FITS Shipboard Applications

February 9, 2022

FITS Shipboard Applications Webinar


This webinar details Times’ FITS connector system and its use in Naval shipboard applications. The FITS connector system is designed to introduce new levels of flexibility and durability in the most grueling environments. Tony Fedor explains how the system meets the latest military requirements to withstand any number of changing conditions. In addition, he covers the improved shielding capabilities and the overall versatility of the FITS connector system.

Watch the video or read the session notes below.

Session Notes

This webinar provides an overview of the Field Installable Termination Systems (FITS™) connector system in Navy shipboard applications. Many of these systems are connected using MIL-DTL-17 coaxial cables, the base specification for military approved coaxial cables. MIL-DTL-17 sets forth the parameters for cable materials, whether they are low- or high-temperature, fluoropolymers, braided materials, etc. It also includes requirements for testing parameters, including mechanical, physical, and environmental testing.

Cables and assemblies that are qualified to MIL-DTL-17 specifications are listed in the Qualified Products Database (QPD) by the Defense Logistics Agency (DLA). There are about 250 “slant sheets” currently in the MIL-DTL-17 (commonly referred to as M17) spec, and they are all completely different with their own set of electrical, physical, and mechanical parameters that set forth the design. Times Microwave Systems® currently maintains more than 160 QPL listings, including high-temperature, low-temperature, armored versions, and many more.

Buyers should use caution when ordering products to meet the M17 spec: some manufacturers use vague terminology such as “M17-type,” “in accordance with M17,” “similar to,” or “equivalent to,” etc., that could lead to false representation. Those designators are not accepted under the current QPL status. For example, a product that states it is “similar to an M17” may fail fluid testing or might not quite meet the electrical characteristics for a broadband test. These issues could have a degradative affect in the performance of any RF system, especially within a military system.

Evolving MIL17 Standards

Back in 1993, there was a MIL standard 454 directive that moved to eliminate the use of PVC on ships. Earlier specs such as MIL-T 24 640, and 24 643 were multiconductor power and control specs that moved to low-smoke zero-halogen parameters. Revision G added requirements for shipboard cables, and a Type 14 crosslink polyolefin jacketing material. This introduced a new series of testing requirements for weathering, abrasion resistance, fluid immersions, heat distortions and a variety of other physical and mechanical properties.

Slant 180 through 200 incorporated direct replacements to RG cables. For instance, an M17 slant 75 is an RG 214 PVC jacketed cable that transitioned into M17-slant 190, a low-smoke zero-halogen version with the Type 14 jacketing, as well as additional features.

Slant 210 through 218 included “unswept” versions that test one discrete frequency many times at 400 MHz. This provides no guarantee of broadband performance, and many are starting to be inactivated for their swept counterparts.

That leads us to the latest specs, slant 220 through slant 229. Times Microwave LLSB®—a series of low loss, highly-shielded designs that provide better overall performance for attenuation and shielding compared to an M17 standard RG cable—fit into this. These are the latest, lowest-loss designs that have been added to the MIL-DTL 17 specification.

In addition to electrical performance, LLSB cables carry the same combustion requirements and testing of the type 14 jacket. So M17 RG and MIL17 slant 220 through 229 cables all meet combustion requirements including flame performance, acid gas, halogen content, smoke and toxicity levels.

The Perfect Mate: FITS Connectors

LLSB cables are fully QPL’d under the M17-DTL or MIL-DTL-220 through 229. To add to this, Times Microwave created FITSä, a Field Installable Termination System incorporating a series of connectors and tools to fit LLSB cables.

The big advantage of FITS is the excellent and consistent RF performance of the connectors. They are truly field-installable with ruggedized performance and a superior plating thickness. We have created DLA part numbers for 16 approved FITS connectors, with new ones coming.

FITS connectors use a bi-metal tin nickel plating. Traditionally, tri-metal plating (zinc, tin, and copper) was used and by comparison, the bi-metal plating performs extremely well in terms of corrosion, including excellent performance with the MIL-STD-810 requirement, or the salt fog test.



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About the author

Tony Fedor Product Manager

Tony Fedor is product manager, cable at Times Microwave Systems. He has extensive experience working with high performance coaxial cable interconnects and related technologies.