Rainfall is an important factor for fading of radio waves at frequencies above 100 MHz 100 GHz 10 GHz 1 GHz TRUE ANSWER : ? YOUR ANSWER : ?
Theoretically electromagnetic radiation field strength varies in inverse proportion to the square of the distance, but when atmospheric attenuation effects and the absorption of the terrain are taken into account the attenuation can be as high as the inverse ___________ power of the distance. Fourth Sixth Fifth Third TRUE ANSWER : ? YOUR ANSWER : ?
At what position is the input signal inserted into a traveling-wave tube? At the cathode end of the helix At the collector end of the helix At the collector At the control grid of the electron gun TRUE ANSWER : ? YOUR ANSWER : ?
A magnetron is operated at a duty cycle of 0.001. It has a peak power output of 100 kilo-watts. Its average power is 100 watts 1,000 watts 1,000,000 watts 10,000 watts TRUE ANSWER : ? YOUR ANSWER : ?
A thin layer of dirt and grime coverts the reflecting surface of the parabolic dish of a radar set. The particular effect on the performance of the radar will be A decrease in gain A reduction in horizontal resolution No noticeable effect A decrease in range TRUE ANSWER : ? YOUR ANSWER : ?
In a pulsed radar set, the function of the duplexer is to Allow the transmitter and the receiver to operate from a common antenna Aid in calibrating the display unit All of these Prevent frequency drift in the klystron TRUE ANSWER : ? YOUR ANSWER : ?
The highest frequency which a conventional vacuum tube oscillator can generate is not limited by the Distributed lead inductance Inter-electrode capacitance Degree of emission from the cathode Electron transit time TRUE ANSWER : ? YOUR ANSWER : ?
The maximum usable range of the usual radar set (on any particular range setting) is determined by The duty cycle The bandwidth of the receiver IF stages The width of the transmitted pulses The interval between transmitted pulses TRUE ANSWER : ? YOUR ANSWER : ?
Which of the following operating frequencies is used for the modern loran navigational system? Loran B: 900 kHz Loran D: 10.2 kHz Loran C: 100 kHz Loran A: 1950 kHz TRUE ANSWER : ? YOUR ANSWER : ?
If the duration of the radar transmitted pulse, on a particular range of operation, is increased, the required bandwidth of the receiver’s IF amplifiers Must be increased Must be doubled May be decreased Must remain as before TRUE ANSWER : ? YOUR ANSWER : ?