T7A01: Receiver sensitivity: Term describes the ability of a receiver

Q: Which term describes the ability of a receiver to detect the presence of a signal?

The correct answer is B: Sensitivity. The correct answer is Sensitivity. Sensitivity describes the ability of a receiver to detect the presence of a signal - specifically, how weak a signal can be and still be detected. Sensitivity is typically measured in microvolts (μV) or decibels relative to a milliwatt (dBm) and represents the minimum signal strength required for the receiver to produce a usable output. For amateur radio operators, high sensitivity is crucial for receiving weak signals, working DX (long-distance contacts), and operating on bands with low signal levels. A more sensitive receiver can detect weaker signals, making it better for weak-signal work. Sensitivity is different from selectivity (ability to separate signals) and linearity (faithful signal reproduction).

Updated: Dec 9, 2025 | Source: 2022-2026 Question Pool | Topic: T7A

T7A01T7A

Which term describes the ability of a receiver to detect the presence of a signal?

Previous Next

Deep Dive: T7A01

The correct answer is Sensitivity. Sensitivity describes the ability of a receiver to detect the presence of a signal - specifically, how weak a signal can be and still be detected. Sensitivity is typically measured in microvolts (μV) or decibels relative to a milliwatt (dBm) and represents the minimum signal strength required for the receiver to produce a usable output. For amateur radio operators, high sensitivity is crucial for receiving weak signals, working DX (long-distance contacts), and operating on bands with low signal levels. A more sensitive receiver can detect weaker signals, making it better for weak-signal work. Sensitivity is different from selectivity (ability to separate signals) and linearity (faithful signal reproduction).

Why Other Answers Are Wrong

Option A (Linearity): Incorrect. Linearity refers to how faithfully a receiver reproduces the input signal without distortion. It's about signal quality, not the ability to detect weak signals. Option C (Selectivity): Incorrect. Selectivity describes a receiver's ability to discriminate between multiple signals and reject unwanted ones. It's about separating signals, not detecting their presence. Option D (Total Harmonic Distortion): Incorrect. THD is a measure of distortion in the output signal, indicating how much the signal is altered. It's a quality metric, not a detection capability.

Exam Tip

Sensitivity = ability to detect weak signals. Think 'S'ensitivity = 'S'ensing weak signals. Selectivity separates signals, linearity preserves quality, THD measures distortion - none describe detection ability.

Memory Aid

Sensitivity = Sensing weak signals. Think 'S'ensitivity = 'S'ensing how 'S'mall a signal you can detect. Lower numbers (μV) = better sensitivity.

Real-World Example

When working a weak DX station on 20 meters, your receiver's sensitivity determines whether you can hear them at all. A receiver with 0.5 μV sensitivity might detect the signal, while one with 2.0 μV sensitivity might miss it completely. High sensitivity is essential for weak-signal work, allowing you to copy signals that less sensitive receivers can't detect.

Source & Coverage

Question Pool: 2022-2026 Question Pool

Subelement: T7A

Reference: 2022-2026 Question Pool · T7 - Practical circuits

Key Concepts

Receiver sensitivity Signal detection Receiver performance Weak signal reception

Verified Content

Question from the official FCC Technician Class pool. Explanation reviewed by licensed amateur radio operators and mapped to the T7A topic.