> Have you seen this? > Mercury Ion Frequency Standard Set > ebay # 7554448004 > Probably an HP prototype, looks not really recent... 1980s? anyone knows more? > Marco IK1ODO
HP worked on Hg ion standards in the late 70's. There was a paper about it published in 1981. Performance claims were 1e-12 accuracy; 2e-13 reproducibility; and 1e-12 root tau stability; about the same as a 1980's era cesium. This unit might be one that HP delivered to USNO for evaluation. What you see for sale is just the electronics bay. All the good stuff (the actual physics rack) is missing and who knows where it is, possibly still at USNO. Note the thick bundle of cut wires. So all you get is a miscellaneous collection of a dozen HP and Varian instruments, which you could buy separately (if you even wanted them) for a fraction of the opening bid. /tvb http://www.LeapSecond.com _______________________________________________ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts