76. Wave guides are pressurised above normal atmospheric pressure for:
    

1. 1. Increasing their power handling capacity
      

   
   
   

   2. Improving the conductivity of their walls
      

   
   
   

   3. Preventing higher order modes from propagating
      

   
   
   

   4. Varying the wave impedence
      

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: C

   NA

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77. For a directional coupler the power is in the range of:
    

1. 1. 40 dB
      

   
   
   

   2. 30 dB
      

   
   
   

   3. 20 dB
      

   
   
   

   4. 10 dB

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: C

   NA

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78. The main advantage of the two hole directional coupler is:
    

1. 1. Low directional coupling
      

   
   
   

   2. High SWR
      

   
   
   

   3. Poor directivity
      

   
   
   

   4. Narrow bandwidth

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: D

   NA

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79. Which of the following is directly measured in sweep reflectometry?
    

1. 1. SWR
      

   
   
   

   2. Impedance
      

   
   
   

   3. Reflection Coefficient
      

   
   
   

   4. Return loss

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: D

   NA

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80. Most of the power measuring microwave devices measure:
    

1. 1. Average power
      

   
   
   

   2. Peak power
      

   
   
   

   3. Instantaneous power
      

   
   
   

   4. None of these

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: A

   NA

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