 |
|
| SCIENCE & TECHNOLOGY |
|
|
|
Overlapping
of FM radio channels Ice
threat to Cassini Trends Prof Yash
Pal THIS UNIVERSE |
|
|
Overlapping of FM radio channels Four private networks have been licensed to operate in Punjab. They include Anil Dhirubhai Ambani owned ADLABs “Big FM” operating nationally at a fixed frequency of 92.7MHZ. Bhaskar (Hindi) Newspaper Group owned “My FM” has been operating nationally at a fixed frequency of 94.3 mhz. Dainik Jagran (Hindi) Newspaper owned “Radio Mantra” is operating all over India on a standard frequency of 91.9 mhz. And “Radio Mirchi” operating on 98.3 mhz. All four of these private FM radio networks are already operating since February in Chandigarh and since April in Jalandhar. On July 27, “My FM” went on the air in Amritsar and since August 1 Ambani’s “Big FM” was simultaneously launched in Amritsar and Patiala. These new private commercial radio stations are very stimulating for business in these cities, but they will experience the problem of interference by neighbouring stations. Punjab has a peculiar situation, all its leading business centers are located close to each other. Chandigarh is located 40 miles away from Patiala and Ludhiana is only 60 miles away from Chandigarh. Jalandhar is only 37 miles away from Ludhiana and 50 miles away from Amritsar. Given the height of the transmitting antennas, the signals from each of these cities will overlap the signals radiated from the neighbouring cities. Rajpura located 16 miles from Patiala and 24 miles from Chandigarh shall experience serious problem of interference on common frequencies. In Rajpura “Big FM” Chandigarh on 92.7 mhz will dominate “Big FM” Patiala on 92.7 mhz. Chandigarh’s high altitude FM antenna at Kasauli has a range of 100 miles for high powered transmitters and 70 miles for low powered transmitters. Jalandhar’s FM range is 40 miles. This means that in Ludhiana all four private channels of Jalandhar and Chandigarh will clash. In case all these stations have common programming, it will work O.K. and each station will save some money. But these private operators are promising city specific programming, which means that the programmes will differ in content from city to city. Interference in such cases will dent the popularity and range specific credibility of each of these channels. Amritsar finds itself in a peculiar situation. Up to 1953, it had a medium-wave radio station, but since then its local stations are various channels of Radio Pakistan Lahore. Lahore serves Amritsar very effectively with two 100 kilowatt medium-wave transmitters and one 50 kilowatt medium-wave transmitter. Now as many as six Lahore based FM channels are invading the air-waves in Amritsar. These are 89.0 mhz City FM, FM 100 Lahore, Radio Pakistan FM 101 Lahore, 101.3 FM Pakistan Live, Mast 103 FM Trade Service International Radio Station and 104.6 FM Punjab University Campus Radio Station Lahore. Luckily none of India’s private FM channels licensed to operate in Punjab, especially in Amritsar has a frequency clashing with Lahore based FM services. On July 27, 2007 after a gap of 54 years, “My FM” 94.3 mhz became the first radio station to start operating from Amritsar. Within a week Reliance owned “Big FM” 92.7 mhz also commenced operations from Amritsar. Some time in the furure months two more private radio stations are likely to set up their shops in Amritsar. Lahore’s frequencies may not clash with those operating in Amritsar, but Jalandhar-based private frequencies certainly will. The FM range of 200 metre high broadcasting antenna at Khurla Kingra Jalandhar is approximately 40 miles. The FM range of Basarke Gillan based broadcasting tower in Amritsar is 30 miles. The direct distance between the two transmitters is 50 miles. That means in a 20 mile zone situated in Tarntaran, Amritsar and Kapurthala districts the signals of fixed frequency private radio services will interfere with each other. At present Jalandhar will be slightly more powerful, but when in 2008, the powerful tower presently under construction shall be completed, the range of Amritsar will extend up to Pathankot in the North and Ferozepore in the South. At that time all the radio stations operating out of Amritsar shall become local in Lahore. That will be the stage when the frequencies operating from Amritsar and Jalandhar shall have to move marginally up or down the dial. America did the same during the sixties, when there was sudden spurt in FM radio. The FCC (U.S.A) took harsh decisions to remedy the problem. The radio stations were asked to choose from vacant frequencies. In some cases decisions were imposed to eliminate interference. In India we may have to do the same especially in Punjab. For example “Big FM 92.7” may have to become 92.6 in Jalandhar and 92.8 in Amritsar. Similar up and down adjustments shall have to be made to other stations too. For radio listeners it won’t amount to much inconvenience, because while tuning on the dial a tiny difference of one decimal point is imperceptible. Punjab’s large commercial cities are clustered too closely, in other larger states such problems may not be significant. The sooner we tackle this problem of inter-city private FM channel interference in Punjab the better it will be for the radio station owners as well as the listening public. The writer is an environmental engineer based in America for the past 27 years. |
|
Images from Cassini beamed back to earth in 2005 showed multiple jets emanating from the moon’s south polar region that scientists suspect arise from warm fractures, known as tiger stripes. The upcoming flyby in March 2008 will offer a unique view of the little-understood plumes shooting out from these fissures but has also raised concern that this could stir up particles that damage the spacecraft. Cassini will pass by Enceladus at an altitude of less than 100 km perhaps moving through some of the spray, which some scientists believe may be made up of water spurting out from the moon under pressure. “These plumes were only discovered two years ago and we are just beginning to understand the mechanisms that cause them,” said Larry Esposito, a researcher at the University of Colorado, who presented his findings at the European Planetary Science Congress in Potsdam, Germany. “A grain of ice or dust less than two millimetres across could cause significant damage to the Cassini spacecraft if it impacted with a sensitive area.” To try to estimate potential damage, Esposito said a team used measurements from the 2005 flyby to understand better the shape and density of the plumes and what causes them. This data helped researchers calculate the amount of water vapor present in the column and develop simulations of the speeds and densities of potentially damaging particles in the plumes.
