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spacetimewithstuartgary · 3 months ago

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A Series of Rare Disturbances in the Stratosphere

It’s been an unsettled winter in the atmosphere above Antarctica. About 30 kilometers above the continent’s icy surface, in the layer known as the stratosphere, a series of warming events took place starting in July 2024.

July temperatures in the stratosphere above Antarctica are typically around minus 80 degrees Celsius (minus 112 degrees Fahrenheit). On July 7, temperatures in the middle of the stratosphere jumped 15°C (27°F), setting a record for the warmest July temperatures observed in the stratosphere in the Antarctic region. The temperature then cooled off on July 22 before rising 17°C (31°F) on August 5.

These sudden stratospheric warming events surprised Lawrence Coy and Paul Newman, atmospheric scientists at NASA’s Goddard Space Flight Center. Coy and Newman develop complex data assimilation and reanalysis models of Earth’s atmosphere for NASA’s Global Modeling and Assimilation Office (GMAO). “The July event was the earliest stratospheric warming ever observed in GMAO’s entire 44-year record,” Coy said.

Westerly winds in this layer of the atmosphere loop around the South Pole in winter, moving about 300 kilometers (200 miles) per hour, forming what is known as the polar vortex. But sometimes something happens that disrupts this symmetric circumpolar flow, causing winds to weaken and the flow to change shape. Instead of circulating the South Pole, the polar vortex becomes elongated and winds weaken; the weakening winds result in considerable stratospheric warming over Antarctica.

The maps above show air temperatures in the middle stratosphere (at about 30 kilometers altitude or 10 hectopascals of pressure) for August 5, 2023 (left) and August 5, 2024 (right). The elongation of the polar vortex and higher temperatures closer to the pole are evident in the 2024 map. Data for the maps are from NASA’s GEOS forward processing (GEOS-FP) model, which assimilates meteorological data from satellite, aircraft, and ground-based observing systems.

The map below shows potential vorticity—a quantity that describes how air masses are spinning—in the stratosphere on August 5, 2024. Areas of high potential vorticity appear yellow and have a clockwise circulation; areas of low potential vorticity appear purple and have a counterclockwise circulation. The polar vortex had elongated and weakened, and the flow of wind was shaped like a peanut instead of its usual circular pattern.

Unlike in the Arctic, which experiences sudden stratospheric warming events about once a year, the polar vortex in the Southern Hemisphere is typically much less active. “Sudden warming events happen in the Antarctic once every five years or so, much less frequently than the Arctic,” Coy said. The reason for this, Coy added, is likely that there is more terrain in the Northern Hemisphere that can disrupt wind flow in the troposphere—the layer of air closest to the ground. These large-scale tropospheric weather systems move upward into the stratosphere and disrupt the polar vortex.

Weather in the Antarctic troposphere was also unusual in July. Temperatures more than 4°C (7.2°F) above average covered large parts of the Antarctic continent, and for the Antarctic region as a whole, the month tied July 1991 as the fifth-warmest July on record. However, Newman noted that attributing the weather that people experience in the troposphere—including a July snowstorm in Australia—to sudden stratospheric warming is not clear cut.

Researchers also continue to investigate the origin of disturbances at the surface that end up disrupting the stratosphere. “Variations in sea surface temperatures and sea ice can perturb these large-scale weather systems in the troposphere that propagate upwards,” Newman said. “But the attribution of why these systems develop is really difficult to do.”

Within the stratosphere, scientists have shown that sudden warming events are tied to higher concentrations of ozone over Antarctica. The stratospheric ozone layer protects life on Earth by absorbing ultraviolet light, which damages DNA in plants and animals (including humans) and can lead to skin cancer. The change of circulation that comes with a stratospheric warming event draws ozone from other latitudes toward the polar region. So far in 2024, the ozone hole over the Southern Hemisphere has been smaller than usual.

NASA Earth Observatory images by Wanmei Liang, using GEOS-FP data courtesy of Lawrence Coy and the Global Modeling and Assimilation Office at NASA GSFC. Story by Emily Cassidy.

#science #space #astronomy #physics #news #nasa #astrophysics #earth observatory

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eopederson · 9 months ago

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Another Eruption in Iceland

"After a lull in activity, fresh lava has once again poured from the Reykjanes peninsula in southwestern Iceland.

The latest eruption—the third in the region since December 2023—began early on February 8, 2024, with lava spraying up to heights of 80 meters (260 feet) along a 3-kilometer (1.8-mile) long fissure near Mount Sýlingarfell. The small peak is north of the fishing village Grindavík and east of the Svartsengi power station and Blue Lagoon geothermal spa.

The image above was acquired on February 10, 2024, by the OLI-2 (Operational Land Imager-2) on Landsat 9. Infrared and visible observations (bands 7-6-3) have been overlain on a natural-color image to help distinguish the heat signature of the lava. Still recent but cooler lava expelled near Grindavík in January appears black.

The topography around the fissure meant that much of the fresh lava flowed east into unpopulated areas rather than south toward Grindavík. Some lava also flowed west into the vicinity of the power plant and spa.

Earthen defensive walls protected both facilities, though lava did burn through a key hot water pipeline and two roads. According to the Icelandic National Broadcasting Service RÚV, authorities are in the process of restoring hot water to homes in the area after conducting repairs on the pipeline.

About seven hours after the eruption began, the MODIS (Moderate Resolution Imaging Spectroradiometer) on NASA’s Terra satellite captured this image of a plume of gas and ash streaming to the southwest. This eruption was effusive—not explosive like the Eyjafjallajökull eruption in 2010—and the plume contained minimal ash, so it did not cause any disruptions to either domestic or international flights.

Volcanic plumes like the one shown here typically contain water vapor, sulfur dioxide, carbon dioxide, and small amounts of other volcanic gases. Researchers from the Icelandic Met Office and the University of Iceland have noted that, at times, magma has interacted with groundwater, adding to the amount of water vapor in the plume. The TROPOMI (Tropospheric Monitoring Instrument) on the Sentinel-5 Precursor missionobserved sulfur dioxide (SO2) within the plume, Michigan Tech volcanologist Simon Carn noted on X.

After the initial burst of activity on February 8, the intensity of the eruption faded. In an update on February 9, the Icelandic Met Office reported that seismic sensors had stopped detecting volcanic tremors and that a recent drone flight showed no activity over the eruption site—signs that the latest eruption was ending.

However, on February 12, the agency reported that the land surface above an underground magma reservoir near Svartsengi had again begun to swell by 0.5 to 1 centimeters per day, a rate similar to what was observed prior to other recent eruptions. “It is therefore highly likely that the cycle continues in a few weeks with another dyke propagation and a volcanic eruption,” the agency said."

NASA Earth Observatory image by Lauren Dauphin, using MODIS data from NASA EOSDIS LANCE and GIBS/Worldview. Story by Adam Voiland.

#vulcanism #ísland #2024 #NASA

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nw7us · 3 years ago

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A Short History of My Shortwave/Ham Interests and Activities

When I was about eight years old, I got a hold of my parent's Sony Multiband Portable radio. The following picture is an image of that model. It has four bands: FM, AM, LW, SW.

I soon discovered that the SW selection held very strange and somewhat exotic sounds and stations. As you might have guessed from above, SW stands for Shortwave--which describes the size of the radio wave used to transmit the signal that the radio can tune and listen in on. (and the other three bands are: LW, for Longwave--those frequencies below 530 kHz; MW, for Mediumwave which is what is used in the domestic broadcast band between 530 kHz and 1750 kHz or so; FM (frequency modulation), the popular band of radio spectrum that everyone seems to enjoy, with music, talk, and other formats). The receiver only receives the Amplitude Modulation (AM) modulation mode, for the LW, MW, and SW bands.

As I began to discover the wide variety of signals--not only odd, interesting noises and pops, whistles, and alien-like sounds, but also a great variety of radio stations from all parts of the world--I became deeply interested in the technical aspects of what made this little radio achieve such great magic.

These exotic signals fascinated me. Some of the signals I could understand, as they were International Broadcast stations from foreign countries--stations like the BBC, Radio South Africa, Radio Moscow, Radio Nederland, and the Deutsche Welle. Many of these stations had English broadcasts, but others were in other languages, which I did not understand.

It seemed very magical that the BBC (England), RSA (Radio South Africa), !CBC (Radio Canada International), Radio Australia, and so many more exotic stations, could be heard by me in the middle of Montana's Rocky Mountains. Hearing these signals lured me into listening and learning more about Shortwave Listening to the point that I was hooked for life.

Other signals were (as I came to learn, later in life) Morse code, RTTY (Radio Teletype), or, time signals. Every day, I would sneak that radio out to a nearby large field, extend the telescoping antenna, and start tuning around to explore what I could discover.

There were nights I would listen to that radio from underneath the bed covers, hoping not to be noticed by my parents. But I heard so many things that I just had to explore as much as I could.

Within the first year, I discovered WWV, and heard the hourly solar and terrestrial activity reports. I was about eight years of age, and never heard of sunspots, or geomagnetic anythings. But, Skylab was just deployed, and I read about the artificial eclipse that they used to study the Sun.

