21. Top loading is sometimes used with an antenna in order to increase its—

1. 1. Effective height

   
   
   

   2. Bandwidth

   
   
   

   3. Beamwidth

   
   
   

   4. Input capacitance

   
   
   

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1. View Hint View Answer Discuss in Forum

   Top loading is sometimes used with an antenna in order to increase its effective height.
   

   Correct Option: A

   Top loading is sometimes used with an antenna in order to increase its effective height.
   

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22. The standard reference antenna for the directive gain is the—

1. 1. Infinitesimal dipole

   
   
   

   2. Isotropic antenna

   
   
   

   3. Elementary doublet

   
   
   

   4. Half-wave dipole

   
   
   

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1. View Hint View Answer Discuss in Forum

   The standard reference antenna for the directive gain is the isotropic antenna.
   

   Correct Option: B

   The standard reference antenna for the directive gain is the isotropic antenna.
   

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23. An antenna that is circularly polarized is the—

1. 1. Helical

   
   
   

   2. Small circular loop

   
   
   

   3. Parabolic reflector

   
   
   

   4. Yagi-Uda

   
   
   

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1. View Hint View Answer Discuss in Forum

   An antenna that is circularly polarized is the helical.

   Correct Option: A

   An antenna that is circularly polarized is the helical.

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24. Which one of the following terms does not apply to the Yagi-Uda array?

1. 1. Good bandwidth

   
   
   

   2. Parasitic elements

   
   
   

   3. Folded dipole

   
   
   

   4. High gain

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: D

   NA

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25. Indicate which one of the following reasons for the use of an earth mat with antennas is false—

1. 1. Impossibility of a good ground connection

   
   
   

   2. Provision of an earth for the antenna

   
   
   

   3. Protection of personnel working underneath

   
   
   

   4. Improvement of the radiation pattern of the antenna

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: C

   NA

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