[[ntpgps]]

Differences

This shows you the differences between two versions of the page.

Link to this comparison view

Both sides previous revision Previous revision
Next revision
Previous revision
ntpgps [2016/02/26 10:02]
admin
ntpgps [2016/02/26 10:21]
admin [ntp gps setup]
Line 1: Line 1:
 ====== ntp gps setup ====== ====== ntp gps setup ======
-This process has been complicated and messy, because of the combination of 1) I don't know what I'm doing, and 2) the resources on this are good but complicated. Almost everything I've figured out has come from these two pages:+This process has been complicated and messy, because of the combination of 1) I don't know what I'm doing, and 2) the resources on this are good but complicated. Almost everything I've figured out has come from these three pages:
   * http://kenyonralph.com/~kenyon/Time_server/   * http://kenyonralph.com/~kenyon/Time_server/
   * http://superuser.com/questions/828036/how-can-i-check-whether-my-ntp-daemon-has-pps-support   * http://superuser.com/questions/828036/how-can-i-check-whether-my-ntp-daemon-has-pps-support
 +  * http://www.rjsystems.nl/en/2100-ntpd-garmin-gps-18-lvc-gpsd.php#qrks
  
 I had to fill in a few holes here and there, so I am going to try and get a comprehensive guide in place here, because I will forget.  I had to fill in a few holes here and there, so I am going to try and get a comprehensive guide in place here, because I will forget. 
- 
 ===== Setup ===== ===== Setup =====
   * dc7900 running ubu server 14.04   * dc7900 running ubu server 14.04
Line 83: Line 83:
 mintc=3, offset=0.492, frequency=22.723, sys_jitter=0.044, mintc=3, offset=0.492, frequency=22.723, sys_jitter=0.044,
 clk_jitter=0.000, clk_wander=0.145</code> clk_jitter=0.000, clk_wander=0.145</code>
 +
 +
 +====== To D0 & Thoughts ======
 +Right now my offset and jitter can be improved. This can be done by:
 +  * Disable all but GPGGA
 +  * Push pulse width to 200ms
 +  * Some people don't like, and have trouble with, the 18x LVC:
 +    * http://support.ntp.org/bin/view/Support/ConfiguringGarminRefclocks
 +  * Similar to above:
 +    * http://support.ntp.org/bin/view/Support/ConfiguringNMEARefclocks
 +    * I think it's worth noting that my jitter is WAY lower than being reported there. One guy is setting 5-10ms jitter while I am seeing <0.024ms jitter. Either that guy has a bad unit and is being a negative nancy, or firmware updates have made them notably better.
 +  * Get serial pass-through working on the TS140. This will take some tinkering but should be doable. Latency is my only concern.
ntpgps.txt ยท Last modified: 2020/02/21 12:04 (external edit)
Driven by DokuWiki Recent changes RSS feed Valid CSS Valid XHTML 1.0