An electrospray head for use in an electro-spraying apparatus comprises a body with an internal surface defining a conduit having an inlet for receiving a fluid to be sprayed and an outlet for emitting the fluid. The electrical distribution center assembly includes an electrical distribution center member, an electrical connector, a support member which retains the electrical connector and includes at least one cam follower projection, at least one cam lever rotatably mounted to the electrical distribution center member, and a driver member for abutting the cam lever arm. A single carrier-frequency division multiple access system can effectively use frequency switched transmit diversity to reduce a peak-to-average power ratio and to maintain a single-carrier property.