> Hi! > > I have powered up my Z3801A and monitored the 10 MHz on a counter (with fancy > histogram and statistics) with the Cs as reference. The Z3801 is moving around > quite a bit and the SatStat shows that it hasn't really converged towards > precission (the 24h time error prediction). Infact, it drops out of lock into > holdover every now and then. When it jumps in or out of hold over, a "large" > (50 mHz) frequency jump is clearly vissible. I have about 1 mHz of Allan > Deviation and about 4 in Standard Deviation. > > I have made comperative measurements of my counter setup by hooking it up to my > Rb, and that is noticeably lower in noise. > > Is this to be expected or not? > > Any thoughts & recommendations? > > Cheers, > Magnus
While watching the syst:stat screen did your Z3801A already complete its multi-hour site survey and the coarse/fine frequency adjustments? If it's still in a start-up acquisition mode ignore the 10 MHz output. If it doesn't lock after a few hours, I'd suggest a full reset. Also check your signal levels, and elevation mask. Did it get your lat/lon/alt correct? The predicted time error won't settle down for a few days (it's a long time constant), so don't worry about that quite yet. Not sure what you mean by "The Z3801 is moving around quite a bit". You should get 10 solid digits of accuracy out of a Z3801A at short sample times. That grows to 11 or 12 over several hours; 12 to 13 over several days (at which point you won't quite be sure if the errors are your counter, your Z3801A, or your cesium). /tvb _______________________________________________ time-nuts mailing list [email protected] https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
