[time-nuts] Coax Connectors (was Re: Opera coordinator has resigned)

[Javier Serrano]

On Sat, Mar 31, 2012 at 9:24 PM, Achim Vollhardt <avollhar at physik.uzh.ch> wrote:
> I do work in high energy physics and we use LEMO and other standards. For
> some years now, I have started to advertise against LEMO (in particular the
> LEMO 00 size), as it is VERY sensitive to mechanical defects and partial
> connection (yes, you can ..). We have found very often defective LEMO
> connections, which could only be detected via time domain reflectometry. Or
> LEMO interfaces, which changed impedance significantly when rotating them in
> the fully mated position.. this list could be extended a lot more. And this
> famous click when mating is inaudible in typical high energy physics
> electronics barracks.. too much fan noise.
>
> In addition, for the very fast signals of modern DAQ systems, LEMO 00 is
> just not up to speed (literally) anymore. If size is not of ultimate
> importance, we switched to SMA, or SMC if size matters.

I am very interested in this, since we just decided to use LEMO 00
over SMC in some of our designs:
http://www.ohwr.org/projects/fmc-projects/wiki/SMC_vs_LEMO
This is for ~100MHz work, so bandwidth was not an issue. Compatibility
with legacy was the major criterion in our case.
I would be interested in reading what people are using as coax
connectors in space-constrained environments like FMC, and why.

Cheers,

Javier