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Collective reception of satellite digital programs can be implemented in several ways:

Systems with multiswitches allow for distributing satellite signals with both polarizations from one or two satellites to all users. Any user can access (with his satellite receiver) any of available programs, the same way as he had individual satellite installation with his own dish. However, only one shared dish is used, and this solution is generally preferred by developers, owners of apartments for rent, as well as the majority of apartment owners and housing managers. It is much better solution for the aesthetic qualities of the building.

Each subscriber has to be connected to a multiswitch output with coaxial cable. It requires to anticipate the installation on the construction stage, or use optimal solutions in existing buildings.

This kind of installations is usually build for up to 100 subscribers.

The offer of multiswitches on the market is very wide, first of all they differ in number of inputs and outputs. The most popular are those marked 5/4, 5/8, 9/4, 9/8 (the first figure means the number of inputs, the second number of outputs). There are also available 5/12, 5/16, 9/12, 9/16 types.

Popular systems of satellite TV use two polarizations: horizontal and vertical, and two bands: low and high. To enable independent reception from any polarization and band there is the need of using in multiswitch installations quatro converters, instead of fullband types used in individual installations. Quatro converters have four outputs allowing to get four combinations of polarization-band.

Multiswitch connects a subscriber outlet to one of converter's output. The demand for switching is performed by control signals 22 kHz, and 14V/18V. In the case of 9-input multiswitches cooperating with two converters (reception of programs from two satellites) the additional signal required for choice of converter is provided by DiSEqC or Tone Burst.

Aside from satellite television, multiswitches distribute terrestrial TV signals that are also available in each subscriber outlet.

Devices and equipment used in multiswitch installations:

Diagram of installation with multiswitches

Employing amplifiers it is possible to cascade even 20 multiswitches. In the case of bigger installations, a division into sub-networks is advised.

In bigger installations there should be used amplifiers SA-501 R70501, SA-511 R70511 (for 5-input multiswitches) or SA-901 R70901, SA-911 (for 9-input multiswitches).

DISADVANTAGES:

• There is possibility of receiving programs from two satellites only
• A little complicated cabling (many sections of cable) - when using more than 20 outlets it is recommended to make a design.

Associated article: Choosing a multiswitch

Receiving stations using these digital receivers enable the subscribers to receive digital satellite broadcasts with regular TV sets, due to conversion of the original signals compressed by MPEG-2 method with QPSK modulation into signals with VSB-AM modulation and PAL color system.

The solution is well suited for networks with 200 or more outlets. But it is also suitable for smaller installations, in the case of tailored offer e.g. in boardinghouses, pensions, hotels. It enables the gests to access e.g. several programs, without a risk of problems with satellite receivers.

One module allows for reception of one program. So the system makes possible to choose a selection of programs that are to be distributed.

The needed cabling has simpler structure than in the case of multiswitches - a series connection of outlets, with one cable line.

A receiver (module) allows for conversion of digital satellite program into analog channel within cable band (special channels - hyper band), or VHF/UHF band, which is receivable by any TV set.

The receiver TP-544 R912061

Example receiving &distribution set

Concept of IF/IF conversion. IF/IF converters of digital satellite broadcasts are used in installations with over 40 outlets, and are suitable for even several hundreds of subscribers. They provide the first satellite IF signals to the outlets, without a need of employing multiswitches. The idea of conversion consists in selecting given transponder - having determined frequency and polarization - and putting it in planned output layout in the 950-2150 MHz band.

This solution allows for distribution signals from several satellites with one cable line. Of course, subscribers need to use DVB receivers. Such installations can provide users with immense number of 240 to 320 digital channels, on the assumption that each transponder transmits eight programs.

View of IF/IF converters in assembling frame

The installation enables a user to receive two digital satellite packages ( as an example: Cyfra+, Polsat Cyfrowy), distributed by one satellite cable line.

For over 40 outlets such system becomes cheaper and easier to implement in comparison to multiswitch installation.

These modules comprise two satellite IF converters allowing for distribution of signals with various polarizations and from many satellites with one cable line, without use of multiswitches. They permit to choose 27 or 36 MHz bandwidth and switch on/off AFC and AGC circuits.

UC-221 is equipped with one input and loopthrough to the next panel, UC-222 has two inputs and no loopthrough (it is used when there is the need of distributing odd number of transponders from one combination of polarization-band).

View of the converter

View of the amplifier

Similar issues are described in the article SMATV systems.

Diagram of the installation with IF/IF converters is here.. We invite readers to send questions and remarks to: pawel@dipol.com.pl