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108
In Article 3 of the Treaty of San Francisco between the Allied Powers and Japan, which came into force in April 1952, the U.S. put the outlying islands of the Ryukyus, including the island of Okinawa—home to over 1 million Okinawans related to the Japanese—and the Bonin Islands, the Volcano Islands, and Iwo Jima into U.S. trusteeship. All these trusteeships were slowly returned to Japanese rule. Okinawa was returned on May 15, 1972, but the U.S. stations troops in the island's bases as a defense for Japan.
How many people lived on the island of Okinawa?
573076172461fd1900a9ce2e
208
over 1 million
109
In Article 3 of the Treaty of San Francisco between the Allied Powers and Japan, which came into force in April 1952, the U.S. put the outlying islands of the Ryukyus, including the island of Okinawa—home to over 1 million Okinawans related to the Japanese—and the Bonin Islands, the Volcano Islands, and Iwo Jima into U.S. trusteeship. All these trusteeships were slowly returned to Japanese rule. Okinawa was returned on May 15, 1972, but the U.S. stations troops in the island's bases as a defense for Japan.
When was Okinawa finally returned?
573076172461fd1900a9ce2f
423
May 15, 1972
110
In Article 3 of the Treaty of San Francisco between the Allied Powers and Japan, which came into force in April 1952, the U.S. put the outlying islands of the Ryukyus, including the island of Okinawa—home to over 1 million Okinawans related to the Japanese—and the Bonin Islands, the Volcano Islands, and Iwo Jima into U.S. trusteeship. All these trusteeships were slowly returned to Japanese rule. Okinawa was returned on May 15, 1972, but the U.S. stations troops in the island's bases as a defense for Japan.
Why did the US have troops on Okinawa?
573076172461fd1900a9ce30
488
as a defense for Japan.
111
In 2010 there was an attempt to register a 51st State Party with the New Zealand Electoral Commission. The party advocates New Zealand becoming the 51st state of the United States of America. The party's secretary is Paulus Telfer, a former Christchurch mayoral candidate. On February 5, 2010, the party applied to register a logo with the Electoral Commission. The logo – a US flag with 51 stars – was rejected by the Electoral Commission on the grounds that it was likely to cause confusion or mislead electors. As of 2014[update], the party remains unregistered and cannot appear on a ballot.
When did the 51st State Party attempt to register in New Zealand?
57307685396df9190009612a
3
2010
112
In 2010 there was an attempt to register a 51st State Party with the New Zealand Electoral Commission. The party advocates New Zealand becoming the 51st state of the United States of America. The party's secretary is Paulus Telfer, a former Christchurch mayoral candidate. On February 5, 2010, the party applied to register a logo with the Electoral Commission. The logo – a US flag with 51 stars – was rejected by the Electoral Commission on the grounds that it was likely to cause confusion or mislead electors. As of 2014[update], the party remains unregistered and cannot appear on a ballot.
What does the 51st State Party advocate?
57307685396df9190009612b
103
The party advocates New Zealand becoming the 51st state of the United States of America
113
In 2010 there was an attempt to register a 51st State Party with the New Zealand Electoral Commission. The party advocates New Zealand becoming the 51st state of the United States of America. The party's secretary is Paulus Telfer, a former Christchurch mayoral candidate. On February 5, 2010, the party applied to register a logo with the Electoral Commission. The logo – a US flag with 51 stars – was rejected by the Electoral Commission on the grounds that it was likely to cause confusion or mislead electors. As of 2014[update], the party remains unregistered and cannot appear on a ballot.
Who is the secretary of the 51st State Party?
57307685396df9190009612c
217
Paulus Telfer
114
In 2010 there was an attempt to register a 51st State Party with the New Zealand Electoral Commission. The party advocates New Zealand becoming the 51st state of the United States of America. The party's secretary is Paulus Telfer, a former Christchurch mayoral candidate. On February 5, 2010, the party applied to register a logo with the Electoral Commission. The logo – a US flag with 51 stars – was rejected by the Electoral Commission on the grounds that it was likely to cause confusion or mislead electors. As of 2014[update], the party remains unregistered and cannot appear on a ballot.
Can people in New Zealand vote for the 51st State Party?
57307685396df9190009612d
534
the party remains unregistered and cannot appear on a ballot.
115
Albania has often been called the 51st state for its perceived strongly pro-American positions, mainly because of the United States' policies towards it. In reference to President George W. Bush's 2007 European tour, Edi Rama, Tirana's mayor and leader of the opposition Socialists, said: "Albania is for sure the most pro-American country in Europe, maybe even in the world ... Nowhere else can you find such respect and hospitality for the President of the United States. Even in Michigan, he wouldn't be as welcome." At the time of ex-Secretary of State James Baker's visit in 1992, there was even a move to hold a referendum declaring the country as the 51st American state. In addition to Albania, Kosovo which is predominately Albanian is seen as a 51st state due to the heavily presence and influence of the United States. The US has had troops and the largest base outside US territory, Camp Bondsteel in the territory since 1999.
Who is the mayor of Tirana?
573076f78ab72b1400f9c514
217
Edi Rama,
116
Albania has often been called the 51st state for its perceived strongly pro-American positions, mainly because of the United States' policies towards it. In reference to President George W. Bush's 2007 European tour, Edi Rama, Tirana's mayor and leader of the opposition Socialists, said: "Albania is for sure the most pro-American country in Europe, maybe even in the world ... Nowhere else can you find such respect and hospitality for the President of the United States. Even in Michigan, he wouldn't be as welcome." At the time of ex-Secretary of State James Baker's visit in 1992, there was even a move to hold a referendum declaring the country as the 51st American state. In addition to Albania, Kosovo which is predominately Albanian is seen as a 51st state due to the heavily presence and influence of the United States. The US has had troops and the largest base outside US territory, Camp Bondsteel in the territory since 1999.
Who said that Albania is the most pro-American country in Europe?
573076f78ab72b1400f9c515
217
Edi Rama
117
Albania has often been called the 51st state for its perceived strongly pro-American positions, mainly because of the United States' policies towards it. In reference to President George W. Bush's 2007 European tour, Edi Rama, Tirana's mayor and leader of the opposition Socialists, said: "Albania is for sure the most pro-American country in Europe, maybe even in the world ... Nowhere else can you find such respect and hospitality for the President of the United States. Even in Michigan, he wouldn't be as welcome." At the time of ex-Secretary of State James Baker's visit in 1992, there was even a move to hold a referendum declaring the country as the 51st American state. In addition to Albania, Kosovo which is predominately Albanian is seen as a 51st state due to the heavily presence and influence of the United States. The US has had troops and the largest base outside US territory, Camp Bondsteel in the territory since 1999.
When did James Baker visit Albania as Secretary of State?
573076f78ab72b1400f9c516
580
1992
118
Albania has often been called the 51st state for its perceived strongly pro-American positions, mainly because of the United States' policies towards it. In reference to President George W. Bush's 2007 European tour, Edi Rama, Tirana's mayor and leader of the opposition Socialists, said: "Albania is for sure the most pro-American country in Europe, maybe even in the world ... Nowhere else can you find such respect and hospitality for the President of the United States. Even in Michigan, he wouldn't be as welcome." At the time of ex-Secretary of State James Baker's visit in 1992, there was even a move to hold a referendum declaring the country as the 51st American state. In addition to Albania, Kosovo which is predominately Albanian is seen as a 51st state due to the heavily presence and influence of the United States. The US has had troops and the largest base outside US territory, Camp Bondsteel in the territory since 1999.
What is the name of the largest US military base outside of US territory?
573076f78ab72b1400f9c517
895
Camp Bondsteel
119
During World War II, when Denmark was occupied by Nazi Germany, the United States briefly controlled Greenland for battlefields and protection. In 1946, the United States offered to buy Greenland from Denmark for $100 million ($1.2 billion today) but Denmark refused to sell it. Several politicians and others have in recent years argued that Greenland could hypothetically be in a better financial situation as a part of the United States; for instance mentioned by professor Gudmundur Alfredsson at University of Akureyri in 2014. One of the actual reasons behind US interest in Greenland could be the vast natural resources of the island. According to Wikileaks, the U.S. appears to be highly interested in investing in the resource base of the island and in tapping the vast expected hydrocarbons off the Greenlandic coast.
When did the US control Greenland?
