Deep Dive: T1B09
The correct answer is D: All these choices are correct. You should not set your transmit frequency exactly at the edge of an amateur band or sub-band for all three reasons mentioned: to allow for calibration error, to prevent modulation sidebands from extending beyond the band edge, and to allow for transmitter frequency drift. Transmitters are not always perfectly calibrated, and their frequency displays may have some error. Additionally, when you modulate a signal (especially with phone modes), sidebands are created that extend beyond your carrier frequency. If you're right at the band edge, these sidebands could extend outside the authorized band. Finally, transmitters can drift in frequency due to temperature changes or component aging. By staying away from band edges, you ensure that even with these factors, your signal and its sidebands remain within the authorized band.
Why Other Answers Are Wrong
This question has no incorrect options since all choices are correct. However, it's important to understand that all three factors (calibration error, sidebands, and drift) are valid reasons to avoid band edges.
Exam Tip
Band edges = Stay away. Remember: All three reasons are valid - calibration error, sidebands, and drift. When you see 'all these choices are correct' and all options are reasonable technical concerns, that's usually the answer.
Memory Aid
**B**and **E**dge = **B**ad **E**verything (think 'BE = Bad Everything' - stay away from edges)
Real-World Example
You're operating on 28.500 MHz, which is at the upper edge of the Technician phone segment (28.300-28.500 MHz). Your transmitter has a slight calibration error showing 28.500 MHz when you're actually on 28.501 MHz. When you modulate with voice, sidebands extend to 28.502 MHz, which is outside your authorized segment. By operating at 28.480 MHz instead, you have a safety margin that accounts for calibration error, sidebands, and any frequency drift.
Source & Coverage
Question Pool: 2022-2026 Question Pool
Subelement: T1B
Reference: FCC Part 97.101
Key Concepts
Verified Content
Question from the official FCC Technician Class pool. Explanation reviewed by licensed amateur radio operators and mapped to the T1B topic.