User's Manual

044-05207 Rev A iii
Preface
Safety
Any personnel involved in installation, operation, or service of units included in a Powerwave Distributed
Antenna System (DAS) must understand and follow the points below.
❑
Powerwave Nexus FT Rack Mount Radios (RMR) are designed to receive and amplify signals from one or
more base stations and retransmit the signals to one or more mobile stations. They also act the other way
round, that is to receive signals from one or more mobile stations, then amplify and retransmit the signals
to the base stations. Powerwave Nexus FT RMR systems must be used exclusively for this purpose and
nothing else.
❑ Units supplied with power from the mains must be connected to grounded outlets and in conformity with
the local prescriptions.
❑ Power supply units supplied from the mains contain dangerous voltage that can cause electric shock.
Disconnect the mains prior to any work in such a unit. Local regulations are to be followed when servicing
such units. Only authorized service personnel are allowed to service units while the mains are connected.
❑ All RF transmitting units, including Nexus FT RMRs, will generate radio signals and thereby give rise to
electromagnetic fields that may be hazardous to the health of any person who is extensively exposed close
to an antenna.
Human Exposure to RF Radiation
Safe distances must be kept when working around antennas. The following paragraphs describe the cautions
to be aware of during the installation and maintenance of antenna systems and how to calculate safety
distances needed for RF radiation at different antenna power and frequencies.
Antennas
To be able to receive and transmit signals, a RMR is connected to a donor antenna directed towards the base
station and a service antenna directed towards the coverage area. A fiber optic cable from the base station
might, however, be substituted for the donor antenna.
Installation and Maintenance of Antenna Systems
Installation and maintenance of all antenna systems must be performed with respect to the radiation exposure
limits for public areas. The antenna radiation level is affected by RMR output power, antenna gain, and
transmission devices such as cables, connectors, splitters and feeders. Also, the system minimum coupling
loss, typically between 25dB and 35dB, is determined by a standard with the purpose to protect base stations
from noise and other performance dropping effects.
Radiation Exposure
The World Health Organization (WHO) and International Commission on Non-Ionising Radiation Protection
(ICNIRP) have determined recommendations for radiation exposure. ICNIRP recommends not to exceed the
following radiation power for public exposure:
Frequency Radiation power
800/900 MHz 4.5W/m²
1800/1900 MHz 9.0W/m²
2100 MHz 10.0W/m²
For antennas larger than 20cm the maximum radiation power can be calculated by using the following formula:
S= P/(4
πr
2
)
S = Radiation power in W/m²
P = Output power in W
r = Distance between antenna and human in meters