573077742461fd1900a9ce35
21
when Denmark was occupied by Nazi Germany
120
During World War II, when Denmark was occupied by Nazi Germany, the United States briefly controlled Greenland for battlefields and protection. In 1946, the United States offered to buy Greenland from Denmark for $100 million ($1.2 billion today) but Denmark refused to sell it. Several politicians and others have in recent years argued that Greenland could hypothetically be in a better financial situation as a part of the United States; for instance mentioned by professor Gudmundur Alfredsson at University of Akureyri in 2014. One of the actual reasons behind US interest in Greenland could be the vast natural resources of the island. According to Wikileaks, the U.S. appears to be highly interested in investing in the resource base of the island and in tapping the vast expected hydrocarbons off the Greenlandic coast.
How much did the US offer to pay for Greenland?
573077742461fd1900a9ce36
213
$100 million
121
During World War II, when Denmark was occupied by Nazi Germany, the United States briefly controlled Greenland for battlefields and protection. In 1946, the United States offered to buy Greenland from Denmark for $100 million ($1.2 billion today) but Denmark refused to sell it. Several politicians and others have in recent years argued that Greenland could hypothetically be in a better financial situation as a part of the United States; for instance mentioned by professor Gudmundur Alfredsson at University of Akureyri in 2014. One of the actual reasons behind US interest in Greenland could be the vast natural resources of the island. According to Wikileaks, the U.S. appears to be highly interested in investing in the resource base of the island and in tapping the vast expected hydrocarbons off the Greenlandic coast.
What university is professor Gudmundur Alfredssson from?
573077742461fd1900a9ce37
501
University of Akureyri
122
During World War II, when Denmark was occupied by Nazi Germany, the United States briefly controlled Greenland for battlefields and protection. In 1946, the United States offered to buy Greenland from Denmark for $100 million ($1.2 billion today) but Denmark refused to sell it. Several politicians and others have in recent years argued that Greenland could hypothetically be in a better financial situation as a part of the United States; for instance mentioned by professor Gudmundur Alfredsson at University of Akureyri in 2014. One of the actual reasons behind US interest in Greenland could be the vast natural resources of the island. According to Wikileaks, the U.S. appears to be highly interested in investing in the resource base of the island and in tapping the vast expected hydrocarbons off the Greenlandic coast.
What is one reason the US would be interested in Greenland?
573077742461fd1900a9ce38
770
the vast expected hydrocarbons off the Greenlandic coast.
123
Poland has historically been staunchly pro-American, dating back to General Tadeusz Kościuszko and Casimir Pulaski's involvement in the American Revolution. This pro-American stance was reinforced following favorable American intervention in World War I (leading to the creation of an independent Poland) and the Cold War (culminating in a Polish state independent of Soviet influence). Poland contributed a large force to the "Coalition of the Willing" in Iraq. A quote referring to Poland as "the 51st state" has been attributed to James Pavitt, then Central Intelligence Agency Deputy Director for Operations, especially in connection to extraordinary rendition.
What had been Poland's stance towards the US, historically?
573077e1396df9190009613a
29
staunchly pro-American
124
Poland has historically been staunchly pro-American, dating back to General Tadeusz Kościuszko and Casimir Pulaski's involvement in the American Revolution. This pro-American stance was reinforced following favorable American intervention in World War I (leading to the creation of an independent Poland) and the Cold War (culminating in a Polish state independent of Soviet influence). Poland contributed a large force to the "Coalition of the Willing" in Iraq. A quote referring to Poland as "the 51st state" has been attributed to James Pavitt, then Central Intelligence Agency Deputy Director for Operations, especially in connection to extraordinary rendition.
What led to the creation of an independent Poland?
573077e1396df9190009613b
207
favorable American intervention in World War I
125
Poland has historically been staunchly pro-American, dating back to General Tadeusz Kościuszko and Casimir Pulaski's involvement in the American Revolution. This pro-American stance was reinforced following favorable American intervention in World War I (leading to the creation of an independent Poland) and the Cold War (culminating in a Polish state independent of Soviet influence). Poland contributed a large force to the "Coalition of the Willing" in Iraq. A quote referring to Poland as "the 51st state" has been attributed to James Pavitt, then Central Intelligence Agency Deputy Director for Operations, especially in connection to extraordinary rendition.
What did Poland contribute to the "Coalition of the Willing"?
573077e1396df9190009613c
406
a large force
126
The Party of Reconstruction in Sicily, which claimed 40,000 members in 1944, campaigned for Sicily to be admitted as a U.S. state. This party was one of several Sicilian separatist movements active after the downfall of Italian Fascism. Sicilians felt neglected or underrepresented by the Italian government after the annexation of 1861 that ended the rule of the Kingdom of the Two Sicilies based in Naples. The large population of Sicilians in America and the American-led Allied invasion of Sicily in July–August 1943 may have contributed to the sentiment.
How many members did the Party of Reconstruction in Sicily have in 1944?
573078662461fd1900a9ce3d
53
40,000 members
127
The Party of Reconstruction in Sicily, which claimed 40,000 members in 1944, campaigned for Sicily to be admitted as a U.S. state. This party was one of several Sicilian separatist movements active after the downfall of Italian Fascism. Sicilians felt neglected or underrepresented by the Italian government after the annexation of 1861 that ended the rule of the Kingdom of the Two Sicilies based in Naples. The large population of Sicilians in America and the American-led Allied invasion of Sicily in July–August 1943 may have contributed to the sentiment.
What did the Party of Reconstruction in Sicily campaign for?
573078662461fd1900a9ce3e
88
for Sicily to be admitted as a U.S. state
128
The Party of Reconstruction in Sicily, which claimed 40,000 members in 1944, campaigned for Sicily to be admitted as a U.S. state. This party was one of several Sicilian separatist movements active after the downfall of Italian Fascism. Sicilians felt neglected or underrepresented by the Italian government after the annexation of 1861 that ended the rule of the Kingdom of the Two Sicilies based in Naples. The large population of Sicilians in America and the American-led Allied invasion of Sicily in July–August 1943 may have contributed to the sentiment.
When did the Allied invasion of Sicily occur?
573078662461fd1900a9ce3f
504
July–August 1943
129
The Party of Reconstruction in Sicily, which claimed 40,000 members in 1944, campaigned for Sicily to be admitted as a U.S. state. This party was one of several Sicilian separatist movements active after the downfall of Italian Fascism. Sicilians felt neglected or underrepresented by the Italian government after the annexation of 1861 that ended the rule of the Kingdom of the Two Sicilies based in Naples. The large population of Sicilians in America and the American-led Allied invasion of Sicily in July–August 1943 may have contributed to the sentiment.
When did the annexation of Sicily by Italy happen?
573078662461fd1900a9ce40
332
1861
130
There are four categories of terra nullius, land that is unclaimed by any state: the small unclaimed territory of Bir Tawil between Egypt and Sudan, Antarctica, the oceans, and celestial bodies such as the Moon or Mars. In the last three of these, international treaties (the Antarctic Treaty, the United Nations Convention on the Law of the Sea, and the Outer Space Treaty respectively) prevent colonization and potential statehood of any of these uninhabited (and, given current technology, not permanently inhabitable) territories.
What are the four categories of terra nullius?
573078ee069b531400832103
81
the small unclaimed territory of Bir Tawil between Egypt and Sudan, Antarctica, the oceans, and celestial bodies
131
There are four categories of terra nullius, land that is unclaimed by any state: the small unclaimed territory of Bir Tawil between Egypt and Sudan, Antarctica, the oceans, and celestial bodies such as the Moon or Mars. In the last three of these, international treaties (the Antarctic Treaty, the United Nations Convention on the Law of the Sea, and the Outer Space Treaty respectively) prevent colonization and potential statehood of any of these uninhabited (and, given current technology, not permanently inhabitable) territories.
What three treaties exist for unclaimed lands?
573078ee069b531400832104
272
the Antarctic Treaty, the United Nations Convention on the Law of the Sea, and the Outer Space Treaty
132
There are four categories of terra nullius, land that is unclaimed by any state: the small unclaimed territory of Bir Tawil between Egypt and Sudan, Antarctica, the oceans, and celestial bodies such as the Moon or Mars. In the last three of these, international treaties (the Antarctic Treaty, the United Nations Convention on the Law of the Sea, and the Outer Space Treaty respectively) prevent colonization and potential statehood of any of these uninhabited (and, given current technology, not permanently inhabitable) territories.
