Glossary

Attenuation: Propagation; The loss of strength a signal undergoes as it travels along a path, whether a cable, a connector or the air. It is measured in decibels (dB): every 3 dB of attenuation cuts the signal power roughly in half. In a long garden hose, water reaches the end with less pressure; in a long or poor-quality cable, the signal reaches the antenna with less strength.
Attenuator: Equipment; A small component placed along a radio cable to reduce the signal strength by a known amount, measured in decibels. It is used on test benches so that one radio does not damage another when they are connected by cable. It is also used on short links, when the signal arrives too strong and impairs reception.
Backhaul: Infrastructure; The segment of a network responsible for carrying data between a local network or access point and a higher-capacity communication infrastructure. In TECER, TVWS can function as backhaul, connecting a remote territory to a point with access to the main telecommunications infrastructure.
Base station: Equipment; The equipment installed at the origin point of a radio communication network or link, responsible for transmitting and, in some cases, receiving signals from connected equipment. In a radio link, the base station transmits the signal toward the remote point where the CPE is installed. Think of it as the speaker end of a phone call: that's where the signal starts out from to reach whoever is on the other side.
Coaxial cable: Equipment; The cable that carries the radio signal between the radio and the antenna. It has a copper wire at the center, surrounded by insulation, a metal mesh and an outer jacket, like a television antenna cable. Every coaxial cable loses part of the signal along the way. This loss grows with length, with frequency and with poorer material quality.
CPE (Customer Premises Equipment): Equipment; The equipment installed at the location where the network connection will be used, responsible for receiving or establishing communication with the transmission infrastructure and distributing the signal locally. In a radio link, the CPE can receive the signal sent by the base station and make the connection available to the local network's equipment. It is like the satellite dish that receives a broadcaster's signal and turns it into a picture on the TV at home.
Decibel (dB): Concept; The unit used to measure signal gains and losses. It works on a proportional scale: every 3 dB of loss cuts the signal power roughly in half, and every 10 dB cuts it to one tenth. For this reason, small losses added up along the path can weaken a signal a great deal.
Diffraction: Propagation; The phenomenon by which a radio wave can propagate around or beyond an obstacle, instead of being completely blocked by it. Diffraction tends to be more significant at lower frequencies, contributing to signal propagation in environments where there is no line of sight between points.
Dynamic spectrum management: Spectrum; The set of techniques and mechanisms used to adapt the use of radio frequencies according to spectrum occupancy and the operating conditions of existing services. Dynamic management can identify available bands, select frequencies and adjust spectrum use to reduce the risk of interference between different communication systems.
Electromagnetic spectrum: Concept; The set of frequencies of electromagnetic waves used for different forms of signal transmission. Radio, television, Wi-Fi and cellular telephony each use different bands of this spectrum, according to specific technical characteristics and usage rules.
Firmware: Concept; The program stored inside an electronic device, such as a radio or a router, that controls its basic operation. Unlike an application installed on a computer, firmware comes from the manufacturer and only changes when it is updated. A firmware error can make a device work poorly even when all of its parts are in good condition.
HF radio: Technology; A radio that operates at high frequency (HF), between 3 and 30 MHz. In this band, the signal can be reflected by the ionosphere (a high layer of the atmosphere) and reach hundreds or thousands of kilometers without intermediate towers. For this reason, it is used for voice communication in regions without mobile phone coverage.
Idle spectrum (white space): Concept; A portion of the television spectrum not being used by any TV channel in a given region and time. These free spaces, also called TV White Spaces, can be used by other technologies, such as TVWS, as long as their use does not interfere with existing services.
Interference: Spectrum; The presence of other radio signals on the same frequency as a link, or on nearby frequencies, which makes it harder to receive the intended signal. It is like trying to hold a conversation in a room where other people are talking loudly at the same time: the voice of the person talking to you is still there, but it becomes harder to understand.
Last mile: Infrastructure; The final segment of a telecommunications network responsible for carrying the connection from the distribution point to end users. In a community network, it can correspond to the infrastructure that distributes the connectivity received through a backhaul link to homes, equipment or shared-use spaces in a community.
Line of sight (LOS): Propagation; The condition in which there is a path free of physical obstacles between the transmitter and receiver of a radio signal. Hills, buildings, trees and other structures can block or weaken the signal. Having line of sight makes signal propagation easier and is necessary for some communication technologies to work properly.
Link: Infrastructure; A communication connection established between two points, through which data is transmitted. In telecommunications networks, a link can use radio, optical fiber or other transmission media. In TECER, the radio link can connect a point located in the city to another situated in a remote territory. It is like a bridge built between two riverbanks: before it, each side stays isolated; after it, the two start exchanging what they need.
LoRa (Long Range): Technology; A radio communication technology designed to transmit small amounts of data over long distances with low power consumption. It is used in applications that need to send information such as messages, sensor readings and location, especially where Wi-Fi or cellular telephony are not available.
