Product Manual

© MiMOMax Wireless Ltd
Tornado Product Manual
40
8.2.3.6 Supply Noise
Regardless of the EMC provisions in the equipment, power wiring from the DC source should not be shared with other
equipment that may introduce excessive noise. Nor should the power cables to the RU be run alongside cables that connect
to other equipment that may produce high current noise or transients, e.g. power relays.
8.2.3.7 Operating from AC Mains:
AC-DC ‘desktop’ power supplies are available from MiMOMax with the required power.
8.2.3.8 Choice of power supply cable size
Table
2 indicates the maximum length of cable that can be used for given supply voltages and cable sizes. It also includes
the maximum loop resistance, so that other combinations can be checked.
Cable length was calculated for 80% power transfer efficiency (or 10.5 volts at the radio, in the case of a 12V supply) with a
26-watt load and supply Vmin. The value used for resistivity of copper was at 70 Celsius. This table is a guide only. Always
check the cable manufactures data before detailed engineering.
Supply voltage
Cross sectional area (mm
2
)
Approx.
AWG
12V
(Vmin = 11v)
24V
(Vmin = 18v)
48V
(Vmin = 36v)
1.85
14
9m
92m
369m
2.5
13
13m
125m
4
1
10
20m
6
1
8
30m
Max loop resistance
0.2 Ω
2.0 Ω
8 Ω
Table 2: Recommended maximum cable length for a given supply cable size
Note 1: The Phoenix Contact MSTB 2,5 HC plug can support stranded wire with a cross sectional area between 0.2 mm
2
and
2.5 mm
2
Longer cable runs will therefore need to use a distribution block, and cable with a smaller size for the final connection.
8.2.3.9 Power over Ethernet
The Tornado product supports passive power over Ethernet through the use of external splitters and injectors, these devices
use the spare Ethernet pairs on Cat5 cable (or better) to carry the power supply passively to the radio over the Ethernet cable.
If the Ethernet cable greater than 20m is used a supply voltage of 48V should be used, at a distance of 20m or less a 24V
supply can be used. The supply current should be kept under 1A when using power over Ethernet including accounting for
voltage drop over the cable. A 48V AC-DC power supply suitable for use with the MiMOMax implementation of PoE is
available.
The PoE Injector shown below is used to introduce the DC power to unused pairs. The PoE and splitter is then used to
separate the Ethernet and power feeds from the Cat5 cable and provide them to the radio. A splitter with a sealed connector
in conjunction with the weather proof hood (shown below) can be used to provide a waterproof connection to the radio. This
allows a single Cat5 cable to be run to an outdoor mounted radio.
PoE Injector