User's Manual
Table Of Contents
- Important Safety Instructions
- Overview
- The ERU assembly
- Do you have everything?
- Safety precautions
- Introduction
- Installing the ERU
- Installation overview
- Installation guidelines and requirements
- Estimating cable requirements
- Assembling the mounting bracket and pipe
- Installing the ERU on solid wood or lap siding
- Installing the ERU on brick or poured concrete
- Installing the ERU on a cinder-block or hollow wall
- Installing the ERU under the eaves
- Installing the ERU on a roof
- Attaching the ERU to the mounting assembly
- Routing and grounding the exterior cables
- Routing cable to the SOMAport
- Troubleshooting
12
External Radio Unit Installation Guide
Overview
The SOMAport has an internal antenna that provides sufficient levels of
performance in most situations. However, certain subscribers may be located too
far away from the nearest basestation to receive a strong radio frequency (RF)
signal. When an antenna, such as the internal SOMAport antenna, is located
inside a building, the signal is weakened because it has to penetrate the walls.
This phenomenon is known as building penetration loss. With the External
Radio Unit (ERU), the radio signals do not have to penetrate the building to
reach the antenna as they do with the internal SOMAport antenna because the
ERU is located outside. It is because the ERU incurs no building penetration loss
that it is able to enhance the operational performance of the SOMAport.
The ERU connects to the SOMAport using a single coaxial cable and is powered
through this cable. No additional power supply is needed.
The ERU contains no moving parts. It has non-line-of-sight functionality, and
the antenna direction is automatically chosen to increase performance. Manual
steering or pointing of the ERU is not required.
The ERU cannot be used as an antenna for other devices. It will not radiate
unless it is connected to a SOMAport.
Antenna detection
If, when the SOMAport is turned on, it detects that the ERU is connected, the
SOMAport will use the ERU exclusively until the power to the SOMAport is
turned off. If no ERU is detected, the SOMAport will use its own internal
antenna until the SOMAport is turned off. The SOMAport decides whether to
use its internal antenna or the ERU antenna each time the SOMAport is turned
on, and does not change antennas until the SOMAport is turned off and back on
again.
WARNING:
The long-term characteristics or the possible physiological
effects of RF electromagnetic fields on humans have not been investigated by
Underwriters Laboratories (UL).