AY Honors/Radio/Answer Key

Radio

Skill Level

2

Year

1928

Version

24.12.2024

Approval authority

General Conference

1

Pass a test and receive your license for the Technical Class Amateur Radio License OR Technician Class Amateur Radio License.

There is only one requirement for this honor. In order to earn the Technician Class Amateur Radio License, an operator must pass a 35 question exam administered by a Volunteer Examiner Coordinator (VEC). No Morse code is required for the Technician Class, but knowledge of FCC regulations and electronics are essential. Study the material presented below, and when you feel you are ready, take some practice tests:

• Practice Tests

When you can consistently pass the practice tests, chances are good that you will be able to pass the real deal. All you need to do when you are ready is find an amateur license examination session near you. This website will help you locate one:

• http://www.arrl.org/arrlvec/examsearch.phtml

Now, let's learn about Amateur Radio!

FCC Rules, station license responsibilities

Amateur Radio

The FCC Rules and Regulations for the "Amateur Radio Service" is defined in the Code of Federal Regulations under Title 47, Part 97. Part 97 is the FCC's regulations for all amateur (ham) radio operations. The link for Part 97 is as follows: https://en.wikipedia.org/wiki/Title_47_CFR_Part_97

Control operator duties

By definition of Part 97.3, a control operator is defined as "An amateur operator designated by the licensee of a station to be responsible for the transmissions from that station to assure compliance with the FCC Rules."

The control operator must be a licenced operator who's license appears in the ULS consolidated licensee database or be "authorized for alien reciprocal operation by §97.107 of part 97."

The control operator is required to monitor transmissions, repair (or have repaired) any equipment that is causing harmful interference, and make sure the transmitting station complies with the rules and regulations set out by the FCC.

A control operator does not have to be the person transmitting, nor does he even have to be in the room to control the radio (If he or she has the ability of remote operation of the station, that is). However, the control operator must be aware of every aspect of the station at all times. This includes: transmission frequency, power/ output of transmission, radio etiquette, etc.

Operating Practices

It is important that you be polite when talking "on the air." Anyone can listen to your conversations. Don't use inappropriate language (like swearing), don't be insulting, and don't cut other people off. Allow others to join conversations. If it is a personal conversation, maybe you should be communicating via a more secure/ private method.

Other things that you should consider when "on the air" is your power settings, repeater use, and frequency usage. If you are talking on a frequency and someone else starts using the same frequency, don't increase your power until only you and your contact can talk. Be courteous and forgiving, move to a different frequency. You may find that some frequencies have priorities assigned to them. For example, the repeater or frequency that you are using is also used by a group of hams that dedicate some of their time to emergency communications. They have been given priority in message traffic when dealing with an emergency or emergency practice sessions. They have been given the primary assignment for that frequency during those events. Should you find them using the repeater or frequency during an official event, move to a different frequency or repeater. At all other times you, as a secondary user, may use the repeater or frequency without hindrance. Also when using a repeater to talk to someone, see if you can communicate without using the repeater. If so, please move to a frequency other than the repeater. If you cannot communicate without using the repeater, that is alright. The repeater was created for that very purpose (to allow people to communicate over farther distances).

Radio and electronic fundamentals

Ohm's Law

A voltage source, V, drives an electric current, I , through resistor, R, the three quantities obeying Ohm's law: V = IR.

Ohm's law states that, in an electrical circuit, the current passing through a conductor between two points is proportional to the potential difference (i.e. voltage drop or voltage) across the two points, and inversely proportional to the resistance between them. In mathematical terms, this is written as:

[math]\displaystyle{ I = \frac {V}{R} }[/math]

where I is the current in amperes, V is the potential difference in volts, and R is a constant, measured in ohms, called the resistance. The potential difference is also known as the voltage drop, and is sometimes denoted by E or U instead of V.

Impedance

Electrical impedance, or simply impedence, describes a measure of opposition to a sinusoidal alternating current (AC). Electrical impedance extends the concept of resistance to AC circuits, describing not only the relative magnitudes of the voltage and current, but also the relative phases. In general impedance is a complex quantity [math]\displaystyle{ \scriptstyle{\tilde{Z}} }[/math] and the term complex impedance may be used interchangeably; the polar form conveniently captures both magnitude and phase characteristics,

[math]\displaystyle{ \tilde{Z} = Z e^{j\theta} \quad }[/math]

where the magnitude [math]\displaystyle{ \scriptstyle{Z} }[/math] gives the change in voltage amplitude for a given current amplitude, while the argument [math]\displaystyle{ \scriptstyle{\theta} }[/math] gives the phase difference between voltage and current. In Cartesian form,

[math]\displaystyle{ \tilde{Z} = R + j\Chi \quad }[/math]

where the real part of impedance is the resistance [math]\displaystyle{ \scriptstyle{R} }[/math] and the imaginary part is the reactance [math]\displaystyle{ \scriptstyle{\Chi} }[/math]. Dimensionally, impedance is the same as resistance; the SI unit is the ohm. The term impedance was coined by Oliver Heaviside in July 1886.

