A downhole signal transmission system for communicating along a string of interconnected downhole components, including: at least one communications line that carries radiofrequency signals along the string of downhole components; at least one communications sub; and a plurality of signal repeaters spaced along said string of downhole components, said signal repeaters being receptive to radiofrequency signals, wherein said at least one communications sub communicates over said at least one communication line by modulating data onto said radiofrequency signals, and wherein said radiofrequency signals bypass at least one signal repeater when said at least one signal repeater fails.