What do the treaties defend against?
573078ee069b531400832105
388
prevent colonization and potential statehood of any of these uninhabited (and, given current technology, not permanently inhabitable) territories.
133
There are four categories of terra nullius, land that is unclaimed by any state: the small unclaimed territory of Bir Tawil between Egypt and Sudan, Antarctica, the oceans, and celestial bodies such as the Moon or Mars. In the last three of these, international treaties (the Antarctic Treaty, the United Nations Convention on the Law of the Sea, and the Outer Space Treaty respectively) prevent colonization and potential statehood of any of these uninhabited (and, given current technology, not permanently inhabitable) territories.
Where is Bir Tawil located?
573078ee069b531400832106
124
between Egypt and Sudan
0
An antenna (plural antennae or antennas), or aerial, is an electrical device which converts electric power into radio waves, and vice versa. It is usually used with a radio transmitter or radio receiver. In transmission, a radio transmitter supplies an electric current oscillating at radio frequency (i.e. a high frequency alternating current (AC)) to the antenna's terminals, and the antenna radiates the energy from the current as electromagnetic waves (radio waves). In reception, an antenna intercepts some of the power of an electromagnetic wave in order to produce a tiny voltage at its terminals, that is applied to a receiver to be amplified.
What device is able to change electric powerinto radio waves and also do the reverse?
572ef1abcb0c0d14000f168a
0
An antenna
1
An antenna (plural antennae or antennas), or aerial, is an electrical device which converts electric power into radio waves, and vice versa. It is usually used with a radio transmitter or radio receiver. In transmission, a radio transmitter supplies an electric current oscillating at radio frequency (i.e. a high frequency alternating current (AC)) to the antenna's terminals, and the antenna radiates the energy from the current as electromagnetic waves (radio waves). In reception, an antenna intercepts some of the power of an electromagnetic wave in order to produce a tiny voltage at its terminals, that is applied to a receiver to be amplified.
What device is often used in conjuntion with the antenna?
572ef1abcb0c0d14000f168b
167
radio transmitter or radio receiver
2
An antenna (plural antennae or antennas), or aerial, is an electrical device which converts electric power into radio waves, and vice versa. It is usually used with a radio transmitter or radio receiver. In transmission, a radio transmitter supplies an electric current oscillating at radio frequency (i.e. a high frequency alternating current (AC)) to the antenna's terminals, and the antenna radiates the energy from the current as electromagnetic waves (radio waves). In reception, an antenna intercepts some of the power of an electromagnetic wave in order to produce a tiny voltage at its terminals, that is applied to a receiver to be amplified.
What process associated with antennas produces a high frequency alternating current?
572ef1abcb0c0d14000f168c
207
transmission
3
An antenna (plural antennae or antennas), or aerial, is an electrical device which converts electric power into radio waves, and vice versa. It is usually used with a radio transmitter or radio receiver. In transmission, a radio transmitter supplies an electric current oscillating at radio frequency (i.e. a high frequency alternating current (AC)) to the antenna's terminals, and the antenna radiates the energy from the current as electromagnetic waves (radio waves). In reception, an antenna intercepts some of the power of an electromagnetic wave in order to produce a tiny voltage at its terminals, that is applied to a receiver to be amplified.
What else can radio waves be called?
572ef1abcb0c0d14000f168d
434
electromagnetic waves
4
An antenna (plural antennae or antennas), or aerial, is an electrical device which converts electric power into radio waves, and vice versa. It is usually used with a radio transmitter or radio receiver. In transmission, a radio transmitter supplies an electric current oscillating at radio frequency (i.e. a high frequency alternating current (AC)) to the antenna's terminals, and the antenna radiates the energy from the current as electromagnetic waves (radio waves). In reception, an antenna intercepts some of the power of an electromagnetic wave in order to produce a tiny voltage at its terminals, that is applied to a receiver to be amplified.
When does an antenna catch electromagnetic waves?
572ef1abcb0c0d14000f168e
474
reception
5
Typically an antenna consists of an arrangement of metallic conductors (elements), electrically connected (often through a transmission line) to the receiver or transmitter. An oscillating current of electrons forced through the antenna by a transmitter will create an oscillating magnetic field around the antenna elements, while the charge of the electrons also creates an oscillating electric field along the elements. These time-varying fields radiate away from the antenna into space as a moving transverse electromagnetic field wave. Conversely, during reception, the oscillating electric and magnetic fields of an incoming radio wave exert force on the electrons in the antenna elements, causing them to move back and forth, creating oscillating currents in the antenna.
What is frequently used to connect elements to the receiver?
572ef9b8c246551400ce4804
123
transmission line
6
Typically an antenna consists of an arrangement of metallic conductors (elements), electrically connected (often through a transmission line) to the receiver or transmitter. An oscillating current of electrons forced through the antenna by a transmitter will create an oscillating magnetic field around the antenna elements, while the charge of the electrons also creates an oscillating electric field along the elements. These time-varying fields radiate away from the antenna into space as a moving transverse electromagnetic field wave. Conversely, during reception, the oscillating electric and magnetic fields of an incoming radio wave exert force on the electrons in the antenna elements, causing them to move back and forth, creating oscillating currents in the antenna.
What particles are pushed through the antenna by a transmitter?
572ef9b8c246551400ce4805
200
electrons
7
Typically an antenna consists of an arrangement of metallic conductors (elements), electrically connected (often through a transmission line) to the receiver or transmitter. An oscillating current of electrons forced through the antenna by a transmitter will create an oscillating magnetic field around the antenna elements, while the charge of the electrons also creates an oscillating electric field along the elements. These time-varying fields radiate away from the antenna into space as a moving transverse electromagnetic field wave. Conversely, during reception, the oscillating electric and magnetic fields of an incoming radio wave exert force on the electrons in the antenna elements, causing them to move back and forth, creating oscillating currents in the antenna.
During transmission does the electric field wave move closer to the antenna?
572ef9b8c246551400ce4806
448
radiate away
8
Typically an antenna consists of an arrangement of metallic conductors (elements), electrically connected (often through a transmission line) to the receiver or transmitter. An oscillating current of electrons forced through the antenna by a transmitter will create an oscillating magnetic field around the antenna elements, while the charge of the electrons also creates an oscillating electric field along the elements. These time-varying fields radiate away from the antenna into space as a moving transverse electromagnetic field wave. Conversely, during reception, the oscillating electric and magnetic fields of an incoming radio wave exert force on the electrons in the antenna elements, causing them to move back and forth, creating oscillating currents in the antenna.
During what process would electrons be vacillating in the antenna?
572ef9b8c246551400ce4807
559
reception
9
The words antenna (plural: antennas in US English, although both "antennas" and "antennae" are used in International English) and aerial are used interchangeably. Occasionally the term "aerial" is used to mean a wire antenna. However, note the important international technical journal, the IEEE Transactions on Antennas and Propagation. In the United Kingdom and other areas where British English is used, the term aerial is sometimes used although 'antenna' has been universal in professional use for many years.
What is an acceptable synonym for antenna?
572efc88cb0c0d14000f16c4
130
aerial
10
The words antenna (plural: antennas in US English, although both "antennas" and "antennae" are used in International English) and aerial are used interchangeably. Occasionally the term "aerial" is used to mean a wire antenna. However, note the important international technical journal, the IEEE Transactions on Antennas and Propagation. In the United Kingdom and other areas where British English is used, the term aerial is sometimes used although 'antenna' has been universal in professional use for many years.
What can sometimes be meant by the term aerial specifically?
572efc88cb0c0d14000f16c5
212
wire antenna
11
The words antenna (plural: antennas in US English, although both "antennas" and "antennae" are used in International English) and aerial are used interchangeably. Occasionally the term "aerial" is used to mean a wire antenna. However, note the important international technical journal, the IEEE Transactions on Antennas and Propagation. In the United Kingdom and other areas where British English is used, the term aerial is sometimes used although 'antenna' has been universal in professional use for many years.
What is one way of referring to more than one antenna?
572efc88cb0c0d14000f16c6
81
antennae
12
The words antenna (plural: antennas in US English, although both "antennas" and "antennae" are used in International English) and aerial are used interchangeably. Occasionally the term "aerial" is used to mean a wire antenna. However, note the important international technical journal, the IEEE Transactions on Antennas and Propagation. In the United Kingdom and other areas where British English is used, the term aerial is sometimes used although 'antenna' has been universal in professional use for many years.
