M17 Cable

Where Is Mil-C-17 Specification Cable Used?

These cables are primarily for communication applications in the military. However, it's possible to purchase these cables and use them in other applications provided you comply with any other relevant requirements such as the National Electrical Code (NEC). They're commonly used in aerospace applications under extreme temperatures and difficult conditions. For example, M17/113 cable is a coaxial cable with a stranded silver-coated, copper-clad steel conductor and a silver-coated copper braid shield using a polytetrafluoroethylene (PTFE) dielectric. It conforms to RG316 but is suitable for use at temperatures from minus 55 degrees Celsius and up to 200 C. Another important consideration of MIL-SPEC cables is a requirement to test for discontinuities along the cable that change the characteristic impedance. Cable manufacturers use continuous swept-frequency tests that in some cases go from 50 MHz through to 10 GHz. These measure the voltage standing wave ratio (VSWR), which determines the degree of voltage reflected by discontinuities in the test sample.

Mil-C-17 Part Number Structure

AWC stocks more than 200 types of Mil C 17 specification cable and understanding the part number structure is crucial.  Part numbers have the following structure:  M17/XXX-YYYY

• M17: This indicates the basic specification as defined in the document MIL-C-17G, G being the current version.
• XXX: This is a three-digit number that refers to the relevant military specification sheet applicable to the part.
• YYYYY: This section of the part number refers to either an existing RG number or a sequential five-digit number.

The part number of the RG316 coaxial cable referred to earlier is M17/113-RG316.

Characteristics of Mil-C-17 Cables

When selecting a cable, it's important to understand that some differences between types are small, whereas others are significant. You can select many using the drop-down menu at the side of the AWC web page. Notable characteristics include:

• Conductors: Conductors can be solid or stranded.
• Stranding: Stranded conductors have 7 or 19 strands
• Conductor materials: There's a wide selection including bare copper, silver-coated copper, silver-coated nickel-plated copper-clad steel, and high resistance wire.
• Dielectric material: Common dielectrics materials used include PTFE and polyethylene.
• Number of conductors: Most MIL-SPEC cables are coaxial types, although the list includes triaxial cables with a conductor and two screens separated by a dielectric material.
• Screen: The screen may be a braid or solid tube.
• Screen materials: These include bare or tinned copper, silver-coated copper, and aluminum.
• Jackets: MIL-SPEC coaxial cables use numerous jacket materials including polyethylene, cross-linked polyethylene, polyurethane, and neoprene.
• Characteristic impedance: Apart from standard 50- and 75-ohm nominal impedance, MIL-SPEC cables include characteristic impedance values from 25 ohms up to 950 ohms.
• Voltage rating: The maximum voltage of Mil17 cables goes from 600 volts up to 15,000 volts.
• Frequency ranges: Maximum frequencies go from 200 MHz up to 50 GHz.
• Minimum operating temperatures: Between -30 C and -65 C.
• Maximum operating temperatures: From 70 C to 275 C.

Alternatives to Mil C 17 Cables

Although Mil-C-17 cables cover an enormously wide range of applications, they're not always the best choice for every application. Other specialty coax cables stocked by  AWC include LMR low-loss cables and Low PIM (passive intermodulation distortion) TCOM coaxial cables.

Contact us for additional information and guidance for selecting Mil-C-17 and other special coaxial and triaxial cables.