On Sat, February 18, 2017 8:20 pm, Mark Sims wrote: > The Star-4 PPS seems to be around 3 times better than the Thunderbolt PPS I have not heard that product mentioned before. Are you referring to this Oscilloquartz product? http://www.oscilloquartz.com/files/1363163133-da_Star4.pdf When I searched I found an old posting from last November from Mark mentioning Star 4, but I don't remember a multi-week thread going on about fine points of connector pin-outs, etc. like there have been for other surplus GPSDO. Were there not many on the used market? -- Chris Caudle