User's Manual

109
Document Number: 0100SM1401 Issue: 10-14
Part I – Installation & Commissioning
Where possible, avoid mounting antennas:
1. Against or adjacent to steel structures.
2. In an area which will have intermittent obstructions
- people walking past, vehicles driving past etc. That is,
mount antennas well above such moving obstructions.
3. Near any electrical equipment.
4. Near metal beams, structures etc.
5. Inside any metal enclosures, tin sheds / warehouses
etc. - (some meshed wire fences act like a “brick wall” to
RF transmissions).
6. Away from guard rails or support beams.
7. Above any pipe work or corrugated iron roofs.
Sometimes installations in such environments are
unavoidable and where this is the case, certain care can
be taken to still help ensure a reliable installation.
If tests indicate poor signal strength then the antennas
at one or both ends of the link should be raised, and/
or moved clear of obstructing objects, or if directional
antennas are employed they should be checked
for correct directional orientation and polarization
(horizontal or vertical signal orientation).
LED Indicators
LED indicators are documented in Part E - Quick
Reference Guide - Hardware of this User Manual.
However, during the installation process check that the
LED indicators are operating correctly.
DC POWER
If all the LEDs are off, no DC power is reaching the radio
modem or the fuse is open. Successful power-up is
indicated by the “Pwr/Tx” LED showing a continuous
GREEN state.
When the transmitter is active the “Pwr/Tx” LED turns
RED.
Sync/No RX LED Indicator
The “Sync/NoRx” LED is used to indicate the state of the
receiver.
A solid or regular flashing GREEN LED shows that the
modem is receiving decodable data.
A solid or flashing RED LED indicates the modem is
receiving un-decodable data, this is typically from an
unwanted source.
ETH port LED Indicators
See the table below for Ethernet port LED indicators.
ANTENNA INSTALLATION
The selection of antennas and their placement can
influence RF link quality.
Antennas are generally mounted to a vertical pole with
either vertical or horizontal polarization as per the license
requirement.
Antennas should be mounted as high as practical and
away from metal surfaces which can cause reflections.
As a typical generic example for selecting the suitable
antenna type, Point to Multipoint (PTMP) systems
generally employ high gain (3, 6, or 9dB gain) omni
directional antennas at the Entry Point/Repeater
sites and either omni directional whips (unity gain) or
preferably high gain directional yagi antennas (9 or 14dB
gain) at the remote sites.
YAGI ANTENNAS
Yagi antennas not only provide signal gain and directivity,
but also provides protection from interfering signals
which are outside the beam width of the antenna. Yagi
antennas help provide optimum performance when
communicating over very long distances.
Yagi antennas are polarized and need to be mounted
either vertically (elements pointing from the ground to the
sky) or horizontally (elements in parallel with the horizon).
When mounting yagi antennas with vertical polarization,
it should be noted that some antennas have a drain hole
in the dipole (loop section of antenna). The small drain
hole on one end of the dipole must be pointed towards
the ground so that water will drain out of the antenna.
OMNI DIRECTIONAL ANTENNAS
Omni directional antennas provide a radiation pattern
of equal strength through 360
0
in the horizontal plane.
This makes them ideal for Entry Point /Repeater radio
antennas in point to multipoint systems because they
can reach a large populous of remote sites.
Omni directional antennas are also used at remote sites
(although yagi antennas are preferred) and are typically
ground independent whip type antennas. The main
reason for using whips at remote sites is for aesthetics as
they are far less obtrusive than a yagi.
Regardless of the type, antennas need to be mounted
properly and in a suitable location as covered below.
ANTENNA PLACEMENT
Antenna placement is of paramount importance and
plays a big part of the antennas and in turn systems
performance.
When choosing antenna locations the aim is to find
the largest path of unobstructed space and locate the
antennas within that space. Locate the antennas as high
as possible and clear of any obstructions.
ETH1/2 LEDS
Ethernet port inactive, no cable connected
Ethernet port active @ 10Mbps
Ethernet port active @ 100Mbps