In this paper, the authors use numerical solutions to the time-dependent Schrödinger equation, perturbation theory, as well as analytic expressions to investigate nondipole effects in the RABBIT technique, studying a helium atom subject to a linearly polarized XUV and a weak IR field. By scanning the time delay between the two fields, they observe modulations in sidebands both for the angular-integrated photoelectron yield and for the forward-backward asymmetry in photoelectron distribution along the light-propagation direction.