NTC - Amateur Class A Examination. Below are elements 8

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NTC - Class A amateur radio examination. Below are Elements 8, 9 and 10. 

6 AUGUST 2006 - 4F3EW

Part 1 of 2

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.	Approximate height of geostationary satellite from the earth's surface
Ans:  36,000 km

2.	What is the most affected frequency band by changes in solar cycle?
Ans: HF

3.	What is the impedance of a tuned RLC at resonance, circuit having the values as follows: R=100 ohms, X(subscript L) (XL) =200 ohms, X(subscript C) (XC) =200 ohms?
Ans: 100 Ohms

4.	In an ordinary hf transmitter the oscillator stage is normally followed by
Ans : Buffer

5.	What is the characteristic for Final Amplifier?
Ans: Stage in microwave transmitter 

6.	What would prevent thermal runaway of a transistor amplifier?
Ans: Bias Stabilization Amplification

7.	What is used as the transmission channel between the transmitter and the antenna in a microwave network?
Ans: Waveguide

8.	Beyond the Horizon Propagation is also known as 
Ans: Troposcatter

9.	Standard broadcast station (AM) uses this type of propagation for most of its signals .
Ans: Groundwave

10.	One of these is not a Hertz type antenna
Ans: AM broadcast tower antenna

11.	The main LC oscillators are the Harley and the 
Ans: Colpitts

12.	The angle between the half power radiation points of an antenna is
Ans: Beamwidth

13.	Antenna gains are measured with respect to
Ans: Isotropic radiator

 14.	The product of power fed to an antenna and its power gain is
Ans: Effective Radiated Power

15.	Field Strength of radiated waves is expressed in
Ans: Volts per meter

16.	Sun spot cycle refers to sun's temperature that varied and causing variations in the coupler. It  occurs normally every
Ans: 11th year

17.	HF uses what type of propagation
Ans: Skywave

18.	Grounded antennas are known as
Ans: Marconi antennas

19.	Satellites that are placed at the equatorial orbit are
Ans: Geostationary satellites

20.	In AM, the ration of the modulating voltage over the carrier voltage is
Ans: Modulation Index

21.	A3 modulation means the carrier is
Ans: Amplitude modulated by voice

22.	What is the highest radio frequency that will be refracted back to the earth called
Ans: Maximum useable frequency

23.	The kind of antenna that needs no grounding
Ans: Herz

24.	An electrical circuit having two identical inductors connected in series having a value equal to 40 millHenrys each is connected in parallel to another inductor whose value is 80mH.  What is the equivalent inductance of the combination!
Ans: 40mH

25. Three capacitors rated at 20, 30 and 60 micro farads are connected in series. Determine their equivalent total capacitance
Ans: 10 microfarads

26.	What is the amplification factor of a triode having a transconductance of  2.4 milliSiemens and a plate resistance of 16KOhm
Ans: 38.4

27.	Class C amplifiers are normally biased
Ans: Greater than the cut off value

28.	In a transistor circuit, the ratio of the common base emitter current to collector current is called
Ans: Alpha

29.	The change in plate current, divided by the change in grid voltage, keeping the plate resistance constant, is a vacuum tube characteristic known as
Ans: Transconductance

30.	Suppressor grids are found in this type of vacuum tube
Ans: Pentodes

31. Determine the resonant frequency of a tuned circuit whose inductance is 150 micro Henrys, and capacitance equal to 150Pf
Ans: 1.026MHz

32.	What is the voltage regulation of a power supply if the no load voltage is 1kv and the full loadvoltage is 1.2KV?
Ans: 20 percent

33.	Vhf frequency falls within the range
Ans: 30-300MHz

34.	The frequency band most useable for groundwave propagation
Ans: 300 - 3000KHz

35.	The magnification factor of a tuned circuit is also know as
Ans: The Q of the circuit

36.	The formula for solving the resonant frequency taking the value of the inductance and capacitance 
Ans: XsubscriptL = Xsubscript C (XL=XC)

37.	What is the frequency range of HF
Ans: 3 - 30 MHz

38.	What is the frequency range of vhf?
Ans: 30 - 300 MHz

39.	What is the frequency range of UHF?
Ans: 300 - 3000MHz

40.	What is the frequency range of MF
Ans: 300 - 3000KHz

41.In an electrical circuit Rsubscript1 (R1) and Rsubscript2 (R2) are connected in series. They are further connected to Rsubscript3 (R3) in parallel. A 240V source is connected across the combination.
       
Determine the following if Rsubscript1 is 100 Ohms, Rsubscript2 is 300 Ohms and Rsubscript3 is  100 Ohms. The total combine resistances of R1 R2 and R3 is

Ans: 80 Ohms

42.	What is the voltage drop across R1?
Ans: 60V

43.	What is the voltage drop across R2?
Ans: 180V