Comprehensive Certification Questions And
Correct Answers (Verified Answers) Plus
Rationales 2026 Q&A | Instant Download Pdf
1. What is the primary purpose of an antenna in a radio system?
A. To store electrical energy
B. To radiate and receive electromagnetic waves
C. To increase battery life
D. To amplify audio signals
The antenna’s main function is to convert electrical signals into
radio waves and vice-versa for communication.
2. What does SWR stand for?
A. Signal Wave Ratio
B. Standing Wave Ratio
C. Standard Wave Reflection
D. System Wave Rating
SWR measures impedance matching between transmission line
and antenna; a key parameter for efficient RF transfer.
,3. Which transmission line type has the lowest loss at VHF/UHF
frequencies?
A. Twin-lead
B. Heliax coaxial cable
C. 300-ohm ladder line
D. RG-58 coax
Heliax offers low attenuation and is preferred for longer runs at
VHF/UHF.
4. What is the characteristic impedance of most common coax used
in commercial installations?
A. 50 ohms
B. 50 or 75 ohms depending on application
C. 600 ohms
D. 12 ohms
Commercial RF systems use 50 Ω for two-way radio and 75 Ω for
broadcast TV.
5. What does “feedline loss” refer to?
A. Loss due to poor grounding
B. Loss of signal strength as RF travels along the line
C. Loss in antenna gain
, D. Loss in modulation quality
Feedline loss is signal attenuation along the transmission line.
6. What tool is used to measure SWR?
A. Multimeter
B. Frequency counter
C. SWR meter
D. Spectrum analyzer
An SWR meter measures forward and reflected power to
determine SWR.
7. Which of the following is a balanced transmission line?
A. RG-8X coax
B. 300-ohm twin-lead
C. Heliax
D. LMR-400
Balanced lines carry equal and opposite currents with no reference
to ground.
8. What happens when SWR is high?
A. Power increases
B. Greater reflected power and potential transmitter stress
C. Lower antenna gain
D. Reduced feedline length
, High SWR causes more reflected power, stressing the transmitter
and reducing efficiency.
9. What is the typical velocity factor of coaxial cable?
A. 10%
B. 50%
C. 60–90% depending on dielectric
D. 100%
Coax velocity factors vary with dielectric type, affecting electrical
length.
10. Which antenna type radiates energy equally in all horizontal
directions?
A. Yagi
B. Omnidirectional vertical
C. Log periodic
D. Patch
Omnidirectional vertical antennas radiate uniformly in the
horizontal plane.
11. A quarter-wave vertical antenna at 146 MHz is
approximately how tall?
A. 1 ft
B. 19–20 inches