TD 90227GB
2006-09-18/ Ver. C
System Installation
On Site Paging System
11
5.5
Antenna Cables
Keep coax cables between transmitter/receiver and antenna as short as possible. Use only
cable type RG-8 or RG-213. The attenuation in these types is about 0.8 dB/10m at VHF,
and 1.5 dB/10m at UHF. (6 dB attenuation reduces coverage by 50%.)
6
Power Supply
All units use 12.5 V DC and can be powered separately, but normally a common power
supply feeds all the units that are placed together in one location. The power supply is
connected to screw terminals on one of the units and then connected in series to the
other units. The wiring from the power supply must be dimensioned so that the voltage
drop to the modules does not exceed 0.5 V at max load. If the total loading exceed the
capacity of the connected power supply, an additional power supply should be used, see
below.
Power cables
Figure 11. Units powered by two power supplies.
7
Current Consumption
When calculating total current load always use the max consumption for each unit:
Control Keyboards
max Load (A)
Fixed Transmitters
max load (A)
T900
0.7
H952T
2.0
T901
0.5
U952T
2.5
H901
1.3
Power Amplifiers
H954
15
U954
10