With the excitement over Skylab, and my new-found fascination with Shortwave and the Sun, I began to ask librarians for books on these topics. I even got ahold of library-loaned scientific journals on Sun science, which revealed a lot about sunspots, and more. Thus was born in me a life-long passion for Space Weather and radio wave propagation--even now, I write about space weather and radio propagation in several magazines.

US Army Signal Corps

After a number of years and after graduating from High School, I entered the US Army. I became a 31M, known as the Multichannel Communications Equipment Operator. But I had a chance to do more than just that MOS. I also worked with TACSAT/STACOM (Satellite), Troposcatter, Microwave, and HF radio modes and equipment, as well as programming and using computers (I’ve been programming computers since 1983, and work now as a senior software engineer).

After being trained as a 31M at Fort Gordon, Georgia, I was stationed in Germany. While in the field for many months at a time, I ended up making rhombic antennas, inverted-V dipoles, and other great HF wire antenna configurations.

I received two Army Achievement Medals for my efforts at helping my unit accomplish its mission. I was instrumental in engineering a communications network that they had been attempting to secure for many years. In addition, I created an SOP (Standard Operating Procedures) manual including the use of Antenna and HF equipment to aid in engineering the communications network.

Connecticut

After spending a few years in Germany, I was finished in the military, and moved to Connecticut. I was hired by The Travelers as a programmer/analyst, and found out that my team leader was an Amateur Radio operator.

It was a natural progression for me to end up (finally!) licensed as a Novice-class amateur radio operator! The same year, I upgraded to the Coded Technician class. At that time, there was no such thing as a Technician Plus and No-Code Technician. There was just a Technician, which required 5 wpm code, and the Technician written element. My assigned, first call sign (as issued by the FCC after I passed the test elements) was, KA1VGL.

I loved getting on the transceiver (a Kenwood TS-520S that I bought from my co-worker), and doing CW Morse code, as well as 10 meter voice! The solar cycle was at a peak (this was 1989). I talked to the whole world on 10 meters Single Side Band (specifically, Upper Side Band, USB). I think I worked 67 countries! I was really excited! I also operated Morse code using CW (continuous wave modulation).

Montana

After a bit of time in Connecticut, I moved to Montana. I drove up to Canada, and then over to the Great Lakes, then made my way back into the States and over to Montana. I had a 10 meter rig (Radio Shack's HTX-100), and talked again, all over the world from the car!

The trip included days when the Aurora (Northern Lights; Aurora Borealis) was active, and I could see them while being near the Great Lakes. Stations were active on 10 meters all night long, at times, during this trip! It was a very excellent experience. (And the Canadian Hams extended a lot of hospitality.)

After settling down in Forsyth, Montana, I setup my radio shack with an end-fed long wire for most bands, and a vertical for 10 meters. I notified the FCC that I had a new address and location, and that I needed a new call sign to reflect my location. My first call, KA1VGL, was issued for the ‘1′ call area. Montana is in the 7 call area. Call areas (or districts) are geographical areas in the United States, numbered from 0 to 9.

The FCC issued me my new call as, N7PMS. Since I was in Montana, I became known as "November Seven, Pesky Montana Skunk." Better than other names... PMS.. caused a lot of conversation among the ham groups I visited on 75 Meters, for instance. The first 20 minutes would just be jokes about me and my call sign. It grew tiresome. I became aware of the amateur radio vanity call sign option offered by the FCC. I figured I would upgrade to a higher class (by passing code and written test elements), and then request a vanity call sign, just to get away from the N7PMS stigmatized call sign.

Washington

After about a year in Montana, I decided that I should head out to the state of Washington. My brother convinced me that there were more job opportunities. This was at the end of the Gulf War, and the economy was a bit slow, making it rough in Montana. My brother who was stationed in Washington (he was still in the US Army) told me that I ought to come to Washington as I might have a chance to work at Microsoft, or something along these lines (eventually, I did work with Microsoft).

Initially, I relocated to Olympia, the capitol city of Washington State. While in Olympia, on April 23, 1998, I upgraded to the Advanced amateur radio class. I also passed my 20 wpm code element for the Amateur Extra.

In June of 1998, I passed the written for Amateur Extra. I was very happy to finally obtain the Amateur Extra class license, as now I had access to the entire ham radio bands across the entire radio spectrum! It is great to be able to have use of all the radio frequencies assigned to the Ham Radio hobby.

On June 2, 1998, the FCC granted me a new Vanity Call. I was assigned, NW7US. This is a vanity call sign, one which I requested. I chose it to reflect that part of the United States that I really loved: From Montana to Alaska, and Washington, this new call sign reflects that I am in the North West area of the 7 call district, in the United States.

Right after the upgrade to Extra, I took a job with a start-up Internet company in Seattle, called, Greatergood.com and I was the primary Web Master and Programmer/Analyst during the first year or so. I relocated to the First Hill area in Seattle, just adjacent to downtown Seattle, but up the hill.

I spent a year working in downtown Seattle, but also working HF with my Outbacker portable antenna, and a Kenwood TS-830S, and an Icom IC-756 Pro II, and an Icom IC-706MKIIG, from my studio apartment on First Hill.

While I lived in Seattle, in a multi-floor apartment building, the antenna farm was mostly an Outbacker Marine (two section) mobile/portable vertical antenna, without the WARC bands, or one of five resonated Hustler mobile antennas. They are comparable in performance on 20 meters and higher. But on 80 and 40 Meters, the Hustlers seemed to perform just a bit better. However, I tended to use the Outbacker in the apartment setting more often due to its easier operation with my limited ground radial situation. On the car, I tended to favor the Hustlers. Occasionally, I used (you'll love this) my patio railing , and the trim around my apartment. I was on the fifth floor apartment (top floor) with a great view of the Space Needle in Seattle, Washington.

Using this compromise antenna configuration, I talked to Russian stations, over the North Pole, and many other stations around the world. It is amazing what one can do! Of course, I had to use the MFJ-1026 Noise Cancelling Phase Unit to cancel out the high noise I had there.

The Journey of DXing Since First Hill in Seattle

Eventually, I moved from First Hill, Seattle, to the Olympic Peninsula, to the small town of Brinnon, on the Hood Canal. There were many very tall trees, and I used them to raise a true wire antenna farm. I had dipoles for 160 Meters, and a fan dipole for 80 Meters through 10 Meters. OUr house was actually a tree house!

That was a fair place from which to chase DX stations, but I was located in a canyon. Thus in three directions, I had challenges due to the mountains blocking any low-angle take off of my radio signals. And, I could equally not hear signals that stations in Seattle could hear and work without any problem.

It was then that I started to write the monthly column on space weather and radio propagation, in CQ Amateur Radio Magazine, Popular Communications magazine, and CQ VHF magazine.

I also continued working on the oldest continuing non-governmental space weather and radio propagation website. I continue running that, to this day (started in the mid-1990s).

After a few years living there in Brinnon (where I remotely worked for Microsoft), I decided to use my savings and moved back to Montana, start a computer business, and buy a home with some land for antenna projects. Relocating to the Bitterroot Valley, I put up a nice 160-Meter doublet, and with an amplifier, worked many countries as I chased the DX.

A year into the new location, and the Internet bubble burst. The housing market crashed. The economy was in a very bad shape, and the unemployment in my area of Montana climbed to 30-some percent as mills closed down! Even the county ran out of money and laid off a third of all personnel (closing the Juvenile Detention facility, down-sizing every department, and so on).

I high-tailed it to Nebraska. Omaha had one of the lowest unemployment figures, so it seemed a good choice. I found a programming job, and settled down. Overall, I worked in several software programming companies in Omaha, while enjoying DXing from the suburbs using a SEA automatic antenna tuner and a random length of wire (about 100 feet).

A number of years later, I moved to Lincoln, Nebraska. At our new home, I used the same antenna as used in Omaha. I worked at two different companies while living in Lincoln, including TD Ameritrade. I crafted software for many different tasks and systems. But, I also continued my radio journey.

For the sake of family, after Covid hit and it was possible to work remotely, I moved to Ohio. Here in Ohio, I have a 220-foot doublet antenna, fed by a 450-ohm ladder line, connected to the rig through a balun and a run of 50-ohm coax. I have increased my DXCC to over 200 confirmed countries, as I write this entry in my blog. My plan is to build a two-wavelength 160-Meter horizontal loop, raised up to about 80 or 90 feet.

My current transceiver is the Icom IC-7610. What a great radio! I can hear stations that are very weak, and actually work them! The current doublet is working quite well, and I have no local noise problem.

Check out the QSO Today interview in which I was asked about my journey, and my passion for space weather and radio propagation. It is Episode 184, with host Eric Guth, 4Z1UG: https://www.qsotoday.com/podcasts/nw7us

Check out the Rain Report interviews, too. I will update this blog entry when those interview segments are posted on line later in December, 2021. The host is Hap Holly.

Stay Tuned to the Blog, to hear more about my journey, and about space weather. Thank you for being a friend. I hope to chat with you on shortwave, on some ham band, using some mode!

