Working my way through testing my collection of FTS1050A oscillators, I find one that erratically has poor time stability for tau > 1 sec. In some multi-day tests it is similar to the others (ADEV well under 1e-12 up to about tau = 1000 sec), but during other tests it is about 4x to 10x worse than the others for tau > 1 sec up to about 50k sec. If it were consistently bad at higher tau, I would think that the heater has gone. But in about half of the 10 multi-day tests I have done with this unit, the stability appears fine. Any ideas about what could cause sometimes good and sometimes not-so-good stability? Thanks- Jim

Hi Bad solder joint would be my guess. Possibly on one of the crystal leads. Cracks form, whiskers grow. Today it’s fine, tomorrow … not so much. Bob > On Apr 25, 2023, at 9:49 AM, AC0XU (Jim) via time-nuts <time-nuts@lists.febo.com> wrote: > > Working my way through testing my collection of FTS1050A oscillators, I find one that erratically has poor time stability for tau > 1 sec. In some multi-day tests it is similar to the others (ADEV well under 1e-12 up to about tau = 1000 sec), but during other tests it is about 4x to 10x worse than the others for tau > 1 sec up to about 50k sec. > > If it were consistently bad at higher tau, I would think that the heater has gone. But in about half of the 10 multi-day tests I have done with this unit, the stability appears fine. > > Any ideas about what could cause sometimes good and sometimes not-so-good stability? > > Thanks- > Jim > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe send an email to time-nuts-leave@lists.febo.com