Well, the $600 Ebay FTS-4060 cesium beam unit seems to be working rather well despite no official LOCK indication. The external unit serial number is 1073 (the internal package is serial number 255). It was made in 1987. No telling how long it was used or stored. It is very clean with no signs of abuse. I have only had it running less than 72 hours. I have to manually ALIGN the unit since the auto align code in the EPROM seems to be corrupted... I need to find a copy of the EPROM or a CPU board to tell for sure.
I have the 1MHz output starting a Tek 509 counter with OCXO timebase and a Thunderbolt 10MHz as the stop. The counter is set for 10E8 averages so this gives a 100 second gate time. Although the Tek 509 is hardly a precision counter, two of them are tracking readings in this configuration with a fixed offset (due to threshold differences) +/- 20ps Over a 12 hour period, virtually all readings were 33ns +/- 5ns. A few readings were from 20ns to 43ns (I suspect mostly due to GPS constellation changes or counter hiccups as the readings quickly returned to the 33nS area). Over the 12 hours the room varied from 20.2 to 21.0 C. Control voltage (across the meter) was from 2.410 to 2.419V. Control voltage is not correlated with room temp so the OCXO oven seems to be doing well. The unit is sitting on a floor and running without the covers and is around three feet from a floor mounted air conditioning vent! _________________________________________________________________ Introducing Live Search cashback . It's search that pays you back! http://search.live.com/cashback/?&pkw=form=MIJAAF/publ=HMTGL/crea=introsrchcashback _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