73 de NW7US dit dit

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spaceexp · 6 years ago

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Clocks, gravity, and the limits of relativity

ESA - Columbus Space Lab patch. 23 May 2019 The International Space Station will host the most precise clocks ever to leave Earth. Accurate to a second in 300 million years the clocks will push the measurement of time to test the limits of the theory of relativity and our understanding of gravity. Albert Einstein’s general theory of relativity predicted that gravity and speed influences time, the faster you travel the more time slows down, but also the more gravity pulling on you the more time slows down.

European space laboratory Columbus where ACES will be installed

On 29 May 1919 Einstein’s theory was first put to the test when Arthur Eddington observed light “bending” around the Sun during a solar eclipse. Forty years later, the Pound-Rebka experiment first measured the redshift effect induced by gravity in a laboratory – but a century later scientists are still searching for the limits of the theory. “The theory of relativity describes our Universe on the large scale, but on the border with the infinitesimally small scale the theory does not jibe and it remains inconsistent with quantum mechanics,” explains Luigi Cacciapuoti, ESA’s Atomic Clock Ensemble in Space (ACES) project scientist. “Today’s attempts at unifying general relativity and quantum mechanics predict violations of the Einstein’s equivalence principle.”

Negative photo of the 1919 solar eclipse

Einstein’s principle details how gravity interferes with time and space. One of its most interesting manifestations is time dilation due to gravity. This effect has been proven by comparing clocks at different altitudes such as on mountains, in valleys and in space. Clocks at higher altitude show time passes faster with respect to a clock on the Earth surface as there is less gravity from Earth the farther you are from our planet. Flying at 400 km altitude on the Space Station, the Atomic Clock Ensemble in Space will make more precise measurements than ever before. Internet of clocks ACES will create an “internet of clocks”, connecting the most accurate atomic timepieces the world over and compare their timekeeping with the ones on humankind’s weightless laboratory as it flies overhead. Comparing time down to a stability of hundreds femtoseconds – one millionth of a billionth of a second – requires techniques that push the limits of current technology. ACES has two ways for the clocks to transmit their data, a microwave link and an optical link. Both connections exchange two-way timing signals between the ground stations and the space terminal, when the timing signal heads upwards to the Space Station and when it returns down to Earth.

ACES clock

The unprecedented accuracy this setup offers brings some nice bonuses to the ACES experiment. Clocks on the ground will be compared among themselves providing local measurements of geopotential differences, helping scientists to study our planet and its gravity. The frequencies of the laser and microwave links will help understand how light and radio waves propagate through the troposphere and ionosphere thus providing information on climate. Finally, the internet of clocks will allow scientists to distribute time and to synchronise their clocks worldwide for large-scale Earth-based experiments and for other applications that require precise timing.

Columbus module with ACES

“The next generation of atomic clocks and the link techniques that we are developing could one-day be used to observe gravitational waves themselves as ESA’s proposed LISA mission,” adds Luigi, “but right now ACES will help us test as best we can Einstein’s theory of general relativity, searching for tiny violations that, if found, might open a window to a new theory of physics that must come.” The clocks have been tested and integrated on the ACES payload and the microwave link for ACES is undergoing tests before final integration with the full experiment. ACES will be ready for launch to the Space Station by 2020. Related links: European space laboratory Columbus: http://www.esa.int/Our_Activities/Human_and_Robotic_Exploration/Columbus Pound-Rebka experiment: https://en.wikipedia.org/wiki/Pound%E2%80%93Rebka_experiment International Space Station Benefits for Humanity: http://www.esa.int/Our_Activities/Human_and_Robotic_Exploration/International_Space_Station_Benefits_for_Humanity Images, Text, Credits: ESA/D. Ducros/NASA/Royal Astronomical Society/CNES. Greetings, Orbiter.ch Full article

#space #science

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leif021 · 3 years ago

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Tropopheric Ducting

Tropospheric propagation occurs when signals are reflected scattered or refracted in the troposphere. “Ducting” effects occur primarily because of temperature inversions at a height of between 500 meters and 1500 meters, and occasionally up to 3000 meters. Such inversions are not caused by local “weather” or terrain, but rather by climatic conditions such as frontal boundaries. Temperature…

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va3dbj · 4 years ago

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WSJT-X 2.4.0 Introduces New Digital Protocol Q65

WSJT-X version 2.4.0 has introduced a new digital protocol called Q65, which is designed for “minimal two-way QSOs over especially difficult propagation paths,” the Quick Start Guide says. “On paths with Doppler spread more than a few hertz, the weak-signal performance of Q65 is the best among all WSJT-X modes. Q65 is particularly effective for tropospheric scatter, ionospheric scatter, and EME…

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#digital #protocol #q65 #wsjt-w

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1librarynet · 4 years ago

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LITERATURE REVIEW ON ENERGY CONSUMPTION AND CONSERVATION IN MOBILE DEVICE

(1)Journal of Theoretical and Applied Information Technology 15th May 2017. Vol.95. No 9 © 2005 – ongoing JATIT & LLS. ISSN: 1992-8645. www.jatit.org. E-ISSN: 1817-3195. COMPUTATION OF EFFECTS OF TROPOSPHERE ON KU BAND DOWN LINK SIGNAL IN TROPICAL REGIONS GOVARDHANI.IMMADI1, M.VENKATA NARAYANA1 SARAT K KOTAMRAJU1, K.CH.SRI KAVYA1, S.V.N.S. MANEESHA2, K.RAVALI2, CH.SRAVANI2 1 Dept. of ECE, K L University, Vaddeswaram, Guntur, Andhra Pradesh, India 2 U G Students, Dept. of ECE, K L University, Vaddeswaram, Guntur, Andhra Pradesh, India E-mail: [email protected] ABSTRACT The electromagnetic signal from the satellite while travelling down to the earth should pass through various layers of the atmosphere like troposphere, stratosphere, ionosphere etc. These layers won’t act as a transparent layer but instead they provide some obstacles in the path of the signal travel and changes the characteristics of the signal. With the advancements in technology the users are not at all compromising in using the applications like data applications, web applications, simultaneous audio video transfers, etc. which results in excess usage of the conventional frequency bands. So, the modern applications are likely to be designed at higher frequency spectrum i.e. Ku, Ka & V bands. The influence of the layers mainly depends upon the frequency of the signal. As we are dealing with the frequencies above 10 GHz the ionosphere acts as a transparent layer but the troposphere influence the signal characteristics. In this paper, we are going to analyze and compute the tropospheric impairments like attenuation due to rain and tropospheric scintillations for the geographical area of K L University, Vaddeswaram located at 16.44oE latitude and 80.62oN longitude. Keywords: Frequency Congestion, Impairments, Tropospheric Scintillations, Rain Attenuation, Beacon Signal. 1.. INTRODUCTION. With the growing population, the need for communication has increased rapidly and many systems are designed to establish the communication effectively. Among the developments in satellite communication, one can highlight the appreciation of VSAT/USAT (very/ultra small aperture terminals) systems designed mainly for data applications, like the DTH(Direct-to- home) services provided by DBS ( Direct Broadcast Satellite) and extending the scope of satellite communications to NGSO (Non Geostationary Orbit) constellations. Fixed satellite services (FSS), conventional geostationary satellite (GSO) systems including all the above systems, steadily tend to work in higher frequency bands to fulfil the growing capacity essentials. [1] But as we go to higher frequencies the signal fading rapidly increases and the quality of the signal rapidly decreases. Because the fading of the signal depends on the operating frequency and the geographical conditions of the receiver. There are. many types of impairments influence the signal during its travel from space to down earth. In this paper, we are going to discuss some of the signal degradation effects. While designing a communication system many factors are to be considered for proper functioning of the system. The radio wave signal while propagating through space must propagate through the layers of the atmosphere troposphere, stratosphere, ionosphere etc. These layers show their impact on the propagating signal and cause signal degradation. But the extent and type of degradation depends mainly on the frequency of the signal. 1.1 Reasons for signal degradation The propagation effects are mainly categorized into two types. They are the ionospheric effects and tropospheric effects. The influence of the effects are mainly concentrated with the operating frequency of the system. The tropospheric effects come into the picture when the frequency is below 3 GHz and if the. 2078.

https://1library.net/document/yee5771y-literature-review-energy-consumption-conservation-mobile-device.html

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the-telescope-times · 7 years ago

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NASA solves how a Jupiter jet stream shifts into reverse

Climate patterns on Jupiter can have striking similarities to those on Earth, making the gas giant a natural laboratory for understanding planetary atmospheres. Credit: NASA SVS/CI, Dan Gallagher Speeding through the atmosphere high above Jupiter's equator is an east-west jet stream that reverses course on a schedule almost as predictable as a Tokyo train's. Now, a NASA-led team has identified which type of wave forces this jet to change direction.

Similar equatorial jet streams have been identified on Saturn and on Earth, where a rare disruption of the usual wind pattern complicated weather forecasts in early 2016. The new study combines modeling of Jupiter's atmosphere with detailed observations made over the course of five years from NASA's Infrared Telescope Facility, or IRTF, in Hawai'i. The findings could help scientists better understand the dynamic atmosphere of Jupiter and other planets, including those beyond our solar system.

