Techniques to start the transmission of packets early at a transmitting device and to play out received packets early at a receiving device in a wireless communication system. The gun holder allows the gun barrel to be adjustably fixed in each of a horizontal and vertical position. The adjustment disc is positioned between the input adaptor and the output adaptor, and an axial alignment of the input adaptor relative to the output adaptor may be varied based on a rotational orientation of the adjustment disc. The second conductive layer is formed on the first conductive layer inside the first opening, and patterned into a predetermined shape.