Free NICET In-Building Public Safety Communications Design Exam Practice Questions

Sample Practice Questions

Try these 10 sample questions from the NICET In-Building Public Safety Communications Design Exam practice bank. Each includes the answer and explanation. Continue with the interactive practice above to review the full question set.

1. 1A project specification proposes using a PLMRS signal booster to extend a licensed station's normal service contour. How should the designer interpret this proposal under 47 CFR 90.219?

   1. A. The extension is allowed if the booster is Class A.
   2. B. The extension conflicts with the permitted use of boosters.
   3. C. The extension is allowed if the building owner consents.
   4. D. The extension is allowed if output stays below 5 W ERP.

   Answer: B

   Explanation: Section 90.219(d)(2) states, "Signal boosters must not be used to extend PLMRS stations' normal operating range." A booster can improve weak coverage within the authorized contour; its class, owner consent, or power limit does not authorize extending that contour.

   Reference: 47 CFR § 90.219 — Use of signal boosters — § 90.219(b), (d)(1)–(2)

2. 2A BDA has 75 dB gain and only 70 dB attenuation around its feedback loop. According to NTIA's feedback analysis, which condition results?

   1. A. A positive 5 dB feedback margin
   2. B. A negative feedback margin permitting oscillation
   3. C. A 145 dB margin preventing feedback
   4. D. A gain-independent stable feedback loop

   Answer: B

   Explanation: NTIA states, "Oscillation occurs when the BDA gain equals or exceeds feedback loop attenuation". Here gain exceeds attenuation by 5 dB, giving a negative margin.

   Reference: In-Building Radio Enhancement Systems for Public Safety — § 3.1, p. 18

3. 3Which paired inputs are needed for the IBRES computer-aided design workflow described by NTIA?

   1. A. Building architecture and RF specifications of system components
   2. B. Building architecture and equipment prices instead of RF specifications
   3. C. RF component specifications and floor area without interior geometry
   4. D. RF component specifications and a generic category without actual architecture

   Answer: A

   Explanation: NTIA states, "The software uses building architectural design information and specifications for various IBRES components". Both physical architecture and component RF parameters inform the design.

   Reference: In-Building Radio Enhancement Systems for Public Safety — § 2.4, p. 13

4. 4A building owner who is not a PLMRS licensee will operate a booster for a public safety agency's assigned frequencies. Which authorization provision belongs in the project specifications?

   1. A. Express licensee consent retained in a recordable format
   2. B. Installer certification retained instead of licensee consent
   3. C. Building-owner approval retained instead of licensee consent
   4. D. Antenna-vendor approval retained instead of licensee consent

   Answer: A

   Explanation: Section 90.219(b)(1)(i) requires non-licensees to "obtain the express consent of the licensee(s) of the frequencies for which the device or system is intended to amplify." It adds, "The consent must be maintained in a recordable format". Installer, owner, and vendor approvals do not substitute for this frequency-licensee consent.

   Reference: 47 CFR § 90.219 — Use of signal boosters — § 90.219(b)(1)(i)

5. 5Why can a BDA still distort its own retransmitted signal even when its feedback loop margin is slightly positive?

   1. A. A positive margin means returned feedback exceeds amplifier input at every frequency.
   2. B. A positive margin means returned feedback cannot combine with the wanted signal.
   3. C. A small positive margin can stop oscillation while leaving significant self-interference.
   4. D. A positive margin means the feedback path contributes attenuation but no phase change.

   Answer: C

   Explanation: NTIA explains, "The FLM is positive, which prevents oscillation, but it is not large enough to protect the signal from interfering with itself." Avoiding oscillation and suppressing feedback distortion are different stability requirements.

   Reference: In-Building Radio Enhancement Systems for Public Safety — § 3.1, p. 18

6. 6For a simplified link model, transmitter power is 30 dBm, transmit antenna gain is 5 dB, receive antenna gain is 2 dB, and total path loss is 80 dB. What received power should be entered as the calculated result?

   1. A. −47 dBm
   2. B. −43 dBm
   3. C. −50 dBm
   4. D. 117 dBm

   Answer: B

   Explanation: NTIA gives "Pr  Pt  Gt  Gr  Lp (dBm)". Thus 30 + 5 + 2 − 80 = −43 dBm. Gains add and total loss subtracts.

   Reference: In-Building Radio Enhancement Systems for Public Safety — Appendix B.5, equation B-24, p. 43

7. 7A PLMRS booster incidentally retransmits an unintended third-party licensee's signal. Which interpretation correctly addresses that third party under 47 CFR 90.219?

   1. A. Its consent is required before any incidental retransmission.
   2. B. Its incidental signal must be assigned a new output channel.
   3. C. Its consent is unnecessary, but operation remains non-interfering.
   4. D. Its lack of required consent exempts the booster from interference action.

   Answer: C

   Explanation: Section 90.219(b)(1)(ii) states, "Consent is not required from third party (unintended) licensees whose signals are incidentally retransmitted." It also states that "signal booster operation is on a non-interference basis". Thus lack of a consent requirement does not remove interference obligations or permit frequency translation.

   Reference: 47 CFR § 90.219 — Use of signal boosters — § 90.219(b)(1)(ii)

8. 8A previously stable BDA begins oscillating when an exterior door opens near an indoor antenna. What physical change explains this behavior?

   1. A. Coupling-path loss falls, increasing feedback at the amplifier input.
   2. B. Coupling-path loss rises, increasing isolation between the antennas.
   3. C. Coupling-path loss falls, reducing feedback at the amplifier input.
   4. D. Coupling-path loss is unchanged because the antennas have not moved.

   Answer: A

   Explanation: NTIA states, "Opening the door reduces propagation loss between the indoor and outdoor antenna." The stronger returned signal reduces isolation margin even without antenna movement.

   Reference: In-Building Radio Enhancement Systems for Public Safety — § 3.1, p. 19, door-opening example

9. 9A designer copies path-loss exponent n and shadowing standard deviation σ from a warehouse model into an office model without validation. Which limitation does NTIA identify?

   1. A. Matching frequency alone establishes both parameters are transferable.
   2. B. Matching floor area alone establishes both parameters are transferable.
   3. C. Both parameters depend on the actual propagation environment.
   4. D. Changing transmit power alone corrects both for the new environment.

   Answer: C

   Explanation: NTIA notes that "we do not expect office buildings, warehouses, suburban areas, and urban areas to have the same n and σ." The environment must support the chosen propagation parameters.

   Reference: In-Building Radio Enhancement Systems for Public Safety — Appendix B.2, pp. 40–41

10. 10For an ordinary building PLMRS booster deployment with no railroad exception, what is the maximum radiated power permitted per retransmitted channel on either link under 47 CFR 90.219(d)(3)?

    1. A. 1 watt ERP
    2. B. 2 watts ERP
    3. C. 10 watts ERP
    4. D. 5 watts ERP

    Answer: D

    Explanation: Section 90.219(d)(3)(i) specifies that radiated power per channel on the forward and reverse links "does not exceed 5 Watts effective radiated power (ERP)." The stated building application does not invoke the separate railroad exception. The question asks for the maximum, so lower compliant settings are not competing answers.

    Reference: 47 CFR § 90.219 — Use of signal boosters — § 90.219(d)(3)(i)–(ii)