TECHNICIAN BANDS RADIO AND SIGNAL FUNDAMENTALS CHPT 2, THE ARRL HAM RADIO LICENSE MANUAL

Understanding Radio Waves To understand BANDS you first must understand what FREQUENCIES are. Why? Bands are Frequency divisions. To understand FREQUENCIES you must have an understanding of RADIO WAVES.

Understanding Radio Waves Signals that travel back and forth between radios, carrying voices, data, and morse code. These radio waves travel at the speed of light (300,000,000 m/s). A radio wave begins its journey as an electrical signal in an antenna that constantly alternates direction. The rate at which the signal changes direction determines the signal’s frequency. The radio wave then travels away from the antenna into space, vibrating or oscillating at the same frequency as the electrical signal. These radio waves are also known as: ELECTROMAGNETIC WAVES Understanding Radio Waves

RADIO OR ELECTROMAGNETIC WAVES What are electromagnetic waves? Electromagnetic waves or EM waves are waves that are created as a result of vibrations between an electric field and a magnetic field. In other words, EM waves are composed of oscillating magnetic and electric fields.

The Electric Field is perpendicular to the Magnetic Field (and visa-versa). These are perpendicular to the Wave Direction of travel.

Wavelength is the physical length from one point of a wave to the same point on the next wave. Usually measured in Meters

Decimal Equivalencies Prefix Symbol Multiplication Factor Tera T 1012 = 1,000,000,000,000 Giga G 109 = 1,000,000,000 Mega M 106 = 1,000,000 Kilo k 103 = 1,000 Hecto h 102 = 100 Deca da 101 = 10 Deci d 10-1 = 0.1 Centi c 10-2 = 0.01 Milli m 10-3 = 0.001 Micro μ 10-6 = 0.000001 Nano n 10-9 = 0.000000001 Pico p 10-12 = 0.000000000001

Formula for Wavelength (in Hz)

Example Wavelength Calculations (300,000,000 m/s) (in Hz) 300,000,000 300,000,000 meters Wavelength = = = 2.0627 meters 145.440 MHz 145,440,000 Hz 300,000,000 Wavelength = = .6714 meters = 67.14 cm 446.780 MHz 300,000,000 = 166.67 meters Wavelength = 1.8 MHz

UNIT OF MEASUREMENT: HERTZ The unit of measurement for frequency is called the Hertz, abbreviated as Hz. One cycle per second is one hertz or 1 Hz. 60 cycles per second is 60 Hz.

FREQUENCY As the signal oscillates, each complete back-and-forth sequence is called a cycle. The number of cycles per second is the signals’ FREQUENCY.

The number of cycles / second = Frequency

AMPLITUDE The Amplitude is the height of the wave. Often this is related to Power.

AMPLITUDE The Amplitude is the height of the wave, and is often related to Power.

PHASE Phase is not a property of just one RF signal, but instead involves the relationship between two or more signals that share the same frequency. The phase involves the relationship between the position of the amplitude crests and troughs of two waveforms. Phase can be measured in distance, time, or degrees. If the peaks of two signals with the same frequency are in exact alignment at the same time, they are said to be in phase. Conversely, if the peaks of two signals with the same frequency are not in exact alignment at the same time, they are said to be out of phase.

The above graph shows two waves that are 90° out of phase

THE BAND PLAN RF SPECTRUM RANGES

RF Spectrum Ranges RANGE NAME ABREVIATION FREQUENCY RANGE Very Low Frequency VLF 3 kHz – 30 kHz Low Frequency LF 30 kHz – 300 kHz Medium Frequency MF 300 kHz – 3 MHz High Frequency HF 3 MHz – 30 MHz Very High Frequency VHF 30 MHz – 300 MHz Ultra High Frequency UHF 300 MHz – 3 GHz Super High Frequency SHF 3 GHz – 30 GHz Extremely High Frequency EHF 30 GHz – 300 GHz

Radio Frequency Spectrum

US AMATEUR RADIO TECHNICIAN PRIVILEGES (Band plan for all Technicians)

US AMATEUR RADIO TECHNICIAN PRIVILEGES UHF

US AMATEUR RADIO TECHNICIAN PRIVILEGES VHF

US AMATEUR RADIO TECHNICIAN PRIVILEGES HF

Popular ARRL Band Plan Diagram