TX RX Systems Inc. Manual 7-9487-3 05/05/11 Page 4
the ability via software interface to switch the tower
top LNA’s input, between either the antenna or an
internal 50 Ohm load. This feature gives field engi-
neers the ability to perform system sensitivity tests
from the ground with or without site noise being
coupled into the system via the antenna.
RF signals from the tower top box are applied at
the rear of the MCU style base control unit at the
TRANS input connector. After passing onto the
deck they are applied to a modem assembly which
is used to couple and de-couple the 2.176 MHz
modem subcarrier communications between the
base and tower top CPU’s. The modem assembly
is also used to inject onto the main transmission
line, the +12 VDC that is required to power the
tower box circuitry.
RF signals leave the modem assembly and are
routed to an amplifier assembly where they pass
through a wideband ceramic filter located in the
input circuit of the assembly. Following the filter is
a variable attenuator which allows adjustment of
Electrical Specifications
Frequency Range
792 to 824 MHz
Impedance
50 Ohms
VSWR
<2 : 1
Connectors
to TTA
to BTS
Test Port input
N - Female
N - Female
BNC - Female
Reserve Gain
electronic attenuator
0 to 15.5 dB
in 0.5 dB steps
Alarm Contacts
Two sets of Form-C Con-
tacts
Nominal 2A @ 30 VDC
or 0.5A @125 VAC
I/O
Ethernet
Power Requirements
Model 428-83H-01-C-110
Model 428-83H-01-C-48
90 - 240 VAC @ 50/60 Hz
-48 VDC
Operating Temp Range
0° C to + 50° C
Mechanical Specifications
Enclosure
Standard EIA 19” Rack
Mount
Dimensions (HWD)
1 RU x 19” x 8”
(38 x 483 x 203 mm)
Net Weight
10.5 lbs
Table 4:
CMU specifications. Values are typical unless
noted otherwise.
Electrical Specifications
Frequency Range
792 to 824 MHz
Multicoupler Net Gain
+1 dB typ; 0 dB min
Distribution Amp Type
Gain
Noise Figure
1 dB compression point
3rd Order Output IP
Quad-coupled dual stage
23 dB
4 dB
27 dBm
46 dBm
Number of Outputs
Split Loss
16 or 32
18 dB
Impedance
50 Ohms
VSWR
<2 : 1
Connectors
to TTA
to BTS
Test Port input
N - Female
BNC-Female
BNC - Female
Reserve Gain
electronic attenuator
0 to 15.5 dB
in 0.5 dB steps
Distribution
electronic attenuator
0 to 3 dB
in 0.5 dB steps
Alarm Contacts
Two sets of Form-C Contacts
Nominal 2A @ 30 VDC
or 0.5A @125 VAC
I/O
Ethernet
Power Requirements
Model 428-83H-01-M
Model 428-83H-01-M-48
90 - 240 Vac @ 50/60 Hz
-48 VDC
Operating Temp Range
0° C to + 50° C
Mechanical Specifications
Enclosure
Standard EIA 19” Rack Mount
Dimensions (HWD)
1 RU x 19” x 14”
(38 x 483 x 356 mm)
Net Weight
11.5 lbs
Table 3:
MCU specifications. Values are typical unless
noted otherwise.
Содержание 428B-83H-01-C-110
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