The U4941 series Field Analyzer is a very portable RF Field Analyzer; that is it has been developed to be used for maintenance inspections and the like, in locations away from the lab bench and often out of doors, in the field. The U4941 / 4941PHS has the input impedance of 50Ω and the U4941N has 75Ω. Even though the analyzer is small and light in mass, it has a color LCD display. To further increase portability there are three power supply choices: a removable battery, AC / DC Adapter or an external DC supply.