User's Manual

AN-50e

user manual

Page 11 of 96

1.7 Lightning Protection

WARNING: The following notes are general recommendations for the system. The

wireless equipment should be installed by a qualified professional installer and

must follow local and national codes for electrical grounding and safety. Failure

to meet safety requirements and/or use of non-standard practices and procedures

could result in personal injury and damage to equipment. A direct lightning strike

may cause serious damage even if these guidelines are followed.

All outdoor wireless equipment is susceptible to lightning damage from a direct hit

or induced current from a near strike. Lightning protection and grounding practices

in local and national electrical codes serve to minimize equipment damage, service

outages, and serious injury. Reasons for lightning damage are summarized as:

- Poorly grounded tower/antenna sites that can conduct high lightning strike

energy into equipment.

- Lack of properly installed lightning protection equipment that can cause

equipment failures from lightning induced currents.

A lighting protection system provides a means by which the energy may enter

earth without passing through and damaging parts of a structure. A lightning

protection system does not prevent lightning from striking; it provides a means for

controlling it and preventing damage by providing a low resistance path for the

discharge of energy to travel safely to ground. Improperly grounded connections

are also a source of noise that can cause sensitive equipment to malfunction.

A good tower grounding system disperses most of the surge energy from a tower

strike away from the building and equipment. The remaining energy on the IF

cable shield and center conductor can be directed safely to ground by using a

lightning arrestor in series with the IF cable.

To limit the equipment damage due to a lightning strike, the following practices

are recommended for the wireless system:

- Provide direct grounding from the antenna mounting bracket, the radio and

antenna and the lightning arrestors to the same

ground point at the base of the

tower or a ground bus on the building. Use the grounding screws on the antenna

bracket and the radio and antenna for terminating the ground wires.

- Install one RF lightning protector between the radio and antenna in series with

the RF cable.

- A lightning arrestor in series with the IF cable at the point of entry to the

building.

- Install a lightning arrestor in series with the IF cable at the transceiver on the

tower/mast.

- The AC wall outlet ground for the terminal must be connected to the same

grounding system as the radio and antenna lightning protectors.

- The ground connection on the back of the terminal should be connected to the

same ground for the building.