Motorola DIMETRA MTS 2, Инструкция по установке, настройке и базовому обслуживанию

Страница: 241 / 517

MTS 2 and MTS 4 Installation, Con
fi
guration and Basic Service Manual MTS 2 RFDS
MTS 2 RFDS
■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■
■
■
In terms of RFDS, MTS 2 uses a low-power, cost effective RFDS placed on top of a
card cage, intended for up to 2 Base Radios.
The RFDS in MTS 2 is made up of the following:
•
One or two Preselectors with integrated high performance low noise ampli
fi
er (LNA). The
supply voltage for the LNA is supplied through the RX out connected to the Base Radios. The
Preselector has two outlets for two Base Radios. The dimensions of the
fi
lter are: 85 x 280 x 70
mm, excluding connectors. The antenna connectors are DIN 7–16, the receive side is connected
with QMA connectors. See the block schematic of the MTS 2 Preselector in
Figure 7-6 .
•
One or two Duplexers rated for up to two TETRA modulated carriers. The antenna connectors
are DIN 7–16, the transmit side is connected with QN connectors. The Duplexer has
an integrated digital VSWR meter. The supply voltage for the digital VSWR meter is
supplied through the CAN Bus interface. The receive side has integrated LNA as for the
Preselector and two RX outputs (QMA). The supply voltage for the LNA is supplied through
the RX ports. The
fi
lter dimensions are approximately: 170 x 280 x 70 mm excluding
connectors. See the block schematic of the MTS 2 Duplexer in Figure 7-8 .
Because the MTS 2 has only up to two carriers, there is no need for Post Filters
for non-duplexed operation (you can achieve non-duplexed operation by using the
Duplexer as the Post Filter and not using the receive path of the Duplexer).
•
Hybrid Combiner. MTS 2 can have either a Hybrid Combiner for transmission on one
antenna, or without combining for transmission on two separate antennas.
MTS 2 is equipped with a digital voltage standing wave radio (VSWR) monitor to ensure site availability at
remote low-traf
fi
c sites and for public safety customers. The digital VSWR monitor can make a quite accurate
VSWR reading because the measurement is relative between the forward and reverse power.
The VSWR monitor does not have the same accuracy in power reading as the digital power monitor (DPM)
in the MTS 4, but it still allows a cost-effective monitoring of the integrity of the antenna.
MTS 2 Filter Tray
The MTS 2
fi
lter tray can carry up to two Duplexers and one Preselector or one Duplexer and two
Preselectors. There is also room for a Hybrid Combiner. The antenna connectors extend from the
MTS 2 junction panel and antenna cables are connected directly onto the
fi
lters.
In Table 7-1 ,
Low Power
is valid for UHF, while
High Power
is valid for both UHF and 800 MHz.
The numbers illustrated are applicable for TETRA with TEDS numbers within parentheses.
6802800U74-N September 2009
7-3