User's Manual

Table Of Contents
8 Web Page Reference
173
Lower Center Frequency: Not displayed for the PTP 49600. Not displayed when Spectrum
Management Control is set to “i-DFS”. The software for the PTP 600 Series Bridge allows a
user to optionally adjust the channel center frequencies. Changing the Lower Center
Frequency attribute causes all channel center frequencies to be offset. It effectively slides the
channelization up or down. See Sections 5.5 to 5.11, depending on the frequency variant.
NOTE
: Because the 4.9 GHz spectrum is restricted by license, the Lower Center Frequency
is fixed for the PTP 49600 and is therefore not displayed.
CAUTION: The lower center frequency attribute must be configured to the same value for
both the master and slave. Failure to do so will cause the wireless link to fail reestablishment.
The only way to recover from this situation is to modify the Lower Center Frequency attribute
so that they are identical on both the master and slave unit.
Default Raster: If this is set to “On”, the list of options presented in the fixed Tx frequency
box is limited by the default raster.
Fixed Tx Frequency, Fixed Rx Frequency: Only displayed when Spectrum Management
Control is set to “Fixed Frequency”. The software for the PTP 600 Series Bridge allows a user
to optionally fix the Transmit and the Receive frequencies for a wireless link. The settings
must be compatible at each end of the link. Once configured, the spectrum management
software will not attempt to move the wireless link to a channel with lower co-channel or
adjacent channel interference. Therefore this mode of operation is only recommended for
deployments where the installer has a good understanding of the prevailing interference
environment. Figure 74 shows an example fixed frequen
cy configuration for a 30 MHz
channel bandwidth. In this example, the Fixed Transmit Frequency is set to 5742 MHz and
the Fixed Receive Frequency is set to 5742 MHz. Care must be taken when configuring the
Fixed Transmit and Receive Frequencies to ensure that both frequencies are on the same
channel raster as the Lower Center Frequency. For example, if the channel raster is 10 MHz,
both the Fixed Transmit and Receive Frequencies must be a multiple of 10 MHz from the
Lower Center Frequency (5752 = 5742 + 10 MHz) and (5782 = 5742 + 10 MHz × 3).
NOTE: A raster limits the selection of the Rx frequency based upon the setting of the Tx
frequency.