Single cable system
A single-cable system, also known as Single Cable Distribution (SCD), is a process in antenna system construction in which an HF signal in the frequency range of 47 - 862 MHz (terrestrial) or 950 - 2250 MHz ( without using DC remote power supply and DiSEqC control signals) Sat area) can be distributed linearly to several participants in a community radio reception system.
Depending on which SAT programs are presumably desired by the participants in the house, for technical reasons only the transponders (satellite) and programs that are considered important can often be distributed over a broadband cable network of any structure in a residential complex.
A single cable system combines various radio transmission methods such as conventional television, VHF, Internet via TV cable, DVB-C, DVB-H, DVB-T, DVB-S in a wide frequency band that is transmitted linearly (as a whole). The consumer decides which signals of the various selected radio transmission methods and interactive services he actually uses on the antenna socket.
Use of static single-cable systems
Static single-cable systems are relatively inexpensive to distribute a limited selection of SAT programs within existing smaller community antenna systems or to expand existing cable television connections for limited SAT reception in residential buildings. Static single-cable systems are often used as an inexpensive alternative for a limited selection of SAT programs.
Static single cable system Cable television
Digital cable TV DVB-C as well as internet via TV cable are already suitable for single cable systems due to the system. (For cable internet only return channel-capable components have to be installed.) Any existing DVB-T signal cannot also be fed into the cable television network if both systems occupy the same frequency range.
Single cable system for digital terrestrial television
Digital terrestrial television DVB-T in all its variants DVB-H, DVB-T Mpeg2, DVB-T Mpeg4, DVB-T2 is already suitable for single-cable use and occupies the frequency range 47–860 MHz.
Simple static single band single cable system (single cable solution)
In a single-band single-cable system, one of the four frequency bands / levels broadcast per satellite is preselected and forwarded as a whole (e.g. Astra 11.7 GHz - 12.75 GHz, horizontal) to several participants in a community antenna system via a coaxial distribution network with any star or tree structure . A Quatro LNB is used as the LNB, the corresponding output is used, the others remain free.
This Einkabelvariante possible by the in April 2007 because of problems with DECT carried transponder change of ProSiebenSat.1 Group (Germany) in the horizontal high band 11.7 GHz - 12.75 GHz, Tr. 107, a comprehensive, attractive range of programs for the German-speaking area; Of the larger German-speaking stations, only arte , Phoenix , One , EinsPlus , tagesschau24 , Tele5 SD, DMAX , Sport 1 , VIVA , Nick / CC Germany and the Austrian and Swiss programs of the ProSiebenSat.1 Group are currently missing - but VIVA and Nick / CC Austria can be received. On HDTV, German-speaking channels only receive Phoenix HD , WDR and Sonnenklar TV as well as encrypted Sky and Tele5.
Retrofit option for existing satellite reception systems: Using a simple static single-cable system, any conventional satellite IF antenna connection (satellite antenna socket from the multi-switch or single LNB) can be retrofitted to connect several satellite receivers (without laying new coaxial cables to the antenna).
A total of around 150 German-language television and 150 German-language radio programs can currently be received with such a simple static single-cable variant.
Current ASTRA HDTV channels that can also be received with this solution will probably switch to Astra Lowband 10.7 GHz – 11.7 GHz as soon as the analog Astra program broadcast ends on April 30, 2012. For this reason, a full-fledged satellite block distribution system or a subscriber-controlled single-cable system is to be preferred to a static single-cable system for HDTV reception, if the cabling is possible. The advantage then is that by eliminating bandwidth-hungry HDTV channels from a cramped single-cable system (11.7 GHz – 12.75 GHz, horizontal), a conventional unencrypted program offering in DVD quality (6 Mbit / s – 8 Mbit / sec DVB-S MPEG2) channels can even grow. An HDTV upgrade option to a programmable static single-cable system, suitable for receiving individual HDTV channels from the Astra low band, is also available in the future.
Simple static single band single cable system, advantages
- Very inexpensive, can be expanded with a programmable single-cable system (also later).
- An NIT ( transponder table ) stored in the satellite receiver does not have to be adjusted.
Simple static single cable system with frequency offset
With the help of a frequency offset (horizontal 1100 MHz – 1680 MHz / 1800 MHz – 2200 MHz, vertical), satellite transponders of different satellite levels were combined into one RF signal by filters and forwarded to several participants.
