The Bird make thru line power meter directional wattmeter is a portable insertion-type instrument for measuring forward and reflected power in coaxial transmission lines. It will accurately measure RF power under any load condition. Plug-in elements are available to fit your frequency and power needs.
The Bird Thru line power meter is shown left with optional elements (sometimes called slugs). This model features N connectors for input and output.
The plug-in elements (slugs) determine the power rating and frequency range of the Bird 43 wattmeter.
The Bird Thru line power meter is the most popular meter for measuring RF powers .The heart of the Thru line meter is the directional coupler transmission line assembly as shown in figure . It is connected in series with the antenna or dummy load. The plug in directional element can be rotated 180o to measure both the forward and reverse power levels.