Leica Geosystems Leica mojo3D - User Manual - Manual (Page 257)

Leica mojo3D, Safety Directions 257
Lightning conductors
Suggestion for design of a lightning conductor for a GNSS system:
1. On non-metallic structures. Protection by air terminals is recommended. An air
terminal is a pointed solid or tubular rod of conducting material with proper
mounting and connection to a conductor. The position of four air terminals
should be uniformly distributed around the antenna at a distance equal to the
height of the air terminal. The air terminal diameter should be 12 mm for copper
or 15 mm for aluminium. The height of the air terminals should be 25 cm to 50
cm. All air terminals should be connected to the down conductors. The diameter
of the air terminal should be kept to a minimum to reduce GNSS signal shading.
2. On metallic structures. Protection is as described for non-metallic structures, but
the air terminals can be connected directly to the conducting structure without
the need for down conductors.