[TowerTalk] Mil Spec Prosistel question

Jim Lux jimlux at earthlink.net
Thu Mar 9 16:33:23 EST 2006

At 10:32 AM 3/9/2006, Jay Terleski wrote:
>I'd be even more interested in the details of the "Navy approval"...
>  > what  requirements (some form of MIL-810 for environments?  MIL-461 for
>  > EMI/EMC?), what testing, etc.
>  >
>  > DoD has literally millions of specifications, some meaningful in this
>  > context, some not.  A water resistance/salt spray test and/or tests over
>  >  temperature would be of great interest to hams. So would any electrical
>  >  tests or life tests. Whether the type size used to indicate the CAGE
>  > code  on the nameplate is correct is less so.
>Thanks for the request, I have posted the brochure for the
>antenna/positioner system, which includes the mil-specs it meets for
>shipboard use.

So the rotator & antenna meets the MIL-HDBK-2036 requirements?
The SPAWAR brochure mostly talks about the antennas, which are VHF/UHF 

MIL-HDBK-2036 is 150+ pages, and covers all sorts of things, so it's useful 
to know which tailoring they applied.  For instance, for shipboard use, 
things can be classified as mission critical or not, sheltered or 
unsheltered, etc.
For instance, it says that for shipboard use, minimal acceptance for EMC is 
in accordance with MIL-461, with levels specified in MIL-HDBK-235-1,-2,-3, 
and -4.

Where the rubber really hits the road, with respect to environmental specs 
is for things like humidity, where the minimal acceptance level is 
basically anything that's ok for a airconditioned space and the fully 
hardened is 100% RH, MIL-STD-810, method 507, over 25C-55C.  Icing ranges 
from nothing to 20 kg/sq meter.  Shock is hammer drop (MIL-S-901) 0.30, 
0.91, and 1.52 meters on each axis.
Temperature could be either -25C to +65C or -25C to 50C (either way, it's 
well below freezing)  Vibe can have multiple specs, depending.

So, what one really needs to know is what test levels they tailored to.

>I can tell you they are riggourous shake and vibration tests as well as
>severe environmental testing. And the equipment is tested as a system
>must be fully functional after hours of testing.  Last week in San
>Diego, they showed me video of vibration testing and drop testing where
>the LPDA elements (see brochure) were vibrating all over, and the boom
>of the antenna was bending by a couple of feet too. all of this in slow
>motion. Just amazing, the forces are huge and you will notice the
>rotator does not have a bearing system above it either.  They clamp the
>antenna mast to the standard Prosistel clamp.  Nothing more.

Indeed, vibe tests are interesting to watch, especially swept sine, where 
you can watch all the screws and bolts back themselves out.

More information about the TowerTalk mailing list