The International Telecommunication Union (ITU) is an agency of the United Nations which regulates information and communication technology issues. It is also the global focal point for governments and the private sector in regards to developing networks and services.

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From wikipedia: The International Telecommunication Union (ITU), in its International Radio Regulations../wiki/Radio_Regulations), divides the world into three ITU regions for the purposes of managing the global radio spectrum. Each region has its own set of frequency allocations, the main reason for defining the regions.

• Region 1 comprises Europe, Africa, the Middle East west of the Persian Gulf including Iraq, the former Soviet Union and Mongolia.

• Region 2 covers the Americas, Greenland and some of the eastern Pacific Islands.

• Region 3 contains most of non-former-Soviet-Union Asia, east of and including Iran, and most of Oceania.

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As an aid, convert the wavelength to frequency:

\begin{align} f_\text{ (MHz)} = \frac{300}{\lambda _\text{ (meters)}} \end{align}

So in this case: \begin{align} f_\text{ (MHz)} &= \frac{300}{6 \text{ m}} \approx 50 \text{ MHz} \end{align}

52.525 MHz is the only frequency in the 6 meter band.

Note:
The distractor answer 49 MHz is even closer to 6 meters in length, however, is outside of the US amateur 6 meter frequency allocation, which is the range 50.0 MHz - 54.0 MHz. The sub-band 50.0 MHz to 50.1 MHz is restricted to CW (Continuous Wave) only.

Hint: Subtract 1 from the band (6) to come up with 5. Only the correct answer (52.525) starts with a 5.

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Tags: frequencies 6 meter

As an aid, you can convert the frequency (\(f\)) to wavelength in meters (\(\lambda\)) :

\begin{align} \lambda_\text{ (m)} = \frac{300}{f_\text{(MHz)}} \end{align}

(300 is approximately the number of Mm/sec light travels in a vacuum.) So in this case: \begin{align} \lambda_\text{ (m)} &= \frac{300}{146.52 \text{ MHz}} = 2.05 \text{ m} \approx 2 \text{ m} \end{align}

144-148Mhz is the frequency range allocated to ham radio operators in the 2 meter band, with 144.0-144.1 being allocated for CW mode only.

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Tags: frequencies 2 meter

300 / frequency = wavelength in meters. 300 / 443.35 is around .70 (this question is easy to spot if you remember the formula, because 443.35 is the only answer that would give you a value less than 1m). The frequencies allocated to amateur radio in the 70cm band are 420-450Mhz.

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Tags: frequencies 70 cm

One common thread in most frequency related questions on the technician exam is that only one of the answers is even in the given band.

300 / frequency = wavelength in meters. 300 / 1296 = 0.23, or 23cm.

You are allowed a calculator on the exam.

The frequencies 1240-1300MHz are allocated to amateur radio operators in the 23cm band.

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Tags: frequencies 23 cm

We have an equation:

Speed of light (c) = wavelength (lambda) * freq. (f) -> lambda = c / f = (3*10^8) / (223.50 * 10^6) = 300/223.50 = 1.34 m

Normally when the result of the 300 / frequency equation lands over a band, it's considered outside that band. In this case, 1.34 is over 1.25, but it is the closest available answer. You must simply know that the 1.25 meter band is significant.

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Frequency bands that are available on a secondary basis can be thought of as frequencies that you can use as long as someone else isn't using it. Some other group or service has primary privileges on that band, and you are allowed to use it as long as you do not cause harmful interference to those primary users.

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All of the choices are correct. Here is each one explained:

1. The frequency you set on a transmitter is actually the carrier frequency which is either at the center of the total bandwidth that you're using (for FM or non-SSB) or at the top or bottom of the bandwidth (for SSB). When you transmit on a frequency, you will actually use a little bit of bandwidth above and/or below that frequency (referred to as deviation) even with a properly calibrated transmitter!

2. Not all transmitters are calibrated perfectly, and so if you set your transmitter exactly on a specific frequency, say the bottom edge of the amateur portion of the band even when using upper sideband (USB), you may actually be transmitting illegally out of band, due to calibration error.

3. Some transmitters may drift a little bit off frequency during transmission as well (due to temperature changes as the radio gets warmer etc).

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On 6 meters, 50.0 - 50.1MHz is allocated to CW mode only. (Morse code)

On 2 meters, 144.0 - 144.1MHz is allocated to CW mode only.

On 1.25 meters, 219.0-220.0 may be used only for Fixed digital message forwarding systems.

Dedicating a small portion of the band, a 100 khz wide sub-band, helps enable the reception of low power signals, such as EME (Earth-Moon-Earth) and propagation beacons, by protecting them from higher bandwidth modes like SSB/FM phone.

Similarly, the dedicated space on 1.25 meters, helps enable the operation of automatically controlled digital message forwarding systems. Reserving that piece of bandwidth from other operations helps prevent interference from other operators, as well as prevents other communications from being interfered with by automatically controlled stations.

For more information, ARRL has published a chart of ham radio bands [PDF].

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Tags: mode-restricted 6 meter 2 meter 1.25 meter

On 6 meters, 50.0 - 50.1MHz is allocated to CW mode only. (Morse code)

On 2 meters, 144.0 - 144.1MHz is allocated to CW mode only.

Dedicating a small portion of the band, a 100 khz wide sub-band, helps enable the reception of low power signals, such as EME (Earth-Moon-Earth) and propagation beacons, by protecting them from higher bandwidth modes like SSB/FM phone.

For more information, ARRL has published a chart of ham radio bands.

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Tags: morse code 2 meter 6 meter mode-restricted