What is the most widely accepted term for an electrical device that converts electric power into radio waves?
572efc88cb0c0d14000f16c7
451
antenna
13
The origin of the word antenna relative to wireless apparatus is attributed to Italian radio pioneer Guglielmo Marconi. In the summer of 1895, Marconi began testing his wireless system outdoors on his father's estate near Bologna and soon began to experiment with long wire "aerials". Marconi discovered that by raising the "aerial" wire above the ground and connecting the other side of his transmitter to ground, the transmission range was increased. Soon he was able to transmit signals over a hill, a distance of approximately 2.4 kilometres (1.5 mi). In Italian a tent pole is known as l'antenna centrale, and the pole with the wire was simply called l'antenna. Until then wireless radiating transmitting and receiving elements were known simply as aerials or terminals.
Who is most associated with the emergence of the word antenna?
572eff08cb0c0d14000f16e6
101
Guglielmo Marconi
14
The origin of the word antenna relative to wireless apparatus is attributed to Italian radio pioneer Guglielmo Marconi. In the summer of 1895, Marconi began testing his wireless system outdoors on his father's estate near Bologna and soon began to experiment with long wire "aerials". Marconi discovered that by raising the "aerial" wire above the ground and connecting the other side of his transmitter to ground, the transmission range was increased. Soon he was able to transmit signals over a hill, a distance of approximately 2.4 kilometres (1.5 mi). In Italian a tent pole is known as l'antenna centrale, and the pole with the wire was simply called l'antenna. Until then wireless radiating transmitting and receiving elements were known simply as aerials or terminals.
When did experimentation with electromagnetic waves begin?
572eff08cb0c0d14000f16e7
137
1895
15
The origin of the word antenna relative to wireless apparatus is attributed to Italian radio pioneer Guglielmo Marconi. In the summer of 1895, Marconi began testing his wireless system outdoors on his father's estate near Bologna and soon began to experiment with long wire "aerials". Marconi discovered that by raising the "aerial" wire above the ground and connecting the other side of his transmitter to ground, the transmission range was increased. Soon he was able to transmit signals over a hill, a distance of approximately 2.4 kilometres (1.5 mi). In Italian a tent pole is known as l'antenna centrale, and the pole with the wire was simply called l'antenna. Until then wireless radiating transmitting and receiving elements were known simply as aerials or terminals.
What is a way to increase the strength of a radio transmission?
572eff08cb0c0d14000f16e8
312
raising the "aerial" wire
16
The origin of the word antenna relative to wireless apparatus is attributed to Italian radio pioneer Guglielmo Marconi. In the summer of 1895, Marconi began testing his wireless system outdoors on his father's estate near Bologna and soon began to experiment with long wire "aerials". Marconi discovered that by raising the "aerial" wire above the ground and connecting the other side of his transmitter to ground, the transmission range was increased. Soon he was able to transmit signals over a hill, a distance of approximately 2.4 kilometres (1.5 mi). In Italian a tent pole is known as l'antenna centrale, and the pole with the wire was simply called l'antenna. Until then wireless radiating transmitting and receiving elements were known simply as aerials or terminals.
How far was Marconi able to get his signal to go using this technique?
572eff08cb0c0d14000f16e9
547
1.5 mi
17
Antennas are required by any radio receiver or transmitter to couple its electrical connection to the electromagnetic field. Radio waves are electromagnetic waves which carry signals through the air (or through space) at the speed of light with almost no transmission loss. Radio transmitters and receivers are used to convey signals (information) in systems including broadcast (audio) radio, television, mobile telephones, Wi-Fi (WLAN) data networks, trunk lines and point-to-point communications links (telephone, data networks), satellite links, many remote controlled devices such as garage door openers, and wireless remote sensors, among many others. Radio waves are also used directly for measurements in technologies including radar, GPS, and radio astronomy. In each and every case, the transmitters and receivers involved require antennas, although these are sometimes hidden (such as the antenna inside an AM radio or inside a laptop computer equipped with Wi-Fi).
What is essential for the mating of the elements that create radio waves?
572f0580dfa6aa1500f8d575
0
Antennas
18
Antennas are required by any radio receiver or transmitter to couple its electrical connection to the electromagnetic field. Radio waves are electromagnetic waves which carry signals through the air (or through space) at the speed of light with almost no transmission loss. Radio transmitters and receivers are used to convey signals (information) in systems including broadcast (audio) radio, television, mobile telephones, Wi-Fi (WLAN) data networks, trunk lines and point-to-point communications links (telephone, data networks), satellite links, many remote controlled devices such as garage door openers, and wireless remote sensors, among many others. Radio waves are also used directly for measurements in technologies including radar, GPS, and radio astronomy. In each and every case, the transmitters and receivers involved require antennas, although these are sometimes hidden (such as the antenna inside an AM radio or inside a laptop computer equipped with Wi-Fi).
How fast are signals produced by antenna transmitted?
572f0580dfa6aa1500f8d576
225
speed of light
19
Antennas are required by any radio receiver or transmitter to couple its electrical connection to the electromagnetic field. Radio waves are electromagnetic waves which carry signals through the air (or through space) at the speed of light with almost no transmission loss. Radio transmitters and receivers are used to convey signals (information) in systems including broadcast (audio) radio, television, mobile telephones, Wi-Fi (WLAN) data networks, trunk lines and point-to-point communications links (telephone, data networks), satellite links, many remote controlled devices such as garage door openers, and wireless remote sensors, among many others. Radio waves are also used directly for measurements in technologies including radar, GPS, and radio astronomy. In each and every case, the transmitters and receivers involved require antennas, although these are sometimes hidden (such as the antenna inside an AM radio or inside a laptop computer equipped with Wi-Fi).
What is one system that uses electromagnetic waves?
572f0580dfa6aa1500f8d577
406
mobile telephones
20
Antennas are required by any radio receiver or transmitter to couple its electrical connection to the electromagnetic field. Radio waves are electromagnetic waves which carry signals through the air (or through space) at the speed of light with almost no transmission loss. Radio transmitters and receivers are used to convey signals (information) in systems including broadcast (audio) radio, television, mobile telephones, Wi-Fi (WLAN) data networks, trunk lines and point-to-point communications links (telephone, data networks), satellite links, many remote controlled devices such as garage door openers, and wireless remote sensors, among many others. Radio waves are also used directly for measurements in technologies including radar, GPS, and radio astronomy. In each and every case, the transmitters and receivers involved require antennas, although these are sometimes hidden (such as the antenna inside an AM radio or inside a laptop computer equipped with Wi-Fi).
What mobile locator and direction finder technology takes advantage of radio waves?
572f0580dfa6aa1500f8d578
743
GPS
21
Antennas are required by any radio receiver or transmitter to couple its electrical connection to the electromagnetic field. Radio waves are electromagnetic waves which carry signals through the air (or through space) at the speed of light with almost no transmission loss. Radio transmitters and receivers are used to convey signals (information) in systems including broadcast (audio) radio, television, mobile telephones, Wi-Fi (WLAN) data networks, trunk lines and point-to-point communications links (telephone, data networks), satellite links, many remote controlled devices such as garage door openers, and wireless remote sensors, among many others. Radio waves are also used directly for measurements in technologies including radar, GPS, and radio astronomy. In each and every case, the transmitters and receivers involved require antennas, although these are sometimes hidden (such as the antenna inside an AM radio or inside a laptop computer equipped with Wi-Fi).
What often inconspicuous part of a laptop computer allows for internet usage?
572f0580dfa6aa1500f8d579
841
antennas
22
One example of omnidirectional antennas is the very common vertical antenna or whip antenna consisting of a metal rod (often, but not always, a quarter of a wavelength long). A dipole antenna is similar but consists of two such conductors extending in opposite directions, with a total length that is often, but not always, a half of a wavelength long. Dipoles are typically oriented horizontally in which case they are weakly directional: signals are reasonably well radiated toward or received from all directions with the exception of the direction along the conductor itself; this region is called the antenna blind cone or null.
What is the main element of an omnidirectional antenna?
572f08f703f9891900756b4d
108
metal rod
23
One example of omnidirectional antennas is the very common vertical antenna or whip antenna consisting of a metal rod (often, but not always, a quarter of a wavelength long). A dipole antenna is similar but consists of two such conductors extending in opposite directions, with a total length that is often, but not always, a half of a wavelength long. Dipoles are typically oriented horizontally in which case they are weakly directional: signals are reasonably well radiated toward or received from all directions with the exception of the direction along the conductor itself; this region is called the antenna blind cone or null.