"Jupiter is much bigger than Earth, much farther from the Sun, rotates much faster, and has a very different composition, but it turns out to be an excellent laboratory for understanding this equatorial phenomenon," said Rick Cosentino, a postdoctoral fellow at NASA's Goddard Space Flight Center in Greenbelt, Maryland, and lead author of the paper published in the Journal of Geophysical Research-Planets.

Earth's equatorial jet stream was discovered after observers saw debris from the 1883 eruption of the Krakatoa volcano being carried by a westward wind in the stratosphere, the region of the atmosphere where modern airplanes achieve cruising altitude. Later, weather balloons documented an eastward wind in the stratosphere. Scientists eventually determined that these winds reversed course regularly and that both cases were part of the same phenomenon.

The alternating pattern starts in the lower stratosphere and propagates down to the boundary with the troposphere, or lowest layer of the atmosphere. In its eastward phase, it's associated with warmer temperatures. The westward phase is associated with cooler temperatures. The pattern is called Earth's quasi-biennial oscillation, or QBO, and one cycle lasts about 28 months. The phase of the QBO seems to influence the transport of ozone, water vapor and pollution in the upper atmosphere as well as the production of hurricanes.

Read more/video ~ phys.org

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monkeyandelf · 5 years ago

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Is the coronavirus the start of an alien invasion?

To say that these are weird times here on planet Earth would probably be an understatement. In fact, for many of us, the current pandemic global feels more like a biblical apocalypse. However, this is not the first time this has happened. In fact, every few decades something akin to the magnitude of the current coronavirus strain emerges, with examples including the 1968 H3N2 virus and, most famous of all, the 1918 Spanish flu that infected 500 million people and caused the death of up to 100 million people according to some estimates. It is not yet known how far the new coronavirus will go. But what we do know is that the current pandemic is something completely different from everything known. This is mainly because it suddenly appeared in human populations. Recall that the outbreak occurred in Wuhan, China, last December. And as experts say, being completely new to people, we haven't had a chance to develop immunities yet, making it much more infectious and potentially dangerous than common flu strains. The novelty and potential threat posed by such a disease has also led to some interesting speculation about its origins. In particular, that the COVID-19 it actually comes from outer space - in other words, that the current pandemic is literally an alien invasion. A threat from outer space The first thing to consider is why aliens would want to attack or invade us. The truth is that there are numerous theories about this scenario, and one idea is that they would look for our water or other resources. There is also a possibility that these aliens want to colonize this planet because it is similar to their home world and they have exploited theirs to the point where it has become uninhabitable, just as we would be doing. But the most sinister theory is that they may want to finish us off. This could be for a variety of reasons: for fun, for our violent history, or for considering ourselves a very real threat. Whatever the reason, in this scenario they would need absolutely nothing from us and they wouldn't even need our world, they would just want to destroy us. It's a pretty ominous concept to ponder, but it's a possibility, and would probably be the easiest option for them. Now, suppose that aliens are really coming and have decided to invade our world, for any of the reasons stated above.

If they just wanted to destroy us, like in that last option, they wouldn't even have to come near us. They could simply send asteroids to hit our planet, causing never-before-seen large-scale tsunamis and mass destruction, or use some other type of weapon of mass destruction from orbit. But if we assume that they need some resource, including us, or that they really want to live on Earth, then they are more likely to need our planet. The truth is that, if we take for granted that they are ultra intelligent and technologically advanced beings, they would not start a war with a species that, although inferior, possesses weapons of mass destruction and that could cause irreparable damage to their precious conquest. So what they would do is easily design a virus that simply eradicates much of the population of the planet and reduce any possibility of defense. It must be said that COVID-19 is already seriously affecting the military troops of the main powers, including the United States. And then it would be a war between weakened humans and aliens, just like a sadistic boy with a magnifying glass burning entire ant hills. The extraterrestrial origin of the coronavirus As we have previously commented, it is true that this is not the first time that humanity must face the threat of a pandemic. But what makes the difference is that so far the scientific community has not been able to find its origin and they are surprised by the high ease of propagation. Not to mention that so far they have not been able to find a vaccine since there are apparently several different strains, in other words, that it is mutating. And then there is another illuminating fact. In February of this year, Professor Chandra Wickramasinghe, a British astrophysicist at the Buckingham Center for Astrobiology, suggested that the coronavirus appeared on our planet through the fragment of a comet which included "Hundreds of billions" of viral particles. As Professor Wickramasinghe explained, in October last year, a fragment of a comet exploded in a brief moment in northeast China. This comet is likely to contain embedded within it a monoculture of infectious particles of the 2019-nCoV virus that survived inside the incandescent meteorite. In addition, he added that infectious agents prevail in space, are carried in comets and can fall to Earth through the troposphere, causing epidemics of human disease.

No protocols And finally we have Nick pope, who worked for 21 years for the British government on the secret investigation into UFOs, who has recently warned that governments they have no protocol or contingency plan for an alien invasion. Pope told the Daily Express that now would be the right time for the arrival of an aggressive invasive species, as currently, all countries in the world are struggling with a rather more tangible threat: the coronavirus, not only as a risk to public health, but also in terms of its potential to trigger a social collapse. Before discarding this theory, think about it, in our increasingly complex and interconnected world, the coronavirus has weakened us and what the government calls "key points" and "critical infrastructure" are defenseless. This would be the ideal time for the arrival of extraterrestrial invaders who, while we are confined, would cut off our basic supplies without being able to do absolutely nothing. Or maybe it's a "False alien invasion" and they want to make us believe the need for a "savior", but that is another story. Basically all we can do is see what happens and hope for the best, that the world survived the coronavirus pandemic. Do you think the coronavirus may be the start of an alien invasion? Read the full article

#AlienInvasion #coronavirus

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spacetimewithstuartgary · 2 months ago

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Arctic Ozone Hits Record High

Ozone concentrations over the Arctic reached a record-high monthly average in March 2024. Due to large-scale weather systems that disturbed the upper atmosphere throughout the 2023-2024 winter, more ozone moved into and persisted in the stratosphere over the Arctic than at any other time in the satellite record.

A team of NASA and University of Leeds scientists reported their findings in a September 2024 paper in Geophysical Research Letters. “Given the absence of high Arctic ozone since the 1970s,” the authors wrote, “the March 2024 record high should be considered a positive harbinger of the future Arctic ozone layer.”

Between December 2023 and March 2024, a series of planetary-scale waves propagated upward through the atmosphere and slowed the stratospheric jet stream that circulates around the Arctic. When that happens, air from the mid-latitudes converges on the pole, sending ozone into the Arctic stratosphere. In addition to the influx of ozone, there was very little of the typical ozone depletion by substances such as chlorine, said Paul Newman, chief scientist for Earth sciences at NASA’s Goddard Space Flight Center and lead author of the study. “It was a very dynamical, active winter in the northern hemisphere,” he said.

More stratospheric ozone is positive for life on Earth. The stratospheric ozone layer is a natural sunscreen, absorbing harmful ultraviolet (UV) radiation. The authors calculated that from April–July 2024, the UV index was 6 to 7 percent lower in the Arctic and 2 to 6 percent lower in the northern hemisphere mid-latitudes. Less UV radiation means less damage to plant DNA and a lower risk of cataracts, skin cancer, and suppressed immune systems in humans and animals.

The activity in March 2024 is in sharp contrast to March 2020, when stratospheric ozone concentrations hit extremely low levels. Without disruption from upper atmospheric wave events, steady circumpolar winds prevented ozone from other latitudes from replenishing the Arctic stratosphere. The stable polar vortex also created colder-than-average conditions, favorable for ozone-depleting reactions to occur.

The maps above show ozone concentrations over the Arctic for March 2020 (left) and March 2024 (right), illustrating the large amount of variation possible there. The monthly averages were calculated by the NASA Ozone Watch team and are based on data acquired by the OMPS (Ozone Mapping Profiler Suite) on the NASA-NOAA Suomi-NPP satellite.

Unlike over Antarctica, where ozone holes form each year, the concentration of ozone over the Arctic is highly variable and subject to the “year-to-year vagaries” of tropospheric and stratospheric weather, Newman said.

The strong wave events from late December 2023 through early March 2024 resulted in the increases in ozone concentration seen in the chart above. Ozone levels peaked in March, as they typically do, and then remained well above average. May, June, July, and August also set new records for monthly average ozone concentrations. “This really is an extraordinary northern summer period,” Newman said.

As for what could have caused the unusual stratospheric weather, the authors looked at a variety of factors without finding a clear answer. The effect of climate change, for example, is difficult to quantify. “There might be a climate factor here, but it’s not obvious,” said Newman. With respect to larger atmospheric patterns such as El Niño and the Quasi-Biennial Oscillation: “Possibly, but the contribution is relatively small.”

In addition to stratospheric weather, which is the primary determinant of Arctic ozone levels, the authors think longer-term trends likely bumped ozone concentrations to record highs. Since the Montreal Protocol phased out production of ozone-depleting chlorofluorocarbons (CFCs) and halons in 1987, ozone levels have been slowly recovering. As such, the high March 2024 levels were within the authors’ expectations: the Goddard chemistry–climate model, GEOSCCM, showed a 1-in-8 chance of a record high by 2025, and more records are anticipated in the future. However, because CFCs persist in the atmosphere for decades, average Arctic ozone is not expected to return to 1980 levels until about 2045, they note.

