In an example aspect, an apparatus includes a balanced power amplifier, which performs amplification in the presence of a variable antenna impedance. The balanced power amplifier includes a quadrature output power combiner coupled to a first power amplifying path and a second power amplifying path, detection circuitry, and control circuitry. The detection circuitry includes at least one power detector coupled to an isolated port of the quadrature output power combiner and a resistor coupled between the isolated port and a ground. The at least one power detector is configured to measure power at the isolated port, which is based on a resistance of the resistor. The control circuitry is configured to adjust operating conditions of a first power amplifier of the first power amplifying path and the second power amplifier of the second power amplifying path based on the power that is measured at the isolated port.