Where should an RF wattmeter be connected for the most accurate readings of transmitter output power?

To measure a transmitter's output power most accurately, the wattmeter must be connected directly at the transmitter's output connector. This ensures that the meter reads the power being generated before any feedline losses occur. If the wattmeter is placed further down the line or at the antenna feed point, the reading will be lower than the actual transmitter output due to attenuation in the coaxial cable. While measuring at the antenna is useful to know the actual power being delivered to the load, measuring the specific transmitter output requires placement directly at the source.