A method for communication includes modulating data in a wireless communication terminal to produce an aggregated-spectrum signal, which includes at least first and second signals in respective first and second spectral bands. The modulated data is transmitted in the first and second signals at respective first and second power levels. The second power level is adjusted separately from the first power level. In some embodiments, one or more instructions to set the first power level are received at the wireless communication terminal, and the first power level is set separately from setting the second power level based on the instructions.