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60-meter Band
The 60-meter band or 5 MHz band is a relatively new amateur radio allocation, first introduced in 2002, that was originally only available in a few countries, such as the United States, United Kingdom, Norway, Finland, Denmark, Ireland and Iceland. Over a number of years however, an increasing proportion of countries' telecommunications administrations together with their government and military users have permitted Amateur Radio operation in the 5 MHz area on a short or longer-term basis, ranging from discrete channels to a frequency band allocation. At the closing meeting of the 2015 ITU World Radiocommunication Conference (WRC-15) on 27 November 2015, amongst the Final Acts signed into the International Radio Regulations was one approving "A Worldwide Frequency Allocation of 5351.5–5366.5 kHz to the Amateur Service on a secondary basis". The ITU's enhanced band allocation limits most amateurs to 15 watts effective isotropic radiated power (EIRP), wit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
The World Of 5 MHz
''The'' () is a grammatical Article (grammar), article in English language, English, denoting persons or things already mentioned, under discussion, implied or otherwise presumed familiar to listeners, readers, or speakers. It is the definite article in English. ''The'' is the Most common words in English, most frequently used word in the English language; studies and analyses of texts have found it to account for seven percent of all printed English-language words. It is derived from gendered articles in Old English which combined in Middle English and now has a single form used with pronouns of any gender. The word can be used with both singular and plural nouns, and with a noun that starts with any letter. This is different from many other languages, which have different forms of the definite article for different genders or numbers. Pronunciation In most dialects, "the" is pronounced as (with the voiced dental fricative followed by a schwa) when followed by a consonant s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Screenshot ITU Provisional Acts WRC 15 - Item 1
screenshot (also known as screen capture or screen grab) is a digital image that shows the contents of a computer display. A screenshot is created by the operating system or software running on the device powering the display. Additionally, screenshots can be captured by an external camera, using photography to capture contents on the screen. Screenshot techniques Digital techniques The first screenshots were created with the first interactive computers around 1960. Through the 1980s, computer operating systems did not universally have built-in functionality for capturing screenshots. Sometimes text-only screens could be dumped to a text file, but the result would only capture the content of the screen, not the appearance, nor were graphics screens preservable this way. Some systems had a BSAVE command that could be used to capture the area of memory where screen data was stored, but this required access to a BASIC prompt. Systems with composite video output could be connec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
YVTO
YVTO is the callsign of the official time signal from the Juan Manuel Cagigal Naval Observatory in Caracas, Venezuela. The content of YVTO's signal, which is a continuous 1 kW amplitude modulated carrier wave at 5.000 MHz, is much simpler than that broadcast by some of the other time signal stations around the world, such as WWV. The methods of time transmission from YVTO are very limited. The broadcast employs no form of digital time code. The time of day is given in Venezuelan Standard Time (VET), and is only sent using Spanish language Spanish ( or , Castilian) is a Romance languages, Romance language of the Indo-European language family that evolved from colloquial Latin spoken on the Iberian peninsula. Today, it is a world language, global language with more than 500 millio ... voice announcements. YVTO also transmits 100 ms-long beeps of 1,000 Hz every second, except for thirty seconds past the minute. The top of the minute is marked by a 0.5 second 800&n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
BPM (time Service)
BPM is the call sign of the official short-wave time signal service of the People's Republic of China, operated by the Chinese Academy of Sciences, broadcasting from CAS's National Time Service Center in Pucheng County, Shaanxi at , roughly 70 km northeast of Lintong, along with NTSC's long-wave time signal BPL on 100 kHz. BPM is broadcast at 2.5, 5.0, 10.0, and 15.0 MHz, the same frequencies as WWV and WWVH, following the schedule listed below: Transmission format BPM transmits different signals on a half-hour schedule, modulated with 1 kHz audio tones to provide second and minute ticks: BPM is idiosyncratic in that it transmits UT1 Universal Time (UT or UT1) is a time standard based on Earth's rotation. While originally it was mean solar time at 0° longitude, precise measurements of the Sun are difficult. Therefore, UT1 is computed from a measure of the Earth's angle with ... time between minutes 25 through to 29 and 55 through to 59, which creates an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
WSPR (Amateur Radio Software)
WSPR (pronounced "whisper") is an acronym for ''Weak Signal Propagation Reporter''. It is a protocol, implemented in a computer program, used for weak-signal radio communication between amateur radio operators. The protocol was designed, and a program written initially, by Joe Taylor, K1JT. The software code is now open source and is developed by a small team. The program is designed for sending and receiving low-power transmissions to test propagation paths on the MF and HF bands. WSPR implements a protocol designed for probing potential propagation paths with low-power transmissions. Transmissions carry a station's callsign, Maidenhead grid locator, and transmitter power in dBm. The program can decode signals with a signal-to-noise ratio as low as −28 dB in a 2500 Hz bandwidth. Stations with internet access can automatically upload their reception reports to a central database called WSPRnet, which includes a mapping facility. The WSPR Protocol The type ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radio Society Of Great Britain
