Orbital angular momentum (OAM) for radio communications has the potential of simultaneously transmitting multiple signals at the same frequency and time resources. This multiplies the achievable channel capacity at a given bandwidth by increasing the available number of simultaneous data streams. One downside of OAM radio communication is the requirement of multimode radio frequency (RF) hardware at both ends of a link, i.e., the transmitter and the receiver. This is not always practically viable, especially as we move toward low-profile receivers in future communication devices. In this work, we present a novel method of OAM-based radio communication with enhanced physical layer security that requires only a single-antenna receiver. We first present the system architecture, then we design and realize a Rotman lens-based circular antenna array transmitter operating at 5.8 GHz. We then experimentally verify the capability of the hardware to create multiple modes. As a proof-of-concept, we propose a communication system that simultaneously uses modes 0 and +1 of the OAM beamformer and in doing so show how a single-antenna receiver can be used for data recovery. We first identify a general analog modulation expression and use the proposed system to transmit digitally modulated data stream to a single-antenna-equipped receiver. A precommunication training sequence is required to realize the proposed approach. The experimental results verify the simulated predictions.