G9 - Antennas 1 G9 – Antennas and Feedlines [4 exam questions - 4 groups] G9A - Antenna feed...

G9 - Antennas1

G9 – Antennas and FeedlinesG9 – Antennas and Feedlines[4 exam questions - 4 groups][4 exam questions - 4 groups]

G9A - Antenna feed lines: characteristic G9A - Antenna feed lines: characteristic impedance and attenuation; SWR impedance and attenuation; SWR calculation, measurement and effects; calculation, measurement and effects; matching networksmatching networks

G9B - Basic antennasG9B - Basic antennas

G9C - Directional antennasG9C - Directional antennas

G9D - Specialized antennasG9D - Specialized antennas

G9 - Antennas2

FeedlinesFeedlines

G9 - Antennas3

Coax Cable Signal Loss (Attenuation) in dB per 100ft

Loss RG-174 RG-58 RG-8X RG-213 RG-6 RG-11 9913 LMR-400

1MHz 1.9dB 0.4dB 0.5dB 0.2dB 0.2dB 0.2dB 0.2dB 0.3dB








1GHz 32.0dB 21.5dB 13.5dB 8.3dB 6.1dB 5.6dB 4.5dB 4.1dB

Imped 50ohm 50ohm 50ohm 50ohm 75ohm 75ohm 50ohm 50ohm

G9 - Antennas4

Standing WavesStanding Waves

G9A01 Which of the following factors G9A01 Which of the following factors determine the characteristic impedance determine the characteristic impedance of a parallel conductor antenna feed line?of a parallel conductor antenna feed line?

A. The distance between the centers of the A. The distance between the centers of the conductors and the radius of the conductorsconductors and the radius of the conductors

B. The distance between the centers of the B. The distance between the centers of the conductors and the length of the lineconductors and the length of the line

C. The radius of the conductors and the C. The radius of the conductors and the frequency of the signalfrequency of the signal

D. The frequency of the signal and the length D. The frequency of the signal and the length of the lineof the line

5 G9 - Antennas

G9A01 Which of the following factors G9A01 Which of the following factors determine the characteristic impedance determine the characteristic impedance of a parallel conductor antenna feed line?of a parallel conductor antenna feed line?

A. The distance between the centers of the A. The distance between the centers of the conductors and the radius of the conductorsconductors and the radius of the conductors

B. The distance between the centers of the B. The distance between the centers of the conductors and the length of the lineconductors and the length of the line

C. The radius of the conductors and the C. The radius of the conductors and the frequency of the signalfrequency of the signal

D. The frequency of the signal and the length D. The frequency of the signal and the length of the lineof the line

6 G9 - Antennas

G9A02 What are the typical characteristic G9A02 What are the typical characteristic impedances of coaxial cables used for impedances of coaxial cables used for antenna feed lines at amateur stations?antenna feed lines at amateur stations?

A. 25 and 30 ohmsA. 25 and 30 ohms

B. 50 and 75 ohmsB. 50 and 75 ohms

C. 80 and 100 ohmsC. 80 and 100 ohms

D. 500 and 750 ohmsD. 500 and 750 ohms

7 G9 - Antennas

G9A02 What are the typical characteristic G9A02 What are the typical characteristic impedances of coaxial cables used for impedances of coaxial cables used for antenna feed lines at amateur stations?antenna feed lines at amateur stations?

A. 25 and 30 ohmsA. 25 and 30 ohms

B. 50 and 75 ohmsB. 50 and 75 ohms

C. 80 and 100 ohmsC. 80 and 100 ohms

D. 500 and 750 ohmsD. 500 and 750 ohms

8 G9 - Antennas

G9A03 What is the characteristic G9A03 What is the characteristic impedance of flat ribbon TV type impedance of flat ribbon TV type twinlead?twinlead?

A. 50 ohmsA. 50 ohms

B. 75 ohmsB. 75 ohms

C. 100 ohmsC. 100 ohms

D. 300 ohmsD. 300 ohms

9 G9 - Antennas

G9A03 What is the characteristic G9A03 What is the characteristic impedance of flat ribbon TV type impedance of flat ribbon TV type twinlead?twinlead?

A. 50 ohmsA. 50 ohms

B. 75 ohmsB. 75 ohms

C. 100 ohmsC. 100 ohms

D. 300 ohmsD. 300 ohms

10 G9 - Antennas

G9A04 What is the reason for the G9A04 What is the reason for the occurrence of reflected power at the point occurrence of reflected power at the point where a feed line connects to an where a feed line connects to an antenna?antenna?

A. Operating an antenna at its resonant A. Operating an antenna at its resonant frequencyfrequency

B. Using more transmitter power than the B. Using more transmitter power than the antenna can handleantenna can handle

C. A difference between feed-line impedance C. A difference between feed-line impedance and antenna feed-point impedanceand antenna feed-point impedance

D. Feeding the antenna with unbalanced feed D. Feeding the antenna with unbalanced feed lineline

11 G9 - Antennas

G9A04 What is the reason for the G9A04 What is the reason for the occurrence of reflected power at the point occurrence of reflected power at the point where a feed line connects to an where a feed line connects to an antenna?antenna?

A. Operating an antenna at its resonant frequencyA. Operating an antenna at its resonant frequency

B. Using more transmitter power than the antenna B. Using more transmitter power than the antenna can handlecan handle

C. A difference between feed-line impedance C. A difference between feed-line impedance and antenna feed-point impedanceand antenna feed-point impedance

D. Feeding the antenna with unbalanced feed lineD. Feeding the antenna with unbalanced feed line

12 G9 - Antennas

G9A05 How does the attenuation of G9A05 How does the attenuation of coaxial cable change as the frequency of coaxial cable change as the frequency of the signal it is carrying increases?the signal it is carrying increases?

A. It is independent of frequencyA. It is independent of frequency

B. It increasesB. It increases

C. It decreasesC. It decreases

D. It reaches a maximum at approximately 18 D. It reaches a maximum at approximately 18 MHzMHz

13 G9 - Antennas

G9A05 How does the attenuation of G9A05 How does the attenuation of coaxial cable change as the frequency of coaxial cable change as the frequency of the signal it is carrying increases?the signal it is carrying increases?

A. It is independent of frequencyA. It is independent of frequency


C. It decreasesC. It decreases

D. It reaches a maximum at approximately 18 D. It reaches a maximum at approximately 18 MHzMHz

14 G9 - Antennas

G9A06 In what values are RF feed line G9A06 In what values are RF feed line losses usually expressed?losses usually expressed?

A. ohms per 1000 ftA. ohms per 1000 ft

B. dB per 1000 ftB. dB per 1000 ft

C. ohms per 100 ftC. ohms per 100 ft

D. dB per 100 ftD. dB per 100 ft

15 G9 - Antennas

G9A06 In what values are RF feed line G9A06 In what values are RF feed line losses usually expressed?losses usually expressed?

A. ohms per 1000 ftA. ohms per 1000 ft

B. dB per 1000 ftB. dB per 1000 ft

C. ohms per 100 ftC. ohms per 100 ft

D. dB per 100 ftD. dB per 100 ft

16 G9 - Antennas

G9A07 What must be done to prevent G9A07 What must be done to prevent standing waves on an antenna feed line?standing waves on an antenna feed line?

