On Mon, 01 Apr 2013 23:57:48 +0200 Magnus Danielson <mag...@rubidium.dyndns.org> wrote:
> On 04/01/2013 10:06 PM, Bob Quenelle wrote: > > I’ve been running an FE-5680 for maybe a total of 50 hours over the last > > several months. I found that an offset setting of 180 made it track GPS and > > (previously-set) LPRO-101 10 MHz signals. Even with power cycling, after > > about 1/2 hour, with an offset setting of 180 the FE-5680 was stable. The > > last time I turned on the FE-5680, it drifted with a setting of 180 and > > needed a new setting of –415 to track the other signals. That’s a change of > > 595 counts and with a resolution of 6.8 uHz per count, a frequency change of > > 4 mHz (0.004 Hz) and 0.4 ppb. Operation at the new setting is stable for > > now. The lock signal indicates lock and the power supply voltage is still > > 15V. I haven’t checked lamp voltage or VCXO voltage as that requires > > opening the case. > > How long have it been turned on since last power-up? > > Let it sit for a day at least. > > I've found that it is easy to be in too much hurry to judge the > situation and trim things efter power-up. The crystal oscillator just > doesn't get the time to settle in. That might be indeed the case. Figure 3 in [1] gives "quite high" frequency aging differences after switch on and long run time. Attila Kinali [1] http://www.pi5.uni-stuttgart.de/common/show_file.php/lectures/100/blaetter/The%20Rubidium%20Clock%20and%20Basic%20Research.pdf -- The people on 4chan are like brilliant psychologists who also happen to be insane and gross. -- unknown _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.