What type of antenna would most likely be a half a wavelength long?
572f08f703f9891900756b4e
177
dipole
24
One example of omnidirectional antennas is the very common vertical antenna or whip antenna consisting of a metal rod (often, but not always, a quarter of a wavelength long). A dipole antenna is similar but consists of two such conductors extending in opposite directions, with a total length that is often, but not always, a half of a wavelength long. Dipoles are typically oriented horizontally in which case they are weakly directional: signals are reasonably well radiated toward or received from all directions with the exception of the direction along the conductor itself; this region is called the antenna blind cone or null.
In which direction would you expect to find a dipole?
572f08f703f9891900756b4f
384
horizontally
25
One example of omnidirectional antennas is the very common vertical antenna or whip antenna consisting of a metal rod (often, but not always, a quarter of a wavelength long). A dipole antenna is similar but consists of two such conductors extending in opposite directions, with a total length that is often, but not always, a half of a wavelength long. Dipoles are typically oriented horizontally in which case they are weakly directional: signals are reasonably well radiated toward or received from all directions with the exception of the direction along the conductor itself; this region is called the antenna blind cone or null.
What is meant by the area where signals cannot be accepted well along the conductor?
572f08f703f9891900756b50
628
null
26
Both the vertical and dipole antennas are simple in construction and relatively inexpensive. The dipole antenna, which is the basis for most antenna designs, is a balanced component, with equal but opposite voltages and currents applied at its two terminals through a balanced transmission line (or to a coaxial transmission line through a so-called balun). The vertical antenna, on the other hand, is a monopole antenna. It is typically connected to the inner conductor of a coaxial transmission line (or a matching network); the shield of the transmission line is connected to ground. In this way, the ground (or any large conductive surface) plays the role of the second conductor of a dipole, thereby forming a complete circuit. Since monopole antennas rely on a conductive ground, a so-called grounding structure may be employed to provide a better ground contact to the earth or which itself acts as a ground plane to perform that function regardless of (or in absence of) an actual contact with the earth.
Are basic antennas expensive?
572f0de1dfa6aa1500f8d59b
69
relatively inexpensive
27
Both the vertical and dipole antennas are simple in construction and relatively inexpensive. The dipole antenna, which is the basis for most antenna designs, is a balanced component, with equal but opposite voltages and currents applied at its two terminals through a balanced transmission line (or to a coaxial transmission line through a so-called balun). The vertical antenna, on the other hand, is a monopole antenna. It is typically connected to the inner conductor of a coaxial transmission line (or a matching network); the shield of the transmission line is connected to ground. In this way, the ground (or any large conductive surface) plays the role of the second conductor of a dipole, thereby forming a complete circuit. Since monopole antennas rely on a conductive ground, a so-called grounding structure may be employed to provide a better ground contact to the earth or which itself acts as a ground plane to perform that function regardless of (or in absence of) an actual contact with the earth.
What is the foundation most often used when creating new antenna models?
572f0de1dfa6aa1500f8d59c
97
dipole antenna
28
Both the vertical and dipole antennas are simple in construction and relatively inexpensive. The dipole antenna, which is the basis for most antenna designs, is a balanced component, with equal but opposite voltages and currents applied at its two terminals through a balanced transmission line (or to a coaxial transmission line through a so-called balun). The vertical antenna, on the other hand, is a monopole antenna. It is typically connected to the inner conductor of a coaxial transmission line (or a matching network); the shield of the transmission line is connected to ground. In this way, the ground (or any large conductive surface) plays the role of the second conductor of a dipole, thereby forming a complete circuit. Since monopole antennas rely on a conductive ground, a so-called grounding structure may be employed to provide a better ground contact to the earth or which itself acts as a ground plane to perform that function regardless of (or in absence of) an actual contact with the earth.
What category do vertical antennas fall under?
572f0de1dfa6aa1500f8d59d
404
monopole antenna
29
Both the vertical and dipole antennas are simple in construction and relatively inexpensive. The dipole antenna, which is the basis for most antenna designs, is a balanced component, with equal but opposite voltages and currents applied at its two terminals through a balanced transmission line (or to a coaxial transmission line through a so-called balun). The vertical antenna, on the other hand, is a monopole antenna. It is typically connected to the inner conductor of a coaxial transmission line (or a matching network); the shield of the transmission line is connected to ground. In this way, the ground (or any large conductive surface) plays the role of the second conductor of a dipole, thereby forming a complete circuit. Since monopole antennas rely on a conductive ground, a so-called grounding structure may be employed to provide a better ground contact to the earth or which itself acts as a ground plane to perform that function regardless of (or in absence of) an actual contact with the earth.
What is used to close the circuit of a dipole antenna?
572f0de1dfa6aa1500f8d59e
619
large conductive surface
30
Antennas more complex than the dipole or vertical designs are usually intended to increase the directivity and consequently the gain of the antenna. This can be accomplished in many different ways leading to a plethora of antenna designs. The vast majority of designs are fed with a balanced line (unlike a monopole antenna) and are based on the dipole antenna with additional components (or elements) which increase its directionality. Antenna "gain" in this instance describes the concentration of radiated power into a particular solid angle of space, as opposed to the spherically uniform radiation of the ideal radiator. The increased power in the desired direction is at the expense of that in the undesired directions. Power is conserved, and there is no net power increase over that delivered from the power source (the transmitter.)
What are different designs aimed at increasing?
572f3f63947a6a140053c816
128
gain of the antenna
31
Antennas more complex than the dipole or vertical designs are usually intended to increase the directivity and consequently the gain of the antenna. This can be accomplished in many different ways leading to a plethora of antenna designs. The vast majority of designs are fed with a balanced line (unlike a monopole antenna) and are based on the dipole antenna with additional components (or elements) which increase its directionality. Antenna "gain" in this instance describes the concentration of radiated power into a particular solid angle of space, as opposed to the spherically uniform radiation of the ideal radiator. The increased power in the desired direction is at the expense of that in the undesired directions. Power is conserved, and there is no net power increase over that delivered from the power source (the transmitter.)
What is different from a monopole antenna with most other antenna types?
572f3f63947a6a140053c817
283
balanced line
32
Antennas more complex than the dipole or vertical designs are usually intended to increase the directivity and consequently the gain of the antenna. This can be accomplished in many different ways leading to a plethora of antenna designs. The vast majority of designs are fed with a balanced line (unlike a monopole antenna) and are based on the dipole antenna with additional components (or elements) which increase its directionality. Antenna "gain" in this instance describes the concentration of radiated power into a particular solid angle of space, as opposed to the spherically uniform radiation of the ideal radiator. The increased power in the desired direction is at the expense of that in the undesired directions. Power is conserved, and there is no net power increase over that delivered from the power source (the transmitter.)
Gain when referring to an antenna refers to what about radiated power?
572f3f63947a6a140053c818
483
concentration
33
Antennas more complex than the dipole or vertical designs are usually intended to increase the directivity and consequently the gain of the antenna. This can be accomplished in many different ways leading to a plethora of antenna designs. The vast majority of designs are fed with a balanced line (unlike a monopole antenna) and are based on the dipole antenna with additional components (or elements) which increase its directionality. Antenna "gain" in this instance describes the concentration of radiated power into a particular solid angle of space, as opposed to the spherically uniform radiation of the ideal radiator. The increased power in the desired direction is at the expense of that in the undesired directions. Power is conserved, and there is no net power increase over that delivered from the power source (the transmitter.)
Where is the power that is distributed originating from?
572f3f63947a6a140053c819
824
the transmitter
34
For instance, a phased array consists of two or more simple antennas which are connected together through an electrical network. This often involves a number of parallel dipole antennas with a certain spacing. Depending on the relative phase introduced by the network, the same combination of dipole antennas can operate as a "broadside array" (directional normal to a line connecting the elements) or as an "end-fire array" (directional along the line connecting the elements). Antenna arrays may employ any basic (omnidirectional or weakly directional) antenna type, such as dipole, loop or slot antennas. These elements are often identical.
How many antenna would make up a phased array?
