10 Facts About Rain Fade and Satellites

Posted on June 2, 2011 by Rashid Faridi

Guest Post by Coleen Torres

Perhaps you have heard the term ‘rain fade’ in regard to satellites internet reception or television satellite reception. Rain fade refers to the fact that moisture in the air between the transmitting satellite and the end user of the signal, can interfere with the satellite signal.
Causes – What kind of moisture are we talking about when we use the term rain fade? It is referring to the presence of rain or snow in the air. Either type of moisture in the air can be a source of interference. The more the moisture, the worse the interference.
Unavoidable – There is no way to totally avoid this interference of moisture with satellite signals, but there are ways to minimize its effects and improve reception.
Best frequencies – There are certain frequencies that move through the moisture in the air better than others. Lower frequencies like ‘L’ and ‘C’ are the best for areas which have a lot of rain. Most tropical areas, which experience ‘rainy seasons’, use the ‘C’ frequency.
Worst frequencies – The higher frequencies, in contrast, experience the most deterioration in their signals due to rain fade. These would be frequencies such as ‘Ku’ and ‘Ka’.
Special techniques – For those using these higher band frequencies there are several special techniques that can be used to improve the reception. Increased rain margins, adaptive uplink power control and reduced bit rates are the three techniques that are usually used.
Rain margins – This refers to the extra communication links that are needed in order to minimize the loss of signal and interference of the satellite signal due to rain or snow in the air. The more additional links that can be established, the less affect will be realized from the precipitation.
Size of dish – One of the ways to increase the rain margin is to increase the size of the satellite dish. The bigger dish provides for the extra communication links needed to minimize the effects of rain fade.
Commercial dishes – A large commercial disk will not be affected by rain fade to the extent that a small consumer satellite disk will be. The interruption of service should be much shorter for a large commercial dish than it is for a homeowner with a small satellite dish.
Bit rates – Increased bit rates can also minimize the effects of rain fade and lower costs involved with satellite reception by decreasing the power draw on a satellite.
Costs – Rain fade interference with satellite signals do not simply affect the end users resulting performance, it also affects the cost. Rain fade can cause a greater power draw on a satellite, which creates a higher cost per bit of transmission.

If you’ve heard that weather is a factor with satellite transmission for internet or television, you have heard correctly. There are systems in place, however, to minimize the issue.

Source 

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3-D Galaxy Map Prepared

Posted on June 1, 2011 by Rashid Faridi

Discovery reports  three-dimensional map of our corner of the universe,after  a survey more than a decade in the making that covers 95 percent of the galaxies out to a distance of about 380 million light years from Earth, has been prepared.The infrared survey features about 45,000 galaxies, including those residing in the 20 percent of the sky that can’t be seen in visual light because they are blocked by gas and stars.

read more here

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Tweeting and Mapping Power Cut in India: A New Initiative

Posted on May 30, 2011 by Rashid Faridi

Many Twitter users have come together to gather information about power cuts in India and make an infographic map. It aims to map the geographical spread of power cuts across the country.

According to Shefaly Yogendra, a London-based investment consultant who rolled out this initiative said, one can participate in this initiative by tweeting #powercutindia. On the other hand, Ajay Kumar, a software engineer, put up a web page that had started mapping power cuts in the country on the basis of the tagged tweets. Now the page can be accessed at http://powercuts.in. A Twitter account by the name of @PowerCutsIn has also been employed to collect data.

First city to be mapped, was Gurgaon. In the first couple of days, 46 reports had been mapped, at a rate of 9.2 reports a day. These reports have further been sorted into categories of “planned”, “unplanned”, “good news” (indicating no power cuts) and “voltage”.

An open Google document, which anyone can read, edit and shared, was also floated online, where people volunteered to do the data crunching and provide tech support. Those involved are trying to take this beyond an empty data-visualisation exercise and trying to figure out what to do with it.

Source:Times of India

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Varanasi: An Old City of India and an Enigma

Posted on May 28, 2011 by Rashid Faridi

The legend of the origin of ‘Banaras’ is narrated in the ‘Kashi Rahasya’ a work attributed to ‘Veda Vyas’, the compiler of the Vedas. It was founded at the request of seven ‘Rishia’ who approached Lord Vishnu and desired to be shown the certain road to salvation. It is atleast certain that Banaras had already acquired a reputation for secular serenity in Puranic age and consequently its antiquity is beyond dispute.

