That’s interesting. I thought it was a form of 1/4 wave ground plane with sloping radials, which per all the research I’ve done (ham radio sites, excerpts from the ARRL Antenna Handbook, etc.) plus ancient past experience normally has around 2.4dBi of gain. Is your gain measurement dBi (referenced to a zero-gain isotropic antenna) or dBd (referenced to a half-wave dipole?)
