A high frequency signal must be conveyed and diffused using suitable rules and equipment. In the system design, the cables placed in the riser column must ensure uniformity of signal between the farthest and closest socket to the roof.
Remember that it is always BETTER "NOT TO LOSE" the signal THAT AMPLIFYING !!!.
OUTDOOR CABLES Normally in the antenna-switchboard stretch are used PVC cables . This thermoplastic tends to degrade when subjected to atmospheric agents, moreover it is not completely impermeable if it is laid in areas where can occur water stagnation . For this connection it is advisable to use our INTSAT series cables whose advantages are:
Descent column, especially if long, must be supported with a very low loss cable. (es. Digisat 5 Elite, Digisat 823 Elite, PROSAT SILVER Elite Ø 6,8 mm).
In presence of multiple columns, the signal should be subdivided using splitters. These components have the function of dividing the signal into equal parts, originating a low loss and a maintaining of impedance accorded. The attenuation of these devices varies according to the number of outputs: generally it goes from 4 dB for 2 outputs, to 8 dB for four outputs.
Before coming to the sockets, the signal must be diveded and SEPARATED from the column, so that any interference or disturbance generated in a utility does not propagate in the system. The device responsible for this function is the SHUNT, which has a very high separation between output and column (> 30 dB).
|
![]() |
1) DISTRIBUTION INPUT
|
This device is made to be connected in cascade: at each passage it has an attenuation of about 1.5 dB.
Warning: it is very important to close column with the LOAD (75 Ohm), otherwise the whole distribution will not be accorded with the switchboard and it will occur reflected waves, signal drops or distortions. Absolutely avoid to connect the socket to the passing terminal of the shunt. Someone, sometimes, use this practise to recover (quickly) the lost signal due to some failure in the system (old cables, small switchboard, broken antenna, etc.). If it is true that in this socket the signal will be greater, it is even more true that the whole system will be compromised.
|
![]() |
IMPORTANT
|
With digital signals is also necessary to shield the entire system from any interference generated by electrical equipment inside or in the nearby of the house. The standard EN 50117, for cables, has introduced the "classes" (B, A, A +, A ++), which identify shielding efficiency.
|
QPSK Costellation. All symbols are at the center with a wide safety margin. |
Very disturbed signal, symbols outside their quadrant can not be decoded. |
Messi & Paoloni Srl Tel. 0712861527 Email: web@messi.it Via Giovanni Conti, 1 60131 Ancona (AN) - Italia Cod. Fiscale 00109100420 Partita Iva 00109100420
EGESTX Engine (Copyright © 2000-2021 NTX Web business)