DIY HP/Agilent 53131A 010 High Stability Timebase Option

Having obtained a reasonably reliable 10Mhz lab reference I decided to calibrate my Frequency Counter only to find that the stock oscillator provided in the HP 53151A is absolutely terrible - a joke even! I looked around for an “010 High Stability Timebase Option“ but they are rare -- and if you can find one not installed in a counter they are very expensive - in the few hundred dollars range at least -- and buying one from HP is, well, expensive in the extreme. There are many second-hand 10MHz OCXO modules available, these are mostly stripped from old telecommunications, satellite or cellular equipment so they are plentiful and relatively cheap to buy too. I decided to make a clone 010 option board for my counter using a second-hand OCXO bought from e-bay. I designed a PCB to get a professional finish as well as a reliable upgrade for my counter. The main goal was to make an option board that just like the original