[time-nuts] Re: Poor's man NTP

[giuseppe at marullo.it]

Hi Rob,
I tried to find a quick way to obtain graphs, and settled using Excel, actually collecting some data but I need to bring the thing with me on a travel so It would take some days to collect like one week of meaningful data in a "stable" room, with logged temperature. Time permitting, I would implement MRTG/Cacti whatever.

This is a very short extract so far:
MJD       s since mid        Clock                     PPM f      RMS                  RMS                      Clock discipline loop time constant
                                           offset                    Offset     jitter                  wander 
59567	80590.679	-0.000000304	-12.205	0.000000954	0.000141	3
59567	80611.861	0	              -12.225	0.000000954	0                           3
59567	80619.845	0.000007995	-12.221	0.000002964	0.001384	3
59567	80627.845	0.000006833	-12.218	0.000002803	0.001753	3
59567	80635.845	0.000003494	-12.216	0.000002876	0.001747	3
59567	80643.845	0.000003515	-12.214	0.000002711	0.001743	3
59567	80651.845	0.000002159	-12.213	0.000002581	0.001673	3
59567	80659.845	0.000001592	-12.212	0.000002438	0.001588	3
59567	80667.845	0.000001244	-12.212	0.000002305	0.001501	3
59567	80675.845	0.000001239	-12.211	0.000002182	0.001421	3
59567	80683.845	0.000001557	-12.211	0.000002069	0.001356	3
59567	80691.845	0.000001607	-12.21	0.000001965	0.001298	3
59567	80699.845	0.000001639	-12.209	0.000001868	0.001247	3
59567	80707.845	0.000001634	-12.208	0.00000178	0.0012	               3
59567	80715.845	0.000001673	-12.207	0.000001699	0.00116	3
59567	80723.845	0.000002483	-12.206	0.000001624	0.001166	3
59567	80731.845	0.000001907	-12.205	0.000001556	0.001139	3
59567	80739.845	0.000001778	-12.204	0.000001494	0.001109	3
59567	80747.845	0.000001579	-12.204	0.000001438	0.001073	3
59567	80755.845	0.000001903	-12.203	0.000001387	0.001056	3
59567	80763.845	0.000001575	-12.202	0.00000134	0.001024	3
59567	80771.845	0.000002168	-12.201	0.000001298	0.001028	3
59567	80779.845	0.000002064	-12.2	0.00000126	0.001027	3

Clock offset is less than 8us(and decreasing), so how come ntpstat gives clock accuracy within 2ms?

BTW, I took a peek at PTP, simply overkill for my needs at the moment.

Giuseppe Marullo
IW2JWW - JN45RQ