IT and Communications Engineer Examination Part 1

By: Firas Abbas

Please choose the most suitable answers from the following multiple choices answers. Note that each

question may have more than one correct answer:

1) The decibel unit (dB) is used to represent :

a) RF Signal Power

b) Attenuation factor

c) Amplification factor

d) Attenuation and amplification factors

e) IF Signals

2) Attenuation can be caused by :

a) Cables

b) Ground

c) Water

d) Air

e) All the above

3) 10Watt RF signal is passed through 6 dB attenuator, the output signal power is :

a) 10 Watt

b) 4 Watt

c) 4 dB

d) 5Watt

e) 2.5 Watt

f) 1.25 Watt

4) +20 dBm RF signal is passed through 13 dB amplifier, what is the output power of amplifier :

a) 33 dBm

b) 2 Watt

c) +7 dBm

d) 4 Watt

e) 33 dB

5) 50 Ohm amplifier is connected to 75 Ohm feeder, the system will have

a) Perfect matching

b) Gain of 125 dB

c) Impedance miss match

d) All the above

6) 0.5 Watt, 50 Ohm power Amplifier, means that the output signal level is :

a) 10 V RMS

b) 20 V RMS

c) 5 V RMS

d) 1 V RMS

e) 0.5 V RMS

7) 10 dBW means :

a) 10 Watt

b) 30 dBm

c) 40 dBm

d) 20 dBm

8) A 33 dBm amplifier is connected to 30m feeder with attenuation factor of 0.1 dB/m, and the

feeder is connected to a transmitting 1.8M dish with gain of 32 dB. What is the received RF

signal power input to the receiver connected to a 20 dB gain RX antenna and 20M feeder of

the same transmitting type? Note the free space loss is 100 dB:

a) - 23 dBm

b) -20 dB

c) +12 dB

d) -20 dBm

e) -48 dBm

9) What is the path loss that will be encountered to a signal with 10 GHz, traveling 100 Km

distance :

a) 120.5 dB

b) 152.5 dB

c) 33.5 dBm

d) 100.5 dB

e) 135.5 dB

10) A -125 dBm signal reached the input of -120 dBm sensitivity receiver, what is the output

power of the receiver :

a) +5 dBm

b) – 5dBm

c) 0 dBm

d) No output signal

e) All the above

11) A + 50 dBm signal at the output of a transmitting antenna experienced a 160 dB path loss in

traveling a certain distance and reached to a 30 dB gain receiving antenna connected to a total

4 dB attenuation cable and to -90 dBm sensitivity receiver, the signal is :

a) Can not be received

b) Can be received and demodulated

c) Very weak signal and out of receiver power range

d) All the above

12) What is the sensitivity of an RF receiver operating with 10 dB S/N ratio, 4 dB NF, and 10

KHz bandwidth :

a) -110 dBm

b) -130 dBm

c) -120 dBm

d) -128 dBm

13) The following cables has the associated impedance :

a) RG-8 50 Ohm

b) RG-6 75 Ohm

c) RG-6 50 Ohm

d) RG-11 50 Ohm

14) F type female connecter has :

a) 120 Ohm impendence

b) 50 Ohm impedance

c) 75 Ohm impedance

d) all the above

15) A 50 Ohm LNB is connected to 50 Ohm feeder, the VSWR is :

a) 100

b) 1.0

c) 1.6

d) infinity

16) A 13 GHz signal traveled towered sky satellite and retransmitted by that satellite towered the

earth but with 11.5 GHz frequency. What is the satellite down conversion factor?

a) 13 GHz

b) 2 GHz

c) 3.5 GHz

d) 1.5 GHz

17) Up converter has 13.050 GHz local oscillator used to frequency translate 1250 MHz IF signal,

what is the output of the of that converter:

a) 12250 MHz

b) 11800 MHz

c) 14300 MHz

d) 13300 MHz

18) 1 GHz IF signal is mixed with 10 GHz local oscillator signal without filtering, the out put of

the mixer is :

a) 1 GHz and 10 GHz signals

b) 11 GHz and 12 GHz signals

c) 9 GHz and 12 GHz

d) all the above

e) non of the above

19) L band modem means that the modem works in the frequency range :

a) 10.95 GHz to 11.7 GHz

b) 12.25 GHz t0 12.75 GHz

c) 12 GHz to 14 GHz

d) 0.95 GHz to 2.15 GHz

e) 0.95 GHz to 1.7 GHz

20) Extended Ku LNB works in the band :

a) 12.25 GHz to 12.75 GHz

b) 13 GHz to 14.5 GHz

c) 950 MHz to 2150 MHz

d) 10.95 GHz to 11.7 GHz

21) Standard Ku BUC works in the band :

a) 13.5 GHz to 14.25 GHz

b) 14 GHz to 14.25 GHz

c) 14 GHz to 14.5 GHz

d) 10.95 GHz to 11.7 GHz

22) VSAT is stands for :

a) Very small array modem

b) Very Large transmitting Antenna

c) Variable satellite angle system

d) Very small aperture terminal

23) VSAT system is consists of :

a) Modem

b) Feeders

c) LNB

d) BUC

e) Parabolic Antenna

f) Offset antenna

g) All the above

24) Offset antenna has 17 degree offset and the satellite elevation angle should be 50 degree, this

means:

a) The Antenna real elevation angle is 57 degree

b) The Antenna real elevation angle is 67 degree

c) The Antenna real elevation angle is 47 degree

d) The Antenna real elevation angle is 33 degree

25) CO-pole OMT means that:

a) LNB polarization is in phase with BUC polarization

b) IF LNB polarization is horizontal, BUC polarization will be horizontal too

c) IF BUC polarization is vertical, LNB polarization is vertical

d) IF BUC polarization is horizontal , LNB polarization is vertical

26) If LNB is vertically polarized in a cross pole OMT, the BUC polarization is :

a) Vertically polarized,

b) Depend on satellite location

c) Horizontally polarized

d) Depends on VSAT location

27) In pointing antenna dish towered a satellite, we need to know:

a) Elevation , azimuth, and polarization of the antenna

b) Satellite GEO location

c) VSAT GEO location

d) Antenna manufacturer

28) LNB is used for :

a) Received signal amplification

b) Received signal up conversion

c) Received signal down conversion

d) Received signal PLL

e) All the above

29) Extended Ku LNB has local oscillator :

a) 10 GHz

b) 13.050 GHz

c) 11300 MHz

d) 12800 MHz

30) The following types of LNBs are common:

a) PLL

b) Down converters

c) DRO

d) Up converters

e) BUC