Which of the following statements about parabolic reflector systems are correct? 1. A front-fed shallow parabolic reflector antenna requires a feed horn with narrow radiation pattern relative to that for a deep dish 2. The noise temperature of a Cassegrain system is the highest when it looks at the horizon 3. The noise temperature of a front-fed parabolic antenna is the lowest when it looks at the Zenith 4. The sidelobe level of a parabolic reflector is highest for uniform aperture illumination Select the correct answer using the codes given below:

Which of the following statements about parabolic reflector systems ar

1.	Which of the following statements about parabolic reflector systems are correct? 1. A front-fed shallow parabolic reflector antenna requires a feed horn with narrow radiation pattern relative to that for a deep dish 2. The noise temperature of a Cassegrain system is the highest when it looks at the horizon 3. The noise temperature of a front-fed parabolic antenna is the lowest when it looks at the Zenith 4. The sidelobe level of a parabolic reflector is highest for uniform aperture illumination Select the correct answer using the codes given below:
A.	1, 2 and 3
B.	1, 3 and 4
C.	1, 2 and 4
D.	2, 3 and 4
Answer» D. 2, 3 and 4

Discussion

No Comment Found

Related MCQs

(A) The TW tube which is a wideband microwave amplifier of the helix is used as a slow wave structure of the device.(R) The phase velocity of the helix can be profiled along the length of the helix.
(A) The variables choosen for the equivalent circuit of a 2 port network in the microwave range of frequencies are travelling waves rather than total voltage and total currents. (R) In microwave range equipment is not readily available to measure total voltage and total currents at the ports of the networks. Short and open circuits are difficult to achieve over a broad-band of frequencies and active devices frequently will not have stability for a short or open circuit.
(A) In some applications, the TM01 mode in circular waveguide is preferred to the TE01 mode or TE11 mode. (R) TM01 mode not only overcomes the problem of rotation of polarisation in circular waveguide but also requires a smaller diameter.
(A) In an oscillation zone of reflex klystron an increase in the reflector voltage results in lighter oscillation frequency. (R) Electron bunches pass through the interaction gap before the retarding field is at a maximum and an increased reflector voltage results in the induced current lagging in voltage.
A 75 ohm transmission line is first short terminated and the minima locations are noted. When the short is replaced by a resistive load RL, the minima locations are not altered and the VSWR is measured to be 3. What is the value of RL?
A square waveguide carries TE11 mode whose axial magnetic field is given by:Hz = H0cos xcos yA/m 8 8Where the waveguide dimensions are in centimetres. What is the cut-off frequency of the mode?
Fig. shows five thin slots on the walls of a rectangular waveguide carrying TE10 mode. Which of these are radiating (R) and which are non-radiating (NR)?R NRA. D, E A, B, C B. A, B, C D, EC. C, EA, B, D D. B, C, E A, D
A microwave tube amplifier uses an axial magnetic field and a radial electric field. This is the:
One of the following microwave diodes is suitable for very low-power oscillators only:
A varactor diode may be useful at microwave frequencies (indicate the false answer):

Discussion

No Comment Found

Related MCQs

Reply to Comment