DOCSIS / Tooway ™     European VSAT service from El Molino Systems SL

The ViaSat DOCSIS/SurfBeam VSAT hub and modem were developed from hardware and software for the cable modem and Direct-to-Home satellite television markets and then extended for use in the WildBlue and Telesat Ka band satellite VSAT systems in the US and Canada.

Components comprise an outdoor offset parabolic antenna plus a Ka band transmit/receive integrated assembly (TRIA) and feed, plus an indoor modem. The antenna is dual optics to improve the cross-polarisation performance while minimising the forward size.

A pair of coaxial cables connect the indoor unit to the outdoor unit.  These carry both DC power, frequency reference and the transmitted and receive carrier signals. The workmanship on the four F connectors on these cables are critical to long term satisfactory operation.  The centre pins must insert fully into the sockets and the outer braids must make good contact also .  Silicone electrical contact grease and self-amalgamating rubber sealing tape is recommended for the outdoor F connectors.

The service will operate on two satellites and on Eurobird 3 in Ku band and on Hotbird 6 in Ka band.  The 96 cm Ku band antenna is shown above.  At Ka band the smaller 67 cm Wildblue, blue coloured, dual optics antenna is used.

All Spanish and French terminals receive the same downstream that is the French one as downlink coverage is the same for both K153 (Spanish) and K159 (French) transponder.  The difference is that Spanish terminals will transmit on K153 while French ones will transmit on K159 as the uplink has a different coverage.

Advanced modulation and turbo FEC coding are combined with dynamic propagation fade mitigation techniques to give your bandwidth the ability to carry more bits in clear sky conditions, which applies for the majority of the time.  Compared with the current DVB-S standard, which uses fixed QPSK modulation and FEC code rates, these features achieve significantly higher average capacity.  Ku band (12/14 GHz) suffers from rain fading and Ka band ( 19/29 GHz ) much more so.  Both benefit from these clever techniques. At Ka band the relatively high satellite eirp downlink beam ( 52 - 55 dBW ) on Hotbird 6 satellite and the four high G/T spot beams for the uplinks help minimise the rain fade problem.

The DOCSIS modem is just 9 x 9 x 1.5 inches, and may be mounted vertically on edge to improve thermal cooling.  It is a neat design which leaves desk top space for other personal computing and telecommunications equipment.  Don't put it where the sun can shine in on it or above  heater!   It interfaces to your computer or home network hub or switch via a standard Ethernet connection and does not require any software installed on your PC.  You may use a wireless router or switch to connect several PCs.