Robotic swarm or multi-agent systems attract increasing attention for extraterrestrial exploration missions, among others. Control of a swarm requires communication among agents and accurate knowledge about their position and orientation. Both can be provided by radio signals exchanged between the agents. For navigation, round-trip delay (RTD) and direction-of-arrival (DoA) are informative signal metrics, as they relate to the relative distances and angles between the agents. DoA estimation is usually performed using antenna arrays. Recently, multi-mode antennas (MMAs) have been suggested as an alternative, but so far only theoretical results exist. This paper presents measurement results for DoA estimation with a single MMA mounted on a rover. The median estimation error of 7.2 • for a moving rover proves the potential of DoA estimation with an MMA.