NTC - Amateur Class B Examination. Below are elements 5

NTC - Class B amateur radio examination. Below is Element 5, also see Elements 6 and 7

1 December 2006 - 4F3EW

See the PARA handbook "So You Want to be a Ham".

These are sample questions which may come up in the above exam. The correct answer (Ans.) is given under the question number and there could be errors.


1.If the radiation resistance of the antenna is 5000 ohms, the power radiated is 125 
           kilowatts, what is the antenna current?
Ans. 5 A

1. Ratio of the maximum deviation to modulating frequency
Ans. modulation index

2. An example of the worst kind of antenna and transmission matching is shown by SWR reading
Ans. 1:1000

3. Undesired oscillations developed in RF amplifier circuit at some frequency higher than normal operating frequency
Ans. parasitic

4. UHF frequency falls within the band
Ans. 300-3000 MHz

5. If a 10 kHz tone is transmitted and the modulation index is 7.5, what is value of maximum deviation?
Ans. 75 kHz

6. To overcome language barrier ______ is used
Ans. Q code

7. The actual length of the radiating element in a Marconi antenna is
Ans. one-quarter

8. A device used for producing FM in transmitter
Ans. reactance modulator

9. Frequency bands used mostly for groundwave propagation such as AM broadcast stations
Ans. 300-3000 kHz

10. Any unwanted form of energy tending to interfere with the proper and easy reception and reproduction of wanted signals
Ans. noise

11. The use of ionosphere in wave propagation utilizes mostly this kind of radio wave
Ans. sky waves

12. Microwave propagation makes use of
Ans. space wave

13. The three basic parts of transistors is base, collector and 
Ans. emitter

14. Communication involving distress should not exceed
Ans. 16 wpm

15. In radioteletype transmission, either ASCII or ________ is used
Ans. Baudot

16.The majority carrier in P-type semiconductor materials are
Ans. holes

16. The power formula is
Ans. P=EI  or P=I(raise to 2)R

17. What is the ratio of collector current to base current of a transistor?
Ans. Beta

18. Half-power points are also known as
Ans. 3 db points

19. Emission of an unmodulated carrier
Ans. N

20. Emission in which the wave carrier is amplitude modulated, single side band (SSB) reduced carrier
Ans. R

21. Emission in which wave carrier is amplitude modulated SSB, vestigial sidebands
Ans. C

22. Emission in which the wave carrier is amplitude modulated, full carrier
Ans.  A

23. The root-mean-square (RMS) value of a sine wave form is equal to
Ans. 70.7 percent of the peak value of the wave

24. What is the ratio of unmodulated carrier power to instantaneous peak power at 100% modulation?
Ans. 25 percent

25. What is the operating frequency of the transceiver if the radio wave is 6 meters long?
Ans. 50 MHz

26. The frequency band most suitable for propagation using the ionosphere is
Ans. HF

27. Ratio of maximum deviation allowed to the modulating frequency is
Ans. modulation index

28. The most ideal SWR in VHF communications
Ans. unity SWR or 1:1 SWR

29. Second harmonic of 500 kHz
Ans. 1000 kHz

30. Two forms of angle modulation are frequency modulation and ________ modulation
Ans. phase

31. F3 emission means carrier is
Ans. frequency modulated by voice

32. To overcome difficulty in spelling, the _____ is used
Ans. phonetic alphabet

33. Which diodes are normally reversed biased?
Ans. Zener diode

34.The symbol used for current amplification factor of transistors is
Ans. beta

34. A circuit element that opposes change in current
Ans. inductor

35. Radiation occurring on frequencies which are whole multiple of the original desired frequency is called
Ans. harmonic

36. Undesired oscillations developed in a radio frequency amplifier circuit at some frequency are called
Ans. parasitic

37. Ideal value of signal to noise ratio
Ans. infinity

38. Frequency range between two half-power points is
Ans. bandwidth

39. How long is the antenna using a frequency which is the 2nd harmonic of the frequency of one meter antenna?
Ans. 0.50 meter

40. The sum of the carrier frequency and the sideband frequency of an amplitude modulated carrier signal 
And. Upperside bands

41. If you decrease the percentage of modulation from 100% to 50%, by what % have you decreased the power in the sidebands?
Ans. 25

42. A frequency band most suitable for groundwave propagation
Ans. MF

43. The frequency bands normally used for the line of sight (LOS) propagation
Ans. 30-300 MHz

44. What emission designation is one in which the main carrier is frequency modulated, while modulated by a single channel containing quantized information without the use of a modulating subcarrrier?
Ans. Fsubscript(1)

45. Polarization of antenna used in high frequency propagation is normally
Ans. horizontal

46. Balanced modulator is a device used to
Ans. suppress the carrier in SSB transmitter

47. A frequency of a transmitted signal wherein the reflected signals disappear and are no longer reflected back to earth
Ans. critical frequency

48. Another name for indirect FM
Ans. Phase modulation

49. Radiation occurring on frequencies which a whole or multiple of occupied divided frequency is called
Ans. Harmonic

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