This single-cable system variant is now largely technically obsolete . On April 2, 2007, ProSiebenSat.1 Germany switched its programs from the Astra transponder No. 104 to the single-cable-friendly horizontal Astra transponder No. 107. Single-cable systems with frequency offset contain a broadband satellite IF amplifier and a remote power supply unit. These can now be used as a satellite power supply unit with an amplifier by connecting a simple two-way distributor (dismantling to a simple single-band, single-cable system ). Typical designations are: CEF211D, DUR EK-1, EKF 1100, GP31D, GP31-ED, SEV 1206. The manufacturer "Smart" now supplies a conversion kit for existing GP31D (ED) single cable systems.
Many residential complexes are currently switching to an H104 single-cable system , which will then offer an option for five additional satellite transponders.
Programmable static single-cable systems
Programmable single-cable systems not only work with passive filters to integrate additional transponders, but also enable a new, individual, optimal satellite IF to be put together by actively converting one or more SAT transponders to a different frequency.
- A distinction is made between simple systems that allow the integration of two additional transponders in the frequency range 950 MHz – 1100 MHz. These two transponders can only be freely selected to a limited extent. B. 104 (DMAX, Sport 1, Tele 5 and some teleshopping programs) and 78 (VIVA, Nick / CC Germany). Typical names are DPA-3/1, DPA31 (a total of around 200 German-language TV channels.)
- There are also transponder-variable static single-cable systems such as H104plus systems. These can implement up to 5 individual additional transponders of your choice (also from other satellite positions) together with all your TV and radio programs by using the PLL frequency synthesizer technology (instead of factory-set programming).
- Professional "programmable single-cable systems" implement the individual transponders very selectively (with the help of SAWs ) as variably as possible. A very good S / N ratio can be achieved with SAWs and the signal can be amplified with little loss of quality, even in very large residential complexes. Such systems are modular and can handle up to 10 transponders (each with typically six TV channels) individually. In combination with just looped through unchanged satellite transponders, comprehensive variability is guaranteed. Typical names are: TSM1000, TSM2000, IRCO, Smart-IF-Choice-Light….
Advantages compared to the simple single-cable systems
- These systems are mainly used to implement several digital transponders, so it is easily possible to put together around 200 desired satellite TV channels and around 200 radio programs in a single-cable system, leaving out unwanted programs.
- Programmable single-cable systems can be operated in combination with simple static single-cable systems (also retrospectively), which saves costs.
- Transponders with interesting programs from different satellites can be combined to form a single new SAT-IF.
- New HDTV digital programs, which after an ASTRA-PAL setting may be broadcast in the future in a concentrated manner in the SAT frequency range 10.70 GHz – 11.70 GHz, can also be integrated into a single-cable IF using a programmable single-cable system (typically any four transponders) .
- Based on market studies that show that an average television household actively uses around eighty TV channels, an optimized single-cable system fulfills this requirement with a program capacity (already in the satellite band) of around 200 TV channels with a factor of 2.5. New compression techniques such as MPEG-4 will increase the potential of TV programs that can be transmitted linearly via a coaxial cable by a third or can then be used for HDTV.
disadvantage
- Professional solutions for a programmable single-cable system that are suitable for adjacent channels result in higher acquisition costs than the other single-cable systems
- An NIT ( transponder table ) stored in the satellite receiver at the factory has to be adapted once for those transponders whose frequency has been changed. Otherwise the programs affected by this will not be found during a normal channel search (exception: DVB-S receiver with blind scan).
- The technical limitation of the maximum number of transponders that can be transmitted in static single-cable systems is a major and insoluble problem for large systems where many different users are interested in as many additional, mostly non-German-language SAT programs as possible (the use of the Unicable Systems (= subscriber-controlled single-cable system) should be considered). Programmable single-cable systems for 10 transponders cost around 1000 euros. A maximum of 30 transponders can then cost around 3000 euros, with additional costs for new antenna sockets and distribution amplifiers as well as wages.
General advantages
Single-cable systems are particularly suitable in residential complexes where, for reasons of tenancy law or monument protection, only a common satellite reception system is possible and where at the same time an existing antenna cabling should be retrofitted for satellite reception without great effort.
- There is no need for an exclusive coaxial line for each connected SAT receiver (star distribution) required for conventional satellite reception systems with satellite block distribution .
- In older houses without star distribution, there is no need for new cabling, which would usually be impracticable, especially for apartment buildings.
- With single-cable systems, additional digital services such as Internet via satellite, digital multi-channel sound, EPG, MHP, SAT data services, etc. are not lost.
- The switching signals otherwise required in the star network (14/18 volts for vertical or horizontal, 22 kHz for changing the frequency band and / or the satellite, see also DiSEqC ) are omitted, so that the mostly already existing tree or bus structure can still be used can be.
- Due to their modular expandability, SAT single-cable systems are no less future-proof than cable television or satellite processing.
- Multiple satellite receivers DVB-S DVB-S2 HDTV, including twin receivers, can be connected in any number to a single common antenna line or antenna socket via simple RF distributors and operated without mutual interference.
