Glossary

Basic Radio Terms

Frequency

The specific radio signal rate being used, measured in hertz. For this project, people may commonly see frequencies described in MHz, such as 868 MHz or 915 MHz.

Band

A range of frequencies grouped together. Examples include HF, VHF, UHF, 868 MHz, 915 MHz, CB, GMRS, amateur radio bands, and Wi-Fi bands.

Bandwidth

The amount of radio spectrum used by a signal. In LoRa settings, bandwidth affects range, speed, airtime, and how well a signal may be received.

RX / Receive

RX means receive. It refers to hearing, detecting, or receiving a signal or packet.

TX / Transmit

TX means transmit. It refers to sending a signal or packet.

Channel

A channel may mean a frequency, a programmed radio channel, or a configured communication path. In Meshtastic, channels are configured message groups with names, keys, and settings.

Modulation

The way information is carried on a radio signal. AM, FM, SSB, digital voice, packet data, and LoRa all use different methods.

AM / Amplitude Modulation

AM means amplitude modulation. It carries information by changing the strength, or amplitude, of the radio wave.

FM / Frequency Modulation

FM means frequency modulation. It carries information by changing the frequency of the radio wave.

SSB / Single Sideband

SSB means single sideband. It is a voice mode commonly used on HF amateur radio and some CB radios. It is more efficient than regular AM, but requires radios on both ends to be tuned carefully.

Analog Transmission

A transmission where the signal varies continuously, such as traditional AM or FM voice. This is different from digital packet-based systems like MeshCore, Meshtastic, DMR, or FT8.

Dead Air

A period when nothing is being transmitted or heard on a channel.

Voice Radio Terms

PTT / Push To Talk

PTT means push to talk. It is the button or control used to transmit on many voice radios.

Squelch

A radio control or setting that keeps the speaker quiet until a signal is strong enough or matches the expected tone/code.

CTCSS / Continuous Tone-Coded Squelch System

CTCSS uses a low audio tone to open squelch on radios set to the same tone. These are often marketed as privacy codes, but they do not make a channel private.

DCS / Digital-Coded Squelch

DCS is another squelch-control system that uses digital codes instead of analog tones. Like CTCSS, it does not encrypt or privatize the channel.

Simplex

Direct radio-to-radio communication on the same frequency, without a repeater.

Duplex

Communication that uses separate transmit and receive frequencies. Repeaters commonly use duplex operation.

Repeater Offset

The difference between the frequency a radio receives on and the frequency it transmits on when using a repeater.

DMR / Digital Mobile Radio

DMR means digital mobile radio. It is a digital voice radio standard used by commercial, public-service, and amateur radio operators. In amateur radio use, DMR often involves repeaters, talkgroups, time slots, and radio IDs.

CW / Morse Code

CW means continuous wave. In amateur radio, CW usually refers to Morse code sent by turning a carrier signal on and off.

FT8

A weak-signal digital mode used by amateur radio operators, usually with a computer handling timing and decoding.

Mesh and Packet Terms

Mesh

A network where devices can pass messages through other devices instead of relying on one central tower, router, or service.

Node

A device that participates in a mesh network. A node may be handheld, portable, vehicle-mounted, fixed indoors, fixed outdoors, battery-powered, or solar-powered.

Repeater

A node placed to help messages travel farther. Repeaters usually work best with height, reliable power, good antenna placement, and weather protection.

Observer

A device or system that listens for mesh activity and may feed logs, analyzers, status tools, or maps. An observer helps document activity, but does not necessarily improve coverage by itself.

Packet

A small unit of digital data sent across a network or radio link.

Hop

One forwarding step in a mesh network.

Hop Limit

A setting that controls how many times a message may be forwarded through the mesh. Higher hop limits can reach farther but can also create more network traffic.

TTL / Time To Live

TTL means time to live. In mesh networking, TTL usually limits how far or how many times a message may be forwarded before it is dropped.

ACK / Acknowledgement

ACK means acknowledgement. It is a confirmation that a message or packet was received.

Direct Message

A message intended for a specific person or node instead of a shared public channel or group.

Telemetry

Status data reported by a device, such as battery level, temperature, uptime, location, signal information, or other device health details.

Region

A defined area or grouping used to organize network behavior. In MeshCore, regions may matter for repeater configuration and traffic handling.

Scope

A setting or concept that controls how far a message or operation is meant to reach. In MeshCore contexts, scope may relate to how traffic is limited, forwarded, or handled.

LoRa / MeshCore / Meshtastic Terms

LoRa / Long Range

LoRa means long range. It is a low-power radio technology used for small data packets over longer distances than many short-range wireless systems.

MeshCore

A LoRa-based mesh communication system used by Hampden County Mesh for local experimentation, repeaters, observers, field testing, logging, and community infrastructure.

Meshtastic

A separate LoRa-based mesh communication project commonly used for off-grid text messaging, position sharing, telemetry, and hobby/community mesh networks.

LongFast

A Meshtastic preset/channel name associated with longer-range, lower-speed communication. Local practice can vary.

ShortFast

A Meshtastic preset associated with shorter-range, faster communication compared with longer-range presets.

Spread Factor / SF

Spread factor is a LoRa setting that affects range, speed, airtime, and how easily a signal can be decoded. Higher spread factors usually favor longer range but use more airtime.

868 MHz

A radio range commonly associated with LoRa and ISM-style operation in parts of Europe and other regions. Rules vary by country and region.

915 MHz

A radio range commonly associated with LoRa and ISM-style operation in the United States and some other regions. Rules vary by country and region.

