NTC - Amateur Class C Examination. Below are elements 4

1. Spectrum analyzers are used to present test signal in _________ .
ans  Frequency		

2. What instrument is used to present test signals in frequency domain?
ans  Spectrum analyzer		

3. Grid-dip meter
ans  Used for measuring resonant frequencies of radio frequency circuits
     
4. Signal generator
ans  Designed to produce AF & RF bands	           
		     			                 
5. To simulate speech signal in SSB communication, this test is used
ans  Two-tone test			

6. The origin of an interfering signal can be located with the use of direction finder by
ans  Triangulation		        

7. To generate pulsating DC voltage, what equipment is used?
 ans  Sweep generator	         		

8. What device is used to connect a balanced line to an unbalanced line?
ans  Balun			

9. Sweep generator is used to generate _________ .
ans  Pulsating DC voltage

10. Dummy antenna is used to 
ans  To prevent unnecessary radiation that may cause interfence

11. The stage in an SSB operational transmitting system where distortion most likely occurs
ans  Modulator
	           
12. What SWR among those mentioned shows the worst impedance match between 
transmission line and antenna?
ans  5:1			

13. Ability of a circuit to discriminate against different signals
 ans  Selectivity	          

14. What is the instrument that measure high and low states of ICs?
 ans  Logic probe
		
15. What is used to effect good impedance match between the transmitter and the antenna?
 ans  Antenna coupler	
	
16. Multi-element antenna provides high directivity aside from
ans  High gain

17. Instrument used to measure voltage in an electrical circuit
ans  Voltmeter		

18. Instrument used to monitor relative RF output during transmitter and antenna adjustments
ans  Grid-dip meter
		
19. Instrument used to measure electric power
ans  Wattmeter		

20. Instrument used to present test signals in frequency domain
ans  Spectrum analyzer		

21. Instrument used to measure resistance with value less than one ohm
ans  Wheatstone bridge

22. A Wheatstone bridge measures
ans  Resistance		        

23. Frequency band used by an AM broadcast station when the radio dial is 860 kHz
ans  Medium Frequency			

24. At frequency 144 MHz, operation is within
ans  VHF			

25. Frequency 430 MHz is within the frequency band called
ans  UHF			

26. Frequency 7.100 MHz is within the
ans  HF				

27. The frequency band most useful for SSB communications is
ans  HF	
	
28. What is the frequency being used for transmission when wavelength is 2 meters long?
ans  150 MHz		

29. If the operating frequency of your radio transmitter is on 7 MHz, the wavelength is 
approximately
ans  40m				

30. If the operating frequency is 150 MHz, the wavelength is
ans  2m		

31. Frequency of operations when the wavelength of the radio signal is one meter long
ans  300 MHz	

32. The wavelength of 150 MHz is
ans  2m	
	
33. What is the second harmonic of 1200 Hz?
ans  2400 Hz			

34. A device used to connect a balanced line to an unbalanced line
ans  Balun
	
35. Why are antenna coupler used?
ans  To effect good match between transmitter  and antenna  
		    		    
36. The origin of an interfering signal can be determined by triangulation using
ans  Radio direction finder

37. Connect a resistor in series with a meter to ________ the measuring range of a voltmeter.
ans   Increase		

38. Wires used in antennas and coils are stranded to prevent
ans  Skin effect
		
39. Tendency of RF current to flow along the surface of wire at high frequencies
ans  Skin effect