1800MHz-1900MHz Off-Air Repeaters (OR Series)
Page
91 080 0701F – Rel.04
CHAPTER 3
3.3
•
Tunnels with a length in the 300-meter to 600-meter range.
Also in this case, one single Off-Air Repeater is sufficient. The repeater is located at the entrance to the
tunnel and equipped with a leaky cable. This cable can be combined with a directional antenna to
irradiate a portion of the area in front of the tunnel exit (Figure 4).
FIGURE 4
•
Tunnels with a length of more than 600 meters.
The signal can be enhanced in two ways:
a) By an Off-Air Repeater at the entrance to the tunnel, connected to a cascade of bi-directional
amplifiers inside the tunnel which re-generate the signal with amplification steps at a distance of
250mt.
÷
400mt. from one another (Figure 5).
FIGURE 5
DOWN
UP
D
O
W
N
L
IN
K
U
P L
IN
K
Power Supply
(230Vac)
OFF-AIR
REPEATER
UP
DOWN
48Vdc Power Supply
and external signals
POWER
SUPPLY
DC
DC
BF
RF
BF
RF-DC-BF
RF
UP
DOWN
DOWN
UP
AMPLIFICATION STEP
RF-DC-BF
BI-DIRECTIONAL
AMPLIFIER
RF-DC-BF
RF-DC-BF
RF-DC-BF
D
O
W
N
L
IN
K
U
P L
IN
K
BI-DIRECTIONAL
AMPLIFIER
Bias-T
OFF-AIR
REPEATER
