5G Xtream ships with dual external antennas.  They should be mounted at least 50 cm apart for optimum performance.  While height is advantageous, consideration should also be given to cable runs.  The standard cables (LMR200) are 7m in length and should not be extended. Typical mounting locations would be the 1st set of spreaders on a sailboat, radar arch or stern pole/solar panel platform. Optional 10 and 20m assemblies are available and these use LMR400 specialist coax for minimum losses.  For the 3rd antenna, it comes with a 7m cable.