572f425b04bcaa1900d767e9
41
two or more
35
For instance, a phased array consists of two or more simple antennas which are connected together through an electrical network. This often involves a number of parallel dipole antennas with a certain spacing. Depending on the relative phase introduced by the network, the same combination of dipole antennas can operate as a "broadside array" (directional normal to a line connecting the elements) or as an "end-fire array" (directional along the line connecting the elements). Antenna arrays may employ any basic (omnidirectional or weakly directional) antenna type, such as dipole, loop or slot antennas. These elements are often identical.
How are antennas oriented when arranged with specific spacing?
572f425b04bcaa1900d767ea
161
parallel
36
For instance, a phased array consists of two or more simple antennas which are connected together through an electrical network. This often involves a number of parallel dipole antennas with a certain spacing. Depending on the relative phase introduced by the network, the same combination of dipole antennas can operate as a "broadside array" (directional normal to a line connecting the elements) or as an "end-fire array" (directional along the line connecting the elements). Antenna arrays may employ any basic (omnidirectional or weakly directional) antenna type, such as dipole, loop or slot antennas. These elements are often identical.
What are the two standard antenna types?
572f425b04bcaa1900d767eb
516
omnidirectional or weakly directional
37
For instance, a phased array consists of two or more simple antennas which are connected together through an electrical network. This often involves a number of parallel dipole antennas with a certain spacing. Depending on the relative phase introduced by the network, the same combination of dipole antennas can operate as a "broadside array" (directional normal to a line connecting the elements) or as an "end-fire array" (directional along the line connecting the elements). Antenna arrays may employ any basic (omnidirectional or weakly directional) antenna type, such as dipole, loop or slot antennas. These elements are often identical.
What determines if the antenna creates a broadside array or an end fire array?
572f425b04bcaa1900d767ec
227
relative phase
38
However a log-periodic dipole array consists of a number of dipole elements of different lengths in order to obtain a somewhat directional antenna having an extremely wide bandwidth: these are frequently used for television reception in fringe areas. The dipole antennas composing it are all considered "active elements" since they are all electrically connected together (and to the transmission line). On the other hand, a superficially similar dipole array, the Yagi-Uda Antenna (or simply "Yagi"), has only one dipole element with an electrical connection; the other so-called parasitic elements interact with the electromagnetic field in order to realize a fairly directional antenna but one which is limited to a rather narrow bandwidth. The Yagi antenna has similar looking parasitic dipole elements but which act differently due to their somewhat different lengths. There may be a number of so-called "directors" in front of the active element in the direction of propagation, and usually a single (but possibly more) "reflector" on the opposite side of the active element.
What type of antenna formation is made up of multiple dipole elements of varying lengths?
572f4583947a6a140053c84a
10
log-periodic dipole array
39
However a log-periodic dipole array consists of a number of dipole elements of different lengths in order to obtain a somewhat directional antenna having an extremely wide bandwidth: these are frequently used for television reception in fringe areas. The dipole antennas composing it are all considered "active elements" since they are all electrically connected together (and to the transmission line). On the other hand, a superficially similar dipole array, the Yagi-Uda Antenna (or simply "Yagi"), has only one dipole element with an electrical connection; the other so-called parasitic elements interact with the electromagnetic field in order to realize a fairly directional antenna but one which is limited to a rather narrow bandwidth. The Yagi antenna has similar looking parasitic dipole elements but which act differently due to their somewhat different lengths. There may be a number of so-called "directors" in front of the active element in the direction of propagation, and usually a single (but possibly more) "reflector" on the opposite side of the active element.
What is the benefit of this formation type?
572f4583947a6a140053c84b
157
extremely wide bandwidth
40
However a log-periodic dipole array consists of a number of dipole elements of different lengths in order to obtain a somewhat directional antenna having an extremely wide bandwidth: these are frequently used for television reception in fringe areas. The dipole antennas composing it are all considered "active elements" since they are all electrically connected together (and to the transmission line). On the other hand, a superficially similar dipole array, the Yagi-Uda Antenna (or simply "Yagi"), has only one dipole element with an electrical connection; the other so-called parasitic elements interact with the electromagnetic field in order to realize a fairly directional antenna but one which is limited to a rather narrow bandwidth. The Yagi antenna has similar looking parasitic dipole elements but which act differently due to their somewhat different lengths. There may be a number of so-called "directors" in front of the active element in the direction of propagation, and usually a single (but possibly more) "reflector" on the opposite side of the active element.
What is the main application of these set ups?
572f4583947a6a140053c84c
213
television reception
41
However a log-periodic dipole array consists of a number of dipole elements of different lengths in order to obtain a somewhat directional antenna having an extremely wide bandwidth: these are frequently used for television reception in fringe areas. The dipole antennas composing it are all considered "active elements" since they are all electrically connected together (and to the transmission line). On the other hand, a superficially similar dipole array, the Yagi-Uda Antenna (or simply "Yagi"), has only one dipole element with an electrical connection; the other so-called parasitic elements interact with the electromagnetic field in order to realize a fairly directional antenna but one which is limited to a rather narrow bandwidth. The Yagi antenna has similar looking parasitic dipole elements but which act differently due to their somewhat different lengths. There may be a number of so-called "directors" in front of the active element in the direction of propagation, and usually a single (but possibly more) "reflector" on the opposite side of the active element.
What is a variation of this antenna type?
572f4583947a6a140053c84d
465
Yagi-Uda Antenna
42
At low frequencies (such as AM broadcast), arrays of vertical towers are used to achieve directionality and they will occupy large areas of land. For reception, a long Beverage antenna can have significant directivity. For non directional portable use, a short vertical antenna or small loop antenna works well, with the main design challenge being that of impedance matching. With a vertical antenna a loading coil at the base of the antenna may be employed to cancel the reactive component of impedance; small loop antennas are tuned with parallel capacitors for this purpose.
For radio broadcast that one would hear in their car what type of towers are used?
572f5908b2c2fd140056805b
53
vertical
43
At low frequencies (such as AM broadcast), arrays of vertical towers are used to achieve directionality and they will occupy large areas of land. For reception, a long Beverage antenna can have significant directivity. For non directional portable use, a short vertical antenna or small loop antenna works well, with the main design challenge being that of impedance matching. With a vertical antenna a loading coil at the base of the antenna may be employed to cancel the reactive component of impedance; small loop antennas are tuned with parallel capacitors for this purpose.
Why is this specific antenna type used?
572f5908b2c2fd140056805c
81
achieve directionality
44
At low frequencies (such as AM broadcast), arrays of vertical towers are used to achieve directionality and they will occupy large areas of land. For reception, a long Beverage antenna can have significant directivity. For non directional portable use, a short vertical antenna or small loop antenna works well, with the main design challenge being that of impedance matching. With a vertical antenna a loading coil at the base of the antenna may be employed to cancel the reactive component of impedance; small loop antennas are tuned with parallel capacitors for this purpose.
If one wished to take an antenna to different locations, which type would be best?
572f5908b2c2fd140056805d
256
short vertical antenna
45
At low frequencies (such as AM broadcast), arrays of vertical towers are used to achieve directionality and they will occupy large areas of land. For reception, a long Beverage antenna can have significant directivity. For non directional portable use, a short vertical antenna or small loop antenna works well, with the main design challenge being that of impedance matching. With a vertical antenna a loading coil at the base of the antenna may be employed to cancel the reactive component of impedance; small loop antennas are tuned with parallel capacitors for this purpose.
What is a problem one might encounter when using a portable antenna?
572f5908b2c2fd140056805e
358
impedance matching
46
An antenna lead-in is the transmission line (or feed line) which connects the antenna to a transmitter or receiver. The antenna feed may refer to all components connecting the antenna to the transmitter or receiver, such as an impedance matching network in addition to the transmission line. In a so-called aperture antenna, such as a horn or parabolic dish, the "feed" may also refer to a basic antenna inside the entire system (normally at the focus of the parabolic dish or at the throat of a horn) which could be considered the one active element in that antenna system. A microwave antenna may also be fed directly from a waveguide in place of a (conductive) transmission line.
What is mainly responsible for the connection of the antenna to its end destinations?
572f5a60b2c2fd140056806b
3
antenna lead-in
47
An antenna lead-in is the transmission line (or feed line) which connects the antenna to a transmitter or receiver. The antenna feed may refer to all components connecting the antenna to the transmitter or receiver, such as an impedance matching network in addition to the transmission line. In a so-called aperture antenna, such as a horn or parabolic dish, the "feed" may also refer to a basic antenna inside the entire system (normally at the focus of the parabolic dish or at the throat of a horn) which could be considered the one active element in that antenna system. A microwave antenna may also be fed directly from a waveguide in place of a (conductive) transmission line.