Higher greenhouse gas concentrations in the stratosphere also accelerate ozone recovery. “This record was likely a result of decreased ozone-depleting substances and increased greenhouse gases. Otherwise, it would have been just a high year and not a record,” said Newman. “I call this year a harbinger of the future.”

NASA Earth Observatory images by Michala Garrison, using data courtesy of NASA Ozone Watch. Story by Lindsey Doermann.

#science #space #nasa #news #earth observatory #arctic

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earthstory · 7 years ago

Photo

The best sprite I've ever seen

A wonderful photo taken on May 28 over the Channel between France and Britain reveals the clearest glimpse of a very rare phenomenon from the ground, and probably the first depicting their natural colour. These wisps of red fluorescent plasma are very short lived (5 milliseconds), and elusive, so snapping one, along with the aurora borealis (the green glow) and the lightning storm that spawned the sprite is a once in a lifetime event. I'd be surprised if we see the like again even in photo. Careful observation of distant storm fronts and aeroplane flights are your best chance of glimpsing them.

No one knows exactly how they happen, though you have to be well away from the storm to see them, since they shoot up above it from the clouds (normal lightning goes between clouds or cloud to ground) and are usually hidden behind the storm. It is thought that they start when balls of ionised air shoot both down and up (some 50-80km into the stratosphere) in the milliseconds after a conventional lightning strike. They send pulses of electrical energy up toward the edge of space (the electrically charged layer known as the ionosphere) instead of down to Earth’s surface. It is speculated that ions and electrons floating about the atmosphere are heated by this field and glow red in response. They are rich with radio noise, and can sometimes occur in clusters.

They were first filmed in the same state in 1989. University of Alaska space physicist Hans Stenbaek-Nielsen thinks that these sprites may create an electrical conduit between the thunderstorm in the troposphere and the ionosphere. He also says that even though they have been studied for more than 20 years little is known about the sequence of events that causes theses amazing events.

The light is produced by atoms, fluorescing as they are excited by the passing currents, either upwards in the case of jets, or downwards in that of sprites. They are thought to be caused by an EMP propagating in the ionosphere. Their electrical energy could affect atmospheric chemistry by helping gases react with each other. These discharges may represent the missing link in Earth's electrical circuit, connecting the surface with the ionosphere, and accounting for the 300,000 volt potential difference between them.

Since they occur at altitudes too low for satellites (due to atmospheric drag pulling them back down) and too high for balloons or aircraft, only remote studies are currently possible. The European Space Agency was funding a microsatellite in 2010, currently being built by the French CNRS, specifically designed to study these phenomena. Named after Taranis, the Gaulish/Celtic god of thunder, it is slated for launch by Arianespace using a Vega or Soyuz rocket in late 2016. Hopefully our understanding of these wonderful flashes will improve once it's operational. Whatever they are, these mysterious and elusive flashes never cease to wow me.

These phenomena were first reliably reported by pilots in world war 2, though authorities doubted them at the time, and fliers stopped mentioning them for fear of losing their wings, much like early NASA astronauts were reluctant to mention the blue flashes of Cherenkov radiation they saw when cosmic rays struck the aqueous humour in their eyes, for fear of being taken off the flight list. No doubt people have been spotting them throughout history, and they must account for some of the generic reports of weird lights in the sky.

Loz

Image credit: Stephane Vetter/http://nuitsacrees.fr/ VIA APOD, https://apod.nasa.gov/apod/astropix.html

http://news.stanford.edu/news/2002/march20/bluejet-320.html http://smsc.cnes.fr/TARANIS/ http://go.nature.com/1hvfLfT http://www.albany.edu/faculty/rgk/atm101/sprite.htm http://bit.ly/1NzuSAL http://bit.ly/1E9u3wM A movie: elf.gi.alaska.edu/movies/output.mpg http://wapo.st/16iBAIR http://elf.gi.alaska.edu/

#Sprite #Atmosphere #Science #Photography #Radiation #Lightning #research #the earth story

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spaceexp · 7 years ago

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NASA Solves How a Jupiter Jet Stream Shifts into Reverse

NASA logo. Dec. 18, 2017 Speeding through the atmosphere high above Jupiter’s equator is an east–west jet stream that reverses course on a schedule almost as predictable as a Tokyo train’s. Now, a NASA-led team has identified which type of wave forces this jet to change direction. Similar equatorial jet streams have been identified on Saturn and on Earth, where a rare disruption of the usual wind pattern complicated weather forecasts in early 2016. The new study combines modeling of Jupiter’s atmosphere with detailed observations made over the course of five years from NASA’s Infrared Telescope Facility, or IRTF, in Hawai’i. The findings could help scientists better understand the dynamic atmosphere of Jupiter and other planets, including those beyond our solar system.

A New Model for Understanding Jupiter's Climate

Video above: New observations and modeling by a NASA-led team can help scientists understand a fast and furious jet stream high above Jupiter’s equator. This jet has a counterpart on Earth that seems to influence the transport of ozone, water vapor and pollution in the upper atmosphere, as well as the production of hurricanes. Image Credits: NASA’s Goddard Space Flight Center/Scientific Visualization Studio/Dan Gallagher. “Jupiter is much bigger than Earth, much farther from the Sun, rotates much faster, and has a very different composition, but it turns out to be an excellent laboratory for understanding this equatorial phenomenon,” said Rick Cosentino, a postdoctoral fellow at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, and lead author of the paper published in the Journal of Geophysical Research-Planets. Earth’s equatorial jet stream was discovered after observers saw debris from the 1883 eruption of the Krakatoa volcano being carried by a westward wind in the stratosphere, the region of the atmosphere where modern airplanes achieve cruising altitude. Later, weather balloons documented an eastward wind in the stratosphere. Scientists eventually determined that these winds reversed course regularly and that both cases were part of the same phenomenon. The alternating pattern starts in the lower stratosphere and propagates down to the boundary with the troposphere, or lowest layer of the atmosphere. In its eastward phase, it’s associated with warmer temperatures. The westward phase is associated with cooler temperatures. The pattern is called Earth’s quasi-biennial oscillation, or QBO, and one cycle lasts about 28 months. The phase of the QBO seems to influence the transport of ozone, water vapor and pollution in the upper atmosphere as well as the production of hurricanes. Jupiter’s cycle is called the quasi-quadrennial oscillation, or QQO, and it lasts about four Earth years. Saturn has its own version of the phenomenon, the quasi-periodic oscillation, with a duration of about 15 Earth years. Researchers have a general understanding of these patterns but are still working out how much various types of atmospheric waves contribute to driving the oscillations and how similar the phenomena are to each other.

Image above: Illustration showing Jupiter and its moon Io. Image Credit: NASA’s Goddard Space Flight Center/CI Lab. Previous studies of Jupiter had identified the QQO by measuring temperatures in the stratosphere to infer wind speed and direction. The new set of measurements is the first to span one full cycle of the QQO and covers a much larger area of Jupiter. Observations extended over a large vertical range and spanned latitudes from about 40 degrees north to about 40 degrees south. The team achieved this by mounting a high-resolution instrument called TEXES, short for Texas Echelon Cross Echelle Spectrograph, on the IRTF. “These measurements were able to probe thin vertical slices of Jupiter’s atmosphere,” said co-author Amy Simon, a Goddard scientist who specializes in planetary atmospheres. “Previous data sets had lower resolution, so the signals were essentially smeared out over a large section of the atmosphere.” The team found that the equatorial jet extends quite high into Jupiter’s stratosphere. Because the measurements covered such a large region, the researchers could eliminate several kinds of atmospheric waves from being major contributors to the QQO, leaving gravity waves as the primary driver. Their model assumes gravity waves are produced by convection in the lower atmosphere and travel up into the stratosphere, where they force the QQO to change direction. The results of simulations were an excellent match to the new set of observations, indicating that they correctly identified the mechanism. On Earth, gravity waves are considered most likely to be responsible for forcing the QBO to change direction, though they don’t appear to be strong enough to do the job alone. “Through this study we gained a better understanding of the physical mechanisms coupling the lower and upper atmosphere in Jupiter, and thus a better understanding of the atmosphere as a whole,” said Raúl Morales-Juberías, the second author on the paper and an associate professor at the New Mexico Institute of Mining and Technology in Socorro. “Despite the many differences between Earth and Jupiter, the coupling mechanisms between the lower and upper atmospheres in both planets are similar and have similar effects. Our model could be applied to study the effects of these mechanisms in other planets of the solar system and in exoplanets.” More information about Jupiter: http://www.nasa.gov/jupiter More information about NASA’s IRTF: http://irtfweb.ifa.hawaii.edu/ Image (mentioned), Video (mentioned), Text, Credits: NASA/Karl Hille/Goddard Space Flight Center, By Elizabeth Zubritsky. Greetings, Orbiter.ch Full article

#space #science

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siva3155 · 5 years ago

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300+ TOP MCQs on SUB INSPECTOR of Police Exam

