Re: [ntp:questions] GPS reception problem in UK

unruh wrote: On 2010-04-18, David Lord wrote: Hi I just noticed that the GPS used as reference for my xtal oscillator clock source has from midnight last night been losing reach. Previous 24 hr to that logging at 6 minute intervals had all 240 entries at 377 but now they are mostly at 0 or st

Re: [ntp:questions] Cheap ($29.90) GPS receiver

David J Taylor wrote: "John Hasler" <> wrote in message news:87zl10gw35.fsf...@thumper.dhh.gt.org... This might be of some interest to some here: I don't know anything about it other than what

Re: [ntp:questions] Cheap ($29.90) GPS receiver

Terje Mathisen wrote: David J Taylor wrote: "John Hasler" <> wrote in message news:87zl10gw35.fsf...@thumper.dhh.gt.org... This might be of some interest to some here: I don't know anythin

Re: [ntp:questions] GPS reception problem in UK

uwe writes: > The ash will change dielectric properties. real and imaginary ( as in > lossy ) If there was enough of it to significantly attenuate microwaves it would dim the sun substantially. It doesn't show up on radar except at densities far higher than that over Europe. -- John Hasler jhas

Re: [ntp:questions] Cheap ($29.90) GPS receiver

uwe writes: > looks like sending of the GPZDA sentence is synced to (internal) PPS That's what I meant. Sorry for being unclear. I suspect that a raw PPS signal might be found somewhere inside the box, but of course not everyone would be willing to open it up and poke around as I would. I'd buy

Re: [ntp:questions] Cheap ($29.90) GPS receiver

Uwe Klein wrote: Terje Mathisen wrote: David J Taylor wrote: "John Hasler" <> wrote in message news:87zl10gw35.fsf...@thumper.dhh.gt.org... This might be of some interest to some here: The pi

Re: [ntp:questions] Cheap ($29.90) GPS receiver

Terje writes: > It would still be limited to the resolution of the rs232 clock, > i.e. ~1ms, instead of the ~1us we usually get from PPS receivers. The documentation claims 1us (again, that just what I read. I don't have one.) The RS232 could be synchronized to the PPS internally. -- John Hasle

[ntp:questions] Timekeeping best practices for virtualized systems

It's from VMware, but I imagine the basics apply to Xen, Hyper-V, and other virtualization solutions: http://kb.vmware.com/selfservice/search.do?cmd=displayKC&docType=kc&externalId=1006427 -- RPM ___ questions mailing list questions@lists.ntp.org http:/

Re: [ntp:questions] Cheap ($29.90) GPS receiver

"Terje Mathisen" <""> wrote in message news:ugut97-uqv2@ntp.tmsw.no... [] It would still be limited to the resolution of the rs232 clock, i.e. ~1ms, instead of the ~1us we usually get from PPS receivers. OTOH, for many users 1-3 ms might be just fine, and statistical processing might make

Re: [ntp:questions] Cheap ($29.90) GPS receiver

>How precise can a 4800 baud serial port be in determining the start of a >start bit? About 1/4800s i.e. about 200 microseconds? Don't the chips >sample at 8 or 16 times baud rate, so couldn't the start bit be determined >to ~25-30 microseconds? And if the baud rate was lot higher (the unit

Re: [ntp:questions] Recommendations for good NIC cards

> > How do you configure it on Linux? > http://freshmeat.net/projects/ethtool/ > ( never used it myself yet ) I've used it from time to time in my guise as "Mr. Netperf" - the biggest issue I have with it is that you have to script it post-boot - the linux folks eschew having module parameters fo

Re: [ntp:questions] Cheap ($29.90) GPS receiver

John Hasler wrote: > Terje writes: >> It would still be limited to the resolution of the rs232 clock, >> i.e. ~1ms, instead of the ~1us we usually get from PPS receivers. > > The documentation claims 1us (again, that just what I read. I don't > have one.) The RS232 could be synchronized to the P

Re: [ntp:questions] Cheap ($29.90) GPS receiver

Terje Mathisen wrote: It would still be limited to the resolution of the rs232 clock, i.e. ~1ms, instead of the ~1us we usually get from PPS receivers. Does it only work at 150 baud, then? Asynch serial resolution is typically 16 * "baud" rate. _

Re: [ntp:questions] Cheap ($29.90) GPS receiver

On 2010-04-19, Rob wrote: > John Hasler wrote: >> Terje writes: >>> It would still be limited to the resolution of the rs232 clock, >>> i.e. ~1ms, instead of the ~1us we usually get from PPS receivers. >> >> The documentation claims 1us (again, that just what I read. I don't >> have one.) The R

Re: [ntp:questions] Cheap ($29.90) GPS receiver

> I think that depends on how you set up the chip. I think you can set it > up so it will interrupt on each byte. This is not terribly efficient for > a serial port driver, but if it is timing you want, then that is > probably what you want. On linux, I use: setserial /dev/ttyS0 low_latency