What is the group of elements used to join the elements of an antenna?
572f5a60b2c2fd140056806c
120
antenna feed
48
An antenna lead-in is the transmission line (or feed line) which connects the antenna to a transmitter or receiver. The antenna feed may refer to all components connecting the antenna to the transmitter or receiver, such as an impedance matching network in addition to the transmission line. In a so-called aperture antenna, such as a horn or parabolic dish, the "feed" may also refer to a basic antenna inside the entire system (normally at the focus of the parabolic dish or at the throat of a horn) which could be considered the one active element in that antenna system. A microwave antenna may also be fed directly from a waveguide in place of a (conductive) transmission line.
What are the type of antennas used with satellite television called?
572f5a60b2c2fd140056806d
307
aperture antenna
49
An antenna lead-in is the transmission line (or feed line) which connects the antenna to a transmitter or receiver. The antenna feed may refer to all components connecting the antenna to the transmitter or receiver, such as an impedance matching network in addition to the transmission line. In a so-called aperture antenna, such as a horn or parabolic dish, the "feed" may also refer to a basic antenna inside the entire system (normally at the focus of the parabolic dish or at the throat of a horn) which could be considered the one active element in that antenna system. A microwave antenna may also be fed directly from a waveguide in place of a (conductive) transmission line.
What can be used in place of a standard transmission line?
572f5a60b2c2fd140056806e
577
microwave antenna
50
Monopole antennas consist of a single radiating element such as a metal rod, often mounted over a conducting surface, a ground plane. One side of the feedline from the receiver or transmitter is connected to the rod, and the other side to the ground plane, which may be the Earth. The most common form is the quarter-wave monopole which is one-quarter of a wavelength long and has a gain of 5.12 dBi when mounted over a ground plane. Monopoles have an omnidirectional radiation pattern, so they are used for broad coverage of an area, and have vertical polarization. The ground waves used for broadcasting at low frequencies must be vertically polarized, so large vertical monopole antennas are used for broadcasting in the MF, LF, and VLF bands. Small monopoles are used as nondirectional antennas on portable radios in the HF, VHF, and UHF bands.
Monopole antennas consist of what element?
572fdec904bcaa1900d76e0d
66
metal rod
51
Monopole antennas consist of a single radiating element such as a metal rod, often mounted over a conducting surface, a ground plane. One side of the feedline from the receiver or transmitter is connected to the rod, and the other side to the ground plane, which may be the Earth. The most common form is the quarter-wave monopole which is one-quarter of a wavelength long and has a gain of 5.12 dBi when mounted over a ground plane. Monopoles have an omnidirectional radiation pattern, so they are used for broad coverage of an area, and have vertical polarization. The ground waves used for broadcasting at low frequencies must be vertically polarized, so large vertical monopole antennas are used for broadcasting in the MF, LF, and VLF bands. Small monopoles are used as nondirectional antennas on portable radios in the HF, VHF, and UHF bands.
What the most common form?
572fdec904bcaa1900d76e0e
309
quarter-wave monopole
52
Monopole antennas consist of a single radiating element such as a metal rod, often mounted over a conducting surface, a ground plane. One side of the feedline from the receiver or transmitter is connected to the rod, and the other side to the ground plane, which may be the Earth. The most common form is the quarter-wave monopole which is one-quarter of a wavelength long and has a gain of 5.12 dBi when mounted over a ground plane. Monopoles have an omnidirectional radiation pattern, so they are used for broad coverage of an area, and have vertical polarization. The ground waves used for broadcasting at low frequencies must be vertically polarized, so large vertical monopole antennas are used for broadcasting in the MF, LF, and VLF bands. Small monopoles are used as nondirectional antennas on portable radios in the HF, VHF, and UHF bands.
What are small monopoles used as?
572fdec904bcaa1900d76e0f
775
nondirectional antennas
53
Monopole antennas consist of a single radiating element such as a metal rod, often mounted over a conducting surface, a ground plane. One side of the feedline from the receiver or transmitter is connected to the rod, and the other side to the ground plane, which may be the Earth. The most common form is the quarter-wave monopole which is one-quarter of a wavelength long and has a gain of 5.12 dBi when mounted over a ground plane. Monopoles have an omnidirectional radiation pattern, so they are used for broad coverage of an area, and have vertical polarization. The ground waves used for broadcasting at low frequencies must be vertically polarized, so large vertical monopole antennas are used for broadcasting in the MF, LF, and VLF bands. Small monopoles are used as nondirectional antennas on portable radios in the HF, VHF, and UHF bands.
What has vertical polarization?
572fdec904bcaa1900d76e10
434
Monopoles
54
The most widely used class of antenna, a dipole antenna consists of two symmetrical radiators such as metal rods or wires, with one side of the balanced feedline from the transmitter or receiver attached to each. A horizontal dipole radiates in two lobes perpendicular to the antenna's axis. A half-wave dipole the most common type, has two collinear elements each a quarter wavelength long and a gain of 2.15 dBi. Used individually as low gain antennas, dipoles are also used as driven elements in many more complicated higher gain types of antennas.
What is the most widley used antenna class?
572fdefb947a6a140053cd8c
41
dipole antenna
55
The most widely used class of antenna, a dipole antenna consists of two symmetrical radiators such as metal rods or wires, with one side of the balanced feedline from the transmitter or receiver attached to each. A horizontal dipole radiates in two lobes perpendicular to the antenna's axis. A half-wave dipole the most common type, has two collinear elements each a quarter wavelength long and a gain of 2.15 dBi. Used individually as low gain antennas, dipoles are also used as driven elements in many more complicated higher gain types of antennas.
What radiates two lobes perpendicular to the antennas axis?
572fdefb947a6a140053cd8d
215
horizontal dipole
56
The most widely used class of antenna, a dipole antenna consists of two symmetrical radiators such as metal rods or wires, with one side of the balanced feedline from the transmitter or receiver attached to each. A horizontal dipole radiates in two lobes perpendicular to the antenna's axis. A half-wave dipole the most common type, has two collinear elements each a quarter wavelength long and a gain of 2.15 dBi. Used individually as low gain antennas, dipoles are also used as driven elements in many more complicated higher gain types of antennas.
Besides low gain antennas, what is also used as driven elements in complicated higher gain types of antennas?
572fdefb947a6a140053cd8e
455
dipoles
57
The most widely used class of antenna, a dipole antenna consists of two symmetrical radiators such as metal rods or wires, with one side of the balanced feedline from the transmitter or receiver attached to each. A horizontal dipole radiates in two lobes perpendicular to the antenna's axis. A half-wave dipole the most common type, has two collinear elements each a quarter wavelength long and a gain of 2.15 dBi. Used individually as low gain antennas, dipoles are also used as driven elements in many more complicated higher gain types of antennas.
How much gain does a half-wave dipole have?
572fdefb947a6a140053cd8f
405
2.15 dBi
58
A necessary condition for the aforementioned reciprocity property is that the materials in the antenna and transmission medium are linear and reciprocal. Reciprocal (or bilateral) means that the material has the same response to an electric current or magnetic field in one direction, as it has to the field or current in the opposite direction. Most materials used in antennas meet these conditions, but some microwave antennas use high-tech components such as isolators and circulators, made of nonreciprocal materials such as ferrite. These can be used to give the antenna a different behavior on receiving than it has on transmitting, which can be useful in applications like radar.
What must be true of the antenna and transmission medium for the repiprocity rule to apply ?
572fe7e6a23a5019007fcb1b
131
linear and reciprocal
59
A necessary condition for the aforementioned reciprocity property is that the materials in the antenna and transmission medium are linear and reciprocal. Reciprocal (or bilateral) means that the material has the same response to an electric current or magnetic field in one direction, as it has to the field or current in the opposite direction. Most materials used in antennas meet these conditions, but some microwave antennas use high-tech components such as isolators and circulators, made of nonreciprocal materials such as ferrite. These can be used to give the antenna a different behavior on receiving than it has on transmitting, which can be useful in applications like radar.
What is called when the direction of the elctrical current does not make a difference to the current?
