Free Practical Antenna Basics (PAB) Practice Questions

Sample Practice Questions

Try these 10 sample questions from the Practical Antenna Basics (PAB) practice bank. Each includes the answer and explanation. Continue with the interactive practice above to review the full question set.

1. 1Before an employee begins telecommunications work covered by OSHA 1910.268, what must the employer establish about safety training?

   1. A.The employee has received the required precautions and safe-practice training.Correct answer: A
   2. B.The employee will receive the required training after completing the first assignment.
   3. C.The employee can substitute a supervisor's presence for the required training.
   4. D.The employee needs the required training only after a reportable incident.

   Explanation: OSHA requires that employees "do not engage in the activities to which this section applies until such employees have received proper training". Training must precede covered work; a supervisor or a future class does not replace it. Previously acquired adequate training can satisfy the requirement.

   Reference: 29 CFR 1910.268 — Telecommunications — 1910.268(c), Training

2. 2What energy conversion makes a transmitting antenna a transducer?

   1. A.Electrical RF energy into an RF signal with greater total power.
   2. B.A modulated RF signal into its recovered baseband message.
   3. C.Electrical RF energy into radiated electromagnetic energy.Correct answer: C
   4. D.An RF carrier into another carrier at a different frequency.

   Explanation: ETA describes transforming "internal voltage energy into electromagnetic output energy". The transmitting antenna couples electrical energy into radiation; amplification, demodulation, and frequency conversion describe different RF functions.

   Reference: Practical Antenna Basics (PAB) Technician Competency Requirements — Page 1, introductory paragraph

3. 3In spectrum regulation, what is a frequency-band allocation?

   1. A.A table entry designating a frequency band for specified radio services.Correct answer: A
   2. B.An agreed-plan entry designating a frequency channel for administrations in an area.
   3. C.An authorization for an identified station to use a particular frequency.
   4. D.An equipment authorization establishing a transmitter model's compliance.

   Explanation: The FCC defines allocation as "Entry in the Table of Frequency Allocations" for services under stated conditions. An agreed-plan channel entry is an allotment; station-specific frequency authorization is an assignment. Equipment authorization addresses a different regulatory object.

   Reference: 47 CFR 2.1 — Terms and definitions — 2.1(c), Allocation (of a frequency band)

4. 4Which additional source of magnetic field is included in the Ampere–Maxwell law besides conduction current?

   1. A.An electric field that is constant in time.
   2. B.A time-varying electric displacement field.Correct answer: B
   3. C.An isolated magnetic charge at rest.
   4. D.A constant electric potential with no field change.

   Explanation: The Ampère equation includes "\frac{\partial{\bf D}}{\partial t}". This time derivative of electric displacement is Maxwell’s displacement-current term, so a changing electric displacement contributes to the magnetic field. Static quantities supply no such time derivative; classical theory has no isolated magnetic-charge term here.

   Reference: MFEM — Maxwell's Equations — Maxwell's Equations, displayed system

5. 5Which conductor construction identifies a twisted-pair line used to carry RF signals?

   1. A.An inner wire surrounded concentrically by a tubular outer conductor.
   2. B.Two insulated conductors wound around each other.Correct answer: B
   3. C.A hollow conducting tube without an inner conductor.
   4. D.A single conductor with no companion return conductor.

   Explanation: Extron describes TP as using "small twisted pairs of wires". This differs from coaxial concentric conductors, hollow waveguide, or a single wire.

   Reference: Extron Glossary of Terms — Twisted Pair — TP — Twisted Pair

6. 6What is the basic structure of a center-fed straight dipole antenna?

   1. A.One wire connected only to a ground plane.
   2. B.A closed wire loop fed at its circumference.
   3. C.Several passive rods without a driven element.
   4. D.Two straight arms separated by a small central feed gap.Correct answer: D

   Explanation: NTIA describes "two straight electric lines separated by a small gap at the center", with the feed at that gap. A ground-referenced single arm, closed loop or unfed parasitic assembly does not have this center-fed dipole structure.

   Reference: Antenna Models for Electromagnetic Compatibility Analyses — Section 3.2.1, page 3-1, Dipole Antenna

7. 7Which radiation property defines the ideal isotropic antenna model?

   1. A.Uniform radiation over all directions in three-dimensional space.Correct answer: A
   2. B.Uniform radiation only around one horizontal circle.
   3. C.Radiation confined to two opposite main lobes.
   4. D.Radiation concentrated along one narrow boresight.

   Explanation: NTIA defines the isotropic radiator as one that "radiates power uniformly in all directions". This is three-dimensional uniformity, unlike one-plane omnidirectionality, a two-lobe pattern, or a narrow boresight beam.

   Reference: Antenna Models for Electromagnetic Compatibility Analyses — Section 2.4.2(a), page 2-5, Isotropic Radiation Pattern

8. 8Which oscilloscope control sets the voltage represented by each vertical division?

   1. A.Horizontal position
   2. B.Vertical sensitivityCorrect answer: B
   3. C.Trigger holdoff
   4. D.Time-base rate

   Explanation: The PAB competencies identify "Voltage control (y-axis)(vertical)". Vertical sensitivity sets volts per division; the time base controls horizontal time, position moves the trace, and holdoff affects triggering.

   Reference: Practical Antenna Basics (PAB) Technician Competency Requirements — Section 8.1.3.2

9. 9A telecommunications crew will work beside traffic that could endanger employees. When should warning signs or other traffic control devices be placed?

   1. A.After equipment has been unloaded into the traffic area.
   2. B.Before work begins in the affected traffic area.Correct answer: B
   3. C.After an approaching driver fails to slow down.
   4. D.When the first work shift ends in the traffic area.

   Explanation: OSHA states, "Before work is begun in the vicinity of vehicular or pedestrian traffic which may endanger employees, warning signs and/or flags or other traffic control devices shall be placed conspicuously". Protection is required before exposure to the traffic hazard.

   Reference: 29 CFR 1910.268 — Telecommunications — 1910.268(d)(1), Employee protection in public work areas

10. 10Which behavior of electrical charge supports continuous RF radiation from a transmitting antenna?

    1. A.Charge oscillates back and forth at the applied RF frequency.Correct answer: A
    2. B.Charge remains stationary on an isolated conductor.
    3. C.Charge flows as an unchanging direct current after transients cease.
    4. D.Charge redistributes once and then remains at rest.

    Explanation: The FCC states, "The RF waves emanating from an antenna are generated by the movement of electrical charges in the antenna." Sustained RF excitation produces oscillating charge/current. Static charge, steady DC after transients, and a completed one-time redistribution do not produce continuous RF radiation.

    Reference: FCC — Radio Frequency Safety: Frequently Asked Questions — What is radiofrequency and microwave radiation?