Properties of Popular Coaxial Cables. Note that attenuation values are given at 400 MHz, but can - and do - often have significantly different values at other frequencies. Always check with a coaxial cable vendor for values specific to the type you plan to use. Type (/U) MIL-C-17: Z 0 (Ω) Dielectric Type: Capacitance (pF/ft) O.D. (in.) dB/100 ft