- An existing system that was designed as a single-cable system can be expanded relatively easily to the more modern Unicable system.
General disadvantages
- Due to the limitation in the number of SAT transponder channels that can be transmitted at the same time, it is not possible to use the entire range of the satellite operator or several satellite offers for additional satellite channels at the same time.
- Since the transponders in static satellite single-cable systems are usually only converted in terms of frequency and not re-modulated, the approximately 30 converted transponders are still QPSK or 8PSK modulated with a bandwidth of up to 36 MHz. A similar, even slightly higher data rate can be achieved with QAM modulation in a terrestrial TV channel with a bandwidth of 8 MHz. In the terrestrial sector, there are significantly more TV channels available than satellite transponders fit into the satellite IF, which means that a headend system has about three times the transmission capacity than a static satellite IF converter solution.
- New transmitters and transmitters that change transponders may not be able to be received (or no longer) with the simple single-cable systems. If the number of transmittable SAT transponder channels is sufficient, an upgrade to a programmable single-cable system is necessary, which causes costs.
It is important that the output voltages are switched off on the end devices or that a SAT socket with a built-in DC block (capacitor) or with a DC blocker is used.
Alternatives
Static satellite single-cable systems can be replaced by cable television, fully-fledged conventional satellite block distribution using multi-switches or by modern Unicable systems (= subscriber-controlled single-cable systems). In particular, the new single-cable standard JESS, which has been the valid European standard (EN 50607) for subscriber-controlled single-cable systems since 2014, makes it possible to supply up to 32 receivers independently of one another and without any program restrictions (including multiple satellite reception) via a single line.
A new alternative is Sat-over-IP technology (also known as Sat-IP), which enables the satellite signals to be converted into local networks . This means that up to four free-to-air TV transmitters are available on IPTV- enabled devices in the basic configuration .
Frequency plan 2.3 GHz single cable system
| 5 MHz-47 MHz | Ethernet over coaxial |
| 87.5 MHz - 108 MHz | VHF |
| 105.25 MHz-463.25 MHz | Cable television PAL , DVB-C |
| 105.25 MHz-855.25 MHz | extended cable television PAL , DVB-C (in some cable networks) |
| 471.25 MHz-855.25 MHz | Terrestrial television PAL , DVB-T |
| 471.25 MHz-855.25 MHz | Sewer preparation for residential complexes PAL |
| 950 MHz-2250 MHz | digital SAT single cable reception |
| 5 MHz-2250 MHz | One cable system as a whole |
glossary
- Channel Stacking System (CSS) or Satellite Channel Router (SCR) or the brand name Unicable describes a method of signal distribution that can supply up to eight receivers per coaxial line with signals by means of remote DC power supply (direct current supply) and superimposed Diseqc control signals.
- SAT IF bandpass filter . When using programmable single-cable systems, it is possible to selectively prepare only a part of the programs and to feed the rest directly through filters (for level adjustment) after the block conversion. Various SAT IF filters are available for this purpose. (In this combination, the processing of the SAT-IF can be optimized particularly cost-effectively).
- Channel-selective SAT IF conversion . Since the reception range of analog and digital receivers is 950 MHz to 2150 MHz, the transponders, which have been processed using a programmable single-cable system, must be converted within this range. The frequency spacing (frequency grid) results from the bandwidth of the transponder and is usually (ASTRA, EUTELSAT) 40 MHz. This means that 28 transponders (1135 MHz divided by 40 MHz = 28) can be implemented in the available frequency range of 1135 MHz (2150 MHz - 1015 MHz = 1135 MHz). Assuming an average number of 6 digital programs per transponder, approx. 168 different programs can be received via the TSM2000-SAT-IF conversion.
swell
- ↑ www.heise.de Internet via TV cable . January 21, 2006.
- ↑ German-language television programs on Astra and Eutelsat
- ↑ German-language radio programs on Astra and Eutelsat
- ↑ ProSiebenSat.1 transponder change March 20, 2007
- ↑ www.digitalfernsehen.de Smart retrofits single-cable systems . April 30, 2007.
- ↑ www.digitalfernsehen.de DPA31 . January 29, 2007.
- ↑ www.digitalfernsehen.de Interest in the variety of digital channels is rather low . March 19, 2007.
- ↑ SAT> IP ( Memento from May 15, 2013 in the Internet Archive )
- ↑ a b c d e f g Limit values for useful levels ( Memento from September 28, 2007 in the Internet Archive ) . www.kathrein.de, August 2000.
- ↑ Channel-selective SAT IF implementation ( Memento from November 28, 2009 in the Internet Archive ) . August 2000.