Abstract: A broadband omnidirectional antenna for rail vehicles comprises a baseplate and a monopole radiator, which comprises a foot point and an opposing end region. The radiator extends away from the baseplate and widens in cross section along the longitudinal axis thereof in at least a first portion located between the foot point thereof and the end region thereof, diverging walls of the radiator forming an accommodating chamber. An inner contour of a shell-shaped or trough-shaped holding and/or accommodating device is adapted at least over part of the periphery to an outer contour of the first portion of the radiator, resulting in at least part of at least the first portion of the radiator dipping into the holding and/or accommodating device and being held thereby. The first end of a holding means is fixed to the baseplate and a second end thereof is fixed to the radiator.