X606 Folded Dipole Omni-directional Radio Modem Antenna. 0 dB Gain. Antenna for use when an installation needs to be attached to the side of a building. It has a 3600 radiation pattern and is independent of ground plain. X604 Half Wave Mast Mounted Omni- Directional Dipole Radio Modem Antenna. 0 dB Gain. Antennas of this type have a 3600 radiation pattern. These antennas are used for general site coverage. It is independent of ground plain.