A. The antenna feed point must be at DC A. The antenna feed point must be at DC ground potentialground potential

B. The feed line must be cut to an odd number B. The feed line must be cut to an odd number of electrical quarter wavelengths longof electrical quarter wavelengths long

C. The feed line must be cut to an even C. The feed line must be cut to an even number of physical half wavelengths longnumber of physical half wavelengths long

D. The antenna feed-point impedance must be D. The antenna feed-point impedance must be matched to the characteristic impedance of matched to the characteristic impedance of the feed linethe feed line

17 G9 - Antennas

G9A07 What must be done to prevent G9A07 What must be done to prevent standing waves on an antenna feed line?standing waves on an antenna feed line?

A. The antenna feed point must be at DC A. The antenna feed point must be at DC ground potentialground potential

B. The feed line must be cut to an odd number B. The feed line must be cut to an odd number of electrical quarter wavelengths longof electrical quarter wavelengths long

C. The feed line must be cut to an even C. The feed line must be cut to an even number of physical half wavelengths longnumber of physical half wavelengths long

D. The antenna feed-point impedance must D. The antenna feed-point impedance must be matched to the characteristic impedance be matched to the characteristic impedance of the feed lineof the feed line

18 G9 - Antennas

G9A08 If the SWR on an antenna feed line G9A08 If the SWR on an antenna feed line is 5 to 1, and a matching network at the is 5 to 1, and a matching network at the transmitter end of the feed line is transmitter end of the feed line is adjusted to 1 to 1 SWR, what is the adjusted to 1 to 1 SWR, what is the resulting SWR on the feed line?resulting SWR on the feed line?

A. 1 to 1A. 1 to 1

B. 5 to 1B. 5 to 1

C. Between 1 to 1 and 5 to 1 depending on the C. Between 1 to 1 and 5 to 1 depending on the characteristic impedance of the linecharacteristic impedance of the line

D. Between 1 to 1 and 5 to 1 depending on the D. Between 1 to 1 and 5 to 1 depending on the reflected power at the transmitterreflected power at the transmitter

19 G9 - Antennas

G9A08 If the SWR on an antenna feed line G9A08 If the SWR on an antenna feed line is 5 to 1, and a matching network at the is 5 to 1, and a matching network at the transmitter end of the feed line is transmitter end of the feed line is adjusted to 1 to 1 SWR, what is the adjusted to 1 to 1 SWR, what is the resulting SWR on the feed line?resulting SWR on the feed line?

A. 1 to 1A. 1 to 1

B. 5 to 1B. 5 to 1

C. Between 1 to 1 and 5 to 1 depending on the C. Between 1 to 1 and 5 to 1 depending on the characteristic impedance of the linecharacteristic impedance of the line

D. Between 1 to 1 and 5 to 1 depending on the D. Between 1 to 1 and 5 to 1 depending on the reflected power at the transmitterreflected power at the transmitter

20 G9 - Antennas

G9A09 What standing wave ratio will G9A09 What standing wave ratio will result from the connection of a 50-ohm result from the connection of a 50-ohm feed line to a non-reactive load having a feed line to a non-reactive load having a 200-ohm impedance?200-ohm impedance?

A. 4:1A. 4:1

B. 1:4B. 1:4

C. 2:1C. 2:1

D. 1:2D. 1:2

21 G9 - Antennas


A. 4:1A. 4:1

B. 1:4B. 1:4

C. 2:1C. 2:1

D. 1:2D. 1:2

22 G9 - Antennas


A. 2:1A. 2:1

B. 50:1B. 50:1

C. 1:5C. 1:5

D. 5:1D. 5:1

23 G9 - Antennas


A. 2:1A. 2:1

B. 50:1B. 50:1

C. 1:5C. 1:5

D. 5:1D. 5:1

24 G9 - Antennas


A. 2:1A. 2:1

B. 1:1B. 1:1

C. 50:50C. 50:50

D. 0:0D. 0:0

25 G9 - Antennas


A. 2:1A. 2:1

B. 1:1B. 1:1

C. 50:50C. 50:50

D. 0:0D. 0:0

26 G9 - Antennas

G9A12 What would be the SWR if you G9A12 What would be the SWR if you feed a vertical antenna that has a 25-ohm feed a vertical antenna that has a 25-ohm feed-point impedance with 50-ohm feed-point impedance with 50-ohm coaxial cable?coaxial cable?

A. 2:1A. 2:1

B. 2.5:1B. 2.5:1

C. 1.25:1C. 1.25:1

D. You cannot determine SWR from impedance D. You cannot determine SWR from impedance valuesvalues

27 G9 - Antennas

G9A12 What would be the SWR if you G9A12 What would be the SWR if you feed a vertical antenna that has a 25-ohm feed a vertical antenna that has a 25-ohm feed-point impedance with 50-ohm feed-point impedance with 50-ohm coaxial cable?coaxial cable?

A. 2:1A. 2:1

B. 2.5:1B. 2.5:1

C. 1.25:1C. 1.25:1


28 G9 - Antennas

G9A13 What would be the SWR if you G9A13 What would be the SWR if you feed an antenna that has a 300-ohm feed an antenna that has a 300-ohm feed-point impedance with 50-ohm feed-point impedance with 50-ohm coaxial cable?coaxial cable?

A. 1.5:1A. 1.5:1

B. 3:1B. 3:1

C. 6:1C. 6:1


29 G9 - Antennas

G9A13 What would be the SWR if you G9A13 What would be the SWR if you feed an antenna that has a 300-ohm feed an antenna that has a 300-ohm feed-point impedance with 50-ohm feed-point impedance with 50-ohm coaxial cable?coaxial cable?

A. 1.5:1A. 1.5:1

B. 3:1B. 3:1

C. 6:1C. 6:1


30 G9 - Antennas

G9 - Antennas31

Vertical AntennasVertical Antennas(Quarter Wavelength Vertical)(Quarter Wavelength Vertical)

Ground Plane

Ground Plane

Ground

Marconi

Radials

Wavelength (meters) = Wavelength (meters) = 300 300 F (MHz)F (MHz)

¼¼λλ vertical length (inches) = Wavelength / 4 x 39 vertical length (inches) = Wavelength / 4 x 39

Quarter wavelength

Meters to inches

G9 - Antennas32

Vertical AntennaVertical Antenna

Standard ¼ wave vertical has a feedpoint impedance of ~35 ohms

Sloping ground radials downward raises feedpoint impedance

G9 - Antennas33

½ ½ λλ Dipole Radiation Dipole Radiation

Radiation pattern for a Radiation pattern for a dipole placed ½ dipole placed ½ λλabove ground looking above ground looking down from above the down from above the antenna.antenna.

Looks like a doughnut Looks like a doughnut around the wire in 3D around the wire in 3D space.space.

Pattern distorts to omnidirectional when placed low to the ground.

G9B01 What is one disadvantage of a G9B01 What is one disadvantage of a directly fed random-wire antenna?directly fed random-wire antenna?

