Techniques and devices for wireless communications are described. A first wireless device may establish a communications link with a second wireless device in a first radio frequency spectrum band. When transmitting a beamformed transmission in the first radio frequency spectrum band, an antenna array at the first wireless device may generate a grating lobe. The grating lobe may result in a beam ambiguity when the first wireless device switches to a second radio frequency spectrum band. The first wireless device may receive one or more reference signals from the second wireless device in the second radio frequency spectrum band. The reference signals may include a respective reference signal for each lobe (e.g., a main lobe and one or more grating lobes) identified in the beamformed communications link in the first radio frequency spectrum band. The first wireless device may use the reference signals to resolve the beam ambiguity.