SUB INSPECTOR of police Objective Questions:-

1. Rana Kumbha constructed the 'Kirtistambha' at Chittor to commemorate his victory against– (A) Ahmadshah of Gujarat (B) Mahmud Khilji of Malwa (C) Khan of Nagpur (D) Rao Jodha of Marwar (Ans : B) 2. The First War of Panipat was fought in A.D. 1526 between– (A) Ibrahim Lodi and Rana sanga (B) Mahmud Lodi and Babur (C) Babur and Rana Sanga (D) Babur and Ibrahim Lodi (Ans : D) 3. Which Moghul emperor first granted the English the licence to trade and to establish factories in India ? (A) Akbar (B) Jahangir (C) Shahjahan (D) Aurangzeb (Ans : B) 4. The 'swadeshi Movement' and 'Boycott of Foreign Things' were started by the Congress in 1905 to protest– (A) Curtailment of the rights of representation granted under the Indian Councils Act, 1892 (B) Partition of Bengal (C) Restrictions imposed on the entry of Indians into Canada (D) Lord Curzon's efforts to establish control over the universities (Ans : B) 5. The Lucknow Congress of 1916 was important, because at this session the party– (A) Repudiated political militancy of the 'garam dal' (B) Signed a pact with the Muslim League (C) Opposed participation of India in the First World War (D) Rejected separate electorates for Muslims and Dalits (Ans : B) 6. In 1932, a compromise, known as the 'Poona Pact', was worked out on the question of separate electorates. Who were the two main leaders involved ? (A) Gandhiji and Lord Irwin (B) Gandhiji and Dr. B. R. Ambedkar (C) Gandhiji and Muhammad Ali Jinnah (D) Gandhiji and Aga Khan (Ans : B) 7. What is the time taken by the Earth to complete one rotation on its imaginary axis ? (A) 24 hr 37 min 23 sec (B) 24 hr (C) 23 hr 56 min 4 sec (D) 23 hr 52 min (Ans : C) 8. In which atmospheric layer is the ozone layer situated ? (A) Troposphere (B) Stratosphere (C) Mesosphere (D) Ionosphere (Ans : C) 9. The Finance Commission makes its recommendations to– (A) The Finance Minister (B) The Planning Commission (C) The Parliament (D) The President (Ans : D) 10. The Chief Minister of Maharashtra is– (A) Ashok Chauhan (B) Sushil Kumar Shinde (C) Sanjay Nirupam (D) Devendra Fadnavis (Ans : D)

