An extremely low-attenuation, and extremely low radiation loss, flexible coaxial cable for microwave energy in the high gigaHertz (GHz) frequency range includes a solid single-strand, smooth, silver-plated center conductor surrounded by a flexible dielectric medium with a plurality of longitudinal, parallel, contiguous conductive strands adjacent to the low-loss dielectric medium for defining the inner surface of the outer conductor concentric about the center conductor. Each of these strands is smooth silver plated. All of these strands run parallel one to another extending longitudinally of the cable, and they are sufficiently numerous for forming at least two full layers of these strands surrounding the dielectric medium. The inner layer of strands is contiguous to the dielectric medium, and the next layer comprises strands nesting in the valleys defined by the respective neighboring strands of the inner layer. These parallel strands are retained tightly embraced against the dielectric medium and against each other by a continuous, uniform, tightly fitting, squeezing wrapping serving of strong, fine filaments or fibers which are wound tightly around the conductive strands of the outer conductor. An outer jacket of flexible impermeable material, such as plastic, surrounds the wrapping serving for protecting the cable.