HPE7-A01 practice question 6 of 25

You are doing tests in your lab and with the following equipment specifications • AP1 has a radio that generates a 10 dBm signal • AP2 has a radio…

Full set: 117 questions
You are doing tests in your lab and with the following equipment specifications • AP1 has a radio that generates a 10 dBm signal • AP2 has a radio that generates a 11 dBm signal • AP1 has an antenna with a gain of 9 dBi • AP2 has an antenna with a gain of 12 dBi. • The antenna cable for AP1 has a 2 dB loss • The antenna cable for AP2 has a 3 dB loss What would be the calculated Equivalent Isotropic Radiated Power (EIRP) for APT?
Answer options
A: 26 dBm
B: 30 dBm
C: 17 dBm Correct answer
D: -12 dBm
Correct Answer:
C. 17 dBm
Explanation

Equivalent Isotropic Radiated Power (EIRP) is the total power radiated from a theoretical isotropic antenna. It is calculated by adding the transmitter power to the antenna gain and subtracting any signal loss that occurs in the transmission line (e.g., antenna cable). The formula is: EIRP = Transmitter Power (dBm) + Antenna Gain (dBi) – Cable Loss (dB) For AP1, the values are: Transmitter Power = 10 dBm Antenna Gain = 9 dBi Cable Loss = 2 dB Calculation: EIRP = 10 dBm + 9 dBi - 2 dB = 17 dBm.

Why Incorrect

A. 26 dBm: This value is an incorrect calculation and does not correspond to the specifications provided for either AP1 or AP2.
B. 30 dBm: This is a common regulatory EIRP limit in some regions (e.g., for UNII-1 and UNII-3 bands in the US), not the calculated value for AP1's specific hardware.
D. -12 dBm: This result would be derived from an incorrect application of the EIRP formula, such as improperly subtracting gain or adding loss.

References

1. Aruba Networks

an HPE Company. ArubaOS 8.6.0.0 User Guide. (2019). In the section on RF Management (ARM)

the concept of EIRP is discussed as the basis for power level management. The guide implicitly uses the standard formula (Transmit Power + Antenna Gain - Cable Loss) to determine the final radiated power. See Chapter: "RF Management (ARM)"

Section: "Power Management".

2. HPE Press. Aruba Certified Mobility Associate (ACMA) Official Certification Study Guide. (2020). The guide covers fundamental RF concepts

including the calculation of EIRP. Chapter 2

"RF Fundamentals

" details the components of an RF system and explains how to calculate link budgets and radiated power using dBm

dBi

and dB loss values. The formula EIRP = Tx Power + Antenna Gain – Cable Loss is a core concept presented.

3. David D. Coleman

David A. Westcott. CWNA Certified Wireless Network Administrator Study Guide

5th Edition. (Sybex

2018). While a general industry certification guide

its principles are foundational to vendor-specific exams like HPE7-A01. Chapter 4

"Radio Frequency Fundamentals

" page 121

explicitly defines the EIRP calculation as: "Transmitter Power (in dBm) – Cable Loss (in dB) + Antenna Gain (in dBi) = EIRP (in dBm)".

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