JDTECK JDIR-37-87 Technical User's Manual - page 5
3. Installation
1. The repeater’s main function is to improve weak RF signals to an area.
2. Selecting the appropriate accessories that are compatible with the
frequency of the repeater is very important for optimal system
performance. A 700MHz Repeater needs to be used with accessories that
supports the 700MHz band. In the same way, choosing accessories in the
1900MHz Band needs to go with a 1900MHz Repeater etc. For multi-
band repeaters, please ensure the peripheral components used supports
all the frequencies needed.
3. The signal strength and quality at the outdoor antenna directly affects the
efficiency of the indoor coverage. Therefore it is very important to choose
the location of the outdoor antenna carefully. With this in mind, it is
recommended that the donor antenna be installed in clear line of sight
(LOS) to the serving sector/s.
4. The repeater is a two-way (full duplex) signal amplifier. Therefore there
needs to be proper isolation between the outdoor antenna and indoor
antenna in order to avoid signal oscillation of the repeater. (Feedback)
There needs to be more than 15dB of isolation above the repeaters gain.
For example, if the repeater gain is 80dB, then you need 95dB of isolation
between outdoor antenna and indoor antenna.
5. The repeater gain is adjustable for both the uplink / downlink individually.
Depending on the environment, the end-user may need to adjust the
repeater gain to achieve optimum performance and desired coverage.
6. The repeater is designed to amplify the input signal, filter it and retransmit
it to the desired area via service antennas. In order to reach the best
performance, the outdoor signal should be better than -80dBm with an
Ec/Io <6 and an RSRQ of <12dB. If the outdoor signal is very weak, then
a pre-amplifier may be used.
7. Calculating the Link budget before setting the repeater gain.
Link budget calculation:
Outdoor signal strength
– Loss of accessories (cable, connectors,
splitters, Directional Couplers, Path Loss) + Antenna gain (outdoor
antenna, indoor antenna) + Repeater gain = Indoor signal strength.
8. For all cellular applications, you need to use 50 Ohm rated coax.
Besides affecting voice quality, using any other impedance of coax will
put an extra load on your repeater and shorten its life span.
3.1 Installation Procedure
Site Survey
Carrier Coordination
Link Budget Calculation
Retransmit Agreement
Install Donor Antenna
Install Cables & Sweep
Install Repeater
Install Indoor Antennas
Commission System
Gain Adjustment
Call & Data Quality
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8
System Optimization