FPV Glossary

From Acro Mode to WDR — a fully cross-referenced glossary of FPV terminology, covering flight controllers, radios, video systems, batteries, and regulations.

FPV is full of acronyms, slang, and jargon that gets thrown around without explanation — PID, ELRS, jello, LiHV, cinewhoop. This glossary collects the terms you’ll actually run into, from beginner basics to gear-review specs, in one searchable reference.

0–9

Term	Full Name	Definition
2.4GHz	—	The most common RC control-link frequency band, used by most radio protocols (ELRS, FrSky, etc.).
5.8GHz	—	The standard frequency band for analog and many digital video transmitters.
900MHz (868/915MHz)	—	Lower frequency band used for long-range control links (Crossfire, ELRS LR mode). 915MHz is US-legal; 868MHz is the EU equivalent. Better penetration through obstacles than 2.4GHz, but slower update rates.
4-in-1 ESC	—	A single board housing four individual ESCs, one per motor — the standard setup on nearly all modern builds instead of four separate ESCs.
4-in-1 radio module	—	A transmitter module containing RF chips from multiple manufacturers, letting one radio bind to FrSky, Spektrum, FlySky, and Futaba protocols.

A

Term	Full Name	Definition
Acro Mode	Acrobatic / Rate / Manual Mode	The default flight mode for freestyle and cinematic FPV — no self-leveling. The quad holds whatever angle you give it, so flips, rolls, and smooth cinematic lines are all possible.
Air Mode	—	A Betaflight feature that keeps the PID loop active even at zero throttle so you retain full pitch/roll/yaw authority during throttle chops or free-fall.
AIO	All-In-One	A board that integrates multiple functions — most often FC + ESC, sometimes with VTX or receiver too. Common on whoops and toothpicks to save weight.
Angle Mode	—	Self-leveling flight mode that also caps maximum tilt angle, preventing flips. The standard beginner/training mode.
ArduPilot	—	Open-source autopilot firmware supporting waypoint navigation, RTH, and other autonomous features — used more on long-range/mapping builds than pure freestyle.
Arm / Disarm	—	Arming enables the motors so the quad is flight-ready; disarming cuts motor power. Always arm at zero throttle, pointed away from people.
AUW	All-Up Weight	Total ready-to-fly weight, battery included — the number used to calculate thrust-to-weight ratio.
AUX Channels	Auxiliary Channels	The switch/dial channels beyond the four stick axes, used to trigger arming, flight modes, beeper, turtle mode, etc.
Avatar	—	Walksnail’s (Caddx-owned) proprietary HD digital FPV video system, released in 2022 as a competitor to DJI’s system.
AWG	American Wire Gauge	Wire thickness measurement — the larger the number, the thinner the wire.

