Disclosed is a dual-band Global Navigation Satellite System antenna with a hollow core. The antenna includes a conductive cylindrical tube with a longitudinal axis. A ground plane, a low-frequency radiator, and a high-frequency radiator are annuli orthogonal to the longitudinal axis. The inner peripheries of the ground plane and the low-frequency radiator are electrically connected to the outer surface of the cylindrical tube. The outer periphery of the high-frequency radiator is electrically connected to the low-frequency radiator. A vertical low-frequency radiating gap is configured between the ground plane and the outer periphery of the low-frequency radiator. A horizontal high-frequency radiating gap is configured between the inner periphery of the high-frequency radiator and the outer surface of the cylindrical tube. In an embodiment, the inner diameter of the cylindrical tube has a value from about 27 mm to about 102 mm, permitting insertion of a post or pole.