Outdoor Antennas with iX10

The iX10 has two antenna ports - WWAN1 and WWAN2 - but the User Guide provides no information on how to use them with outdoor antennas.

Is there an advantage to having two outdoor antennas (such as space diversity)? If so, how far apart should they be from each other?

Does it make a difference if both antennas are omnidirectional?

Are both WWAN1 and WWAN2 ports the same? If not, what is the difference?