Detailed localisation of the quench start in Nb3Sn accelerator magnets by voltage measurements requires a large number of voltage taps, which is less feasible in long prototype coils. Localisation with quench antennas is a proven concept for longitudinal quench localisation in full length accelerator magnets. Quench antennas are also excellent vibration detection tools, and give important information on the cause of the quench. Dedicated quench antennas were produced using state of the art flexible printed circuit boards. The quench antennas were tested at the CERN based SM18 superconducting magnet test facility in Nb3Sn model magnets; the results were validated with voltage measurements and compared with numerical model predictions.