RSGB 2018 Convention lecture - PI4: the Digtal mode for beacons and why it is a success

Bo Hansen, OZ2M Many digital modes have been tested for VHF beacon use and have been found to have problems. PI4 was developed by a team in Denmark to overcome these issues. The first PI4 + CW + carrier beacon, OZ7IGY, has been using the mixed mode for more than five years. The presentation explains why PI4 has become a success both among many VHF beacon operators and users. Today more than 25 beacons use PI4 transmissions in their sequence with at least eight different hardware implementations available and more are planned.