Ya ever go to someone's web site, to find something specific, but then see just how much a site has to look-through that you can just get-lost in it? Well, this is one of them:
https://www.ko4bb.com/ko4bb.com/getsimple/ All sorts of good Tech & Engineering INFO here, but yes, lots of link, pages, & PIC's, out of date as well. Still, COOL!!!! What I went to was the INFO on the Tremble Thunderbolt GPS DO systems, (Global Positioning Satellite Disciplined Oscillator), meaning this system GEN-Locks to the GPS cesium-based FREQ timing system of the US Navy, like TV stations & laboratory calibration facilities use. So, one hell of a learning curve here, but a nice capability to have indeed!
http://www.leapsecond.com/pages/tapr-tbolt/