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T1B09

COMMISSION'S RULES · Frequency allocations; Emission modes; Spectrum sharing; Transmissions near band edges; Contacting the International Space Station; Power output

T1B09§ 97.101(a), 97.301(a-e)T1B →

Why should you not set your transmit frequency to be exactly at the edge of an amateur band or sub-band?

  1. ATo allow for calibration error in the transmitter frequency display
  2. BSo that modulation sidebands do not extend beyond the band edge
  3. CTo allow for transmitter frequency drift
  4. DAll these choices are correct
Why Your transmitted signal is not a single point; it occupies bandwidth, so an SSB or FM carrier set right at the edge will push sidebands outside the allocation. On top of that, the dial reading may be off by some calibration error and the oscillator can drift with temperature, all of which can put part of your emission out of band. Section 97.301 assigns band limits to your entire emission, not just the carrier, so operators leave a margin of a few kHz inside the edge.
Watch out Each individual reason listed is true on its own, so picking just the sidebands answer or just the drift answer misses the other valid reasons.
Your whole signal must fit inside the band: sidebands, dial error and drift all argue for staying a few kHz in.
HamSandwich explanation, first draft. The question and answers are the NCVEC text.
47 CFR 97.101(a) General standards.

(a) In all respects not specifically covered by FCC Rules each amateur station must be operated in accordance with good engineering and good amateur practice.

(b) Each station licensee and each control operator must cooperate in selecting transmitting channels and in making the most effective use of the amateur service frequencies. No frequency will be assigned for the exclusive use of any station.

(c) At all times and on all frequencies, each control operator must give priority to stations providing emergency communications, except to stations transmitting communications for training drills and tests in RACES.

(d) No amateur operator shall willfully or maliciously interfere with or cause interference to any radio communication or signal.

eCFR text as of 1 Sep 2026 · read on ecfr.gov
47 CFR 97.301 Authorized frequency bands.

The following transmitting frequency bands are available to an amateur station located within 50 km of the Earth's surface, within the specified ITU Region, and outside any area where the amateur service is regulated by any authority other than the FCC.

(a) For a station having a control operator who has been granted a Technician, General, Advanced, or Amateur Extra Class operator license or who holds a CEPT radio-amateur license or IARP of any class:

(b) For a station having a control operator who has been granted an Amateur Extra Class operator license, who holds a CEPT radio amateur license, or who holds a Class 1 IARP license:

(c) For a station having a control operator who has been granted an operator license of Advanced Class:

(d) For a station having a control operator who has been granted an operator license of General Class:

(e) For a station having a control operator who has been granted an operator license of Novice Class or Technician Class:

eCFR text as of 1 Sep 2026 · read on ecfr.gov
← T1B08 All of T1B T1B10 →

The rest of T1B

  1. T1B01 Which of the following frequency ranges are available for phone operation by Technician licensees?
  2. T1B02 Which of the following U.S. amateur radio operators are allowed to contact the International Space Station (I…
  3. T1B03 Which frequency is in the 6-meter amateur band?
  4. T1B04 Which amateur band includes 146.52 MHz?
  5. T1B05 Which of the following bands include frequencies where Technicians are authorized to use digital modes such a…
  6. T1B06 On which HF bands does a Technician class operator have phone privileges?
  7. T1B07 Which of the following VHF/UHF band segments are limited to CW only?
  8. T1B08 How are US amateurs restricted in segments of bands where the Amateur Radio Service is secondary?
  9. T1B09 Why should you not set your transmit frequency to be exactly at the edge of an amateur band or sub-band?
  10. T1B10 Where may SSB phone be used in amateur bands above 50 MHz?
  11. T1B11 What is the maximum peak envelope power output for Technician class operators in their HF band segments?
  12. T1B12 Except for some specific restrictions, what is the maximum peak envelope power output for Technician class op…
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