A. It must be longer than 1 wavelengthA. It must be longer than 1 wavelength

B. You may experience RF burns when B. You may experience RF burns when touching metal objects in your stationtouching metal objects in your station

C. It produces only vertically polarized C. It produces only vertically polarized radiationradiation

D. It is not effective on the higher HF bandsD. It is not effective on the higher HF bands

34 G9 - Antennas

G9B01 What is one disadvantage of a G9B01 What is one disadvantage of a directly fed random-wire antenna?directly fed random-wire antenna?

A. It must be longer than 1 wavelengthA. It must be longer than 1 wavelength

B. You may experience RF burns when B. You may experience RF burns when touching metal objects in your stationtouching metal objects in your station

C. It produces only vertically polarized C. It produces only vertically polarized radiationradiation

D. It is not effective on the higher HF bandsD. It is not effective on the higher HF bands

35 G9 - Antennas

G9B02 What is an advantage of G9B02 What is an advantage of downward sloping radials on a quarter downward sloping radials on a quarter wave ground-plane antenna?wave ground-plane antenna?

A. They lower the radiation angleA. They lower the radiation angle

B. They bring the feed-point impedance closer B. They bring the feed-point impedance closer to 300 ohmsto 300 ohms

C. They increase the radiation angleC. They increase the radiation angle

D. They bring the feed-point impedance closer D. They bring the feed-point impedance closer to 50 ohmsto 50 ohms

36 G9 - Antennas

G9B02 What is an advantage of G9B02 What is an advantage of downward sloping radials on a quarter downward sloping radials on a quarter wave ground-plane antenna?wave ground-plane antenna?

A. They lower the radiation angleA. They lower the radiation angle

B. They bring the feed-point impedance closer B. They bring the feed-point impedance closer to 300 ohmsto 300 ohms

C. They increase the radiation angleC. They increase the radiation angle

D. They bring the feed-point impedance D. They bring the feed-point impedance closer to 50 ohmscloser to 50 ohms

37 G9 - Antennas

G9B03 What happens to the feed-point G9B03 What happens to the feed-point impedance of a ground-plane antenna impedance of a ground-plane antenna when its radials are changed from when its radials are changed from horizontal to downward-sloping?horizontal to downward-sloping?

A. It decreasesA. It decreases


C. It stays the sameC. It stays the same

D. It reaches a maximum at an angle of 45 D. It reaches a maximum at an angle of 45 degreesdegrees

38 G9 - Antennas

G9B03 What happens to the feed-point G9B03 What happens to the feed-point impedance of a ground-plane antenna impedance of a ground-plane antenna when its radials are changed from when its radials are changed from horizontal to downward-sloping?horizontal to downward-sloping?

A. It decreasesA. It decreases


C. It stays the sameC. It stays the same

D. It reaches a maximum at an angle of 45 D. It reaches a maximum at an angle of 45 degreesdegrees

39 G9 - Antennas

G9B04 What is the low angle azimuthal G9B04 What is the low angle azimuthal radiation pattern of an ideal half-radiation pattern of an ideal half-wavelength dipole antenna installed 1/2 wavelength dipole antenna installed 1/2 wavelength high and parallel to the wavelength high and parallel to the Earth?Earth?

A. It is a figure-eight at right angles to the A. It is a figure-eight at right angles to the antennaantenna

B. It is a figure-eight off both ends of the B. It is a figure-eight off both ends of the antennaantenna

C. It is a circle (equal radiation in all directions)C. It is a circle (equal radiation in all directions)

D. It has a pair of lobes on one side of the D. It has a pair of lobes on one side of the antenna and a single lobe on the other sideantenna and a single lobe on the other side

40 G9 - Antennas

G9B04 What is the low angle azimuthal G9B04 What is the low angle azimuthal radiation pattern of an ideal half-radiation pattern of an ideal half-wavelength dipole antenna installed 1/2 wavelength dipole antenna installed 1/2 wavelength high and parallel to the wavelength high and parallel to the Earth?Earth?

A. It is a figure-eight at right angles to the A. It is a figure-eight at right angles to the antennaantenna

B. It is a figure-eight off both ends of the B. It is a figure-eight off both ends of the antennaantenna

C. It is a circle (equal radiation in all directions)C. It is a circle (equal radiation in all directions)

D. It has a pair of lobes on one side of the D. It has a pair of lobes on one side of the antenna and a single lobe on the other sideantenna and a single lobe on the other side

41 G9 - Antennas

G9B05 How does antenna height affect G9B05 How does antenna height affect the horizontal (azimuthal) radiation the horizontal (azimuthal) radiation pattern of a horizontal dipole HF antenna?pattern of a horizontal dipole HF antenna?

A. If the antenna is too high, the pattern becomes A. If the antenna is too high, the pattern becomes unpredictableunpredictable

B. Antenna height has no effect on the patternB. Antenna height has no effect on the pattern

C. If the antenna is less than 1/2 wavelength high, C. If the antenna is less than 1/2 wavelength high, the azimuthal pattern is almost omnidirectionalthe azimuthal pattern is almost omnidirectional

D. If the antenna is less than 1/2 wavelength high, D. If the antenna is less than 1/2 wavelength high, radiation off the ends of the wire is eliminatedradiation off the ends of the wire is eliminated

42 G9 - Antennas

G9B05 How does antenna height affect G9B05 How does antenna height affect the horizontal (azimuthal) radiation the horizontal (azimuthal) radiation pattern of a horizontal dipole HF antenna?pattern of a horizontal dipole HF antenna?

A. If the antenna is too high, the pattern becomes A. If the antenna is too high, the pattern becomes unpredictableunpredictable

B. Antenna height has no effect on the patternB. Antenna height has no effect on the pattern

C. If the antenna is less than 1/2 wavelength C. If the antenna is less than 1/2 wavelength high, the azimuthal pattern is almost high, the azimuthal pattern is almost omnidirectionalomnidirectional

D. If the antenna is less than 1/2 wavelength high, D. If the antenna is less than 1/2 wavelength high, radiation off the ends of the wire is eliminatedradiation off the ends of the wire is eliminated

43 G9 - Antennas

G9B06 Where should the radial wires of a G9B06 Where should the radial wires of a ground-mounted vertical antenna system ground-mounted vertical antenna system be placed?be placed?

A. As high as possible above the groundA. As high as possible above the ground

B. Parallel to the antenna elementB. Parallel to the antenna element

C. On the surface or buried a few inches below C. On the surface or buried a few inches below the groundthe ground

D. At the top of the antennaD. At the top of the antenna

44 G9 - Antennas

G9B06 Where should the radial wires of a G9B06 Where should the radial wires of a ground-mounted vertical antenna system ground-mounted vertical antenna system be placed?be placed?

A. As high as possible above the groundA. As high as possible above the ground

B. Parallel to the antenna elementB. Parallel to the antenna element

C. On the surface or buried a few inches C. On the surface or buried a few inches below the groundbelow the ground

D. At the top of the antennaD. At the top of the antenna

45 G9 - Antennas

G9B07 How does the feed-point G9B07 How does the feed-point impedance of a 1/2 wave dipole antenna impedance of a 1/2 wave dipole antenna change as the antenna is lowered from change as the antenna is lowered from 1/4 wave above ground?1/4 wave above ground?

