106. Which of the following antennas is best excited from a waveguide?

1. 1. Biconical

   
   
   

   2. Horn

   
   
   

   3. Helical

   
   
   

   4. Discone

   
   
   

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1. View Hint View Answer Discuss in Forum

   Horn antennas is best excited from a waveguide

   Correct Option: B

   Horn antennas is best excited from a waveguide

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107. One of the following is very useful as a multiband HF receiving antenna. This is the—

1. 1. Conical horn

   
   
   

   2. Folded dipole

   
   
   

   3. Log-periodic

   
   
   

   4. Square loop

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: C

   NA

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108. One of the following consists of nonresonant antennas—

1. 1. The rhombic antenna

   
   
   

   2. The folded dipole

   
   
   

   3. The end-fire array

   
   
   

   4. The broadside array

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: A

   NA

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109. An ungrounded antenna near the ground—
     

1. 1. Acts as a single antenna of twice the height

   
   
   

   2. Is unlikely to need an earth mat

   
   
   

   3. Acts as an antenna array

   
   
   

   4. Must be horizontally polarized

   
   
   

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1. View Hint View Answer Discuss in Forum

   An ungrounded antenna near the ground acts as an antenna array.
   

   Correct Option: C

   An ungrounded antenna near the ground acts as an antenna array.
   

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110. Helical antennas are often used for satellite tracking at VHF because of—

1. 1. Troposcatter

   
   
   

   2. Superrefraction

   
   
   

   3. Ionospheric refraction

   
   
   

   4. The Faraday effect

   
   
   

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1. View Hint View Answer Discuss in Forum

   Helical antennas are often used for satellite tracking at VHF because of the Faraday effect.
   

   Correct Option: D

   Helical antennas are often used for satellite tracking at VHF because of the Faraday effect.
   

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