Radio Communication Basics

Invisible waves created by wiggling electrons, used in wireless communication.

Communication that doesn't need physical wires, using radio waves instead.

A repeating wave shape, used to transmit information in radio signals.

The number of sine wave cycles per second, measured in Hertz (Hz).

The distance of a full sine wave cycle, measured in meters.

A device that sends radio signals into the air.

A device that picks up and interprets radio signals.

Using different frequencies to prevent interference between multiple radio signals.

Different ranges of frequencies used for various wireless technologies.

Lower frequency band for radio transmission, historically chosen due to limitations of early electronics.

Higher frequency band for radio transmission, allocated after AM due to technological advancements allowing increased frequencies.

Radio system capable of transmitting and receiving simultaneously, often using separate frequencies for transmission and reception.

Radio system that can either transmit or receive at a time; one at a time.

Radio waves carry information through the air over great distances.

The range of frequencies between 20Hz and 20kHz that the human ear can perceive.

The use of radio waves for communication to transmit and receive information

Disturbing influences on radio signals, causing reception problems. This can originate from thermal noise within the receiver, or interference from other sources.

Radio waves travel at the speed of light, propagating through space as electromagnetic waves.

The process of creating an electric field in one conductor by varying a magnetic field in a nearby conductor.

A medium for transmitting data that is physically contained (e.g., twisted pair, coaxial cable).

A medium for transmitting data that is not contained or physically bound (e.g., microwaves, infrared, satellite).

A technology for transmitting data using light pulses through thin glass or plastic fibers.

Fiber optic cable that allows multiple light paths to travel through the fiber.

Fiber optic cable that allows only one light path to travel through the fiber.

The human voice frequency range spans from 0 Hz to 4000 Hz. This means the sounds we produce using our vocal cords are within this range.

Different ranges of frequencies used for specific wireless technologies. Different devices like cell phones, GPS, and even garage door openers operate on their own frequency bands.

AM radio was developed before FM. Early electronic capabilities had limitations, making it easier to transmit at lower frequencies. When FM technology advanced, it could use higher frequency bands. Therefore, AM radio is lower frequency, while FM is higher frequency.

All wireless technologies use radio waves to communicate, from cell phones and Wi-Fi to radio broadcasts and GPS receivers.

A simple circuit using a battery and coin can act as a radio transmitter by creating alternating current that generates radio waves.

Radio signals use sine waves, repeating patterns that represent information and are transmitted at different frequencies.

The frequency of a sine wave is measured in Hertz (Hz), which indicates the number of cycles per second. Higher frequency means more cycles per second.

Radio waves are unbound media, meaning they don't require physical wires to transmit data. This contrasts with bound media like cables.

Radar systems use radio waves to detect objects by sending out signals and measuring the time it takes for them to bounce back.

Microwave ovens use high-frequency radio waves to heat food by making the water molecules vibrate.

The size of an antenna is related to the frequency of the signal it transmits or receives. Higher frequencies require smaller antennas, while lower frequencies need larger ones.

Radio waves travel along the Earth's surface, following its contours. They are good for shorter distances and lower frequencies.

Radio waves bounce off the ionosphere (a layer in the atmosphere) and return to Earth. This allows long-distance communication.

When a radio wave bounces off objects, creating multiple paths to the receiver. These paths can combine constructively or destructively, impacting signal quality.

When multiple waves combine in a way that their amplitudes add up, resulting in a stronger signal.

When multiple waves combine in a way that their amplitudes cancel each other out, resulting in a weaker signal.

A fluctuation in signal strength due to multipath, resulting in periods of weak or distorted reception.

The available range of frequencies for wireless communication is limited, leading to frequency reuse and spectrum allocation.

Assigning the same frequency to different transmitters in different geographic locations to maximize spectrum utilization.

Signal strength weakens as it travels through the air and encounters obstacles like walls and people.

Objects in the path of radio waves can absorb, reflect, or diffract the signal, impacting signal strength and reception.

A device that converts electrical signals into radio waves or vice versa.

Energy that travels in the form of waves made up of electric and magnetic fields.

A system that uses multiple antennas spread across a wide area to improve coverage and capacity in wireless networks, especially in buildings and large campuses.

A standard defining how wireless devices communicate, commonly known as Wi-Fi. It defines how data is sent and received over a network.

A wireless broadband communication standard for covering larger areas like cities or towns, used for internet access.

A direct connection between two devices, ideal for long distances and dedicated services, often used in backhauls.

A connection where one source device broadcasts to multiple receivers, ideal for sharing a connection across multiple facilities.

A network where devices are connected to each other, allowing for flexibility, self-healing, and easy expansion.

A wireless communication network that allows users to make calls and access data using cell towers.

The high-speed connection that links cell towers to the core network, ensuring smooth data flow.

The two main types of antennas in Distributed Antenna Systems (DAS) are Omni Directional and Directional.

An Omni Directional antenna broadcasts radio signals in all directions.

A Directional antenna focuses radio signals in a single direction.

Analog signals have continuous values, while digital signals are quantized, meaning they have a limited set of values.

A multipath is a single path a radio wave takes from the transmitter to the receiver in a physical environment.

Different multipath lengths cause the radio signals to reach the receiver at different times, potentially causing interference.

Radio waves interact with the physical environment, such as buildings and trees, creating multiple paths for the signal to travel.

The worst-case scenario is when two multipath signals arrive at the receiver with opposite phases, canceling each other out.