— Reuter |
|
Trends Experts had argued previously that the 18-foot-tall T. rex’s bulk would have meant it was a slow-moving scavenger, but new calculations using a supercomputer suggest the T. rex could run nearly 18 mph. Scientists from the University of Manchester calculated the running speeds of five meat-eating dinosaurs that varied in size from a 6.6-pound Compsognathus to the 6.6-ton T. rex. The fastest of the group was the Compsognathus, which could reach a top speed of 40 mph - 5 mph faster than the estimate for the fastest living animal on two legs, the ostrich, according to the study.
— AP Pigeons on the pill Hollywood residents believe they’ve found a humane way to reduce their pigeon population and the messes the birds make: the pill. Over the next few months a birth control product called OvoControl P, which interferes with egg development, will be placed in bird food in new rooftop feeders. “We think we’ve got a good solution to a bad situation,” said Laura Dodson, president of the Argyle Civic Association, the group leading the effort to try the new contraceptive. “The poop problem has become unmanageable and this could be the answer.” Community leaders planned to announce the OvoControl P pilot program, which Dodson believes is the first of its kind in the nation, at a news conference Monday.
— AP |
|
THIS UNIVERSE
In this universe all the heavenly bodies (like stars, planets etc.) have been provided fixed amount of material at the time of their formation. It is my idea that this fixed amount of material remains fixed for all time? Am I correct? The universe is a very active entity when we observe it over long periods of time. Let us first look at our moon. Its surface is badly scarred by the impact of large and small meteorites. Unlike on our earth, these wounds remain visible for long because the moon does not have winds and weather to wipe out their traces. Collision with meteorites must have brought in lot of material from outside. It is inevitable that over its lifetime our earth must have suffered intense bombardment by comets and asteroids. Indeed it is believed that a massive collision billions of years ago broke up a large piece of earth that became our moon! It has been surmised that comets that came from outer reaches of the solar system to impact our planet might have brought much of the water on earth; comets are known to consist mostly of water ice and dust. All this implies material accumulation or depletion. Stars do not remain with the material they start with. As they evolve they produce energy through fusion reactions in which mass is converted into energy that makes them shine. Their active surface produces flares and eruptions in which much material is thrown out as a wind of charged particles. We know this because we can sense the effects of such a wind produced by our nearest star, our Sun. Stars do not live forever the way they look when first observed. Their evolution can have varied consequences. Loss of mass due to supernovae, capture by a heavier star coming into the neighbourhood, ending up as a neutron star or a black hole could be their destiny depending on their initial mass. Going up to a higher level of association we have to recognise that stars are members of families we call galaxies and therefore subject to the upheavals in that family. Astronomers have discovered a large number of instances where galaxies are seen to be in collision with each other. The chaos, birth and rebirth that happen at such locations present violent cosmic dramas in which ownership of any “original” material is a meaningless concept. When we think of all this activity and chaos, we must keep reminding ourselves that the times involved are much longer than the brief moment of human presence in the universe. In a poetic sense we can say that concentrations of matter moving with different velocity and coming in close to other concentrations evolve like living matter. In some sense stars and galaxies are also living! They are born, they go through middle age and they die or transform, to be born again! |
Tiny grains of ice or particles of space dust could significantly damage the Cassini spacecraft when it passes close by Saturn’s moon Enceladus next March, scientists said on Thursday.
The Tyrannosaurus rex would have been able to outrun soccer star David Beckham, according to research published by the Royal Society scientific academy.