B

Term	Full Name	Definition
Backpack	—	A small WiFi module (used with ELRS/HDZero) that clips to a VTX or goggles for wireless configuration.
Bando	—	Slang for an abandoned building — a favorite freestyle location for its obstacles, gaps, and empty rooms.
Band / Channel	—	A frequency range (band) subdivided into individual channels; VTXs transmit on a specific channel within a band to avoid clashing with nearby pilots.
BEC	Battery Eliminator/Elimination Circuit	A voltage regulator that steps battery voltage down to a stable lower voltage (commonly 5V, sometimes 9V/10V) to power the receiver, camera, or VTX.
Betaflight (BF)	—	The dominant open-source flight controller firmware for FPV drones, tuned via the Betaflight Configurator app.
Bidirectional DShot	—	A DShot variant that also sends RPM telemetry back from ESC to FC, enabling RPM-based noise filtering.
Bind	—	The pairing process that links a radio transmitter to a receiver (or a VTX to a goggle module) so they communicate exclusively with each other.
BLHeli	—	ESC firmware family (BLHeli_S for 8-bit, BLHeli_32 for 32-bit hardware) used to configure motor direction, beacon tones, and bidirectional DShot.
Blackbox	—	Betaflight’s onboard flight data logger, recording gyro, PID, RC input, and motor output for post-flight tuning analysis.
BNF	Bind-and-Fly	A pre-built, pre-tuned quad that includes a receiver but no transmitter — you bind your own radio to fly it.
Bootloader	—	Firmware-level mode that lets a flight controller receive new firmware over USB, typically entered via a boot button or short.
Brownout	—	A momentary voltage drop that resets the FC or receiver mid-flight, usually from a bad connection or excessive voltage sag.
Brushed Motor	—	Older, simpler motor type using physical brushes; found mainly on legacy tiny whoops. Cheaper but less durable/powerful than brushless.
Brushless Motor	—	The standard FPV motor type — no physical brushes, driven electronically by the ESC. More efficient, powerful, and durable.
Buzzer / Beeper	—	An onboard alarm (or motor-driven “beeper” tone) used to help locate a crashed drone in grass or brush.
Bitrate	—	The data rate (in Mbps) at which onboard/DVR footage is encoded. Higher bitrate preserves more detail and holds up better under grading, at the cost of file size — a key spec when comparing digital systems’ recording quality.
BVLOS	Beyond Visual Line of Sight	Flying beyond the point where the pilot or a spotter can maintain unaided visual contact — legally restricted in most jurisdictions without a specific waiver.

C

Term	Full Name	Definition
C Rating	—	A LiPo’s discharge rating — multiplied by capacity (Ah) to estimate max continuous current. Manufacturer C-ratings are frequently inflated, so treat them as rough guidance.
Capacitor (Cap)	—	A component soldered across ESC power pads to smooth voltage spikes and reduce electrical noise that would otherwise degrade video or flight performance.
Carbon Fiber (CF)	—	The standard frame material — light, rigid, and crash-resistant, though electrically conductive (so shorts are a risk during builds).
CC2500	—	An RF chip found in older radio internal modules, supporting protocols like FrSky ACCST and Futaba SFHSS.
Cell (S)	—	A single 3.7V-nominal LiPo cell; battery packs are described by how many cells are wired in series (e.g., 4S ≈ 14.8V).
Channel (video)	—	A specific frequency slot within a VTX band, used to avoid interference between nearby pilots.
Cinelifter	—	A large quad (typically 7"–10"+ props, often X8/8-motor) purpose-built to carry heavy cinema cameras like a Blackmagic Pocket or RED Komodo.
Cinewhoop	—	A ducted (prop-guarded) quad built for smooth, close-proximity cinematic footage. Slower and more stable than freestyle rigs, safer to fly near people.
CLI	Command Line Interface	Betaflight’s text-based configuration console for advanced settings, backup/restore (“CLI dumps”), and factory resets.
Crossfire (CRSF)	—	TBS’s proprietary long-range radio protocol on 868/915MHz, known for excellent range and link reliability.
CW / CCW	Clockwise / Counter-Clockwise	Propeller rotation direction — every quad uses two of each, and mismatched props will prevent proper lift-off.
CE Marking	Conformité Européenne	The EU compliance mark confirming a VTX/RF product meets regional radio, safety, and emissions regulations — required for legal sale and use in the EU/EEA.
Cloverleaf Antenna	—	A circularly polarized antenna style built from three looping “leaves” — a common, durable choice for VTX/VRX pairs.
Codec	—	The compression format used to encode recorded video (commonly H.264 or H.265/HEVC). H.265 offers better quality per bit but demands more processing power to edit.
Color Space	—	The defined range of colors a camera captures or a display can show (e.g., Rec.709 for standard HD, Rec.2020 for wider-gamut HDR) — relevant when comparing how “true to life” different systems’ footage looks.

