[time-nuts] Opera coordinator has resigned

[Jim Lux]

On 4/1/12 2:25 PM, Dr. David Kirkby wrote:
> On 04/ 1/12 03:33 PM, Jim Lux wrote:
>> On 4/1/12 3:01 AM, Dr. David Kirkby wrote:
>>> On 03/31/12 09:38 PM, Jim Lux wrote:
>
>>>> I don't think so. Yes, they're only rated for 500 cycles, but there's a
>>>> paper by a guy at Maury Microwave that I ran across when trying to get
>>>> statistics on the reflection coefficient variation, and he set up a
>>>> automated rig to mate/demate SMAs something like 10,000 times.
>>>
>>> I suspect that the jig he built does a better job of aligning them than
>>> what humans do. We put them on not quite square, move them around until
>>> the thread mates etc. I wonder if his jig tried to replicate a human or
>>> not?
>>
>> Nope.. back and forth in a straight line. He was measuring repeatability.
>
>
> So it tells us nothing very much about the life of them in normal use,
> with a human mating and demating them. - or even the repeatability of
> the reflection coefficient with a human in the equation.
>


Not a whole lot, but the whole paper goes into the various factors 
involved.  Ultimately, it winds up that the mismatch from SMAs is
a) a whole lot less than the usual "worst case" spec of 1.05:1 or 1.03:1 
(which is basically a measurement limit)
and
b) doesn't change much with many mate/demate cycles

He did look at things like coupling nut friction and what not.