PMP 400/430 and PTP 200/230 Series
Motorola PMP Solutions User Guide Supplement
Issue 6.0 May 2011
Page 53 of 77
A 5.4-GHz SM or BH with an integrated antenna has an
External
Gain
of
17
dB.
The antenna sold with the connectorized 5.4 or 5.8 GHz AP has a gain of 18 dB and
cable loss of approximately 1 dB, giving an
External
Gain
of
17
dB.
A 4.9 GHz SM or BH with an integrated antenna has an
External
Gain
of
17
dB.
The antenna sold with the connectorized 4.9 GHz AP has a gain of 18 dB and cable loss
of approximately 1 dB, giving an
External
Gain
of
17
dB.
Any radio using DFS will use the
External
Gain
to appropriately adjust sensitivity to radar
signals. The use of DFS is determined by the
Region Code
setting on the Configuration
=> Home page.
The Auto-TPC used by the PMP 400/430 and PTP 230 Series system takes into account
the
External
Gain
so as not to exceed national or regional EIRP limits.
Procedure for setting the External Gain
1. If using a BH or SM with an integrated antenna or a connectorized AP with the
connectorized antenna sold with it, leave the
External
Gain
on the Configuration =>
Radio page set to the factory default of
17
dB.
If using another antenna, set the
External
Gain
to the gain of the antenna minus the loss
in coaxial cable and connectors.
IMPORTANT!
Ensure the
External Gain
is set correctly. Setting it low or high can lead
to either a system overly sensitive to DFS events or a system not
transmitting at its full legal power.
4.6
NETWORK CONTROL PARAMETERS
Parameters for High Priority/DiffServ, NAT, DHCP, VLAN, MIR, and CIR are configured the same
as they are in standard Canopy. The operator may (or may not) want to take advantage of the
higher possible MIR to provide greater bandwidth to a given SM.
4.7
FORWARD ERROR CORRECTION
PMP 400/430 and PTP 200 Series radios use FEC (Forward Error Correction) to extend the
range of the modules. They use Reed-Solomon error correction optimized at 3/4 coding. The
coding rate is not settable by the operator.
4.8
CYCLIC PREFIX (CONFIGURABLE ONLY ON PTP 200/230 BH & PMP
430 AP/SM)
OFDM technology uses a cyclic prefix, where a portion of the end of a symbol (slot) is repeated at
the beginning of the symbol (slot) to allow multi-pathing to settle before receiving the desired
data. A 1/4 cyclic prefix means that for every 4 bits of throughput data transmitted, an additional
bit is used, A 1/8 cyclic prefix means that for every 8 bit of throughput data transmitted, an
additional bit is used.