D

Term	Full Name	Definition
D-term (Derivative)	—	The PID component that dampens overshoot/oscillation in the flight controller’s correction loop.
Deadcat Frame	—	A frame geometry with front arms swept outward so props stay out of the camera’s field of view — common on cinematic and freestyle builds alike.
Demag Compensation	—	An ESC setting that corrects for back-EMF-induced sync issues in the motor.
Desync	—	When an ESC loses timing sync with its motor, causing stutter, sudden power loss, or stall — usually at low throttle or from electrical noise.
DFU	Device Firmware Update	A mode for flashing new firmware directly onto a flight controller via USB.
Digital FPV	—	Video systems (DJI, Walksnail/Avatar, HDZero) that transmit a digitized signal instead of analog waves, trading a bit of latency for much higher image clarity.
Diversity Receiver	—	A receiver using two (or more) antennas/tuners that automatically selects the stronger signal, improving reception reliability.
DJI	Da Jiang Innovation	The dominant consumer drone maker; in FPV, “DJI” usually refers to their digital HD FPV system (O3/O4 Air Unit + Goggles).
DShot	Digital Shot	The standard digital protocol for FC-to-ESC throttle commands (DShot150/300/600/1200), replacing older analog protocols like Oneshot.
DVR	Digital Video Recording	Recording of the FPV feed — built-in on digital systems, or via an add-on module on analog setups.
Dynamic Idle	—	A Betaflight feature that adjusts motor idle speed on the fly to prevent desync at low throttle.
Dynamic Range	—	A camera’s ability to retain detail in both bright and dark areas of the same frame simultaneously — critical for shooting into shadow or bright sky.
D-Cinelike	—	A flatter, desaturated color profile (used on DJI’s digital systems, among others) that preserves more dynamic range and shadow/highlight detail for color grading in post, versus a punchy “straight out of camera” look.
Dynamic Power	—	An ELRS feature that automatically adjusts transmit power based on link quality/RSSI, balancing range against reduced RF interference and battery draw.

E

Term	Full Name	Definition
EdgeTX	—	The actively developed open-source radio firmware fork of OpenTX, running on most modern transmitters.
ELRS (ExpressLRS)	—	An open-source, low-latency, long-range radio protocol that has become the de facto standard control link for new builds.
EmuFlight	—	A Betaflight fork with different filtering/PID behavior, historically favored by some whoop pilots.
ESC	Electronic Speed Controller	Converts FC commands into precise motor power, drawing current from the battery. Modern builds use 4-in-1 ESC boards.
Expo	Exponential	A stick-response curve that softens sensitivity near center stick for finer control, without reducing max rate at full deflection.

F

Term	Full Name	Definition
F4 / F7 / H7	—	Flight controller processor generations, in ascending order of processing power, UART count, and feature headroom.
FAA	Federal Aviation Administration	The US aviation regulator governing drone/FPV flight rules, registration, and airspace authorization.
Failsafe	—	The pre-configured behavior a quad executes when it loses radio signal — typically disarm/drop or, with GPS, an automated return.
FC	Flight Controller	The drone’s central processor — reads gyro/sensor data, runs the PID loop, and commands the ESCs.
Feedforward (FF)	—	A PID component that reacts to the speed of stick movement rather than existing error, improving responsiveness to sharp inputs.
FOV	Field of View	The angular width of what a camera (or goggle display) shows, measured in degrees.
Frame	—	The physical structure — almost always carbon fiber — that all components mount to; sized by prop diameter (e.g., “5-inch frame”).
Freestyle	—	A flying style centered on acrobatic tricks and flow rather than racing or slow cinematic shots.
FrSky	—	A long-established radio brand/protocol (ACCST/ACCESS) still found on many bind-and-fly receivers, though increasingly displaced by ELRS.
FCC	Federal Communications Commission	The US regulator whose certification governs legal RF output power and emissions for VTXs, receivers, and radios sold/operated in the US.
FRIA	FAA-Recognized Identification Area	Designated US airspace where Remote ID broadcast is not required to fly.