Firmware

The software installed on a radio device or microcontroller.

Flashing

Installing or replacing firmware on a device.

OTA / Over The Air

OTA means over the air. It usually refers to sending updates or configuration wirelessly instead of using a USB cable.

BLE / Bluetooth Low Energy

BLE means Bluetooth Low Energy. It is a short-range wireless technology often used for phone-to-device connections, configuration, sensors, and accessories.

API / Application Programming Interface

API means application programming interface. It is a way for software tools to talk to each other.

Antennas and RF Measurements

Antenna

The part of a radio system that sends or receives radio signals.

Rubber Duck Antenna

A short flexible antenna commonly used on handheld radios. It is convenient, but usually not the best-performing antenna.

Whip Antenna

A straight or flexible antenna often used on handheld, mobile, or portable radio equipment.

Dipole Antenna

A simple antenna made from two conductive elements. Dipoles are common in many parts of radio because they are simple, useful, and easy to understand.

Omnidirectional Antenna

An antenna designed to send or receive signal in all horizontal directions around the antenna.

Yagi Antenna

A directional antenna that focuses signal more strongly in one direction.

Coax / Feed Line

The cable that carries radio-frequency energy between a radio and antenna.

Connector

The physical plug or jack used to connect radios, antennas, adapters, and coax.

Ground Plane

A conductive surface or set of radials that helps some antennas work properly.

Polarization

The orientation of a radio wave or antenna, commonly vertical or horizontal. Matching polarization can improve signal performance.

Gain

A measure of how an antenna focuses signal in some directions compared with others.

dBi

dBi means decibels relative to an isotropic radiator. It describes antenna gain compared with a theoretical antenna that radiates equally in every direction.

dBd

dBd means decibels relative to a dipole antenna. It describes antenna gain compared with a standard half-wave dipole.

dBm

dBm means decibels relative to one milliwatt. It is commonly used to describe radio power levels and received signal strength.

SWR / Standing Wave Ratio

SWR means standing wave ratio. It describes how well an antenna system is matched to the radio and feed line. Very high SWR can reduce performance and may damage some transmitters.

Signal Quality

RSSI / Received Signal Strength Indicator

RSSI means received signal strength indicator. It is a measurement of how strong a received signal appears to the radio.

SNR / Signal-to-Noise Ratio

SNR means signal-to-noise ratio. It compares the desired signal against background noise. A better SNR usually means the signal is easier to decode.

Duty Cycle

The percentage of time a radio transmits over a period of time. Limiting airtime is good practice on shared radio channels.

Airtime

The amount of time a transmission occupies the channel. Long airtime can reduce how much room is available for other traffic.

Line of Sight

A mostly clear path between radio devices. Hills, buildings, trees, and terrain still matter even when devices are close together.

Terrain

The physical landscape around a radio path, including hills, valleys, buildings, trees, rivers, roads, and dense neighborhoods.

Coverage

The area where a device, repeater, observer, or network can be heard or used.

Dead Spot

An area where a device does not hear or reach expected traffic.

Bands and Services

HF / High Frequency

HF means high frequency. It covers 3 to 30 MHz and can support long-distance communication under some conditions.

VHF / Very High Frequency

VHF means very high frequency. It covers 30 to 300 MHz and is commonly used for local and regional radio communication.

UHF / Ultra High Frequency

UHF means ultra high frequency. It covers 300 MHz to 3 GHz and is used by many handheld radios, repeaters, data links, and local communications systems.

FRS / Family Radio Service

FRS means family radio service. It is a short-range personal radio service commonly used by small handheld radios.

GMRS / General Mobile Radio Service

GMRS means general mobile radio service. It is used for personal and family communications and can include repeaters, depending on rules and licensing.

CB / Citizens Band

CB means citizens band. It is a personal radio service commonly associated with 27 MHz AM and SSB voice communication.

Amateur Radio / Ham Radio

Amateur radio is a licensed radio service for technical learning, experimentation, public service, and communication.

ISM Band

ISM means industrial, scientific, and medical. ISM bands are shared radio ranges used by many devices, including some LoRa systems.

Wi-Fi

Wi-Fi is a local wireless networking technology commonly used for internet access and local networks.

Satellite

A radio relay or payload in orbit. Some amateur radio satellites can repeat voice or digital signals between ground stations.

Security, Keys, and Privacy

End-to-End Encryption

A way of protecting messages so that only the intended endpoints should be able to read them.

AES-256 / Advanced Encryption Standard 256-bit

AES-256 means Advanced Encryption Standard using 256-bit keys. It is a widely used symmetric encryption method. Encryption strength also depends on how keys are generated, shared, stored, and protected.

Public Key

A cryptographic key that can be shared. Other devices or users may use a public key to identify a node or send encrypted information to it, depending on the system.

Private Key

A cryptographic key that should be kept secret. Do not post private keys publicly.

Field Testing and Maps

Coverage Test

A practical check to see what a device can hear or reach from a specific area.

Wardriving

Driving around with a device or logging setup to observe radio or mesh coverage over an area. It should be done safely, without interacting with devices while driving.

Field Note

A short observation from real use, such as what device was used, where it was tested, what was heard, what did not work, and what terrain or placement mattered.

Live Activity

Recently observed network activity shown on a map or dashboard. Live activity does not mean the map is complete or that every shown node is operated by Hampden County Mesh.

Observed Activity

Activity heard or reported by an observer, public feed, analyzer, log, or community report.

Site-Maintained System

A device, server, page, tool, or service maintained directly by Hampden County Mesh. Not every node, packet, or marker seen in the area is site-maintained.