4 Through the program for educational modernization (1989-1994), the Ministry of Public Education created Education Via Satellite Net (Edusat) as an answer to the countrys growing demand for educational services, including disperse and rural populations by using television. The pupose of this educational tv system is to address: literacy training, basic education, high school and technical and technological education all of which are the responsability of the Public Education Ministry.
5 Edusat Net has more than 30,000 installed reception systems throughout the country at several institutions such as: Telemiddleschools, Technical middle schools, General middle schools, Grammar schools, Indigenous education centers, Teachers centers, State Technical Institutions, Universities, Military bases, Correctional Institutions, Federal Electoral Intstitute in several states, Hospitals, National Council for Educational Encouragement Nacional (CONAFE), National Institute for Adult Education (INEA), State Education Ministries and some Latin American Universities
7 Before commenting on any expansion, growth or technological migration for EDUSAT Net it is important to quickly mention its origin and current characteristics. Edusat Net was born from the need to continue broadcasting Telemiddleschool (Telesecundaria) which in 1991 was done through open tv using Imevisión (Government channel) and its national broadcasting net. When the government sold Imevisión, it was forced to consider an alternative that required less time to implement, since the agreements undersigned by SEP, to continue with the service were too expensive. It also needed to have national coverage because Telemiddleschools are found in rural areas.
8 The technology that met these requirements was Digicipher 1, an advanced technology and best satellite provider at the time (Audio Digital Compression, Video). This technology evolved by optimizing the use of a satellite transponder bandwidth and Digicipher 2 technology was acquired. Both technologies are currently used side by side and allow quality coverage for Edusat Net. By using the most sophisticated encription technologies Edusat Net was born as a closed technology since the transmitters and receptors both have to be of the same brand to work properly, for obvious reasons.
9 Taking the disadvantages of this system into account, some processes for the growth of the net have been facilitated by negotiating delivery times and favorable volume pricing. Also, since few brands exist the logistics for control, administration and following of these programs has been simpler. Almost 17,600 pieces of equipment are DC1 (of which 80% are in Telemiddleschools) and almost 14,400 are DC-2. The use of two technologies and two satellites means that these two equipments are not interchangeable without a re-orientation and configuration process that requires skilled technical personnel.
10 In this sense any strategy for massive receptor substitution should consider the demand of technical resources, materials and equipment, this would require as well as the time that such a job would take. Motorola has stopped producing DC-1 and although it claims it can service DC-2 for five more years, it does so under mandatory upgrading conditions and at very high prices. It may be worth mentioning that pulling this equipment from the market has been done purely from a commercial and not technological standpoint, thus the argument for obsolescence is not precise.
11 Edusat Nets satellite uplink is currently being done byTelecomunicaciones de México (TELECOMM) at its Contel Iztapalapa facilities, where the signal is digitalized, encoded and multiplexed for: 12 TV channels through DC-2 encoder technology, 8 TV channels vía DC-1 encoder. To transmit these services through two satellites (Sol 2 and Satmex 5), as well as 4 corresponding channels to radio signals. For satellite transmission and reception, General Instruments proprietary technology is used (now Motorola).
13 EDUSAT COVERAGE DC-1 SYSTEM (8 TV CHANNELS) Edusat Net on Solidaridad II satellite uses Digicipher 1 (DC-1) technology. It currently covers 16,600 receptors placed mainly in rural areas, as is the case of Telemiddleschools and Indigenous grammar schools. SOLIDARIDAD II SATELLITE
14 EDUSAT COVERAGE SYSTEM DC-2 (16 TV CHANNELS) Edusat Net on Satmex 5 satellite uses Digicipher 2 (DC-2) technology, approximate coverage is of 13,400 receptors.
15 dBw 6025 60116039 6008.25 MHz 30 34 2.5284 6043 36 1.5 8 TV CHANNELS 4 RADIO CHANNELS DC-1 1 TV CHANNEL WEGENERDVB SOLIDARIDAD 2 SATELLITE SIGNALS TRANSPONDER 3N
19 Normal equipment deterioration indicates that the DC-1 equipment is more susceptible to failure, both in transmission and reception equipment, they are however more robust and resistant for Telemiddleschool use. Since DC-1 equipment is no longer made, it must be substituted by DVB technology when it fails. Due to the actual state of Edusat Net there are four fundamental axes that must be consolidated in the short and medium term.
20 Controlled expansion and growth of Edusat Nets infrastructure. Keeping current technology, actively participating in establishing policies and procedures so that each of the countrys states implements its investment projects while the three remaining axes are met. Edusat Nets technological migration: Toward standard international open platform with the participation of diverse brands and models that guarantee inter- operability. (DVB-RCS)
21 Edusat Net´s Diversification. Using cable TV systems to broadcast at least two Net channels having the universal offer of educational TV, including the National Network of educational and cultural tv broadcasters. Technological converging between TV, computers and Information technology. Edusat Nets future will depend on its capacity to add its teaching advantages, the possibilities of digital environments, and automated controlled programming by SUN 12000 servers.
24 Migration Program (Stages) 1.- Net widening.- Every new system that is installed will be done by pointing the Solidaridad 2 satellite in Ku band, we will take advantage of this point to start training at the national level. 2.- Telemiddleschool susbstitution.- All equipment will be substituted before the beginning of the next school cycle (August 2993), State structural support will be used for this process. 3.- Satellite change.- Once the 14,000 telesmiddleschools migration is completed all remaining band C equipment, DC1 as well as DC2 will be changed.
25 Using DVB standard on Edusat Net.- Performance tests have been done on this standard and they have been acceptable, but we only have one tv channel to support the Telemiddleschool system. Ku band teleport (DGTVE).- Tests have to be performed on the controlled access system (IRDETO) and also verify the access parameters to the Mexican satellites to be able to use less than 90 centimeter diameter receptor antenna (TVRO).
27 DVB technological standard was created to achieve a uniform environment for digital tv dissemination. Once DVB standards have been published, they will be available to anyone in the world, notwithstanding were they have been developed and are therefore open standards. With the introduction of DVB technology, the net will be able to use different brands of satellite receptors (set top box). This diversity of brands on the market will allow the lowering of costs to acquire said receptors.
28 The transmitting (Andrew) antenna are 7.3 meters in diameter, this process will take place in 45 days, meantime, 10,214 pieces of DVB equipment have been delivered to different states and 20,000 systems are planned to be delivered before the beginning of the school cycle. By using these tools and technological support, Educational TV is seeking to contribute to improve the learning environment in classrooms considering the teacher as the axis for this change and who will be previously trained to use the technological media that the SEP has at its disposal.