Copper is the wire for military applications. In terms of stability, a steel core is often used. The advantages of using galvanized copper conductors are the low costs (industrial application), increased SOLUBILITY and corrosion resistance. Tinted conductor, however, has the disadvantage of an increased loss. For military applications, we use coaxial cables at HighTemp a silver-plated coating. Benefit, lowest loss, best corrosion resistance with best solderability.

Harbour Industries is the leading provider of QPL-approved MIL-DTL-17 cables in the high-speed sector. All 50-Ohm designs are swept for VSWR to ensure product quality. To meet demanding customer requirements, Harbour manufactures special versions of MIL-DTL-17 cables. The supplier TIMES Microwave is approved for the low-temperature range (minus 40°C to 85°C).

Electrical Performance - PTFE vs. FEP
Per MIL-C-17, the dielectric material for Ml 7/93-RGl 78 is specified as PTFE (polytetrafluoroethylene). The sample under evaluation was made with FEP (Fluorinated Ethylene Propylene). FEP is an inferior dielectric relative to temperature rating and dissipation factor. FEP has a relatively high dissipation factor which adversely effects high frequency performance. This was evident in the fact that the sample under evaluation failed to meet the requirement for attenuation at 3 GHz. If the cable is used at frequencies above 3 GHz, the performance will be further compromised.
All that was non-compliant relative to the RG178 sample held tme for the "RG316" cable. The exception was the high frequency attenuation. While the principle and resulting effects of using FEP in lieu of PTFE remains the same, the specification was written to leave a significant amount of room for enter. In addition, the "RG316" sample under evaluation failed to meet the MIL-C-17 requirements for VSWR at low frequencies. The discrepant cable was marked with the Ml7/113-RG316 designation even though the manufacturer's name printed on the cable was not an approved source of supply for this cable.

Electrical Performance - PTFE vs. PFA
On a third sample from another manufacturer, the center conductor met the MIL-C-17 specification, but the braid wire tested low for plating thickness. If there is not sufficient silver plating, problems with conosion and copper migration could occur. The dielectric used in this coax cable was PFA (perfluoroalkoxy). The diameter varied significantly with a
.001" variance observed within a 6- inch spectrum. While PFA has a temperature rating comparable to PTFE, its dissipation factor is similar to that of PEP. Consequently, it is prone to the sarne high frequency performance problems as an PEP dielectric. This was evidenced by the fact that the cable sample under evaluation not only didn't meet the attenuation at 3 GHz. The cable also failed VSWR at 1 GHz from one end of the sample length.

The MIL-C-17 Specification as an Industry Standard
In summary, the importance of MIL-C-17 QPL (Qualified Products List) approval cannot be overemphasized. Qualified approval ensures: (a) the cable is manufactured using only qualified, high quality materials, (b) the cable conforms to all test require ments through a series of rigorous quality control tests and (c) the cable has gone through an annual govem mental review of test data. Because these standards exist, there is little room for data manipulation and material substitution to comprornise quality. A product made today will be con structed of the same materials and to the same high standards as it was in the past, and will be in the future. Falsely labeling cable as if it were on the QPL list is illegal in the United States. While certainly the laws of the USA do not necessarily extend beyond its borders, mislabeling of product is not only dishonest but will guarantee neither quality nor consistency. In addition, rnisrepresentation of a prod uct's component parts can lead to lia bility concems if said product fails and is found to be contrary to specification requirements. Harbour Industries is proud to be a qualified supplier of MIL-C-17 coax cables since 1975. In addition to military applications, Harbour's MIL-C-17 coax cables are frequently selected for use in commercial communication systems, antenna systems and RF instrumentation. Many of these applications have electrical performance requirements even more demanding than the MIL-C-17 specification, but the requirements present no problem for Harbour due to years of engineering and manufacturing experience. 

Due to the production in the USA, our standard layouts are 1000ft / 305m or 5000ft / 1525m. Ask for our delivery service for ring material. We supply the ring material from 25m rings.