SUB INSPECTOR of Police Exam Questions 11. The author of the book, Gulliver's Travels is– (A) Jonathan Swift (B) Charles Dickens (C) Charles Lamb (D) T. S. Eliot (Ans : A) 12. Red soil is commonly found in the States of– (A) Punjab and Rajasthan (B) Himachal Pradesh and Haryana (C) Rajasthan and Himachal Pradesh (D) Tamil Nadu and Andhra Pradesh (Ans : D) 13. When did the Reserve Bank of India become a State-owned institution ? (A) 1956 (B) 1952 (C) 1950 (D) 1949 (Ans : D) 14. Who was the President of the Constituent Assembly which was constituted to frame the Constitution of India ? (A) Pt. Jawaharlal Nehru (B) Sardar Vallabhbhai Patel (C) Dr. Rajendra Prasad (D) Dr. Bhimrao Ambedkar (Ans : C) 15. Which part of our Constitution primarily reflects Mahatma Gandhi's principles ? (A) The Preamble (B) Part III-Fundamental Rights (C) Part IV-Directive Principles of State Policy (D) Part IV A-Fundamental Duties (Ans : C) 16. Which of the following is a Fundamental Right as provided under Part III of the Constitution ? (A) Promotion of educational and economic interests of the Scheduled Castes, Scheduled Tribes and other weaker sections (B) Right to reside and settle in any part of India (C) Right of workers to participate in the management of industries (D) None of the above (Ans : B) 17. 1n case of conflict between the Central and State law on a subject in the Concurrent List– (A) The law which was passed first prevails (B) The law of State prevails (C) The law of Centre prevails (D) Both laws stand nullified (Ans : C) 18. Part IV A of the Constitution lays down the Fundamental Duties of the citizens. Which of the following is not a duty included among Fundamental Duties ? (A) To profess and propagate one's own religion (B) To develop the scientific temper, humanism and the spirit of enquiry and reform (C) To safeguard public property and to abjure violence (D) To value and preserve the rich heritage of our composite culture (Ans : A) 19. Taxes on income, other than on agricultural income, are– (A) Levied and collected by the Central Government and appropriated by it (B) Levied and collected by the Central Government but assigned to States within which they are leviable (C) Levied and collected by the Central Government but distributed between the States and the Centre (D) Levied by the Central Government but collected and appropriated by the State Governments (Ans : C) 20. A, 5-point formula was proposed by India to define relations between sovereign States, which was known as 'Panchsheel' formula. India signed the first 'Panchsheel Agreement' in 1954. Which was the country with which this agreement was signed ? (A) China (B) Pakistan (C) Bhutan (D) Sri Lanka (Ans : A) 21. Which one of the following Amendments has been described as Mini Constitution ? (A) 42nd (B) 43rd (C) 52nd (D) 59th (Ans : A) 22. Which of the following organs of the United Nations Organization elects / elect judges of the International Court of Justice ? (A) The Economic and Social Council (B) The Security Council and the General Assembly (C) The Trusteeship Council and the Economic and Social Council (D) The Security Council (Ans : B) 23. In blogging, the blogger, with the help of his computer and the Internet– (A) Puts out his ideas, information, photos, etc., on the Internet, which can be accessed by any other person (B) Visits the Web site of another person and makes changes in the information posted thereon (C) Accesses another person's computer and steals secret information stored therein (D) Accesses another computer and continuously exchanges information with it Ans : (A) 24. Power from powerhouses is often transmitted as alternating current at 33000 volts or more. Why is power transmitted as such high voltage ? (A) Transmission is faster at high voltages (B) Transmission loss is lower at high voltages (C) It is difficult to generate electricity at lower voltage (D) None of the above (Ans : B) 25. When a patient's blood pressure is taken, the pressure exerted by blood on the walls of the blood vessels is measured. At what stage is this pressure measured ? (A) When the heart sends out oxygenated blood to the body parts (B) When deoxygenated blood goes into the heart (C) At both the stages (D) At the in-between stage (Ans : C) 26. The winner of Indian Premier League, 2012 is– (A) Chennai Super Kings (B) Delhi Daredevils (C) Kolkata Knight Riders (D) Mumbai Indians (Ans : C) 27. Which of the following is a tribal group of Africa ? (A) Eskimos (B) Ainu (C) Fula (D) None of these (Ans : D) 28. The Chairman of the Madhya Pradesh Public Service Commission is– (A) Prof. P. K. Dubey (B) Prof. P. K. Joshi (C) A. K. Pandey (D) P. K. Pandey (Ans : C) 29. The words 'satyameva Jayate' in the National Emblem are taken from– (A) Mahabharata (B) Mundaka Upanishad (C) Kautilya's Arthashastra (D) Samaveda (Ans : B) 30. The Tropic of Cancer does not pass through– (A) India (B) Egypt (C) Mexico (D) Iran (Ans : B) 31. Which country in Europe is called the 'Land of Midnight Sun' ? (A) Norway (B) Finland (C) Iceland (D) Sweden (Ans : A) 32. Swami Vivekananda gained fame and recognition in the Western World after his address to the World Congress of Major Religions in 1893. In which city was this congress held ? (A) London (B) Paris (C) Berlin (D) Chicago (Ans : D) 33. Where was Mother Teresa born ? (A) India (B) Albania (C) Hungary (D) Poland (Ans : B) 34. Who was the first navigator to circumnavigate the Earth by the sea route ? (A) Ferdinand Magellan (B) Marco Polo (C) Vasco da Gama (D) Christopher Columbus (Ans : A) 35. Which of the following countries was discovered by the famous Portuguese navigator Vasco da Gama? (A) India (B) China (C) Australia (D) New Zealand (Ans : A) 36. What is an ecosystem ? (A) The unit of man and all living beings which interact with each other (B) The unit comprised of man, other living beings and the plant kingdom (C) The unit comprised of all living beings and their environment (D) That part of the Earth and the atmosphere where living beings are found (Ans : B) 37. Malaria affects lakhs of Indians every year. Which part of the body is damaged by this disease ? (A) Heart (B) Lungs (C) Spleen (D) Liver (Ans : C) 38. How does the Sun get its energy ? (A) From gravitational pressure (B) From nuclear fission (C) From nuclear fusion (D) None of the above (Ans : C) 39. The Shahnama, written by Firdausi, tells the tale of kings of one country .Which is this country ? (A) Egypt (B) India (C) Turkey (D) Persia (Ans : D) 40. Which of the following statements is correct ? (A) The entropy of the world keeps on increasing (B) The entropy of the world keeps on decreasing (C) The entropy of the world is constant (D) The entropy of the world increases and decreases in a cyclic manner (Ans : A) 41. The frequency range of FM radio broadcast in India is– (A) 102 MHz -132 MHz (B) 80 MHz -102 MHz (C) 88 MHz -108MHz (D) 78 MHz -102 MHz (Ans : C) 42. Who among the following has not been awarded the Nobel Prize for Literature ? (A) Derek Walcott (B) Dario Fo (C) Toni Morrison (D) Robert Richardson (Ans : D) 43. Two large temple complexes have been found in Angkorwat, Cambodia. Which religion are they associated with? (A) Hinduism (B) Buddhism (C) Shintoism (D) None of these (Ans : A) 44. Fidel Castro ousted a dictator from Cuba in 1959. Who was this dictator ? (A) Duvalier (B) Batista (C) Pinochet (D) None of these (Ans : B) 45. Wheels of passenger vehicles are fitted with tyres and tubes which are filled with air. What is the main reason for not filling up the tubes with water ? (A) Filling them with water will increase the weight (B) If they are filled with water, the force of shocks on passengers, generated by uneven surface of the road, will increase very considerably (C) Air is cheaper than water (D) It would not be convenient to fill up the tubes with water (Ans : B) 46. As mother is B's sister and C's daughter. B's daughter is P who is Q's sister. If C is not Q's grandmother, how is C related to Q? (A) Father (B) Mother (C) Grandfather (D) Aunt (Ans : C) 47. Four boys are wearing clothes of different colours. Ravi is not wearing white and Ajay is not wearing blue. If Sohan is wearing red, what is the colour of Sachin's clothes ? (A) Blue (B) White (C) Yellow (D) Cannot be determined (Ans : D) 48. A factory makes shoes of two types, A-type and B-type. Both require the same amount of leather which is available in such quantity that 80 pairs of shoes can be made per day. It takes twice as long to make A-type shoes as B-type. The capacity of the factory is such that if only B-type shoes were to be made, 100 pairs could be produced in one day. A-type shoes require some special material which is available in quantities sufficient for 40 pairs per day. The special material required for B-type shoes is available in quantities sufficient for 70 pairs per day. If the factory makes a profit of Rs. 200 per pair on A-type shoes and Rs. 150 per pair on 8-type shoes how many pairs of shoes of each type should it produce every day for maximum profit ? (A) A-type 40 and B-type 20 (B) A-type 10 and B-type 70 (C) A-type 20 and B-type 60 (D) None of the above (Ans : D) 49. A leap year is chosen at random. What is the probability that this year would have 53 Mondays ? (A) 1/7 (B) 2/7 (C) 3/7 (D) None of these (Ans : B) 50. Three horses, A, B and C, are participating in a race. If the probability of A winning the race is twice the probability of B winning it and the probability of B winning the race is twice the probability of C winning it, what is the probability that either B or C will win the race ? (A) 1/7 (B) 2/7 (C) 3/7 (D) None of these (Ans : C) 51. Some men are travelling with their horses. At one point of time, half the men are riding their horses while the rest are walking along leading their horses. If the number of legs on the ground at that time is 40, what is the number of horses in the party ? (A) 8 (B) 10 (C) 12 (D) None of these Ans : (A) 52. A family is comprised of father, mother, son and daughter. The father's age is 3 times the age of the daughter. The son is half as old as his mother and is 7 years older than his sister. If the father is 9 years older than his wife, what is the mother's age ? (A) 45 years (B) 50 years (C) 60 years (D) None of these Ans : (C) 53. Six friends went for a vacation and stayed in a resort where nine cottages in a row were available for them. They all stayed in separate cottages. Mohan, Rani and Chitra did not stay in the cottages at the two ends. Nobody stayed next to Mohan and Salman. There was only one empty cottage between Mohan and Chitra. Jayant's cottage was adjacent to both Chitra and Anil. Rani stayed next to the cottage at the beginning. Which cottages remain empty after they are accommodated ? (A) Nos. 1, 6, 8 (B) Nos. 4, 6, 8 (C) Nos. 3, 5, 9 (D) Nos. 2, 5, 7 Ans : (A) 54. A plane mirror is kept in front of a clock. If the actual time is 3 : 25, what time would the reflection show (if we notice only the positions of the two hands of the clock and do not pay attention to the numerals on the dial) ? (A) 9 : 55 (B) 8 : 35 (C) 3 : 25 (D) None of these Ans : (B) 55. A person has five coins. If he knows for certain that– 1. Coin no.1 is genuine; 2. One of the remaining four coins is counterfeit and its weight is different from the others. then what is the minimum number of weighings which will enable him to find out which coin is counterfeit and whether it is heavier or lighter than the others ? (A) 1 (B) 2 (C) 3 (D) 4 Ans : (B) 56. Six students are taking coffee in the coffeehouse. A and Bare from Delhi while the others C, D, P and Q are from Bhopal. D and Q are tall while the others are short. A, C and D are girls while the others are boys. Who is the tall girl from Bhopal ? (A) C (B) D (C) P (D) Q Ans : (C) 57. What is the missing number ? 0 1 2 3 1 3 4 16 2 5 6 ? (A) 22 (B) 106 (C) 39 (D) None of these Ans : (C) 58. The remnants of one of the most ancient civilizations of the world, 'Indus Valley Civilization', were first discovered in Harappa. Where is this Harappa situated ? (A) Sind, Pakistan (B) Punjab, India (C) Punjab, Pakistan (D) Haryana, India Ans : (A) 59. In 1950s, the Archaeological Survey of India found several sites in one part of India which yielded evidence that the Mohenjodaro-Harappa Civilization was centred, not in Indus Valley, but in this part of India. In which present State are these sites situated ? (A) Maharashtra (B) Gujarat (C) Rajasthan (D) Punjab Ans : (B) 60. River Narmada flows down from Amarkantak Hills to the sea. What is the name of the area where it meets the sea ? (A) Gulf of Kutch (B) Gulf of Khambat (C) Gulf of Mannar (D) Bay of Bengal Ans : (B) 61. Commonwealth Games, 2010 were held at– (A) Colombo (B) London (C) NewDelhi (D) Seoul Ans : (C) 62. Karera Sanctuary is situated at– (A) shivpuri (B) Mandsaur (C) Damoh (D) Tikamgarh Ans : (A) 63. Barman Fair is held at– (A) Sodalpur (B) Porsa (C) Pipaliya Khurd (D) Gadarwara Ans : (D) 64. Who is the 'Man of the Tournament' of World Cup Cricket, 2011 ? (A) Yuvraj Singh (B) Kumar Sangakara (C) Ricky Ponting (D) Jacques Kallis Ans : (A) 65. Which of the following National Highways does not pass through Madhya Pradesh ? (A) NH27 (B) NH28 (C) NH 78 (D) NH 79 Ans : (B) 66. How many tiers of administration are there in Panchayati Raj in Madhya Pradesh ? (A) A single tier-at village level (B) Two tiers-at village and district levels (C) Three tiers-at village, block and district levels (D) Four tiers-at village, block district and State levels Ans : (C) 67. In the Bhopal Gas Tragedy of 1984, which was the gas that had leaked out ? (A) Carbon monoxide (B) Hydrogen sulphide (C) Ethyl cyanide (D) Methyl isocyanate Ans : (D) 68. Who founded the Ramakrishna Mission ? (A) Ramakrishna Paramhans (B) Swami Dayananda Saraswati (C) Swami Vivekananda (D) Shankaracharya Ans : (C) 69. Which architect has prepared the plan for Chandigarh city ? (A) Edwin Lutyens (B) Le Corbusier (C) Charles Correa (D) None of these Ans : (B) 70. Who got the Khajuraho temples constructed ? (A) Chhatrasal (B) Kings of Parmar dynasty (C) Kings of Chandel dynasty (D) King Bhoja Ans : (C) 71. Who was the founder of the Chola dynasty in South India ? (A) Karikala (B) Parantaka (C) Rajaraja (D) None of these Ans : (D) 72. Which was the most famous festival of the Vijayanagar empire ? (A) Ramnavami (B) Brahmotsava (C) Mahanavami (D) Vasantotsava Ans : (C) 73. The famous caves at Ajanta-Ellora contain statues and murals associated with– (A) Hinduism (B) Buddhism (C) Jainism (D) All of these Ans : (D) 74. Which 'pir' lies in the famous 'mazar' at Ajmer ? (A) Muin-ud-din Chishti (B) Nizam-ud-din Auliya (C) Baba Farid (D) Sheikh salim Chishti Ans : (A) 75. Where was the Jain Seer Lord Mahavira born ? (A) Lumbini (Nepal) (B) Kunda (Bihar) (C) Shravanbelgola (Karnataka) (D) None of these Ans : (B) 76. Who was the first 'Guru' of the Sikhs? (A) Guru Amardas (B) Guru Nanakdev (C) Guru Arjundev (D) Guru Tegh Bahadur (Ans : B) 77. Gaya district of Bihar is associated with the name of Mahatma Buddha. In this district– (A) Mahatma Buddha was born (B) Mahatma Buddha gained enlightenment (C) Mahatma Buddha delivered his first sermon (D) Mahatma Buddha expired (Ans : B) 78. The ambitious road development project of India, known as the 'Golden Quadrangle Project', will join four important places. Which are these places? (A) srinagar, Kannyakumari, Porbandar and silchar (B) Amritsar, Ahmedabad, Bengaluru and Guwahati (C) Delhi, Mumbai, Kolkata and Chennai (D) Jalandhar, Pune, Hyderabad and Dibrugarh (Ans : C) 79. The first Indian satellite was launched into space in 1975. What was it called ? (A) Aryabhatta (B) Rohini (C) Insat-1A (D) IRS-1A (Ans : A) 80. Ashok Chakra is awarded for– (A) Bravery in the face of enemy, during a war (B) Bravery during anti-terrorist operations (C) Life-saving (D) All of the above (Ans : A) 81.The Defence Research and Development Organization of India has developed a missile which can be launched from a submarine. What is it named ? (A) BrahMos (B) Astra (C) Prithvi-4 (D) K-15 (Ans : D) 82. The 'Param' series of super-computers was developed in India by which of the following institutions ? (A) Indian Institute of Sciences (B) Centre for Development of Advanced Computing (C) Tata Institute of Fundamental Research (D) Electronic Corporation of India (Ans : B) 83. Quite often, deltas are formed at river mouths. What is the reason for formation of delta ? (A) The flow of the river slows down considerably by the time it meets the sea. Hence, the sand and pieces of rocks carried by the river fall off at its mouth and collect in the form of a delta (B) The tide in the sea stops the river from flowing into the sea the sand and pieces of rocks carried along by the river current fall off and form a delta (C) Salts are present in seawater. When the river meets the sea, the sand and rock particles suspended in the river water get precipitated and they settle down at the bottom to form a delta (D) None of the above Ans : (A) 84. Food is cooked more quickly in pressure cooker, because– (A) The boiling point of water is lowered in it (B) The boiling point of water is raised in it (C) It absorbs heat quickly (D) It retains heat for a longer time (Ans : B) 85. Optical fibers are hair-thin tubes of special glass and light can pass through them from end to end. Their special property is that light continues to travel through them even when they are bent. Which property of light underlies this phenomenon ? (A) Total internal reflection (B) Refraction (C) Diffraction (D) Polarization (Ans : A) 86. Why are Polaroids used in sunglasses ? (A) For the sake of fashion (B) To reduce the glare (C) To improve resolving power of the eyes (D) None of the above (Ans : B) 87. When an aeroplane is flying at a great height, the sky appears black to its passengers. Why ? (A) The dust particles and droplets of water present in the atmosphere absorb the light and do not allow it to reach the eyes of the passengers (B) The atmosphere is very rare at great heights and so the scattering of light is negligible (C) The light is so polarized that no part of it is able to reach the eye of the passengers (D) None of the above (Ans : B) 88. The image formed by an object on the retina of the human eye is– (A) Real and inverted (B) Real and upright (C) Virtual and inverted (D) Virtual and upright (Ans : A) 89. A heater running on 220 volt takes 5 minute to boil a quantity of water. If the heater is run on 110 volt instead of 220 volt, how much time will it take to boil the same quantity of water ? (A) 10 minute (B) 15 minute (C) 20 minute (D) 25 minute (Ans : C) 90. A GM counter is used for detecting– (A) Underground oil (B) Coal (C) Radioactivity (D) Methane gas (Ans : C) 91. In which organ of the body is the red blood corpuscle made ? (A) Liver (B) Bone marrow (C) Kidneys (D) Heart (Ans : B) 92. The edible potato is the modified form of which part of the plant ? (A) Roots (B) Stem (C) Flower (D) None of these (Ans : B) 93. What is the main constituent of 'Gobar Gas' (biogas) ? (A) Hydrogen (B) Carbon monoxide (C) Acetylene (D) Methane (Ans : D) 94. What is the 'non-stick' substance used in cookwares ? (A) Polymonochlorotrifluoroethylene (B) Polymethyl methacrylate (C) Polyacrylonitrile (D) Polytetrafluoroethylene (Ans : D) 95. The gas used for cooking (LPG) is chiefly a mixture of– (A) Methane and carbon monoxide (B) Hydrogen and nitrogen (C) Butane and propane (D) Propane and nitrogen (Ans : C) 96. One card is pulled out at random from a well-shuffled deck of playing cards (52 cards). This is seen to be a card of hearts. It is put back and the deck is shuffled again. Another card is now pulled out of the deck. What is the probability of the second card being a black king ? (A) 1/104 (B) l/52 (C) 1/26 (D) None of these (Ans : C) 97. Why does a foul smell emanate from some ponds, tanks, etc. ? (A) Pesticides and other organic chemicals reach the water body and kill off fishes, etc., living therein, causing the foul smell (B) Fertilizers used in farming reach the water body and give rise to excessive growth of aqueous plants. When these plants die, excessive quantities of organic matter are collected, depleting dissolved oxygen and causing foul smell (C) Household wastes contain small quantities of mercury, cadmium, copper, zinc, etc., which pollute the water bodies, causing the death of fishes and other aquatic organisms and leading to foul smell (D) None of the above (Ans : B) 98. Government of India calendars show dates both in Christian era (AD) and Saka era. In which year did the Saka era start ? (A) 150 BC (B) 130 BC (C) 56 BC (D) AD 78 (Ans : D) 99. Who was the first woman ruler of India ? (A) Nurjahan (B) Razia Sultan (C) Chandbibi (D) Durgavati (Ans : B) 100. Who founded the Chalukya dynasty in South India ? (A) Harihara (B) Pulakesin (C) Parantaka (D) Bukka (Ans : B) SUB INSPECTOR Question Papers and Answers pdf Download Read the full article

