Yep that's them!
~searches '10-32 connector' on ebay~
Heh, and now I know why they are also called microdot, not '10-32 connectors'. Because there is a common plumbing connector called '10-32'.
Goodness me, microdot != micro-price.
#10-32 is a common screw size in the US, so I'm sure the results will be littered with irrelevant things. Quite poor choice in naming the connector.
Apparently I have a lot to learn about grounding triax. I'd have grounded the outer braid at the receiving end. Um... never mind, I'll work it out.
The microdot cables (or the ones IVe seen) are generally only coax, not triax. But stuff gets a bit different when youre going 10's of meters rather than all on the same bench. If the shield of the coax were hard grounded to the chassis, and you hooked it to a an accelerometer attached to a motor housing, and the ground potential varied by a few hundred mV then you get a few mA flowing back and forth in the cable, possibly coupling into the center conductor, and also, your accelerometer output will have the 50/60 hz superimposed on it, and current flowing in and out of the center conductor as the outer conductor voltage changes, etc... a real trainwreck, ruining your low noise.
Since the HP instrument pictured supports ~4V of floating the shield of the coax above ground, if you were hooking the same way, then the floating input varies just fine, and the only current flowing in the shield of the cable is caused by the capacitance of the instrument. It gives it a pseudo differential input (if its not an actual differential input)
If you're doing an extended run above that, then switching to triax could be warranted, and you'd hard-ground the shield to the chassis on one end only to provide some EMI/RFI shielding. We used triax that wasnt low TE noise for ICP gauges that ran for 100+ meters. Though in the RF/EMI testing I did the LMR performed better than the triax, however stuff could be different frequencies, etc.
Ha ha I love it when google fails. OK, so LMR is just a cable class spec like RG? Or is it an acronym for something?
LMR is times microwaves brand (and I think other competitors use it too? not 100% on that) of low-loss double shielded coax. It comes in different sizes, LMR-100 is usually a drop in replacement for RG-174/RG-316, LMR-195 is usually a drop in replacement for RG-58 (and by usually I mean depending on your connector design/tolerances) There is LMR-200 if you want the benefits of it being slightly better than LMR-195, but using completely different connectors, etc
http://www.timesmicrowave.com/cms/products/cables/lmr/