          The description of the city in Sanskrit literature is usually found with the names of Kashi and Varanasi. The name of Kashi remain current and in Varanasi was abandoned, and Banaraswas in common use till late. Dr. Sampurnanand. The first Chief Minister of Uttar Pradesh renamed it as Varanasi.

          Kashi is derived from ‘Kash’ meaning’ to shine’ and construed as ‘sole illumination’. The nameVaranasiis most probably due to rivers ‘Varuna’ in the north and ‘Assi’ in the south of the city.

          The first historical reference to this city, however, dates back to the days of ‘Buddha’. Sarnath symbolizes the site where Buddha made his first converts. In the 5th century A.D. Fahein visited the city of Banaras. Two centuries later, Hieun-Tsang foundBanaras densely populated and its inhabitants in flourishing state.

          In Ain-e-Akbari there are references about this city. Earlier Mahmud Ghazni visited Banaras in 1019 and 1022 A.D. We also find a reference of Banarasof the time of Babar. The district Gazetteer 6 refers to the fact that troops of Babar were garrisoned at Banaras under Jalal-ud-din. Later on he was compelled to abandon the place and retired to Chunar.

          Akbar also faced great resistance and the area did not fall in the hands of Akbar tell the eastern expedition of Khan-i-Zaman in 1559.Banaras flourished immensely under the tolerant rule of Akbar and once again it assumed its ancient position as the religious centre of the Hindu World.

          The history of Banaras during the first part of the nineteenth century is mainly a record of administrative development under the British rule. Since the mutiny of 1857 Banaras had remain obscene and unimportant and connected chiefly with the improvement of communication, development of the city and various reforms in administration. Nevertheless in the mean time the city has functioned as a religious centre of the Hindus and a somewhat important centre of Commerce in the Purvanchal although it was not important in the national context.

          Although it has been the seat of east-while Banaras state, it is primarily known as the biggest religious centre of the Hindus. It has also been a big centre of Indian renaissance. Famous writers of the Hindu language Tulsi Das, Baba Harish Chandra, Jai Shanker Prasad, Pandit Ram Chandra Shukla and Prem Chandra made this city important with their writings  and made the city a cultural and literary one oat the time. The city is a big centre of tourist attraction ad earns foreign exchange for the country. Later on it has attracted the attention of industrialist and apart from its cottage industries like Zari Sarees, wooden toys etc. The complex of heavy industry is fast building in and around the town.

          Varanasi is the larger city in the middle ganga plan situated on the left Kankar infested high levee of the Ganga crescent, planned out of not a very good site for expansion on the back; the three cultural nuclei of Kedareshwar, Visheshwar and Onkarshwar are separated from each other by the Godavari and the Mandakini, the two venerable rivers, one representing the Ganga of the south and other of the north. The city exerted a potent force for national integration through the imperceptible process of cultural assimilation. The confluence of the Saryu of Varanasi with the Ganga provided the burning ghat, hallowed by trhe memory of Harishchandra, the kig of ancient Awadh and as such, the block to the south came to be known as Awadh. This again means the integration of the Awadh culture of the north with the other cultural currents embedded inVaranasi. These discrete blocks coalesced with each other being joined by the Kedareshwar-Visheshwar lane, the life lie of ancient Varanasi, running parallel to the crescentic Ganga through the crest of the levee over a wooden bridge on the Godawari in the present Dasaswamedh area (preserved in the name of a Mohalla ‘Dedasi Ka Pul’,bridge of  Dedasi). The main  residential area has developed roughly like a bow theGangaforming its string. New residential areas have gone up along the outer roads, like the Durgan-Kund, Vidyapith road and the Jagatganj-Civil Court Road. There are a number of planned colonies now and many emerging up in the city which is fast expanding. Having the first bridge in 1882 on the Ganga in the whole of the Middle GangaValley, the city had the maximum advantage of growth, and has increased its population manifold. It is the world famous centre for handicraft products, and true to its cultural history it is the most famous educational centre with three universities. The city has now developed a metropolitan character. The city, in fact, works as a growth engine for the adjoining Purvanchal region. The city is now also spreading on the road connecting to Allahabad which is G.T. Road. City has functional links with Allahabad city.

Links,Sources and Further Readings:

Wikipedia

  About.com

Posted in Cities, India, Urban Studies | 6 Comments