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certainheartrunaway · 5 years ago

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144 and 1240 MHz bands – WRC-23 Agenda Items – Update

IARU was represented at the meeting of CEPT Project Team A (responsible for some aspects of the CEPT position for WRC-19), held in Prague from June 17-21.

The IARU Region 1 website reports:

Of particular interest were discussions on two proposed Agenda items for WRC-23, concerning the sharing of the 1240-1300 MHz band with the Galileo navigation system and the proposal from France to study a range of frequencies, including the 144 MHz amateur band, for future aeronautical applications.

The output from PTA does not carry forward the Galileo proposal, but it is likely that further discussions will take place prior to the Conference Preparatory Group meeting in August. Meantime work on this issue will also continue in other specialist CEPT forums. IARU will continue to support this approach and it believes this will be the most efficient method for developing the sharing guidance required to protect Galileo operations in a timely manner.

Regarding new aeronautical frequencies (including 144-146 MHz), the proposal was not strongly opposed by administrations and has been carried forward to the higher level CEPT Conference Preparatory Group (CPG) meeting in August for final adoption.

IARU views with grave concern any proposal to include the 144 MHz band in the proposed aeronautical agenda item and will be making every effort to fully protect amateur radio interests and seek the support of regulators in this regard.

The band 144-146 MHz is allocated globally to the amateur and amateur satellite services on a primary basis. It is the only globally harmonised VHF band for the amateur and amateur satellite service. As such it is an important and widely used part of the amateur spectrum with a vast installed base of both terrestrial/maritime amateur users and systems and operational satellite stations including the International Space Station (ISS).

This heavily used band supports a large number of repeater stations, segments for weak-signal long distance terrestrial and EME (Earth-Moon-Earth) communications, satellite and ISS usage, data services, as well as conventional terrestrial and tropospheric communications. The Primary status of the band has also enabled a number of amateur aeronautical uses including on manned flights and high-altitude balloons. Supporting all of this is a wide variety of commercial and experimental equipment, ranging from ultra-low noise preamplifiers for sensitive receivers, software defined radios and transmitting systems that can deliver high EIRP levels when needed to overcome high loss propagation paths.

Given the propagation to/from an aircraft at altitude, it is entirely possible that harmful interference to sensitive amateur and amateur satellite receivers will be caused over a 1,000 km radius of a single aircraft.

IARU will shortly be providing a brief to Member Societies and other interested parties, asking them to discuss the French proposal with their administrations well in advance of the August CEPT-CPG meeting.

It is possible that France will seek to introduce into other Regional Telecommunications Organisations (RTO) the same proposal to study the 144-146 MHz band for aeronautical use. IARU will provide a brief shortly to enable representations to be made to administrations in countries under those RTOs for protection of this amateur spectrum allocation.

Source: IARU Region 1 http://iaru-r1.org/

Download the documents from the CEPT SPG Project Team A meeting in Prague June 17-21 from https://cept.org/ecc/groups/ecc/cpg/cpg-pt-a/client/meeting-documents/?flid=5624

France proposes 144-146 MHz for Aeronautical Mobile Service http://www.southgatearc.org/news/2019/june/france-proposes-144-146-mhz-for-aeronautical-mobile-service.htm

1240-1300 MHz band discussed by CEPT WGFM and CPG/PTA https://amsat-uk.org/2019/05/31/1240-1300-mhz-band-discussed-by-cept-wgfm-and-cpg-pta/

Could a new licence class help counter threats at VHF and above? http://www.southgatearc.org/news/2019/june/could-a-new-licence-counter-threats-at-vhf-and-above.htm

Source:AMSAT UK

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