harder than it seems. There's a lot of isolation among >> systems on ISS - partly for safety, partly from history, partly from >>

Re: [time-nuts] ISS NTP operation problems.

Jim, On 2021-01-08 17:31, Lux, Jim wrote: > On 1/8/21 7:17 AM, Hal Murray wrote: >> j...@luxfamily.com said: >>> If the pathway is like the ones to/from ISS that I am familiar with, >>> they're using the Ku-band or S-band link through TDRSS. In both >>> cases,  the >>> signal has to go from White

Re: [time-nuts] ISS NTP operation problems.

> > Is this a new problem or has it being happening since day 1? > It's unclear how long it has been happening. The team responsible for managing the NTP Server noticed irregularities with its ability to sync to ground but we don't know how long it had been going on for. In an effort to fix it

Re: [time-nuts] ISS NTP operation problems.

Poul-Henning, On 2021-01-08 17:10, Poul-Henning Kamp wrote: > > Hal Murray writes: > >> There is a huff-puff filter, I think it's optional. > I think it is more likely that the median-filter is causing trouble. > > If you let the poll-rate ramp all the way up to 1024 seconds, the >

Re: [time-nuts] ISS NTP operation problems.

On Fri, Jan 8, 2021 at 11:40 AM Lux, Jim wrote: > > On 1/8/21 6:59 AM, Magnus Danielson wrote: > > Hi Jim, > > > > On 2021-01-08 15:06, Lux, Jim wrote: > >> On 1/8/21 12:24 AM, Poul-Henning Kamp wrote: > >>> > >>> Steven Sommars writes: > >>> > There is a ~600-700 msec RTT between

Re: [time-nuts] ISS NTP operation problems.

On 2021-01-08 16:58, Hal Murray wrote: > p...@phk.freebsd.dk said: >> If you path is not stable, or you flip between different servers with >> different delays and/or assymetries, your time will not be stable. > Ahh. Thanks for the reminder. > > There is a huff-puff filter, I think it's

Re: [time-nuts] ISS NTP operation problems.

Hal, On 2021-01-08 16:17, Hal Murray wrote: > j...@luxfamily.com said: >> If the pathway is like the ones to/from ISS that I am familiar with, >> they're using the Ku-band or S-band link through TDRSS. In both cases, the >> signal has to go from White Sands (or Guam) up to TDRSS, which is in

Re: [time-nuts] small multi-timezone display

ClockSync is a nice Android NTP app, which displays NTP time and system time and can sync the system time to NTP if you have root access. Phones may need to be rooted for this to work. The ClockSync FAQ has a good explanation of these issues. > --Jim Harman

Re: [time-nuts] ISS NTP operation problems.

Is this a new problem or has it being happening since day 1? Jim Palfreyman On Fri, 8 Jan 2021 at 5:42 pm, Steven Sommars wrote: > At the end of November a question > was > posed to the ntp.org list concerning NTP problems

Re: [time-nuts] small multi-timezone display

Old iphones maybe cheap or you may have one. Since LTE4 I guess is in the process of being turned off old iphone 5s will no longer work. My wife now has a iphone 6 and I have ordered a battery for the 5 because it is a useful widget that looks good and can use wi-fi. Granted thats a small screen

[time-nuts] small multi-timezone display

I’d investigate whether there was an Android “World Clock” app whose display had your requirements, then buy an Android tablet in your price range and with the appropriate form factor. (I like the “World Clock” app on my iPhone, but I’ve never encountered a cheap iPhone.) -- J. L. Sloan

Re: [time-nuts] small multi-timezone display

On 1/7/2021 9:35 PM, Lux, Jim wrote: I've got a shelf about 80cm long that I'd like to have 4 timezones displayed on. The obvious easy solution is go buy 4 clocks and put them there. MFJ makes a dual time zone, radio-disciplined clock for the US amateur radio market that might meet your

[time-nuts] Cheap 5370B on german fleabay

In case any timenuts in EU still do not have one... -- 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.

Re: [time-nuts] PRS10 not locking to 1PPS

Hi, The PRS 10 is now locking to the 1 PPS from the GPS. I have checked by using an external Time interval analyser and phase deviation between Input and output PPS is stable. Also I can see that the magnetic MR setting is steered. So, the PRS10 is locking again to GPS and the MR is within the

Re: [time-nuts] ISS NTP operation problems.

