Deep Dive: E4D13
The correct answer is A: -51 dBm. What is the received signal level with a transmit power of 10 W (+40 dBm), a transmit antenna gain of 6 dBi, a receive antenna gain of 3 dBi, and a path loss of 100 dB is -51 dBm. Received = 40 + 6 + 3 - 100 = -51 dBm. For amateur radio operators, this is important for link budget calculations. Understanding this helps when planning communications.
Why Other Answers Are Wrong
Option B (-54 dBm): Incorrect. -54 dBm is too low - the calculation gives -51 dBm. -54 dBm is wrong. Option C (-57 dBm): Incorrect. -57 dBm is too low - the calculation gives -51 dBm. -57 dBm is wrong. Option D (-60 dBm): Incorrect. -60 dBm is too low - the calculation gives -51 dBm. -60 dBm is wrong.
Exam Tip
Received signal level = transmit power + transmit gain + receive gain - path loss. Think 'R'eceived = 'T'ransmit + 'G'ains - 'L'oss. Received = 40 + 6 + 3 - 100 = -51 dBm. Not -54dBm, not -57dBm, not -60dBm - just -51 dBm.
Memory Aid
Received signal level = transmit power + transmit gain + receive gain - path loss. Think 'R'eceived = '-5'1 dBm. Received = 40 + 6 + 3 - 100 = -51 dBm. Important for link budget calculations.
Real-World Example
Received signal level calculation: Transmit 40 dBm + transmit antenna 6 dBi + receive antenna 3 dBi - path loss 100 dB = -51 dBm received. This is the received signal level - -51 dBm.
Source & Coverage
Question Pool: 2024-2028 Question Pool
Subelement: E4D
Reference: 2024-2028 Question Pool · E4 - Amateur Practices
Key Concepts
Verified Content
Question from the official FCC Extra Class pool. Explanation reviewed by licensed amateur radio operators and mapped to the E4D topic.