What is meant by "repeater offset”?
The correct answer is A: The difference between a repeater's transmit and receive frequencies. Repeater offset refers to the frequency difference between where the repeater receives (input frequency) and where it transmits (output frequency). This offset allows the repeater to receive and transmit simultaneously without interference.
For example, a 2-meter repeater might receive on 146.160 MHz and transmit on 146.760 MHz - the offset is 600 kHz. The offset can be positive (repeater transmits higher than it receives) or negative (repeater transmits lower than it receives). This frequency separation is essential for repeater operation and prevents the repeater from interfering with its own receiver.
Exam Tip
Repeater offset = Frequency difference. Remember: Offset is the difference between the repeater's receive (input) and transmit (output) frequencies. For 2 meters, it's typically 600 kHz; for 70 cm, it's 5 MHz.
Memory Aid
"**R**epeater **O**ffset = **R**eceive **O**utput **D**ifference (think 'RO = ROD')"
Real-World Application
You're setting up your radio to use a repeater. The repeater output is 146.760 MHz, and the offset is 600 kHz. Your radio automatically calculates the input frequency as 146.160 MHz (600 kHz lower). When you transmit, you're on 146.160 MHz, and the repeater retransmits on 146.760 MHz. The 600 kHz difference is the offset.
FCC Part 97.205Key Concepts
Why Other Options Are Wrong
Option B: Incorrect. Repeater offset is not about time delay. It's about frequency separation between input and output.
Option C: Incorrect. Repeater identification is done on the same frequencies, not on a separate frequency. Offset refers to the frequency difference, not identification.
Option D: Incorrect. Offset is not about the number of transmit frequencies. It's the difference between one input and one output frequency.
题目解析
The correct answer is A: The difference between a repeater's transmit and receive frequencies. Repeater offset refers to the frequency difference between where the repeater receives (input frequency) and where it transmits (output frequency). This offset allows the repeater to receive and transmit simultaneously without interference. For example, a 2-meter repeater might receive on 146.160 MHz and transmit on 146.760 MHz - the offset is 600 kHz. The offset can be positive (repeater transmits higher than it receives) or negative (repeater transmits lower than it receives). This frequency separation is essential for repeater operation and prevents the repeater from interfering with its own receiver.
考试技巧
Repeater offset = Frequency difference. Remember: Offset is the difference between the repeater's receive (input) and transmit (output) frequencies. For 2 meters, it's typically 600 kHz; for 70 cm, it's 5 MHz.
记忆口诀
**R**epeater **O**ffset = **R**eceive **O**utput **D**ifference (think 'RO = ROD')
实际应用示例
You're setting up your radio to use a repeater. The repeater output is 146.760 MHz, and the offset is 600 kHz. Your radio automatically calculates the input frequency as 146.160 MHz (600 kHz lower). When you transmit, you're on 146.160 MHz, and the repeater retransmits on 146.760 MHz. The 600 kHz difference is the offset.
错误选项分析
Option B: Incorrect. Repeater offset is not about time delay. It's about frequency separation between input and output. Option C: Incorrect. Repeater identification is done on the same frequencies, not on a separate frequency. Offset refers to the frequency difference, not identification. Option D: Incorrect. Offset is not about the number of transmit frequencies. It's the difference between one input and one output frequency.
知识点
Repeater offset, Frequency difference, Input frequency, Output frequency
Verified Content
Question from official FCC Technician Class question pool. Explanation reviewed by licensed amateur radio operators.