User's Guide Part 1

Table Of Contents
Chapter 3: System planning Radio spectrum planning
Available spectrum
The available spectrum for operation depends on the regulatory band. When configured with
the appropriate license key, the unit will only allow operation on those channels which are
permitted by the regulations.
Certain regulations have allocated certain channels as unavailable for use:
ETSI has allocated part of the 5.4 GHz band to weather radar.
UK and some other European countries have allocated part of the 5.8 GHz band to Road
Transport and Traffic Telematics (RTTT) systems.
The number and identity of channels barred by the license key and regulatory band is
dependent on the channel bandwidth and channel raster selected.
Barred channels are indicated by a No Entrysymbol displayed on the Spectrum Expert web
page (Spectrum Expert page in radar avoidance mode on page 7-37).
Channel bandwidth
Select the required channel bandwidth for the link. The selection depends upon the regulatory
band selected.
The wider the channel bandwidth, the greater the capacity. As narrower channel bandwidths
take up less spectrum, selecting a narrow channel bandwidth may be a better choice when
operating in locations where the spectrum is very busy.
Both ends of the link must be configured to operate on the same channel bandwidth.
Frequency selection
Regions without mandatory radar detection
In regions that do not mandate DFS, choose
DSO
or
Fixed Frequency
:
Dynamic Spectrum Optimization (DSO)
: In this mode, the unit monitors the spectrum
looking for the channel with the lowest level of interference. Statistical techniques are used
to select the most appropriate transmit and receive channels. The unit can be configured
such that it operates in DSO mode, but does not operate on selected channels. This allows
a frequency plan to be implemented in cases where multiple links are installed in close
proximity.
Fixed Frequency
: In this mode, the unit must be configured with a single fixed transmit
frequency and a single fixed receive frequency. These may set to the same value or to
different values. This mode should only be considered in exceptional circumstances, for
example where it is known that are no sources of interference on the selected channels.
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