FCC Technician Class Exam Study Guide - 2014-2018/Subelement T1 Group B
In this section, there is a certain amount of memorization when it comes to usage of spectrum. There are portions of the available spectrum that are reserved for certain modes. Certain portions of the spectrum also have limit on data speed (faster data can have an exceptionally wide footprint in the spectrum). These limitations are described in tables located in 97.301 and 97.305.
The usage of the words "frequency" and "wavelength" are used interchangeably and that is because they are two different words that describe the same thing. It is only by chance that we dial a frequency as opposed to dialing a wavelength on a radio receiver. The two domains are mathematical inverses of each other.
Where is the speed of light which is rounded to meters per second. The is the wavelength in meters. The is frequency in Hertz, which is cycles per second.
Mathematically the units cancel out.
So the wavelength is in meters per 1 cycle, the length of one full oscillation of a radio wave as it travels at nearly the speed of light through the atmosphere. This is important: The wavelength is the length of a full oscillation of a radio signal as it travels at nearly the speed of light through the atmosphere.
Many radar installations fire incredibly short bursts of signal where, if it were visible like a laser beam in fog, for a very brief moment, you would be able to see the beginning, the end, as well as the dark regions in between these points where the signal intensity is zero, thus separating each individual wave.
Back to our test, here's a shortcut. If we take our frequency in MHz (Megahertz is divided by a million) and the speed of light of million meters per second, we get a slightly simplified equation.
For example 146.200 Mhz is in the 2 meter band because meters. Likewise 50 Mhz is the 6 meter band.
A number of these problems can be calculated instead of being memorized. All you have to remember is the formula. Consider these problems as 'freebies'.
The Question PoolEdit
- What is the ITU?
- A. An agency of the United States Department of Telecommunications Management
- B. A United Nations agency for information and communication technology issues
- C. An independent frequency coordination agency
- D. A department of the FCC
The ITU resides under the United Nations and they seek to create international agreements towards a band plan that satisfies each nations needs while also minimizing interference. The correct answer is B.
- Why are the frequency assignments for some U.S. Territories different from those in the 50 U.S. States?
- A. Some U. S. Territories are located in ITU regions other than region 2
- B. Territorial governments are allowed to select their own frequency allocations
- C. Territorial frequency allocations must also include those of adjacent countries
- D. Any territory that was in existence before the ratification of the Communications Act of 1934 is exempt from FCC frequency regulations
There are U.S. territories that do reside outside the ITU Region 2 of North America. Those stations, despite having rules governed by the FCC, must comply with the ITU Region they are transmitting from. Even places such as Hawaii that is Region 2, cannot engage in amateur conversation with stations located just west in Region 3 on certain frequencies. The correct answer is A.
- Which frequency is within the 6 meter band?
- A. 49.00 MHz
- B. 52.525 MHz
- C. 28.50 MHz
- D. 222.15 MHz
You can look this equivalency up in 97.301(a), but there is a mathematical explanation as well. Frequency and Wavelength are mathematical inverses with each other. The proportionality constant is 300,000,000. 300,000,000 / x = 6 as our equation would have 50,000,000 as our result. 52.525 MHz is the closest number. The correct answer is B.
- Which amateur band are you using when your station is transmitting on 146.52 MHz?
- A. 2 meter band
- B. 20 meter band
- C. 14 meter band
- D. 6 meter band
You can look up the band plan in 97.301(a). (Section (a) is the technician privileges.) There is a different approach to get close to the same answer. Frequency in Hertz and wavelength in meters are mathematical inverses of each other. The constant or proportionality is 300,000,000 which is the speed of light in meters per second. 300,000,000/146,520,000 is approximately equal to 2 meters. The correct answer is A.
- Which 70 cm frequency is authorized to a Technician Class license holder operating in ITU Region 2?
- A. 53.350 MHz
- B. 146.520 MHz
- C. 443.350 MHz
- D. 222.520 MHz
In 97.301(a), the center column being ITU Region 2, the 70 cm band is bounded from 420 to 450 MHz. Only 443.350 is within this boundary. The correct answer is C.
- Which 23 cm frequency is authorized to a Technician Class licensee?
- A. 2315 MHz
- B. 1296 MHz
- C. 3390 MHz
- D. 146.52 MHz
This is codified in 97.301(a). In that chart, it doesn't matter which ITU region you are in, the allocation is the same. The 23 cm band is described as 1240 to 1300 MHz. Of the four choices, only 1296 is within that range. The correct answer is B.
- What amateur band are you using if you are transmitting on 223.50 MHz?
- A. 15 meter band
- B. 10 meter band
- C. 2 meter band
- D. 1.25 meter band
Aside from looking up the equivalency in 97.301(a), you can convert frequency to wavelength with a division: c/f=lambda where c=300,000,000 m/s which is the speed of light, f is the frequency in Hertz (cycles for second) and lambda is the wavelength in meters. 300/224 is closest to 1.25. The answer is D.
- Which of the following is a result of the fact that the amateur service is secondary in some portions of the 70 cm band?
- A. U.S. amateurs may find non-amateur stations in the bands, and must avoid interfering with them
- B. U.S. amateurs must give foreign amateur stations priority in those portions
- C. International communications are not permitted on 70 cm
- D. Digital transmissions are not permitted on 70 cm
Reference to 97.303. There is overlap in portions of the band plan. Some organization have priority use of some frequencies and we, as hobbyists, should yield to their communication needs. The correct answer is A. Foreign stations are also secondary and may also be expected to yield based on their nation's international agreements.
- Why should you not set your transmit frequency to be exactly at the edge of an amateur band or sub-band?
- A. To allow for calibration error in the transmitter frequency display
- B. So that modulation sidebands do not extend beyond the band edge
- C. To allow for transmitter frequency drift
- D. All of these choices are correct
Reference to 97.101(a) and 97.301(a-e). The correct answer is D.
- Which of the bands above 30 MHz that are available to Technician Class operators have mode-restricted sub-bands?
- A. The 6 meter, 2 meter, and 70 cm bands
- B. The 2 meter and 13 cm bands
- C. The 6 meter, 2 meter, and 1.25 meter bands
- D. The 2 meter and 70 cm bands
Reference to 97.301(e) and 97.305(c). The correct answer is C.
- What emission modes are permitted in the mode-restricted sub-bands at 50.0 to 50.1 MHz and 144.0 to 144.1 MHz?
- A. CW only
- B. CW and RTTY
- C. SSB only
- D. CW and SSB
Reference to 97.301(a) and 97.305(a)(c). The correct answer is A.
- Why are frequency assignments for U.S. stations operating maritime mobile not the same everywhere in the world?
- A. Amateur maritime mobile stations in international waters must conform to the frequency assignments of the country nearest to their vessel
- B. Amateur frequency assignments can vary among the three ITU regions
- C. Frequency assignments are determined by the captain of the vessel
- D. Amateur frequency assignments are different in each of the 90 ITU zones
Reference to 97.301. The ITU coordinates to usage of spectrum across it's three regions. Even though you are a citizen of a nation located primarily in Region 2, the operator is expected to comply with the band plan assigned to the location that he is transmitting from. The correct answer is B.'
- Which emission may be used between 219 and 220 MHz?
- A. Spread spectrum
- B. Data
- C. SSB voice
- D. Fast-scan television
This question is one of those that requires a bit of memorization. Let's take a look at the CFR 97.305(c) where the usage of the bands are assigned. The section of the band between 219 and 220 is reserved for data. So if you want to listen or communicate in this medium, you odds may be pretty good here. The correct answer is B. Spread spectrum is the vague answer that doesn't refer to any mode is particular.