2014 Tech study guide: ITU, frequency allocations, modes

The ITU is a United Nations agency for information and communication technology issues.(T1B01) There are three ITU regions. North American amateur stations are located in ITU region 2.

One of the reasons that it is important to know about the ITU zones is important is that different zones often have different frequency assignments. For example, the frequency assignments for some U.S. Territories different from those in the 50 U.S. States because some U. S. Territories are located in ITU regions other than region 2. (T1B02) [97.301] Similarly, frequency assignments for U.S. stations operating maritime mobile are not the same everywhere in the world because amateur frequency assignments can vary among the three ITU regions. (T1B12) [97.301]

Because operation outside of the amateur radio bands is a serious offense, it is important to know about the frequencies and bands that amateur radio operators can use:

  • 52.525 MHz is a frequency within the 6 meter band. (T1B03)
  • The 2 meter band is the amateur band are you using when your station is transmitting on 146.52 MHz. (T1B04)
  • 443.350 MHz is the 70 cm frequency is authorized to a Technician Class license holder operating in ITU Region 2. (T1B05)
  • 1296 MHz is a 23 cm frequency is authorized to a Technician Class licensee. (T1B06)
  • 1.25 meter band is the amateur band are you using if you are transmitting on 223.50 MHz. (T1B07)

All of these choices are correct when thinking about why you should not set your transmit frequency to be exactly at the edge of an amateur band or sub-band (T1B09):

  • To allow for calibration error in the transmitter frequency display
  • So that modulation sidebands do not extend beyond the band edge
  • To allow for transmitter frequency drift

In addition to defining which frequencies are available to amateur radio operators, the FCC also defines sub-bands for various modes. For example, CW only is the emission mode permitted in the mode-restricted sub-bands at 50.0 to 50.1 MHz and 144.0 to 144.1 MHz (T1B11) [97.301(a), 97.305 (a)(c)]. The 6 meter, 2 meter, and 1.25 meter bands are the bands available to Technician Class operators that have mode-restricted sub-bands (T1B10) [97.301(e), 97.305(c)]. The use of SSB phone in amateur bands above 50 MHz is permitted in at least some portion of all the amateur bands above 50 MHz. (T2B13)

Amateur radio frequency operators share some bands with users from other services. Sometimes, amateurs are the primary users, such as the 2m band, but sometimes amateur radio operators are secondary users. One result of the fact that the amateur service is secondary in some portions of the 70 cm band is that U.S. amateurs may find non-amateur stations in the bands, and must avoid interfering with them. (T1B08) [97.303]

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