A. It steadily increasesA. It steadily increases

B. It steadily decreasesB. It steadily decreases

C. It peaks at about 1/8 wavelength above C. It peaks at about 1/8 wavelength above groundground

D. It is unaffected by the height above groundD. It is unaffected by the height above ground

46 G9 - Antennas

G9B07 How does the feed-point G9B07 How does the feed-point impedance of a 1/2 wave dipole antenna impedance of a 1/2 wave dipole antenna change as the antenna is lowered from change as the antenna is lowered from 1/4 wave above ground?1/4 wave above ground?



C. It peaks at about 1/8 wavelength above C. It peaks at about 1/8 wavelength above groundground

D. It is unaffected by the height above groundD. It is unaffected by the height above ground

47 G9 - Antennas

G9B08 How does the feed-point G9B08 How does the feed-point impedance of a 1/2 wave dipole change impedance of a 1/2 wave dipole change as the feed-point location is moved from as the feed-point location is moved from the center toward the ends?the center toward the ends?



C. It peaks at about 1/8 wavelength from the C. It peaks at about 1/8 wavelength from the endend

D. It is unaffected by the location of the feed D. It is unaffected by the location of the feed pointpoint

48 G9 - Antennas

G9B08 How does the feed-point G9B08 How does the feed-point impedance of a 1/2 wave dipole change impedance of a 1/2 wave dipole change as the feed-point location is moved from as the feed-point location is moved from the center toward the ends?the center toward the ends?



C. It peaks at about 1/8 wavelength from the C. It peaks at about 1/8 wavelength from the endend

D. It is unaffected by the location of the feed D. It is unaffected by the location of the feed pointpoint

49 G9 - Antennas

G9B09 Which of the following is an G9B09 Which of the following is an advantage of a horizontally polarized as advantage of a horizontally polarized as compared to vertically polarized HF compared to vertically polarized HF antenna?antenna?

A. Lower ground reflection lossesA. Lower ground reflection losses

B. Lower feed-point impedanceB. Lower feed-point impedance

C. Shorter RadialsC. Shorter Radials

D. Lower radiation resistanceD. Lower radiation resistance

50 G9 - Antennas

G9B09 Which of the following is an G9B09 Which of the following is an advantage of a horizontally polarized as advantage of a horizontally polarized as compared to vertically polarized HF compared to vertically polarized HF antenna?antenna?

A. Lower ground reflection lossesA. Lower ground reflection losses

B. Lower feed-point impedanceB. Lower feed-point impedance

C. Shorter RadialsC. Shorter Radials

D. Lower radiation resistanceD. Lower radiation resistance

51 G9 - Antennas

G9B10 What is the approximate length for G9B10 What is the approximate length for a 1/2-wave dipole antenna cut for 14.250 a 1/2-wave dipole antenna cut for 14.250 MHz?MHz?

A. 8 feetA. 8 feet

B. 16 feetB. 16 feet

C. 24 feetC. 24 feet

D. 32 feetD. 32 feet

52 G9 - Antennas


A. 8 feetA. 8 feet




53 G9 - Antennas


A. 42 feetA. 42 feet




54 G9 - Antennas


A. 42 feetA. 42 feet




55 G9 - Antennas

G9B12 What is the approximate length for G9B12 What is the approximate length for a 1/4-wave vertical antenna cut for 28.5 a 1/4-wave vertical antenna cut for 28.5 MHz?MHz?

A. 8 feetA. 8 feet




56 G9 - Antennas

G9B12 What is the approximate length for G9B12 What is the approximate length for a 1/4-wave vertical antenna cut for 28.5 a 1/4-wave vertical antenna cut for 28.5 MHz?MHz?

A. 8 feetA. 8 feet




57 G9 - Antennas

G9 - Antennas58

Beam AntennasBeam Antennas(Yagi Antenna)(Yagi Antenna)

GainGain

BoomBoom

Feed

line

Feed

line

Reflect

or

Reflect

or

Dir

ect

oD

irect

orr

Dri

ven

D

riven

Ele

men

tEle

men

t

The reflectorThe reflectoracts like a acts like a

mirrormirror

The directorThe directoracts like aacts like a

lenslens

G9 - Antennas59

Yagi Radiation PatternYagi Radiation Pattern

The yagi antenna The yagi antenna focuses RF energy in focuses RF energy in one direction, giving one direction, giving the appearance ofthe appearance ofgetting “free power.”getting “free power.”

This This free powerfree power or or Effective Radiated Effective Radiated Power (ERP) can be Power (ERP) can be expressed as antenna expressed as antenna Gain in Decibels (dB) Gain in Decibels (dB) over a dipole (dBd) or over a dipole (dBd) or isotropic resonator isotropic resonator (dBi).(dBi).

G9 - Antennas60

Quad antennaQuad antenna

G9 - Antennas61

Delta LoopDelta Loop

G9C01 Which of the following would G9C01 Which of the following would increase the bandwidth of a Yagi increase the bandwidth of a Yagi antenna?antenna?

A. Larger diameter elementsA. Larger diameter elements

B. Closer element spacingB. Closer element spacing

C. Loading coils in series with the elementC. Loading coils in series with the element

D. Tapered-diameter elementsD. Tapered-diameter elements

62 G9 - Antennas

G9C01 Which of the following would G9C01 Which of the following would increase the bandwidth of a Yagi increase the bandwidth of a Yagi antenna?antenna?

A. Larger diameter elementsA. Larger diameter elements

B. Closer element spacingB. Closer element spacing

C. Loading coils in series with the elementC. Loading coils in series with the element

D. Tapered-diameter elementsD. Tapered-diameter elements

63 G9 - Antennas

G9C02 What is the approximate length of G9C02 What is the approximate length of the driven element of a Yagi antenna?the driven element of a Yagi antenna?

A. 1/4 wavelengthA. 1/4 wavelength

B. 1/2 wavelengthB. 1/2 wavelength

C. 3/4 wavelengthC. 3/4 wavelength

D. 1 wavelengthD. 1 wavelength

64 G9 - Antennas

G9C02 What is the approximate length of G9C02 What is the approximate length of the driven element of a Yagi antenna?the driven element of a Yagi antenna?





65 G9 - Antennas

G9C03 Which statement about a three-G9C03 Which statement about a three-element, single-band Yagi antenna is element, single-band Yagi antenna is true?true?

A. The reflector is normally the shortest A. The reflector is normally the shortest parasitic elementparasitic element

B. The director is normally the shortest B. The director is normally the shortest parasitic elementparasitic element

C. The driven element is the longest parasitic C. The driven element is the longest parasitic elementelement

D. Low feed-point impedance increases D. Low feed-point impedance increases bandwidthbandwidth

66 G9 - Antennas

G9C03 Which statement about a three-G9C03 Which statement about a three-element, single-band Yagi antenna is element, single-band Yagi antenna is true?true?