572fe7e6a23a5019007fcb1c
154
Reciprocal
60
A necessary condition for the aforementioned reciprocity property is that the materials in the antenna and transmission medium are linear and reciprocal. Reciprocal (or bilateral) means that the material has the same response to an electric current or magnetic field in one direction, as it has to the field or current in the opposite direction. Most materials used in antennas meet these conditions, but some microwave antennas use high-tech components such as isolators and circulators, made of nonreciprocal materials such as ferrite. These can be used to give the antenna a different behavior on receiving than it has on transmitting, which can be useful in applications like radar.
What is one material that does not have this quality?
572fe7e6a23a5019007fcb1d
529
ferrite
61
A necessary condition for the aforementioned reciprocity property is that the materials in the antenna and transmission medium are linear and reciprocal. Reciprocal (or bilateral) means that the material has the same response to an electric current or magnetic field in one direction, as it has to the field or current in the opposite direction. Most materials used in antennas meet these conditions, but some microwave antennas use high-tech components such as isolators and circulators, made of nonreciprocal materials such as ferrite. These can be used to give the antenna a different behavior on receiving than it has on transmitting, which can be useful in applications like radar.
How can the lack of this quality be used in an everyday way?
572fe7e6a23a5019007fcb1e
680
radar
62
Antennas are characterized by a number of performance measures which a user would be concerned with in selecting or designing an antenna for a particular application. Chief among these relate to the directional characteristics (as depicted in the antenna's radiation pattern) and the resulting gain. Even in omnidirectional (or weakly directional) antennas, the gain can often be increased by concentrating more of its power in the horizontal directions, sacrificing power radiated toward the sky and ground. The antenna's power gain (or simply "gain") also takes into account the antenna's efficiency, and is often the primary figure of merit.
How could one deide what type of antenna is nedded for a project?
572fe81ab2c2fd14005685a9
42
performance measures
63
Antennas are characterized by a number of performance measures which a user would be concerned with in selecting or designing an antenna for a particular application. Chief among these relate to the directional characteristics (as depicted in the antenna's radiation pattern) and the resulting gain. Even in omnidirectional (or weakly directional) antennas, the gain can often be increased by concentrating more of its power in the horizontal directions, sacrificing power radiated toward the sky and ground. The antenna's power gain (or simply "gain") also takes into account the antenna's efficiency, and is often the primary figure of merit.
What would most likely be the main concern in making this decision?
572fe81ab2c2fd14005685aa
199
directional characteristics
64
Antennas are characterized by a number of performance measures which a user would be concerned with in selecting or designing an antenna for a particular application. Chief among these relate to the directional characteristics (as depicted in the antenna's radiation pattern) and the resulting gain. Even in omnidirectional (or weakly directional) antennas, the gain can often be increased by concentrating more of its power in the horizontal directions, sacrificing power radiated toward the sky and ground. The antenna's power gain (or simply "gain") also takes into account the antenna's efficiency, and is often the primary figure of merit.
How would you distribute power to allow for a greater gain?
572fe81ab2c2fd14005685ab
432
horizontal directions
65
Antennas are characterized by a number of performance measures which a user would be concerned with in selecting or designing an antenna for a particular application. Chief among these relate to the directional characteristics (as depicted in the antenna's radiation pattern) and the resulting gain. Even in omnidirectional (or weakly directional) antennas, the gain can often be increased by concentrating more of its power in the horizontal directions, sacrificing power radiated toward the sky and ground. The antenna's power gain (or simply "gain") also takes into account the antenna's efficiency, and is often the primary figure of merit.
What is often the most imprtant crediting factor of antennas?
572fe81ab2c2fd14005685ac
591
efficiency
66
Resonant antennas are expected to be used around a particular resonant frequency; an antenna must therefore be built or ordered to match the frequency range of the intended application. A particular antenna design will present a particular feedpoint impedance. While this may affect the choice of an antenna, an antenna's impedance can also be adapted to the desired impedance level of a system using a matching network while maintaining the other characteristics (except for a possible loss of efficiency).
Which antenna type would be best for a project requiring a specific frequency?
572fe85db2c2fd14005685b1
0
Resonant antennas
67
Resonant antennas are expected to be used around a particular resonant frequency; an antenna must therefore be built or ordered to match the frequency range of the intended application. A particular antenna design will present a particular feedpoint impedance. While this may affect the choice of an antenna, an antenna's impedance can also be adapted to the desired impedance level of a system using a matching network while maintaining the other characteristics (except for a possible loss of efficiency).
How could an antenna be made to coordinate with the needed frequency?
572fe85db2c2fd14005685b2
111
built or ordered
68
Resonant antennas are expected to be used around a particular resonant frequency; an antenna must therefore be built or ordered to match the frequency range of the intended application. A particular antenna design will present a particular feedpoint impedance. While this may affect the choice of an antenna, an antenna's impedance can also be adapted to the desired impedance level of a system using a matching network while maintaining the other characteristics (except for a possible loss of efficiency).
What factor would result in a desired feedback independence?
572fe85db2c2fd14005685b3
188
particular antenna design
69
Resonant antennas are expected to be used around a particular resonant frequency; an antenna must therefore be built or ordered to match the frequency range of the intended application. A particular antenna design will present a particular feedpoint impedance. While this may affect the choice of an antenna, an antenna's impedance can also be adapted to the desired impedance level of a system using a matching network while maintaining the other characteristics (except for a possible loss of efficiency).
If you were unable to choose the antenna you wanted how could you still achieve this result?
572fe85db2c2fd14005685b4
403
matching network
70
An antenna transmits and receives radio waves with a particular polarization which can be reoriented by tilting the axis of the antenna in many (but not all) cases. The physical size of an antenna is often a practical issue, particularly at lower frequencies (longer wavelengths). Highly directional antennas need to be significantly larger than the wavelength. Resonant antennas usually use a linear conductor (or element), or pair of such elements, each of which is about a quarter of the wavelength in length (an odd multiple of quarter wavelengths will also be resonant). Antennas that are required to be small compared to the wavelength sacrifice efficiency and cannot be very directional. Fortunately at higher frequencies (UHF, microwaves) trading off performance to obtain a smaller physical size is usually not required.
What is the essential difference in radio waves transmitted by an antenna?
572fe8da04bcaa1900d76e8b
64
polarization
71
An antenna transmits and receives radio waves with a particular polarization which can be reoriented by tilting the axis of the antenna in many (but not all) cases. The physical size of an antenna is often a practical issue, particularly at lower frequencies (longer wavelengths). Highly directional antennas need to be significantly larger than the wavelength. Resonant antennas usually use a linear conductor (or element), or pair of such elements, each of which is about a quarter of the wavelength in length (an odd multiple of quarter wavelengths will also be resonant). Antennas that are required to be small compared to the wavelength sacrifice efficiency and cannot be very directional. Fortunately at higher frequencies (UHF, microwaves) trading off performance to obtain a smaller physical size is usually not required.
How can this be adjusted more easily than changing antenna types?
572fe8da04bcaa1900d76e8c
104
tilting the axis
72
An antenna transmits and receives radio waves with a particular polarization which can be reoriented by tilting the axis of the antenna in many (but not all) cases. The physical size of an antenna is often a practical issue, particularly at lower frequencies (longer wavelengths). Highly directional antennas need to be significantly larger than the wavelength. Resonant antennas usually use a linear conductor (or element), or pair of such elements, each of which is about a quarter of the wavelength in length (an odd multiple of quarter wavelengths will also be resonant). Antennas that are required to be small compared to the wavelength sacrifice efficiency and cannot be very directional. Fortunately at higher frequencies (UHF, microwaves) trading off performance to obtain a smaller physical size is usually not required.
When might the size of an antenna cause an issue?
572fe8da04bcaa1900d76e8d
238
at lower frequencies
73
An antenna transmits and receives radio waves with a particular polarization which can be reoriented by tilting the axis of the antenna in many (but not all) cases. The physical size of an antenna is often a practical issue, particularly at lower frequencies (longer wavelengths). Highly directional antennas need to be significantly larger than the wavelength. Resonant antennas usually use a linear conductor (or element), or pair of such elements, each of which is about a quarter of the wavelength in length (an odd multiple of quarter wavelengths will also be resonant). Antennas that are required to be small compared to the wavelength sacrifice efficiency and cannot be very directional. Fortunately at higher frequencies (UHF, microwaves) trading off performance to obtain a smaller physical size is usually not required.
There is a relationship between the size of the antenna and the size of the wavelength with what antenna type?
572fe8da04bcaa1900d76e8e
281
Highly directional