G

Term	Full Name	Definition
Gap	—	Any tight opening — a window, gap between trees, etc. — that freestyle pilots fly through as a trick.
Ghost	—	ImmersionRC’s 2.4GHz long-range radio protocol, a competitor to TBS Tracer.
Gimbal	—	Either a motorized camera stabilizer, or (in radio context) the two stick assemblies on a transmitter.
Goggles	—	The FPV headset displaying the live video feed — analog or digital, box-style or compact optics.
GPS Rescue	—	Betaflight’s semi-autonomous “fly home” feature using GPS data if signal is lost; less robust than full autopilot RTH in iNav/ArduPilot.
Ground Effect	—	Turbulent air bouncing off the ground at low altitude, causing a bouncy or unstable feel during hover or landing.
Gyro	Gyroscope	The sensor measuring rotational rate on all three axes — the single most critical input to the PID stabilization loop.
Global Shutter	—	A sensor readout method that captures an entire frame at once, eliminating rolling-shutter skew — rare and expensive in FPV cameras, but eliminates “jello” at the source rather than masking it with mounting or filtering.

H

Term	Full Name	Definition
HDZero	—	A low-latency digital FPV system especially popular in racing, offering HD clarity with near-analog responsiveness.
Horizon Mode	—	A hybrid flight mode: self-levels near center stick but allows flips/rolls at full deflection.
Hybrid Switches	—	An ELRS feature that packs multiple low-resolution AUX switch channels into the space of one full-resolution channel, freeing up channels for other uses without hurting link performance.

I

Term	Full Name	Definition
I-term (Integral)	—	The PID component correcting for persistent drift/error over time.
iNav	—	A Betaflight-derived firmware focused on GPS navigation, waypoints, and autonomous flight — common on long-range and fixed-wing builds.
IMU	Inertial Measurement Unit	The sensor package (gyro + accelerometer, sometimes + magnetometer) that gives the FC its orientation and motion data.
IPEX / U.FL	—	Tiny coaxial antenna connectors common on small receivers and VTXs; IPEX4 is functionally identical to U.FL.
IPD	Interpupillary Distance	The adjustable spacing between goggle lenses/displays to match the pilot’s eyes — critical for image sharpness and avoiding eye strain.

J

Term	Full Name	Definition
Jello	Jello Effect	Wobbly, wavy video distortion caused by high-frequency vibration reaching the camera — fixed via prop balancing, soft-mounting, or better PID/filter tuning.
JST	—	A family of small connector types used for battery leads (esp. on whoops) and LED wiring.

K

Term	Full Name	Definition
KISS	Keep It Simple, Stupid	A proprietary FC/ESC ecosystem by Flyduino, known for a distinct flight feel with minimal tuning required.
KV	—	A motor’s RPM-per-volt rating at no load. Higher KV suits smaller props/lower cell counts; lower KV suits larger props/higher voltage.

L

Term	Full Name	Definition
Latency	—	The delay between camera capture and what the pilot sees in goggles. Analog is typically ~1–5ms; digital systems like DJI O3/O4 run roughly 20–40ms.
LC Filter	—	An inductor-capacitor circuit that filters power-line noise before it reaches the video system.
Li-ion	Lithium-Ion	A battery chemistry with higher energy density but lower discharge rate than LiPo — favored for long-range/endurance builds, not high-current freestyle.
LiHV	High-Voltage LiPo	A LiPo variant chargeable to 4.35V/cell (vs. standard 4.20V) for extra capacity and punch, common in 1S whoop packs.
LiPo	Lithium Polymer	The standard FPV battery chemistry — high discharge rate and energy density, but requires careful charging/storage handling.
Line of Sight (LOS)	—	Flying by watching the aircraft directly rather than through the FPV feed.
Long Range	—	Builds and flying style optimized for maximum distance/endurance over agility.
LQ	Link Quality	A percentage measuring how much control-link data arrives intact — often a better failsafe-risk indicator than raw RSSI.
LAANC	Low Altitude Authorization and Notification Capability	A US FAA system providing near-real-time airspace authorization for flying in controlled airspace near airports.
Lux Rating	—	A camera sensor’s minimum-light sensitivity spec (lower lux = better low-light performance) — a headline comparison point for digital FPV systems shooting dusk/night footage.

