A transmitter has an output power of 200 watts. The coaxial and connector losses are 3 dB in total, and the antenna gain is 9 dBd. What is the approximate Effective Radiated Power of this system?

First, calculate the total system gain or loss in decibels. The antenna has a gain of +9 dBd, and the feedline has a loss of -3 dB. This gives a net system gain of +6 dB (9 - 3 = 6). In decibel math for power, every 3 dB represents a doubling of power. Therefore, a net gain of +6 dB means the power doubles twice (2 x 2 = 4). The system radiates 4 times the input power in the favored direction. Multiplying the 200 watts of transmitter output power by the multiplier of 4 gives an Effective Radiated Power (ERP) of 800 watts.