The Radio Society of Great Britain (RSGB) is the United Kingdom's recognised national society for amateur radio operators. The society was founded in 1913 as the London Wireless Club, making it one of the oldest organisations of its kind in the world. Through its work, it represent the interests of the UK's 80,000 licensed radio amateurs in the United Kingdom and certain dependent territories of the United Kingdom at the International Amateur Radio Union, acting as a medium for communication between the licensed operators and the UK government. Role The RSGB has traditionally acted as the organisation through which its members interact with the telecommunications regulatory authority of the United Kingdom, Ofcom. Although Ofcom has used its web site to solicit opinions directly from all amateur radio enthusiasts and other interested parties, the RSGB continues to advise and to seek to influence Ofcom on the likely impact of proposed changes in many areas – from decisions on ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radio Propagation Beacon
An amateur radio propagation beacon is a radio beacon, whose purpose is the investigation of the propagation of radio signals. Most radio propagation beacons use amateur radio frequencies. They can be found on LF, MF, HF, VHF, UHF, and microwave frequencies. Microwave beacons are also used as signal sources to test and calibrate antennas and receivers. The International Amateur Radio Union (IARU) and its member societies coordinate beacons established by radio amateurs. Transmission characteristics Most beacons operate in continuous wave (A1A) and transmit their identification (call sign and location). Some of them send long dashes to facilitate signal strength measurement. A small number of beacons transmit Morse code by frequency-shift keying (F1A). A few beacons transmit signals in digital modulation modes, like radioteletype (F1B) and PSK31 (G1B). Legality In the US, unattended beacons on frequencies lower than the 10-meter band are not legal. 2200-meter beacons ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ionosonde
An ionosonde, or chirpsounder, is a special radar for the examination of the ionosphere. The basic ionosonde technology was invented in 1925 by Gregory Breit and Merle A. Tuve and further developed in the late 1920s by a number of prominent physicists, including Edward Victor Appleton. The term ''ionosphere'' and hence, the etymology of its derivatives, was proposed by Robert Watson-Watt. Components An ionosonde consists of: * A high frequency (HF) radio transmitter, automatically tunable over a wide range. Typically the frequency coverage is 0.5–23 MHz or 1–40 MHz, though normally sweeps are confined to approximately 1.6–12 MHz. * A tracking HF receiver which can automatically track the frequency of the transmitter. * An antenna with a suitable radiation pattern, which transmits well vertically upwards and is efficient over the whole frequency range used. * Digital control and data analysis circuits. The transmitter sweeps all or part of the HF frequency ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ionogram
An ionosonde, or chirpsounder, is a special radar for the examination of the ionosphere. The basic ionosonde technology was invented in 1925 by Gregory Breit and Merle A. Tuve and further developed in the late 1920s by a number of prominent physicists, including Edward Victor Appleton. The term ''ionosphere'' and hence, the etymology of its derivatives, was proposed by Robert Watson-Watt. Components An ionosonde consists of: * A high frequency (HF) radio transmitter, automatically tunable over a wide range. Typically the frequency coverage is 0.5–23 MHz or 1–40 MHz, though normally sweeps are confined to approximately 1.6–12 MHz. * A tracking HF receiver which can automatically track the frequency of the transmitter. * An antenna with a suitable radiation pattern, which transmits well vertically upwards and is efficient over the whole frequency range used. * Digital control and data analysis circuits. The transmitter sweeps all or part of the HF frequency ra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ionosphere
The ionosphere () is the ionized part of the upper atmosphere of Earth, from about to above sea level, a region that includes the thermosphere and parts of the mesosphere and exosphere. The ionosphere is ionized by solar radiation. It plays an important role in atmospheric electricity and forms the inner edge of the magnetosphere. It has practical importance because, among other functions, it influences radio propagation to distant places on Earth. History of discovery As early as 1839, the German mathematician and physicist Carl Friedrich Gauss postulated that an electrically conducting region of the atmosphere could account for observed variations of Earth's magnetic field. Sixty years later, Guglielmo Marconi received the first trans-Atlantic radio signal on December 12, 1901, in St. John's, Newfoundland (now in Canada) using a kite-supported antenna for reception. The transmitting station in Poldhu, Cornwall, used a spark-gap transmitter to produce a signal with a freq ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Critical Frequency
In telecommunication, the term critical frequency has the following meanings: * In radio propagation by way of the ionosphere, the limiting frequency at or below which a wave component is reflected by, and above which it penetrates through, an ionospheric layer. * At near vertical incidence, the limiting frequency at or below which incidence, the wave component is reflected by, and above which it penetrates through, an ionospheric layer. Critical Frequency changes with time of day, atmospheric conditions and angle of fire of the radio waves by antenna. The existence of the critical frequency is the result of electron limitation, ''i.e.,'' the inadequacy of the existing number of free electrons to support reflection at higher frequencies. In signal processing the ''critical frequency'' it is also another name for the Nyquist frequency. Critical frequency is the highest magnitude of frequency above which the waves penetrate the ionosphere and below which the waves are reflected b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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