Just got a Racal-Dana off Fleabay, and surprisingly, it works great other than the mushy buttons.
One nice thing is it came with the OCXO, which according to the manual, is stable to 3x10^-9/day (averaged over 10 days, 3 months continuous use), and ±3x10^-9/°C.
This seems, to me, pretty favorable vs. the Gerry Sweeney OCXO hack using this:
http://www.isotemp.com/wp-content/uploads/2011/03/OCXO-131.pdfThough, it does seem that it's nearly an order of magnitude better to use the Isotemp OCXO (0.5ppb vs 3ppb for the OCXO the unit came with). Though, not sure that matters that much for me. Am I missing something?
Other question is, I'd like to fix the mushy buttons. I've seen several posts on it, and it seems the common fix is to use something like these: P12227SCT-ND, then either mod them to have the cross tops, or to mod the buttons (cutting out the fins so they fit on the round actuators). I'd rather do the first option, but I guess Racal-Dana had a fire-sale on buttons when they designed this thing, as it has over 30 of them! Anyone have a good/easy way to do the mod? Someone mentioned heat molding... or use a Dremel. Downside of the former is materials, and the latter is I think the actuator rotates, so cutting it becomes... tricky I would think.
Anyone done either? Have tips?
Oh, unit also came with the battery option (which added a good 2.5kg to the shipping weight, easy). The battery dates to the mid-late 80's... think there's any chance at all it's still usable? I don't overly care, and I've pulled it at this point, but I'd be curious. It's 6 cells, so it's basically a "flattened" car battery. Guess I could just try charging it and monitor the voltage...