M

Term	Full Name	Definition
mAh	Milliamp-Hours	Battery capacity rating — higher mAh means more energy (and more weight/flight time).
Magic Smoke	—	Slang for the smoke released when a component shorts or fries — once it’s out, the part is dead.
MMCX	—	A mid-size antenna connector, more robust than U.FL, common on VTXs.
Mode 1 / Mode 2	—	Transmitter stick layout conventions — Mode 2 (throttle on the left) is the global standard for FPV.
Motor	—	The brushless unit spinning each propeller; described by stator size (e.g., 2306) and KV rating.
MultiGP	—	The largest organized FPV drone racing league.
MSP	MultiWii Serial Protocol	Communication protocol between Betaflight and its configurator software.
Model Match	—	An ELRS safety feature that pairs a receiver to a specific model/aircraft profile on the radio, preventing an armed quad from responding to inputs meant for a different model.

N

Term	Full Name	Definition
Naked GoPro	—	A GoPro with its housing and non-essential parts stripped to save weight — common on cinewhoops and lighter freestyle builds.
ND Filter	Neutral Density Filter	An optical filter reducing incoming light, allowing slower shutter speeds for natural cinematic motion blur.

O

Term	Full Name	Definition
OpenTX	—	The predecessor open-source radio OS to EdgeTX; still referenced in older documentation and community discussion.
OSD	On-Screen Display	Telemetry (voltage, RSSI, timer, etc.) overlaid on the live video feed.
OLED vs LCD	—	The two dominant goggle display panel types. OLED delivers deeper blacks and higher contrast; LCD panels are typically cheaper and can achieve higher peak brightness.
Omni-Directional Antenna	—	An antenna radiating signal roughly equally in all directions — the standard choice for the drone side of the link, versus directional antennas used for long-range ground stations.

P

Term	Full Name	Definition
P-term (Proportional)	—	The primary PID correction force — higher P means snappier response, but too much causes oscillation.
Pack	—	Slang for a LiPo battery (“ripping packs” = flying aggressively through several batteries).
PDB	Power Distribution Board	Distributes battery power to ESCs and peripherals — largely absorbed into 4-in-1 ESC boards on modern builds.
PID	Proportional-Integral-Derivative	The core control-loop algorithm that keeps the drone stable and translates stick input into motor output.
Pitch	—	The nose-up/nose-down rotation axis (also, separately, a propeller’s theoretical travel distance per revolution).
PNP	Plug-and-Play	A pre-built quad sold without a receiver — you install your own to match your radio system.
Prop / Propeller	—	The spinning blades generating thrust, sized by diameter, pitch, and blade count (e.g., 5×4.3×3).
Prop Wash	—	Turbulent air from the quad’s own propellers, causing oscillation when descending or turning sharply through it.
Punch-Out	—	A rapid full-throttle vertical ascent, demonstrating raw power and testing battery voltage sag.
PWM / PPM	Pulse Width / Position Modulation	Legacy analog signal protocols for RC channels, largely replaced by digital serial protocols (SBUS, CRSF).
Packet Rate	—	How often the transmitter sends control packets to the receiver (e.g., 50/150/250/500Hz on ELRS). Higher rates mean lower latency and snappier response but shorter range; lower rates trade responsiveness for distance.
Part 107	—	The FAA certification required for commercial (non-hobby) drone operations in the US — directly relevant for pilots doing paid B2B video work.
Patch Antenna	—	A flat, directional antenna style commonly used on goggle VRX modules to pull in a focused signal from ahead of the pilot.

Q

Term	Full Name	Definition
Quad / Quadcopter	—	A four-motor drone — the default FPV airframe configuration.

