RG-401

RG-401 Semi-Rigid coaxial cable is a MIL-DTL-17 qualified series providing mode free operation to 19 GHz. The sold tin-plated copper tube effectively provides 100% RF shielding with shielding effectiveness exceeding 110 dB, and enables the dielectric and center conductor to remain precisely spaced. This results in optimum impedance control as well as the lowest possible insertion loss and weight to size ratios.

It has become common practice to use the RG401 designator when referring to the equivalent size conformable or flexible cable as opposed to the strict MIL-DTL-17 RG-401 i.e., Semi-Rigid, type. In the interest of minimising confusion it is not recommended to use this designator unless specifically requesting the MIL-DTL-17 semi-rigid cables.

0.250" (quarter inch) Semi-Rigid cables can be found in a range of ultra-high performance systems such as high power electronic warfare applications, radar, and microwave radios. The 6.35 mm overall diameter and 22.23 mm bend radius restricts its usage, making it unsuitable for small electronics.

As with all semi-rigid coaxial cables specialised tools must be used to form the cable into shape without damaging the wall of the outer tubing. Reforming a cable is difficult and often results in damage to the outer conductor, causing ripples in the outer wall that will affect the electrical performance of the cable assembly.