On 1/8/21 6:59 AM, Magnus Danielson wrote: Hi Jim, On 2021-01-08 15:06, Lux, Jim wrote: On 1/8/21 12:24 AM, Poul-Henning Kamp wrote: Steven Sommars writes: There is a ~600-700 msec RTT between the ground NTP servers and the ISS NTP server. How stable is that ? Is there a lot of

Re: [time-nuts] ISS NTP operation problems.

On 1/8/21 7:17 AM, Hal Murray wrote: j...@luxfamily.com said: If the pathway is like the ones to/from ISS that I am familiar with, they're using the Ku-band or S-band link through TDRSS. In both cases, the signal has to go from White Sands (or Guam) up to TDRSS, which is in GEO, and then back

Re: [time-nuts] ISS NTP operation problems.

Using NTP, with long and asymmetric path delays, seems like a recipe for disaster. Can they not simply use a GPS receiver? ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to

Re: [time-nuts] ISS NTP operation problems.

Hal Murray writes: > There is a huff-puff filter, I think it's optional. I think it is more likely that the median-filter is causing trouble. If you let the poll-rate ramp all the way up to 1024 seconds, the median filter can get "stuck" for almost an hour before it notices that

Re: [time-nuts] ISS NTP operation problems.

p...@phk.freebsd.dk said: > If you path is not stable, or you flip between different servers with > different delays and/or assymetries, your time will not be stable. Ahh. Thanks for the reminder. There is a huff-puff filter, I think it's optional. It assumes the physical path is stable

Re: [time-nuts] ISS NTP operation problems.

Hal Murray writes: > NTP likes symmetric delays. That's strictly speaking to true: NTP *assumes* symmetric delays. If your path is not symmetric, you can a time offset of half the asymmetry. If your path is stable you can calibrate that out with a temporary reference or something.

Re: [time-nuts] ISS NTP operation problems.

j...@luxfamily.com said: > If the pathway is like the ones to/from ISS that I am familiar with, > they're using the Ku-band or S-band link through TDRSS. In both cases, the > signal has to go from White Sands (or Guam) up to TDRSS, which is in GEO, > and then back down to ISS. Is the back

Re: [time-nuts] ISS NTP operation problems.

Hi Jim, On 2021-01-08 15:06, Lux, Jim wrote: > On 1/8/21 12:24 AM, Poul-Henning Kamp wrote: >> >> Steven Sommars writes: >> >>> There is a ~600-700 msec RTT between the ground NTP servers and the >>> ISS NTP server. >> How stable is that ? >> >> Is there a lot of sample-to-sample jitter

Re: [time-nuts] small multi-timezone display

Jim a interesting request. The 4 clocks are going to drive you a bit crazy. They will drift this way and that and then there are all of the time changes. I actually use 4 X 14" clocks off of the same clock drive so they stay in sync. Just hate drifting second hands. Big advantage seriously low

Re: [time-nuts] small multi-timezone display

Hi > On Jan 7, 2021, at 10:35 PM, Lux, Jim wrote: > > I've got a shelf about 80cm long that I'd like to have 4 timezones displayed > on. > > The obvious easy solution is go buy 4 clocks and put them there. > > But, being a member of this list - anyone know of a off the shelf multizone >

Re: [time-nuts] ISS NTP operation problems.

Hi, On 2021-01-08 09:24, Poul-Henning Kamp wrote: > > Steven Sommars writes: > >> There is a ~600-700 msec RTT between the ground NTP servers and the ISS NTP >> server. > How stable is that ? > > Is there a lot of sample-to-sample jitter ? > > Have they clamped the poll-rate on the S2 ?

[time-nuts] Ready for a Negative Leap Second?

The Earth’s rotation was a bit faster during 2020. https://www.space.com/earth-spinning-faster-negative-leap-second.html Originally published on Live Science. greg chicago ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to

[time-nuts] Technical information on Peltier Modules

Following earlier discussions on the pros and cons of Peltier modules for temperature control of crystal oscillators, DigiKey have just launched a range of small devices. However, the reason for posting that information here is that their web page contains a wealth of information on the

Re: [time-nuts] ISS NTP operation problems.

Steven Sommars writes: > There is a ~600-700 msec RTT between the ground NTP servers and the ISS NTP > server. How stable is that ? Is there a lot of sample-to-sample jitter ? Have they clamped the poll-rate on the S2 ? -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20