[time-nuts] NTP REFCLOCK for a Jackson Fury??

Scott Mace smace at intt.net
Thu Oct 17 14:00:47 EDT 2013


I think the Fury does not guarantee that the PTIME:TCODE will be near 
the 1-PPS leading edge.  When I tried it with the HPGPS driver and a 
net4501, ntpd wasn't happy with it.  I also needed leap second 
processing to work, holdover notification, and to collect other data 
from it.  The GPGGA sentence is on-time even if you are asking the Fury 
to do other things with SCPI commands.  Try setting your Fury hpgps 
driver fudge flag4 to 1 and I bet it will stop working well.  This flag 
logs the system:print output.

	Scott

On 10/17/2013 10:24 AM, Bill Dailey wrote:
> Interesting.. I see something completely different with my Fury.
>
> My hard-coded fudge factor is 0.077 yielding:
>
> Every 2.0s: ntpq -p                                     Thu Oct 17 10:20:00
> 2013
>
>       remote           refid      st t when poll reach   delay   offset
> jitter
> ==============================================================================
> -four2.fairy.mat 64.250.177.145   2 u   12   64  377   72.493   17.784
> 0.524
> -66-162-15-65.li 64.236.96.53     2 u   33   64  377   50.226   15.291
> 1.181
> +barricade.rack9 209.51.161.238   2 u   10   64  377   22.908    1.075
> 0.362
> -ccadmin.cycores 130.207.244.240  2 u   38   64  377   39.218    3.972
> 1.241
>   192.168.1.171   .INIT.          16 u    - 1024    0    0.000    0.000
> 0.000
> +SHM(0)          .FURY.           0 l    6   16  377    0.000    0.526
> 0.034
> *SHM(1)          .PPSF.           0 l    5   64  377    0.000    0.008
> 0.001
> -europium.canoni 193.79.237.14    2 u   32   64  377  116.177   -1.573
> 0.992
>
> So... i could fine tune my fudge some but the point is the jitter is fairly
> low.  (fury is from the sentences and ppsf is pps from fury).
>
> My soekris (soekris is the .171) numbers were much better but it is
> inoperable for some reason.
>
> Doc
>
>
> On Thu, Oct 17, 2013 at 9:59 AM, Tim Shoppa <tshoppa at gmail.com> wrote:
>
>> Back in 2003 or so, in the Z3801A with hpgps ntpd refclock driver, I had to
>> add a negative offset of -0.98 seconds to the driver's decoding of
>> PTIME:TCODE? to get it to be right in combination with PPS refclock.
>>
>> The documentation in the Z3801A manual correctly described the actual
>> behavior.... "PTIME:TCODE? Provides timecode message 980 to 20 ms prior to
>> 1 PPS of indicated time".
>>
>>
>>
>> On Thu, Oct 17, 2013 at 9:40 AM, Scott Mace <smace at intt.net> wrote:
>>
>>> I posted a patch for the Fury to work with ntpd in Oct 2008.  It uses the
>>> GPGGA output.  The PTIME:TCODE? command is not "on-time" with the 1-PPS
>>> output on the Fury, so the HPGPS driver does not work.
>>>
>>> http://www.febo.com/pipermail/**time-nuts/2008-October/033901.**html<
>> http://www.febo.com/pipermail/time-nuts/2008-October/033901.html>
>>>
>>> the ntp-fury.diff:
>>> http://www.febo.com/pipermail/**time-nuts/attachments/**
>>> 20081020/846021fe/attachment-**0001.bin<
>> http://www.febo.com/pipermail/time-nuts/attachments/20081020/846021fe/attachment-0001.bin
>>>
>>>
>>>
>>>          Scott
>>>
>>>
>>>
>>> On 10/16/2013 04:44 PM, Frank Hughes wrote:
>>>
>>>> Hi,
>>>>
>>>> What NTP REFCLOCK can be used for a Jackson Fury?
>>>>
>>>> I know that the Jackson Fury docs suggest using:
>>>> http://www.realhamradio.com/**gpscon-info.htm<
>> http://www.realhamradio.com/gpscon-info.htm>
>>>>
>>>> But that means I would have to put up a windows server
>>>> to replace the FreeBSD ntpd server I built for use w/ the Trimble TB.
>>>>
>>>> Looking for open source options, if possible.
>>>>
>>>> Thanks,
>>>> Frank
>>>> KJ4OLL
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