A. The reflector is normally the shortest A. The reflector is normally the shortest parasitic elementparasitic element

B. The director is normally the shortest B. The director is normally the shortest parasitic elementparasitic element

C. The driven element is the longest parasitic C. The driven element is the longest parasitic elementelement

D. Low feed-point impedance increases D. Low feed-point impedance increases bandwidthbandwidth

67 G9 - Antennas

G9C04 Which statement about a three-G9C04 Which statement about a three-element; single-band Yagi antenna is element; single-band Yagi antenna is true?true?

A. The reflector is normally the longest A. The reflector is normally the longest parasitic elementparasitic element

B. The director is normally the longest parasitic B. The director is normally the longest parasitic elementelement

C. The reflector is normally the shortest C. The reflector is normally the shortest parasitic elementparasitic element

D. All of the elements must be the same lengthD. All of the elements must be the same length

68 G9 - Antennas

G9C04 Which statement about a three-G9C04 Which statement about a three-element; single-band Yagi antenna is element; single-band Yagi antenna is true?true?

A. The reflector is normally the longest A. The reflector is normally the longest parasitic elementparasitic element

B. The director is normally the longest parasitic B. The director is normally the longest parasitic elementelement

C. The reflector is normally the shortest C. The reflector is normally the shortest parasitic elementparasitic element

D. All of the elements must be the same lengthD. All of the elements must be the same length

69 G9 - Antennas

G9C05 How does increasing boom length G9C05 How does increasing boom length and adding directors affect a Yagi and adding directors affect a Yagi antenna?antenna?

A. Gain increasesA. Gain increases

B. Beamwidth increasesB. Beamwidth increases

C. Weight decreasesC. Weight decreases

D. Wind load decreasesD. Wind load decreases

70 G9 - Antennas

G9C05 How does increasing boom length G9C05 How does increasing boom length and adding directors affect a Yagi and adding directors affect a Yagi antenna?antenna?

A. Gain increasesA. Gain increases

B. Beamwidth increasesB. Beamwidth increases

C. Weight decreasesC. Weight decreases

D. Wind load decreasesD. Wind load decreases

71 G9 - Antennas

G9C06 Which of the following is a reason G9C06 Which of the following is a reason why a Yagi antenna is often used for radio why a Yagi antenna is often used for radio communications on the 20 meter band?communications on the 20 meter band?

A. It provides excellent omnidirectional A. It provides excellent omnidirectional coverage in the horizontal planecoverage in the horizontal plane

B. It is smaller, less expensive and easier to B. It is smaller, less expensive and easier to erect than a dipole or vertical antennaerect than a dipole or vertical antenna

C. It helps reduce interference from other C. It helps reduce interference from other stations to the side or behind the antennastations to the side or behind the antenna

D. It provides the highest possible angle of D. It provides the highest possible angle of radiation for the HF bandsradiation for the HF bands

72 G9 - Antennas

G9C06 Which of the following is a reason G9C06 Which of the following is a reason why a Yagi antenna is often used for radio why a Yagi antenna is often used for radio communications on the 20 meter band?communications on the 20 meter band?

A. It provides excellent omnidirectional A. It provides excellent omnidirectional coverage in the horizontal planecoverage in the horizontal plane

B. It is smaller, less expensive and easier to B. It is smaller, less expensive and easier to erect than a dipole or vertical antennaerect than a dipole or vertical antenna

C. It helps reduce interference from other C. It helps reduce interference from other stations to the side or behind the antennastations to the side or behind the antenna

D. It provides the highest possible angle of D. It provides the highest possible angle of radiation for the HF bandsradiation for the HF bands

73 G9 - Antennas

G9C07 What does "front-to-back ratio" G9C07 What does "front-to-back ratio" mean in reference to a Yagi antenna?mean in reference to a Yagi antenna?

A. The number of directors versus the number A. The number of directors versus the number of reflectorsof reflectors

B. The relative position of the driven element B. The relative position of the driven element with respect to the reflectors and directorswith respect to the reflectors and directors

C. The power radiated in the major radiation C. The power radiated in the major radiation lobe compared to the power radiated in lobe compared to the power radiated in exactly the opposite directionexactly the opposite direction

D. The ratio of forward gain to dipole gainD. The ratio of forward gain to dipole gain

74 G9 - Antennas

G9C07 What does "front-to-back ratio" G9C07 What does "front-to-back ratio" mean in reference to a Yagi antenna?mean in reference to a Yagi antenna?

A. The number of directors versus the number A. The number of directors versus the number of reflectorsof reflectors

B. The relative position of the driven element B. The relative position of the driven element with respect to the reflectors and directorswith respect to the reflectors and directors

C. The power radiated in the major radiation C. The power radiated in the major radiation lobe compared to the power radiated in lobe compared to the power radiated in exactly the opposite directionexactly the opposite direction

D. The ratio of forward gain to dipole gainD. The ratio of forward gain to dipole gain

75 G9 - Antennas

G9C08 What is meant by the "main lobe" G9C08 What is meant by the "main lobe" of a directive antenna?of a directive antenna?

A. The magnitude of the maximum vertical A. The magnitude of the maximum vertical angle of radiationangle of radiation

B. The point of maximum current in a radiating B. The point of maximum current in a radiating antenna elementantenna element

C. The maximum voltage standing wave point C. The maximum voltage standing wave point on a radiating elementon a radiating element

D. The direction of maximum radiated field D. The direction of maximum radiated field strength from the antennastrength from the antenna

76 G9 - Antennas

G9C08 What is meant by the "main lobe" G9C08 What is meant by the "main lobe" of a directive antenna?of a directive antenna?

A. The magnitude of the maximum vertical A. The magnitude of the maximum vertical angle of radiationangle of radiation

B. The point of maximum current in a radiating B. The point of maximum current in a radiating antenna elementantenna element

C. The maximum voltage standing wave point C. The maximum voltage standing wave point on a radiating elementon a radiating element

D. The direction of maximum radiated field D. The direction of maximum radiated field strength from the antennastrength from the antenna

77 G9 - Antennas

G9C09 What is the approximate G9C09 What is the approximate maximum theoretical forward gain of a maximum theoretical forward gain of a three element, single-band Yagi antenna?three element, single-band Yagi antenna?

A. 9.7 dBiA. 9.7 dBi

B. 9.7 dBdB. 9.7 dBd

C. 5.4 times the gain of a dipoleC. 5.4 times the gain of a dipole

D. All of these choices are correctD. All of these choices are correct

78 G9 - Antennas

G9C09 What is the approximate G9C09 What is the approximate maximum theoretical forward gain of a maximum theoretical forward gain of a three element, single-band Yagi antenna?three element, single-band Yagi antenna?

A. 9.7 dBiA. 9.7 dBi

B. 9.7 dBdB. 9.7 dBd

C. 5.4 times the gain of a dipoleC. 5.4 times the gain of a dipole


79 G9 - Antennas

G9C10 Which of the following is a Yagi G9C10 Which of the following is a Yagi antenna design variable that could be antenna design variable that could be adjusted to optimize forward gain, front-adjusted to optimize forward gain, front-to-back ratio, or SWR bandwidth?to-back ratio, or SWR bandwidth?