Low Earth orbit satellite (LEO): Technology; A satellite that circles a few hundred kilometers from the Earth (LEO stands for low Earth orbit), much closer than traditional communication satellites. The shorter distance reduces the time data takes to go and come back. Internet services such as Starlink use thousands of these satellites, because each one covers a small area and moves quickly across the sky.
Mesh network: Network architecture; A network architecture in which devices can connect to each other and forward data through different paths. Each device can act as a communication point and relay data to other nodes in the network. This organization reduces dependence on a single central point and can increase network resilience when one of the paths becomes unavailable.
Meshtastic: Technology; Free software that uses LoRa radios to form decentralized mesh networks. Devices can exchange text messages, location information and other data without depending on an internet connection or cellular networks. Nodes can relay messages, allowing communication to reach devices beyond the direct range of a single radio.
Node: Network architecture; Each device that takes part in a network and can send, receive or forward data. In a mesh network, nodes can communicate with nearby devices and relay information, contributing to the formation of the different communication paths.
Non line of sight (NLOS): Propagation; The condition in which there is some physical obstacle between the transmitter and receiver of a radio signal. Vegetation, terrain, buildings and other structures can prevent line of sight. Some lower frequencies can maintain communication even under these conditions because they have greater capacity for diffraction and propagation around obstacles.
Off-grid: Energy; The term used to describe systems that operate independently of the conventional electrical grid. These systems need their own power source, such as solar panels and batteries, to keep equipment running. In communication networks, this setup allows infrastructure to keep operating in places without reliable access to the electrical grid.
Packet loss: Concept; On the internet, data travels split into small blocks called packets. Packet loss happens when some of these blocks do not reach their destination, which makes the connection slow or unstable even when the devices are connected. It is like a letter sent on several sheets, some of which get lost in the mail.
Radio frequency (RF): Concept; The range of frequencies used to transmit wireless signals, such as radio, television, mobile phone and Wi-Fi signals. People speak of RF connections, cables or connectors to refer to the parts the radio signal passes through before reaching the antenna or after leaving it.
SDR (Software Defined Radio): Equipment; A radio system in which part of the functions traditionally performed by specific electronic components is carried out by software. This allows configuring and testing different frequencies, transmission and reception modes using the same physical equipment, making SDR a useful tool for research, monitoring and experimentation with radio signals.
Sector antenna: Equipment; An antenna that concentrates the signal over a range of directions instead of spreading it equally all around. A base station can use several sector antennas, each one facing a part of the territory. It is like a flashlight, which lights up a beam, compared with a light bulb, which lights up in every direction.
Signal reflection: Propagation; The deflection of a radio signal when it meets a surface, such as water, walls, terrain or vegetation. An antenna can receive the reflected signal even when it is not pointed at the transmitter, but this signal usually arrives weaker and more disorganized.
Spectrum analyzer: Equipment; Equipment used to visualize and measure the occupancy of radio frequencies in a given band of the spectrum. It allows identifying present signals, power levels and possible sources of interference, helping in the choice of frequencies and the configuration of radio links. It is like an ear able to tell apart, at the same time, every radio station playing in a given region, except instead of sound, it sees frequency.
Spectrum saturation: Spectrum; The situation in which a frequency band is so occupied by signals that little free space remains for new transmissions without interference. It can happen in regions with many broadcasters, wireless networks or devices operating at the same time.
Sub-gigahertz band (UHF and VHF): Frequency; The set of radio frequencies below 1 GHz, including bands historically used by over-the-air television. Because they have a longer wavelength, these frequencies can reach greater distances and have greater propagation capacity in environments with obstacles than the higher frequencies used by Wi-Fi.
Test bench: Infrastructure; The assembly of equipment in a controlled environment, such as a laboratory table, to check that it works before taking it to the field. On the bench, radios can be connected to each other with cables and attenuators, without antennas, which removes environmental variables such as distance, vegetation and interference.
TVWS (TV White Space): Technology; A technology that uses television channels not currently in use in a given region to transmit digital data. TVWS takes advantage of free space in the television spectrum to establish data connections, and can be used to extend connectivity in regions where conventional infrastructure is limited. It is like taking an empty lane on a multi-lane road: the TV channel is not in use there at that moment. TVWS uses that free space to connect places that common infrastructure does not reach.
Type approval (homologation): Concept; The certification, carried out in Brazil by Anatel (the national telecommunications regulator), that a piece of telecommunications equipment meets the country's technical rules. Equipment without type approval cannot be sold or regularly used in Brazil, which makes it harder to buy technologies that are uncommon in the Brazilian market.
Vector network analyzer (VNA): Equipment; An instrument that sends a radio signal through a cable, an antenna or another component and measures how much of that signal passes through and how much is reflected back. It is used to find out whether a cable loses too much signal, whether an antenna is tuned to the working frequency or whether a connector is faulty. The NanoVNA is a portable, low-cost model.