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APPLICATION OF 9-INPUT MULTISWITCHES OF MSV-9xx SERIES
Here's an example of installation diagram in apartment building. The system provides each outlet with all available terrestrial broadcasts and satellite programs from two satellites (in the example - Astra 19.2E and HotBird 13E). The antennas (including high-gain UHF antenna A2670) and triplexer are mounted on the roof. The set of channel amplifiers and rest of the equipment are placed inside the building. The amplifiers allow to equalize the input levels of the terrestrial signals, which is very important in the case so large distribution networks.
The distribution network is comprised of TERRA multiswitches of MSV series and satellite taps with different tap attenuation levels. The biggest advantage of such a system is its flexibility. Thanks to the wide range of TERRA multiswitches, the designer has virtually limitless possibilities of creating the network and choosing the right equipment. The system is expandable and allows to implement new functions in the future.
The diagram shown below allows to distribute terrestrial and satellite signals to 224 subscriber outlets. The individual MSV-932 R70732 multiswitches can be replaced by models with a smaller number of outputs. There are available MSV multiswitches with 4, 8, 12, 16, 24 or 32 outputs. Each of the risers can be split into two subnetworks. Designing multiswitch systems it is worth to remember about double-tuner PVRs - each of them requires two independent signal lines.
The whole system is powered from two SA-501 R70501 amplifiers via H lines. Amplifiers of this series are characterized by current capacity equal to 2 A. It means is that in a typical installation one device can power 8-10 multiswitches. Converting it into the number of subscriber outlets - with the use of a single connection to the power network we can deploy up to 300 outlets.
A very important issue is the choice of a suitable cable. On one hand - the cable should be easy to lay in long trays, on the other - it has to provide the best physical parameters such as attenuation, impedance matching and shielding effectiveness. The last parameter is critical in multiswitch installations due to the fact that the trays group 5 or 9 cables running in parallel and carrying different signals (combinations of polarization/band). To avoid problems with interference, manifested by inadequate signals from some transponders, the cables must ensure at least 85 dB screening efficiency. Taking into consideration cables used in subscriber installations, TRISET-113 E1015 with 92% braid coverage has the highest screening efficiency, about 100dB (A+/A++ class).
The advantages of building SMATV systems based on TERRA multiswitches of MSV series:
- high scalability and flexibility of installations
- unlimited design possibilities
- possibility of powering the whole distribution network from a single amplifier or multiswitch (one amplifier of SA series can power up to 8-10 multiswitches)
- double-row arrangement of outputs reducing dimensions of the devices
- standardized arrangement outputs allowing to connect several devices using fast F connectors
- the parameters given by the manufacturer -TERRA company - are guaranteed values (e.g. isolation between inputs), which ensures repeatability of the equipment; the actual parameters are even better
Tap system for two satellites, suitable for 60-1000 outlets
SatNet program allows to design a practical implementation of the system.
To select the right components, the data for the design must contain:
- network topology,
- levels of satellite signals,
- levels of terrestrial signals,
- attenuation of the cable/s.
Each element of the installation has its control points (connections with the rest of the network, including the cable runs). Clicking on them, the user of the program can see detailed characteristics (signal levels for different frequencies). If the signals meet the adopted criteria, they are colored in green, if some levels are too low - in blue, if too high - in red. In the diagram below all the points are in green - the project is consistent with the assumptions.
Screenshot from SatNet utility