A. The physical length of the boomA. The physical length of the boom

B. The number of elements on the boomB. The number of elements on the boom

C. The spacing of each element along the C. The spacing of each element along the boomboom


80 G9 - Antennas

G9C10 Which of the following is a Yagi G9C10 Which of the following is a Yagi antenna design variable that could be antenna design variable that could be adjusted to optimize forward gain, front-adjusted to optimize forward gain, front-to-back ratio, or SWR bandwidth?to-back ratio, or SWR bandwidth?

A. The physical length of the boomA. The physical length of the boom

B. The number of elements on the boomB. The number of elements on the boom

C. The spacing of each element along the C. The spacing of each element along the boomboom


81 G9 - Antennas

G9C11 What is the purpose of a gamma G9C11 What is the purpose of a gamma match used with Yagi antennas?match used with Yagi antennas?

A. To match the relatively low feed-point A. To match the relatively low feed-point impedance to 50 ohmsimpedance to 50 ohms

B. To match the relatively high feed-point B. To match the relatively high feed-point impedance to 50 ohmsimpedance to 50 ohms

C. To increase the front to back ratioC. To increase the front to back ratio

D. To increase the main lobe gainD. To increase the main lobe gain

82 G9 - Antennas

G9C11 What is the purpose of a gamma G9C11 What is the purpose of a gamma match used with Yagi antennas?match used with Yagi antennas?

A. To match the relatively low feed-point A. To match the relatively low feed-point impedance to 50 ohmsimpedance to 50 ohms

B. To match the relatively high feed-point B. To match the relatively high feed-point impedance to 50 ohmsimpedance to 50 ohms

C. To increase the front to back ratioC. To increase the front to back ratio

D. To increase the main lobe gainD. To increase the main lobe gain

83 G9 - Antennas

G9C12 Which of the following is an G9C12 Which of the following is an advantage of using a gamma match for advantage of using a gamma match for impedance matching of a Yagi antenna to impedance matching of a Yagi antenna to 50-ohm coax feed line?50-ohm coax feed line?

A. It does not require that the elements be A. It does not require that the elements be insulated from the boominsulated from the boom

B. It does not require any inductors or B. It does not require any inductors or capacitorscapacitors

C. It is useful for matching multiband antennasC. It is useful for matching multiband antennas


84 G9 - Antennas

G9C12 Which of the following is an G9C12 Which of the following is an advantage of using a gamma match for advantage of using a gamma match for impedance matching of a Yagi antenna to impedance matching of a Yagi antenna to 50-ohm coax feed line?50-ohm coax feed line?

A. It does not require that the elements be A. It does not require that the elements be insulated from the boominsulated from the boom

B. It does not require any inductors or B. It does not require any inductors or capacitorscapacitors

C. It is useful for matching multiband antennasC. It is useful for matching multiband antennas


85 G9 - Antennas

G9C13 Approximately how long is each G9C13 Approximately how long is each side of a quad antenna driven element?side of a quad antenna driven element?





86 G9 - Antennas

G9C13 Approximately how long is each G9C13 Approximately how long is each side of a quad antenna driven element?side of a quad antenna driven element?





87 G9 - Antennas

G9C14 How does the forward gain of a G9C14 How does the forward gain of a two-element quad antenna compare to two-element quad antenna compare to the forward gain of a three-element Yagi the forward gain of a three-element Yagi antenna?antenna?

A. About 2/3 as muchA. About 2/3 as much

B. About the sameB. About the same

C. About 1.5 times as muchC. About 1.5 times as much

D. About twice as muchD. About twice as much

88 G9 - Antennas

G9C14 How does the forward gain of a G9C14 How does the forward gain of a two-element quad antenna compare to two-element quad antenna compare to the forward gain of a three-element Yagi the forward gain of a three-element Yagi antenna?antenna?

A. About 2/3 as muchA. About 2/3 as much

B. About the sameB. About the same

C. About 1.5 times as muchC. About 1.5 times as much

D. About twice as muchD. About twice as much

89 G9 - Antennas

G9C15 Approximately how long is each G9C15 Approximately how long is each side of a quad antenna reflector element?side of a quad antenna reflector element?

A. Slightly less than 1/4 wavelengthA. Slightly less than 1/4 wavelength

B. Slightly more than 1/4 wavelengthB. Slightly more than 1/4 wavelength

C. Slightly less than 1/2 wavelengthC. Slightly less than 1/2 wavelength

D. Slightly more than 1/2 wavelengthD. Slightly more than 1/2 wavelength

90 G9 - Antennas

G9C15 Approximately how long is each G9C15 Approximately how long is each side of a quad antenna reflector element?side of a quad antenna reflector element?

A. Slightly less than 1/4 wavelengthA. Slightly less than 1/4 wavelength

B. Slightly more than 1/4 wavelengthB. Slightly more than 1/4 wavelength

C. Slightly less than 1/2 wavelengthC. Slightly less than 1/2 wavelength

D. Slightly more than 1/2 wavelengthD. Slightly more than 1/2 wavelength

91 G9 - Antennas

G9C16 How does the gain of a two-G9C16 How does the gain of a two-element delta-loop beam compare to the element delta-loop beam compare to the gain of a two-element quad antenna?gain of a two-element quad antenna?

A. 3 dB higherA. 3 dB higher

B. 3 dB lowerB. 3 dB lower

C. 2.54 dB higherC. 2.54 dB higher

D. About the sameD. About the same

92 G9 - Antennas

G9C16 How does the gain of a two-G9C16 How does the gain of a two-element delta-loop beam compare to the element delta-loop beam compare to the gain of a two-element quad antenna?gain of a two-element quad antenna?

A. 3 dB higherA. 3 dB higher

B. 3 dB lowerB. 3 dB lower

C. 2.54 dB higherC. 2.54 dB higher

D. About the sameD. About the same

93 G9 - Antennas

G9C17 Approximately how long is each G9C17 Approximately how long is each leg of a symmetrical delta-loop antenna?leg of a symmetrical delta-loop antenna?




D. 2/3 wavelengthD. 2/3 wavelength

94 G9 - Antennas

G9C17 Approximately how long is each G9C17 Approximately how long is each leg of a symmetrical delta-loop antenna?leg of a symmetrical delta-loop antenna?




D. 2/3 wavelengthD. 2/3 wavelength

95 G9 - Antennas

G9C18 What happens when the feed G9C18 What happens when the feed point of a quad antenna is changed from point of a quad antenna is changed from the center of either horizontal wire to the the center of either horizontal wire to the center of either vertical wire?center of either vertical wire?

A. The polarization of the radiated signal A. The polarization of the radiated signal changes from horizontal to verticalchanges from horizontal to vertical

B. The polarization of the radiated signal B. The polarization of the radiated signal changes from vertical to horizontalchanges from vertical to horizontal

C. The direction of the main lobe is reversedC. The direction of the main lobe is reversed

D. The radiated signal changes to an D. The radiated signal changes to an omnidirectional patternomnidirectional pattern

96 G9 - Antennas

G9C18 What happens when the feed G9C18 What happens when the feed point of a quad antenna is changed from point of a quad antenna is changed from the center of either horizontal wire to the the center of either horizontal wire to the center of either vertical wire?center of either vertical wire?