The impedance of an ideal resistor is purely real and is referred to as a resistive impedance:

[math]\displaystyle{ \tilde{Z}_R = R. }[/math]

Ideal inductors and capacitors have a purely imaginary reactive impedance:

[math]\displaystyle{ \tilde{Z}_L = j\omega L, }[/math]

[math]\displaystyle{ \tilde{Z}_C = \frac{1}{j\omega C} \, . }[/math]

Power

Electric power is defined as the rate at which electrical energy is transferred by an electric circuit. The SI unit of power is the watt. When electric current flows in a circuit, it can transfer energy to do mechanical or thermodynamic work.

In direct current resistive circuits, electrical power is calculated using Joule's law:

[math]\displaystyle{ P = VI \, }[/math]

where P is the electric power, V the voltage, and I the electric current.

In the case of resistive loads, Joule's law can be combined with Ohm's law (I = V/R) to produce alternative expressions for the dissipated power:

[math]\displaystyle{ P = I^2 R = \frac{V^2}{R}, }[/math]

where R is the electrical resistance.

In alternating current circuits, energy storage elements such as inductance and capacitance may result in periodic reversals of the direction of energy flow. The portion of power flow that, averaged over a complete cycle of the AC waveform, results in net transfer of energy in one direction is known as real power (also referred to as active power). That portion of power flow due to stored energy, that returns to the source in each cycle, is known as reactive power.

The relationship between real power, reactive power and apparent power can be expressed by representing the quantities as vectors. Real power is represented as a horizontal vector and reactive power is represented as a vertical vector. The apparent power vector is the hypotenuse of a right triangle formed by connecting the real and reactive power vectors. This representation is often called the power triangle. Using the Pythagorean Theorem, the relationship among real, reactive and apparent power is:

[math]\displaystyle{ \mbox{(apparent power)}^2 = \mbox{(real power)}^2 + \mbox{(reactive power)}^2 }[/math]

Real and reactive powers can also be calculated directly from the apparent power, when the current and voltage are both sinusoids with a known phase angle between them:

[math]\displaystyle{ \mbox{(real power)} = \mbox {(apparent power)}\cos(\theta) }[/math]

[math]\displaystyle{ \mbox{(reactive power)} = \mbox {(apparent power)}\sin(\theta) }[/math]

The ratio of real power to apparent power is called power factor and is a number always between 0 and 1.

The above theory of reactive power and the power triangle is true only when both the voltage and current is strictly sinusoidal. Therefore is more or less abandoned for low voltage distribution applications where the current normally is rather distorted. It can still be used for high voltage tranmission applications and, with some care, for medium voltage applications where the current normally is less distorted.

Passive circuits

Passive circuits are circuits consisting of only resistors, capacitors, and inductors. Most undergraduate electronics programs dedicate two semesters to the analysis of passive circuits. It is unrealistic to expect to learn even the rudiments of this subject in a single chapter. Instead, we refer you to Circuit Theory for a more thorough treatment than is possible here.

Active circuits

Active circuits contain components that require a power source to operate. Such components include diodes, transistors, integrated circuits (which are constructed from diodes and transistors integrated onto a common substrate), and tubes. Active circuits, like passive circuits, are the topic of at least two semesters of undergraduate study. As such, we refer you to Electronics rather than attempting to treat this complex topic here.

Station setup and operation

Amateur Radio station setup

Communication modes and methods

The most common methods of communication are AM (Amplitude Modulation), SSB (Single Sideband), FM (Frequency Modulation), CW (Continuous Wave) also known as Morse Code, and RTTY (Radio Teletype). Of these, the favorites are SSB, FM, and CW. To look at a larger list of ways to communicate as a ham operator, see List of amateur radio modes. Many of these methods of communications can be used on multiple bands and multiple different frequencies within those bands. Each method has specific frequencies that it is allowed to be used in. For example: on the 2 meter band, frequencies from 144.000-144.100 is specifically for CW, 144.900-145.200 won't allow CW but will let you use FM.

Most ham radio operators use simplex (Radio to Radio) communications for any conversations that they have. This is especially true of hams using hand held transceivers (HTs) on UHF (Ultra High Frequency) and VHF (Very High Frequency). Repeaters are common for use on UHF & VHF. Repeaters are used when hams cannot communicate clearly on simplex. The repeater will receive the transmission signal of one ham and retransmit it at a higher power level to the other ham. Hams that have higher license will operate on HF (High Frequency) and will use SSB and CW to communicate farther distances. HF communications does not require the use of repeaters due to the method of communication. HF operators will often use much more power for distant contacts. HF operators can also use directional antennas to bounce radio waves off the atmosphere, the moon, and even certain satellites.

Because of the type of communications that a Technician License is allowed to use. We will be focusing on FM and CW. FM is one of the simplest forms of communications. To operate FM as a ham radio operator, all one must do is set the desired frequency that you wish to communicate on and press the PTT (Push To Talk) button. Press the PTT button for 1 second and then begin by identifying yourself with your call sign. Don't be frustrated if nobody answers you when you call out over the radio waves, nobody may be listening to that particular frequency. Many people have mobile rigs (ham radios in their cars) and are most often found on the radio on their way to and from work. CW is a little more challenging than FM, but not much. CW requires that you get a ham radio rig that will actually transmit Morse code. You must also get a Morse code key (a device that you use to tap out the code on the radio). CW allows you to operate on frequencies that other modes will not allow.

Special operations

Emergency and Public Service Communications

Radio waves, propagation, and antennas

Amateur Radio antenna

Electrical and RF safety

References