With a pulsed dipolar electron paramagnetic resonance technique named double electron–electron resonance (DEER), we measure nanometer distances between spin labels attached to biomolecules. If more than one spin type is present (A and B), we can separately address AA, AB, and BB distances via distinct spectroscopic channels, increasing the information content per sample. Here, we investigate the appearance of unwanted channel crosstalks in DEER and suggest ways to identify and suppress them.