Key Topic 64: Voltage, Current, and Power Relationships

Question 1

3-64J1: What is the current flowing through a 52 ohm line with an input of 1,872 watts?

A. 0.06 amps.
B. 6 amps.
C. 28.7 amps.
D. 144 amps.

Answer 1

B. 6 amps.

Question 2

3-64J2: The voltage produced in a receiving antenna is:

A. Out of phase with the current if connected properly.
B. Out of phase with the current if cut to 1/3 wavelength.
C. Variable depending on the station’s SWR.
D. Always proportional to the received field strength.

Answer 2

D. Always proportional to the received field strength.

Question 3

3-64J3: Which of the following represents the best standing wave ratio (SWR)?

A. 1:1
B. 1:1.5
C. 1:3
D. 1:4

Answer 3

A. 1:1

Question 4

3-64J4: At the ends of a half-wave antenna, what values of current and voltage exist compared to the remainder of the antenna?

A. Equal voltage and current.
B. Minimum voltage and maximum current.
C. Maximum voltage and minimum current.
D. Minimum voltage and minimum current.

Answer 4

C. Maximum voltage and minimum current.

Question 5

3-64J5: An antenna radiates a primary signal of 500 watts output. If there is a 2nd harmonic output of 0.5 watt, what attenuation of the 2nd harmonic has occurred?

A. 10 dB.
B. 30 dB.
C. 40 dB.
D. 50 dB.

Answer 5

B. 30 dB.

Question 6

3-64J6: There is an improper impedance match between a 30 watt transmitter and the antenna, with 5 watts reflected. How much power is actually radiated?

A. 35 watts.
B. 30 watts.
C. 25 watts.
D. 20 watts.

Answer 6

C. 25 watts.