A holder, electrical supply, and optional radio frequency transmitter unit to hold, supply power to, and receive a data signal from an operating electronic device when the device (e.g., MP3 player) is held in the unit is disclosed. Electrical power enters the unit's power acquisition portion (e.g., cigarette lighter adapter) from an external source and flows to the electronic device via the holder. A data signal from the electronic device is processed by an radio frequency transmitter in the unit, and the resulting radio frequency signal is broadcast by an antenna (e.g., gooseneck) that preferably forms a repositionable mechanical connection between the holder and the power acquisition unit.