Audio signals received via short wave radio are characterized by impulsive noise as well as sustained background noise. A group of three students developed a system containing both linear digital filters and nonlinear median filters to remove noise from short-wave radio signals. The superior performance of the median filter in removing the impulsive noise was clear in the demonstration with real signals. The combination of median filtering with linear filtering was found to provide the best solution. The on-the-fly parameter update feature was useful in this system to switch between the linear filter and median filter in real-time, and also to demonstrate the effects of window size in the median filter and bandwidth in the linear filter.