[ntp:questions] New ntp Server

Mark C. Stephens marks at non-stop.com.au
Thu Dec 8 07:53:15 UTC 2011


Hello Sir Unrah,


I just use ntpq -p. I am using Dave Harts rather excellent port to windows:

C:\Program Files\NTP\bin>ntpq -p
     remote           		refid      	st 	t 	when 	poll 	reach   	delay   	offset 	 jitter
==============================================================================
*GPS_NMEA(1)     	.GPS.           	 0	 l    	1   	16  	377    	0.000   	-0.139   	0.059
oPPS(1)         	     	.PPS.            	0	 l   	 -   	16  	377    	0.000  	-0.007   	0.002

I restarted ntpd a couple of hours ago so these number will improve.

That is a good question, are we talking seconds for offset and jitter here? 


Mark


-----Original Message-----
From: unruh [mailto:unruh at invalid.ca] 
Sent: Thursday, 8 December 2011 4:54 PM
To: questions at lists.ntp.org
Subject: Re: [ntp:questions] New ntp Server

On 2011-12-08, Mark C. Stephens <marks at non-stop.com.au> wrote:
> Oh no I am quite happy with my hp3325A ;)
>
>
> Well Okay, after a slight detour trying to get ilo100 to work, I loaded centos 6.0 x64 on the DL165 G2 (computer) and found it has 3.3V PCI slots. So none of my Serial I/O cards fit, being 5V. I have seen people take a dremel to them to cut a 3.3V notch, but I am not a 100% sure this works. 
>
> Centos 6.0 is really impressive I have to say. Also the PPS kernel module is already built and installed, just need to load it.
>
> So the plan now is to connect a HP58534A GPS Timing Antenna to the only serial port and compare the difference.
>
> On a windows box with the same antenna, I get offset of 0.010 and jitter 0.001 off the PPS, and ~0.020 offset on the NMEA.
>  I think I will try to split the output of the GPS timing antenna into both the windows and Linux boxen to compare accuracy on the different O/S's. 

Not sure what you mean when you say you get offset of .010 (I assume the units a ms, not sec) Ie, what are you using to determine the offset? 
For nmea and offset of .02 sec is not unreasonable, so maybe you are
>From PPS you should get offsets at the few microsecond level (.000002
sec) on Linux. 


>
> I'll let you know how it goes!
>
>
> Mark
>
>
> -----Original Message-----
> From: Rick Jones [mailto:rick.jones2 at hp.com]
> Sent: Thursday, 8 December 2011 12:16 PM
> To: questions at lists.ntp.org
> Subject: Re: New ntp Server
>
> unruh <unruh at invalid.ca> wrote:
>> Nothing except that he wrote down an incomprehensible line of numbers 
>> and expected people to know that was a computer, rather than a 
>> printer, or an atomic clock.
>
> You were expecting maybe an HP 4972A?-) (10 Mbit/s Ethernet network 
> analyzer from *many* years ago) or perhaps an HP P/N 19511-80014?-)
>
> rick jones
> --
> The glass is neither half-empty nor half-full. The glass has a leak.
> The real question is "Can it be patched?"
> these opinions are mine, all mine; HP might not want them anyway... :) feel free to post, OR email to rick.jones2 in hp.com but NOT BOTH...





More information about the questions mailing list