[Milsurplus] ID Cables

[Don Davis]

Mike says:


. Some time ago, the "Perry
> Initiative" even did away with all Mil-Specs and Standards and in order to
> use one now a waiver has to be issued on the contract. All in the name of
> saving money. Of course, in the mean time, equipment is failing left and
> right in the field. Component manufacturers do not even make parts to
> Mil-Specs. any longer.

Well, yes & no.  MIL specs, STDs and HDBKs are still very much with us.  My
designs use all MIL-PRF-xxxxx or MIL-STD or MIL-xxxx parts.  Admittedly this
is for space, and we run all class S or E parts.  If we can't get the right
quality, we up-screen lesser quality parts.  Only infrequently are we
allowed to use class B or modified class S.  There are any number of folks
supplying MIL parts (IR, Intersil, etc.) for a large sum.  We still buy all
of our magnetic devices to MIL-981 or MIL-T-27 (a very old spec).  A large
number of specs have been combined, replaced, or have become cover-sheeted
mfgr's data sheets, however.

Basic difference between MIL spec parts and comm'l parts is qualification of
the part to spec, screening of each part or lot screening (or both), and
some type of traceability of materials and components used.

You might be thinking of COTS - Commercial Off-The-Shelf - where small items
(cellphones, handheld radios, or???) are procured based on ultimate
performance, and not how or what is inside the unit.  Instead of requiring a
mfgr to perform worst-case analyses and procure piece parts to particular
standards, they can submit samples for qualification, and perform Group A
screening on each delivered end item to end-item performance specs.  In this
way you can use all Radio Shack parts, but have a decent reliability if you
over-design the unit (design aganst failure - Taguchi methods, etc.).

We tried a bit of this in the space business with mixed results.  It's a
shame to see a $250M bird crap out due to a couple of dumb failures that
could have been prevented with 10% more cost.

My motto:  "Performance, cost, reliability:  pick any two...."  original
author unknown.

73s

Don Davis   AD6PB