A dual polarised omnidirectional antenna apparatus (20) capable of operating in transmit and receive, comprising at least two dual polarised directional antennas (21) configured to be mountable in a substantially equi-spaced distributed array around and pointing away from a platform, wherein the antenna apparatus (20) is configured such that, when operated in transmit, the dual polarised directional antennas operate in phase with each other to deliver a combined omnidirectional, dual polarised, performance. This increases operational bandwidth and mitigates interference effects in communications applications.