Q. In a reflex klystron oscillator, repeller electrode is at

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Q. A quarter wave line short circuited at load end behaves as

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Q. A (75 - J50) ohm load is connected to a coaxial of Z0 = 75 ohm at 10 GHz. The best method of matching is to connect

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Q. The width of a radio beam from a 1 m diameter parabolic antenna at 1 GHz is about

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Q. To couple a coaxial line to a parallel wire line it is best to use

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Q. Assertion (A): A quarter wave transformer is used to match a resistive load to a transmission line.

Reason (R): A quarter wave transformer is a transmission line of quarter wave length.

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Q. Assertion (A): Magnetron is generally used in n mode.

Reason (R): Frequency for π mode can be easily separated from adjacent modes.

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Q. A balun should have

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Q. Assertion (A): The velocity factor of a line is the ratio of wave velocity on the line to speed of light.

Reason (R): If the conductors of a line are immersed in a non magnetic insulating liquid, the wave velocity increases.

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Q. The directivity in a receiving antenna

1. increases the intercept area in forward direction
2. reduces the noise picked up from other sources
3. provides a means of discriminating against undesired signals originating in directions other than in which the desired transmitter lies.

Which of the above statements are correct?

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Q. Assertion (A): PIN diode can be used as attenuator and limiter.

Reason (R): PIN diode has a thin intrinsic layer.

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Q. The bunching action which occurs in multicavity klystron amplifier can be represented by Applegate diagram

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Q. The cut off wavelength in circular waveguide

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Q. In Reflex Klystron oscillator the focussing electrode is at a high potential

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Q. Consider the following statements:

1. Impedance of Gunn diode is about tens of ohms.
2. Impedance of Impatt diode is a few ohms.
3. Impedance of Impatt diode are of the same order.
4. Impedance of Impatt diode is more than that of Gunn diode.

Which of the above statement are correct?

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Q. In high frequency circuits impedance matching can be done by

1. open circuited stubs
2. short circuited stubs
3. λ/4 transformer

Which of the above correct?

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Q. The directive gain of a transmitting antenna is proportional to

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Q. In a loss line RL < Z0, then

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Q. Assertion (A): A backward wave oscillator can be used as a sweep generator.

Reason (R): The frequency of oscillation of a backward wave oscillator can be changed by varying the voltage which controls the beam velocity.

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Q. If a line having Z₀ = 300 ∠ 0 W is open circuited at far end, VSWR is

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