ELEMENT 2 - TECHNICIAN CLASS


Question Pool

SUBELEMENT T9 -- ANTENNAS AND FEED LINES [2 Exam Questions -- 2 Groups] T9A Wavelength vs. antenna length; ½ wavelength dipole and ¼ wavelength vertical antennas; multiband antennas T9A01 (D)
How do you calculate the length (in feet) of a half-wavelength dipole antenna? A. Divide 150 by the antenna’s operating frequency (in MHz) [150/f(in MHz)]
B. Divide 234 by the antenna’s operating frequency (in MHz) [234/f (in MHz)]
C. Divide 300 by the antenna’s operating frequency (in MHz) [300/f (in MHz)] D. Divide 468 by the antenna’s operating frequency (in MHz) [468/f (in MHz)] T9A02 (B)
How do you calculate the length (in feet) of a quarter-wavelength vertical antenna? A. Divide 150 by the antenna’s operating frequency (in MHz) [150/f (in MHz)] B. Divide 234 by the antenna’s operating frequency (in MHz) [234/f (in MHz)] C. Divide 300 by the antenna’s operating frequency (in MHz) [300/f (in MHz)]
D. Divide 468 by the antenna’s operating frequency (in MHz) [468/f (in MHz)] T9A03 (C)
How long should you make a quarter-wavelength vertical antenna for 440 MHz (measured to the nearest inch)? A. 12 inches
B. 9 inches C. 6 inches D. 3 inches T9A04 (A)
How long should you make a quarter-wavelength vertical antenna for 28.450 MHz (measured to the nearest foot)? A. 8 ft B. 12 ft
C. 16 ft
D. 24 ft T9A05 (C)
How long should you make a quarter-wavelength vertical antenna for 146 MHz (measured to the nearest inch)? A. 112 inches
B. 50 inches C. 19 inches D. 12 inches T9A06 (A)
If an antenna is made longer, what happens to its resonant frequency? A. It decreases B. It increases
C. It stays the same
D. It disappears T9A07 (B)
If an antenna is made shorter, what happens to its resonant frequency? A. It decreases B. It increases C. It stays the same
D. It disappears T9A08 (A)
How could you decrease the resonant frequency of a dipole antenna? A. Lengthen the antenna B. Shorten the antenna
C. Use less feed line
D. Use a smaller size feed line T9A09 (B)
How could you increase the resonant frequency of a dipole antenna? A. Lengthen the antenna B. Shorten the antenna C. Use more feed line
D. Use a larger size feed line T9A10 (A)
What is one advantage to using a multiband antenna? A. You can operate on several bands with a single feed line B. Multiband antennas always have high gain
C. You can transmit on several frequencies simultaneously
D. Multiband antennas offer poor harmonic suppression T9A11 (D)
What is one disadvantage to using a multiband antenna? A. It must always be used with a balun
B. It will always have low gain
C. It cannot handle high power D. It can radiate unwanted harmonics T9B Parasitic beam directional antennas; polarization, impedance matching and SWR, feed lines, balanced vs. unbalanced (including baluns) T9B01 (C)
What is a directional antenna? A. An antenna that sends and receives radio energy equally well in all directions
B. An antenna that cannot send and receive radio energy by skywave or skip propagation C. An antenna that sends and receives radio energy mainly in one direction D. An antenna that uses a directional coupler to measure power transmitted T9B02 (A)
How is a Yagi antenna constructed? A. Two or more straight, parallel elements are fixed in line with each other B. Two or more square or circular loops are fixed in line with each other
C. Two or more square or circular loops are stacked inside each other
D. A straight element is fixed in the center of three or more elements that angle toward the ground T9B03 (B)
How many directly driven elements do most parasitic beam antennas have? A. None B. One C. Two
D. Three T9B04 (A)
What is a parasitic beam antenna? A. An antenna in which some elements obtain their radio energy by induction or radiation from a driven element B. An antenna in which wave traps are used to magnetically couple the elements
C. An antenna in which all elements are driven by direct connection to the feed line
D. An antenna in which the driven element obtains its radio energy by induction or radiation from director elements T9B05 (D)
What are the parasitic elements of a Yagi antenna? A. The driven element and any reflectors
B. The director and the driven element
C. Only the reflectors (if any) D. Any directors or any reflectors T9B06 (B)
What is a cubical quad antenna? A. Four straight, parallel elements in line with each other, each approximately ½-electrical wavelength long B. Two or more parallel four-sided wire loops, each approximately one-electrical wavelength long C. A vertical conductor ¼-electrical wavelength high, fed at the bottom
D. A center-fed wire ½-electrical wavelength long T9B07 (D)
What type of non-directional antenna is easy to make at home and works well outdoors? A. A Yagi
B. A delta loop
C. A cubical quad D. A ground plane T9B08 (D)
What electromagnetic-wave polarization does most man-made electrical noise have in the HF and VHF spectrum? A. Horizontal
B. Left-hand circular
C. Right-hand circular D. Vertical T9B09 (D)
What does standing-wave ratio mean? A. The ratio of maximum to minimum inductances on a feed line
B. The ratio of maximum to minimum capacitances on a feed line
C. The ratio of maximum to minimum impedances on a feed line D. The ratio of maximum to minimum voltages on a feed line T9B10 (A)
Where would you install a balun to feed a dipole antenna with 50-ohm coaxial cable? A. Between the coaxial cable and the antenna B. Between the transmitter and the coaxial cable
C. Between the antenna and the ground
D. Between the coaxial cable and the ground T9B11 (B)
Why does coaxial cable make a good antenna feed line? A. You can make it at home, and its impedance matches most amateur antennas B. It is weatherproof, and it can be used near metal objects C. It is weatherproof, and its impedance is higher than that of most amateur antennas
D. It can be used near metal objects, and its impedance is higher than that of most amateur antennas

END OF SUB-ELEMENT T9