R

Term	Full Name	Definition
Rate	RC Rate	Determines rotation speed (deg/sec) per unit of stick deflection — higher rates feel snappier and more aggressive.
Receiver (RX)	—	The onboard module that receives commands from the transmitter and passes them to the FC.
Remote ID	—	An FAA (and equivalent international) requirement for drones to broadcast identification and location data.
RPM Filtering	—	A Betaflight feature using bidirectional DShot motor RPM data to precisely notch out motor-frequency noise.
RSSI	Received Signal Strength Indicator	A measure of raw radio signal strength, shown in OSD — most useful on analog-style control links.
RTF	Ready-to-Fly	A complete package (drone, radio, goggles) — charge and fly out of the box.
RTH	Return to Home	A GPS-based feature that autonomously flies the aircraft back to its launch point.

S

Term	Full Name	Definition
SBUS	—	A common serial protocol (FrSky/Futaba origin) carrying all RC channels over a single wire.
Smart Audio (SA)	—	A protocol (TBS-originated) letting the FC control VTX channel/band/power via OSD instead of physical buttons; IRC Tramp is the ImmersionRC equivalent.
Stack	Flight Stack	The FC mounted above (or alongside) the 4-in-1 ESC, usually sold as a matched combo.
Standoff	—	Threaded spacers connecting frame plates or separating stack boards.
Sub-250	—	Any build under 250g total takeoff weight, which avoids stricter registration requirements in many jurisdictions.
SRRC	State Radio Regulation of China	China’s regulatory certification for RF devices, including VTXs and radios — the third major compliance mark alongside FCC (US) and CE (EU), and one manufacturers often list to indicate legal max power per region.
Starvis / Starvis II	—	Sony’s line of back-illuminated CMOS sensors known for strong low-light sensitivity — used in several digital FPV camera modules and a frequent spec callout in low-light comparison content.

T

Term	Full Name	Definition
Telemetry	—	Data sent back from the aircraft to the radio/OSD — voltage, RSSI/LQ, GPS position, etc.
Throttle	—	The stick controlling overall motor power/thrust.
Tiny Whoop	—	A small ducted micro-quad (roughly 65–85mm) built for safe indoor flying.
Toothpick	—	An ultralight, un-ducted 2.5"–3.5" quad on minimal skinny-armed frames.
TPU	Thermoplastic Polyurethane	A flexible 3D-printing material used for camera mounts, antenna holders, and other flexible parts.
Turtle Mode	Flip Over After Crash	Reverses two motors to right an upside-down quad after a crash without a manual walk-over.
TRUST	The Recreational UAS Safety Test	A free, mandatory FAA knowledge test for recreational drone pilots in the US.
True Diversity	—	A receiver design using two full, independent RF receiver chains (each with its own antenna and tuner) rather than simple antenna-switching — offers meaningfully better signal reliability than “basic diversity,” which only switches antennas on a single chain.

U

Term	Full Name	Definition
UART	Universal Asynchronous Receiver/Transmitter	Serial ports on the FC used to connect receivers, VTX control lines, GPS modules, etc.
U.FL	—	See IPEX above — the small coax antenna connector standard on compact VTXs/receivers.

V

Term	Full Name	Definition
VLOS	Visual Line of Sight	The legal requirement (in many jurisdictions) that the pilot or a spotter maintain unaided visual contact with the aircraft.
VRX	Video Receiver	Receives the VTX’s video signal, either built into goggles or as a separate module.
VTX	Video Transmitter	Sends the FPV camera’s live feed to the goggles; rated in output power (mW).
VTX Table	—	A Betaflight configuration defining a specific VTX’s supported channels/power levels for SmartAudio/Tramp control.

W

Term	Full Name	Definition
Walksnail	—	The Caddx-owned brand behind the Avatar digital FPV system.
Whoop	—	Generic shorthand for any small ducted micro-quad, from the original Tiny Whoop line.
WDR	Wide Dynamic Range	A camera processing feature that balances exposure across a scene’s brightest and darkest areas simultaneously — helps prevent blown-out highlights or crushed shadows when flying from shade into bright sky.