A. The polarization of the radiated signal A. The polarization of the radiated signal changes from horizontal to verticalchanges from horizontal to vertical

B. The polarization of the radiated signal B. The polarization of the radiated signal changes from vertical to horizontalchanges from vertical to horizontal

C. The direction of the main lobe is reversedC. The direction of the main lobe is reversed

D. The radiated signal changes to an D. The radiated signal changes to an omnidirectional patternomnidirectional pattern

97 G9 - Antennas

G9C19 What configuration of the loops of G9C19 What configuration of the loops of a two-element quad antenna must be a two-element quad antenna must be used for the antenna to operate as a used for the antenna to operate as a beam antenna, assuming one of the beam antenna, assuming one of the elements is used as a reflector?elements is used as a reflector?

A. The driven element must be fed with a balun A. The driven element must be fed with a balun transformertransformer

B. The driven element must be open-circuited on B. The driven element must be open-circuited on the side opposite the feed pointthe side opposite the feed point

C. The reflector element must be approximately C. The reflector element must be approximately 5% shorter than the driven element5% shorter than the driven element

D. The reflector element must be approximately D. The reflector element must be approximately 5% longer than the driven element5% longer than the driven element

98 G9 - Antennas

G9C19 What configuration of the loops of G9C19 What configuration of the loops of a two-element quad antenna must be a two-element quad antenna must be used for the antenna to operate as a used for the antenna to operate as a beam antenna, assuming one of the beam antenna, assuming one of the elements is used as a reflector?elements is used as a reflector?

A. The driven element must be fed with a balun A. The driven element must be fed with a balun transformertransformer

B. The driven element must be open-circuited B. The driven element must be open-circuited on the side opposite the feed pointon the side opposite the feed point

C. The reflector element must be approximately C. The reflector element must be approximately 5% shorter than the driven element5% shorter than the driven element

D. The reflector element must be D. The reflector element must be approximately 5% longer than the driven approximately 5% longer than the driven elementelement

99 G9 - Antennas

G9C20 How does the gain of two 3-G9C20 How does the gain of two 3-element horizontally polarized Yagi element horizontally polarized Yagi antennas spaced vertically 1/2 antennas spaced vertically 1/2 wavelength apart typically compare to wavelength apart typically compare to the gain of a single 3-element Yagi?the gain of a single 3-element Yagi?

A. Approximately 1.5 dB higherA. Approximately 1.5 dB higher

B. Approximately 3 dB higherB. Approximately 3 dB higher

C. Approximately 6 dB higherC. Approximately 6 dB higher

D. Approximately 9 dB higherD. Approximately 9 dB higher

100 G9 - Antennas

G9C20 How does the gain of two 3-G9C20 How does the gain of two 3-element horizontally polarized Yagi element horizontally polarized Yagi antennas spaced vertically 1/2 antennas spaced vertically 1/2 wavelength apart typically compare to wavelength apart typically compare to the gain of a single 3-element Yagi?the gain of a single 3-element Yagi?

A. Approximately 1.5 dB higherA. Approximately 1.5 dB higher

B. Approximately 3 dB higherB. Approximately 3 dB higher

C. Approximately 6 dB higherC. Approximately 6 dB higher

D. Approximately 9 dB higherD. Approximately 9 dB higher

101 G9 - Antennas

G9D01 What does the term "NVIS" mean G9D01 What does the term "NVIS" mean as related to antennas?as related to antennas?

A. Nearly Vertical Inductance SystemA. Nearly Vertical Inductance System

B. Non-Visible Installation SpecificationB. Non-Visible Installation Specification

C. Non-Varying Impedance SmoothingC. Non-Varying Impedance Smoothing

D. Near Vertical Incidence Sky waveD. Near Vertical Incidence Sky wave

102 G9 - Antennas

G9D01 What does the term "NVIS" mean G9D01 What does the term "NVIS" mean as related to antennas?as related to antennas?

A. Nearly Vertical Inductance SystemA. Nearly Vertical Inductance System

B. Non-Visible Installation SpecificationB. Non-Visible Installation Specification

C. Non-Varying Impedance SmoothingC. Non-Varying Impedance Smoothing

D. Near Vertical Incidence Sky waveD. Near Vertical Incidence Sky wave

103 G9 - Antennas

G9D02 Which of the following is an G9D02 Which of the following is an advantage of an NVIS antenna?advantage of an NVIS antenna?

A. Low vertical angle radiation for working A. Low vertical angle radiation for working stations out to ranges of several thousand stations out to ranges of several thousand kilometerskilometers

B. High vertical angle radiation for working B. High vertical angle radiation for working stations within a radius of a few hundred stations within a radius of a few hundred kilometerskilometers

C. High forward gainC. High forward gain

D. All of these choices are correctD. All of these choices are correct104 G9 - Antennas

G9D02 Which of the following is an G9D02 Which of the following is an advantage of an NVIS antenna?advantage of an NVIS antenna?

A. Low vertical angle radiation for working A. Low vertical angle radiation for working stations out to ranges of several thousand stations out to ranges of several thousand kilometerskilometers

B. High vertical angle radiation for working B. High vertical angle radiation for working stations within a radius of a few hundred stations within a radius of a few hundred kilometerskilometers

C. High forward gainC. High forward gain

D. All of these choices are correctD. All of these choices are correct105 G9 - Antennas

G9D03 At what height above ground is an G9D03 At what height above ground is an NVIS antenna typically installed?NVIS antenna typically installed?

A. As close to one-half wave as possibleA. As close to one-half wave as possible

B. As close to one wavelength as possibleB. As close to one wavelength as possible

C. Height is not critical as long as it is C. Height is not critical as long as it is significantly more than 1/2 wavelengthsignificantly more than 1/2 wavelength

D. Between 1/10 and 1/4 wavelengthD. Between 1/10 and 1/4 wavelength

106 G9 - Antennas

G9D03 At what height above ground is an G9D03 At what height above ground is an NVIS antenna typically installed?NVIS antenna typically installed?

A. As close to one-half wave as possibleA. As close to one-half wave as possible

B. As close to one wavelength as possibleB. As close to one wavelength as possible

C. Height is not critical as long as it is C. Height is not critical as long as it is significantly more than 1/2 wavelengthsignificantly more than 1/2 wavelength

D. Between 1/10 and 1/4 wavelengthD. Between 1/10 and 1/4 wavelength

107 G9 - Antennas

G9D04 What is the primary purpose of G9D04 What is the primary purpose of antenna traps?antenna traps?

A. To permit multiband operationA. To permit multiband operation

B. To notch spurious frequenciesB. To notch spurious frequencies

C. To provide balanced feed-point impedanceC. To provide balanced feed-point impedance

D. To prevent out of band operationD. To prevent out of band operation

108 G9 - Antennas

G9D04 What is the primary purpose of G9D04 What is the primary purpose of antenna traps?antenna traps?

