This paper presents optimization of the hot air welding process parameters for the formation of textile transmission lines and the electro-conductive properties of these manufactured transmission lines. A dedicated manufacturing set-up has been developed to allow a reliable and flexible textile signal transmission line at adequate conductivity. In order to manufacture textile transmission lines, different welding parameters with different conductive yarns and welding tapes were considered. Layered fabric structures consisting of textile transmission lines and fabrication tolerances were determined, as well as electro-conductive properties for welded samples. It was found that the choice of welding parameters, depending on the materials used for the formation of textile transmission lines, is extremely important for obtaining good electro-conductive properties. In addition, welding tapes and thermoplastic materials play an important role during the set-up of welding process parameters. Results statistically confirmed that welding tapes with conductive yarns can significantly cause a variety of changes in the signal qualities of welded textile transmission lines. The obtained results based on conductivity and signal-to-noise ratios are really promising for the manufacturing of e-textile transmission lines via hot air welding technology.