GS25, Safety Directions
9
DANGER
If the product is used with accessories, for example on masts, staffs, poles, you may
increase the risk of being struck by lightning. Danger from high voltages also exists
near power lines. Lightning, voltage peaks, or the touching of power lines can cause
damage, injury and death.
Precautions:
• Do not use the product in a thunderstorm as you can increase the risk of being
struck by lightning.
• Be sure to remain at a safe distance from electrical installations. Do not use the
product directly under or close to power lines. If it is essential to work in such an
environment contact the safety authorities responsible for electrical installations
and follow their instructions.
• If the product has to be permanently mounted in an exposed location, it is advis-
able to provide a lightning conductor system. A suggestion on how to design a
lightning conductor for the product is given below. Always follow the regulations in
force in your country regarding grounding antennas and masts. These installations
must be carried out by an authorised specialist.
• To prevent damages due to indirect lightning strikes (voltage spikes) cables, for
example for antenna, power source or modem should be protected with appro-
priate protection elements, like a lightning arrester. These installations must be
carried out by an authorised specialist.
• If there is a risk of a thunderstorm, or if the equipment is to remain unused and
unattended for a long period, protect your product additionally by unplugging all
systems components and disconnecting all connecting cables and supply cables, for
example, instrument - antenna.
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 can 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 conduc-
tors.
Air terminal
arrangement, plan
view
a) Antenna
b) Support structure
c) Air terminal
GS_039
a
b
c