A. To permit multiband operationA. To permit multiband operation

B. To notch spurious frequenciesB. To notch spurious frequencies

C. To provide balanced feed-point impedanceC. To provide balanced feed-point impedance

D. To prevent out of band operationD. To prevent out of band operation

109 G9 - Antennas

G9D05 What is the advantage of vertical G9D05 What is the advantage of vertical stacking of horizontally polarized Yagi stacking of horizontally polarized Yagi antennas?antennas?

A. Allows quick selection of vertical or A. Allows quick selection of vertical or horizontal polarizationhorizontal polarization

B. Allows simultaneous vertical and horizontal B. Allows simultaneous vertical and horizontal polarizationpolarization

C. Narrows the main lobe in azimuthC. Narrows the main lobe in azimuth

D. Narrows the main lobe in elevationD. Narrows the main lobe in elevation

110 G9 - Antennas

G9D05 What is the advantage of vertical G9D05 What is the advantage of vertical stacking of horizontally polarized Yagi stacking of horizontally polarized Yagi antennas?antennas?

A. Allows quick selection of vertical or A. Allows quick selection of vertical or horizontal polarizationhorizontal polarization

B. Allows simultaneous vertical and horizontal B. Allows simultaneous vertical and horizontal polarizationpolarization

C. Narrows the main lobe in azimuthC. Narrows the main lobe in azimuth

D. Narrows the main lobe in elevationD. Narrows the main lobe in elevation

111 G9 - Antennas

G9D06 Which of the following is an G9D06 Which of the following is an advantage of a log periodic antenna?advantage of a log periodic antenna?

A. Wide bandwidthA. Wide bandwidth

B. Higher gain per element than a Yagi B. Higher gain per element than a Yagi antennaantenna

C. Harmonic suppressionC. Harmonic suppression

D. Polarization diversityD. Polarization diversity

112 G9 - Antennas

G9D06 Which of the following is an G9D06 Which of the following is an advantage of a log periodic antenna?advantage of a log periodic antenna?

A. Wide bandwidthA. Wide bandwidth

B. Higher gain per element than a Yagi B. Higher gain per element than a Yagi antennaantenna

C. Harmonic suppressionC. Harmonic suppression

D. Polarization diversityD. Polarization diversity

113 G9 - Antennas

G9D07 Which of the following describes a G9D07 Which of the following describes a log periodic antenna?log periodic antenna?

A. Length and spacing of the elements A. Length and spacing of the elements increases logarithmically from one end of increases logarithmically from one end of the boom to the otherthe boom to the other

B. Impedance varies periodically as a function B. Impedance varies periodically as a function of frequencyof frequency

C. Gain varies logarithmically as a function of C. Gain varies logarithmically as a function of frequencyfrequency

D. SWR varies periodically as a function of D. SWR varies periodically as a function of boom lengthboom length

114 G9 - Antennas

G9D07 Which of the following describes a G9D07 Which of the following describes a log periodic antenna?log periodic antenna?

A. Length and spacing of the elements A. Length and spacing of the elements increases logarithmically from one end of increases logarithmically from one end of the boom to the otherthe boom to the other

B. Impedance varies periodically as a function B. Impedance varies periodically as a function of frequencyof frequency

C. Gain varies logarithmically as a function of C. Gain varies logarithmically as a function of frequencyfrequency

D. SWR varies periodically as a function of D. SWR varies periodically as a function of boom lengthboom length

115 G9 - Antennas

G9D08 Why is a Beverage antenna not G9D08 Why is a Beverage antenna not used for transmitting?used for transmitting?

A. Its impedance is too low for effective A. Its impedance is too low for effective matchingmatching

B. It has high losses compared to other types B. It has high losses compared to other types of antennasof antennas

C. It has poor directivityC. It has poor directivity


116 G9 - Antennas

G9D08 Why is a Beverage antenna not G9D08 Why is a Beverage antenna not used for transmitting?used for transmitting?

A. Its impedance is too low for effective A. Its impedance is too low for effective matchingmatching

B. It has high losses compared to other B. It has high losses compared to other types of antennastypes of antennas

C. It has poor directivityC. It has poor directivity


117 G9 - Antennas

G9D09 Which of the following is an G9D09 Which of the following is an application for a Beverage antenna?application for a Beverage antenna?

A. Directional transmitting for low HF bandsA. Directional transmitting for low HF bands

B. Directional receiving for low HF bandsB. Directional receiving for low HF bands

C. Portable direction finding at higher HF C. Portable direction finding at higher HF frequenciesfrequencies

D. Portable direction finding at lower HF D. Portable direction finding at lower HF frequenciesfrequencies

118 G9 - Antennas

G9D09 Which of the following is an G9D09 Which of the following is an application for a Beverage antenna?application for a Beverage antenna?

A. Directional transmitting for low HF bandsA. Directional transmitting for low HF bands

B. Directional receiving for low HF bandsB. Directional receiving for low HF bands

C. Portable direction finding at higher HF C. Portable direction finding at higher HF frequenciesfrequencies

D. Portable direction finding at lower HF D. Portable direction finding at lower HF frequenciesfrequencies

119 G9 - Antennas

G9D10 Which of the following describes a G9D10 Which of the following describes a Beverage antenna?Beverage antenna?

A. A vertical antenna constructed from A. A vertical antenna constructed from beverage cansbeverage cans

B. A broad-band mobile antennaB. A broad-band mobile antenna

C. A helical antenna for space receptionC. A helical antenna for space reception

D. A very long and low directional receiving D. A very long and low directional receiving antennaantenna

120 G9 - Antennas

G9D10 Which of the following describes a G9D10 Which of the following describes a Beverage antenna?Beverage antenna?

A. A vertical antenna constructed from A. A vertical antenna constructed from beverage cansbeverage cans

B. A broad-band mobile antennaB. A broad-band mobile antenna

C. A helical antenna for space receptionC. A helical antenna for space reception

D. A very long and low directional receiving D. A very long and low directional receiving antennaantenna

121 G9 - Antennas

G9D11 Which of the following is a G9D11 Which of the following is a disadvantage of multiband antennas?disadvantage of multiband antennas?

A. They present low impedance on all design A. They present low impedance on all design frequenciesfrequencies

B. They must be used with an antenna tunerB. They must be used with an antenna tuner

C. They must be fed with open wire lineC. They must be fed with open wire line

D. They have poor harmonic rejectionD. They have poor harmonic rejection

122 G9 - Antennas

G9D11 Which of the following is a G9D11 Which of the following is a disadvantage of multiband antennas?disadvantage of multiband antennas?

A. They present low impedance on all design A. They present low impedance on all design frequenciesfrequencies

B. They must be used with an antenna tunerB. They must be used with an antenna tuner

C. They must be fed with open wire lineC. They must be fed with open wire line

D. They have poor harmonic rejectionD. They have poor harmonic rejection

123 G9 - Antennas

G9 - Antennas124

G9 – Antennas and FeedlinesG9 – Antennas and Feedlines[4 exam questions - 4 groups][4 exam questions - 4 groups]

G9 - Antennas 1 G9 – Antennas and Feedlines [4 exam questions - 4 groups] G9A - Antenna feed...

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Transcript of G9 - Antennas 1 G9 – Antennas and Feedlines [4 exam questions - 4 groups] G9A - Antenna feed...