An antenna that radiates 5 KW in its optimum direction and 50 watts in the opposite direction has a front to back ratio of

1.   20 dB

2.  40 dB

3.  10 dB

4.  None of these

4

20 dB

Explanation :
No Explanation available for this question

A linear time invariatiant system has an impulse response , t>0. If the initial conditions are zero and the input is , the output for t >0 is

1.

2.

3.

4.  None of these

4

Explanation :
No Explanation available for this question

If U be the unit step function, then which of the following waveform will be convolution of u(t)-u(t-1) with U(t)- U(t-2)

1.

2.

3.

4.

4

Explanation :
No Explanation available for this question

In a two-port network containing linear bilateral passive circuit elements, which one of the following conditions for Z-parameters would hold

1.  Z11 = Z12

2.  Z12Z21 = Z11Z22

3.  Z11 Z12 = Z22 Z21

4.  Z12 = Z21

4

Z11 = Z12

Explanation :
No Explanation available for this question

A resonant antenna is a system with

1.  Zero SWR

2.   A very high SWR

3.  A very low SWR

4.  None of these

4

A very high SWR

Explanation :
No Explanation available for this question

Figure eight directional pattern

1.  Figure eight directional pattern

2.  Pencil beam directional pattern

3.  Circular directional pattern

4.  None of these

4

Circular directional pattern

Explanation :
No Explanation available for this question

Effective a radiated power (ERP) of an antenna which receives 1 KW from the transmitter and has a power gain of 10 dB in the desired direction is

1.  10 KW

2.  2 KW

3.  10 KW

4.  None of these

4

10 KW

Explanation :
No Explanation available for this question

The radiation resistance of a long wire resonant antenna (5 λ) long will be

1.  73 Ω

2.  142 Ω

3.  365 Ω

4.  730 Ω

4

142 Ω

Explanation :
No Explanation available for this question

The dual of the network shown in the figure.

1.

2.

3.

4.

4

Explanation :
No Explanation available for this question

The effective height of an antenna is slightly greater than physical height because

1.  Wave velocity in conductor is less than its velocity in free space

2.  Wave velocity in conductor is more than its velocity in free space

3.  Resistance of conductor is less than that of free space

4.  None of the above

4