rtl_power_fftw is a program that obtains a power spectrum from RTL devices using the FFTW library to do FFT.

It is inspired by the program rtl_power in librtlsdr. However, the said program has several deficiencies that limit its usage in demanding environments, such as radio astronomy. An inspection of rtl_power in hope of modifying it and obtaining better performance resulted in the conclusion that it would be an infeasible task. Measurements of FFT performance showed that the leading library in the field of FFT - fftw - makes mincemeat of the routine used in rtl_power, even on simple processors such as raspberryPi.