VTx

VTx, short for Video Transmitter, is the RF component used in unmanned aerial vehicles (UAVs) to send live video from an onboard camera to a ground-based receiver. In a typical FPV system, the VTx takes the video signal from the camera or video encoder, modulates it onto a carrier, amplifies the signal, and outputs it through an antenna. The ground receiver then demodulates and displays the video on goggles or a monitor.

Most VTx units operate in the 5.8 GHz ISM band, though alternatives exist in other bands. They offer multiple channels to avoid interference, and channel selection can be manual via jumpers or adjustable in some models. Power output varies widely, from tens of milliwatts to several watts, with higher power extending range but increasing heat and potential interference. Regulatory rules in many jurisdictions limit effective isotropic radiated power (EIRP) and specify permitted bands and usage conditions.

VTx devices come in several types. Analog VTx transmit a continuous video signal and are common in hobbyist FPV for low latency. Digital VTx, used with newer digital FPV systems, can provide higher image quality and resilience to interference but may introduce latency. Many VTx support features such as remote power control, digital or software-configurable interfaces (for example, SmartAudio), and “pit mode” to reduce transmission during ground operations.

Technical considerations include input voltage range (often 5–12 V or higher on more capable units), connectors (SMA, MMCX, or board-mounted coax), and heat management, as high-power units can run hot. Safety and compliance require adhering to local RF regulations and using appropriate antennas to minimize interference and exposure.