We experimentally verify the statistical stability of ultrawideband time-reversal-based imaging of targets in discrete random media using electromagnetic waves. The measurements are carried out using a time-domain radar system that provides useful bandwidth of up to 40 GHz. We study the effect of the excitation bandwidth, discrete scatterers permittivity and fractional volume, and radar aperture size on the image stability. We also address the problem of imaging nonstationary targets in random media, where we verify the statistical stability of a differential time-reversal technique suited for tracking.