Product Manual

Product Manual for Tornado Radio Unit
51
Lightning protection
Lightning protection is important to ensure the protection of the tower, antenna and the radio equipment hardware.
Below shows the point earthing concept recommended.
The technique recommended to protect the radio unit, antenna, feeder and tower uses earthing kits in strategic
places. The key points are: adjacent to the feeder connector at the antenna, where the feeder leaves the base of
the tower and where the feeder enters the building structure. If earthing kits supplies are limited or connection to
an earth point is difficult, then order of importance of the earthing locations is as follows:
(a) For a top mounted antenna acting for lightning protection:
1. At antenna connection point.
2. At the tower base.
3. At the entry to the building.
(b) For a general mounting of antenna:
1. At the entry to the building.
2. At the tower base.
3. At the antenna connector.
Earthing kit
Earthing kits
1/2" heliax cable
Polyphase
discharge
unit
Coax to
cabinet
45º cone of
protection
Lightning protection
A gas discharge unit is required to release high voltage charges developed between the cable inner and outer.
There are two types available, a transmitting and a receiving variant. The transmitting variant is the larger. It is very
important that these variants are not confused because the lower discharge potential rating for the receiver unit will
be triggered by transmitting voltages. This will cause a high VSWR and poor performance.