126. In both the sequential-lobing and conical-scan tracking techniques of radar, the measurements of angular errors in two orthogonal coordinates (azimuth and elevation) require that a minimum of:
     

1. 1. Three pulses be processed
      

   
   
   

   2. Two pulses be processed
      

   
   
   

   3. Four pulses be processed
      

   
   
   

   4. Only one pulse be processed

   
   
   

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   NA

   Correct Option: C

   NA

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127. Noise temperature (T) and gain (G) are two important parameters of satellite antennas. Which one of the following antennas has the largest G/T radio?
     

1. 1. Parabolic reflector
      

   
   
   

   2. Cassegranian antenna
      

   
   
   

   3. Pyramidal horn antenna
      

   
   
   

   4. Dipole antenna

   
   
   

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   NA

   Correct Option: C

   NA

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128. In antenna measurements using two aperture antennas of dimensions D₁ and D₂, the minimum separation between the two should be (λ is the free-space wavelength of radiation used):
     

1. 1. (D1 + D2)/(2λ)
      

   
   
   

   2. (D1² + D2²)/(8λ)
      

   
   
   

   3. (D1² + D2²)/(λ)
      

   
   
   

   4. (D1²·D2 ²)/(2λ)

   
   
   

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   NA

   Correct Option: D

   NA

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129. When electromotive waves travel along a metallic waveguide in which there is a discontinuity due to some lossy material field in a small length and the other end is terminated with a matched load, the discontinuing will cause:
     

1. 1. Progressive waves throughout the line
      

   
   
   

   2. Standing waves on the generator side and progressive waves on the matched load line
      

   
   
   

   3. Progressive waves on the generator side and standing waves on the load side.

   
   
   

   4. Standing waves throughout the line
      

   
   
   

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   NA

   Correct Option: A

   NA

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130. The skin depth at 1000 MHz, in comparison with that at 500 MHz is:
     

1. 1. 2
      

   
   
   

   2. 1/√2
      

   
   
   

   3. √2
      

   
   
   

   4. 1/2

   
   
   

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   NA

   Correct Option: C

   NA

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