Video Transmitter

VTX

VTX which transmits the video from FPV camera wirelessly to a video receiver (VRx), which can then shown on your monitor or FPV Goggles.

Digital and Analog

ANALOG System transmitting videos at 640x480

Cheap price
Small Size
Low latency

DIGITAL System transmitting videos at 720p or 1080p

Expensive
Large and bulky
Extra of lag in your feed could be the difference in your reaction time to an obstacle or gate

Output Power

The higher output (rated in terms of milliwatts or mW), the further distance you can go and better signal penetration is possible (such as flying through a grove of trees). But more heat that will be generated by the VTx, as well as more power consumed from your battery. overheat. If overheats, it tends to reduce the power which means you might lose video signal.
The most important thing is to ensure good airflow to keep your VTX cool.

Use high power as much as possible?
25mW is great for indoor flying and races with many pilots. It can angachieve 1km, 200m should handle 2Km-3Km range easily. When flying with a group of people, selecting too high power output might interfere on other pilots video signal, it can loss of control, even if it’s just for a second.

High power isn’t always a good thing when you fly in certain environment where there are lots of signal reflection such as a garage or stadium. Signals can bounce off the floor, ceiling and walls and introduce interference to your video.

Some country are limit to 25mW without a license. Please check your local regulation.

Channels

5.8GHz (5800MHz) is preferred for FPV because it’s legal in many countries, and the antennas can be made very small. The channels available on a VTX are the preset frequencies, most VTX’s only support 5 bands, A, B, E, F and R.

Why race organizers use Race band?
That’s because the bandwidth or the separation between race band is the highest.

Some manufacturers now provide access to a much wider area of the radio spectrum.

72-channel equipment can access frequencies down to 5.3GHz.

Isn’t it a good thing to have an expanded ability for more pilots flying at once?

We don't suggest use these channels.

It’s Illegal in some country.
From 5650MHz to 5925MHz "commonly called the 5.8GHz band" is open for use to anyone.
All of the channels in “Boscam A”, “Boscam B”, “Immersion/Fat Shark”, and “Raceband” fall within the allocated 5.8GHz band. The “Boscam E” band has a few offensive channels: E4, E7 and E8 are outside the allocation, making them illegal to use.

“L” , “U” and “o” bands, operating from 5.3–5.6GHz, fall entirely outside the frequency allocation.

The “H” band does stay within 5.8GHz, but it offers almost no actual benefit over Raceband.

In the end, none of these extra channels are truly useful.

May have other people use these bands
Just because you check your goggles before you power up and see static doesn’t mean

a channel is clear. Many types of radio transmissions won’t show up on video goggles.
example: weather radar can pick up transmissions at 5.3GHz.

Your antenna isn’t designed for it
Antennas are tuned for a specific frequency. They work best at or near this frequency,

and their ability to pick up signals outside of that often drops off sharply.
They are designed to do this on purpose, so they reject unwanted signals from other

bands and reduce interference.

This Pagoda antenna performs very well at 5.8GHz,

but really poorly at 5.3GHz! (In this graph, lower is better.)

Smart Audio

You can normally change VTX channels via Dip switches, Push button
Remote controller (using IR or Bluetooth technology)

Smart audio is a feature that allows users to change VTX channels and power outputs from your goggles or transmitter.
There are 2 different protocols
Tramp Telemetry from ImmmersionRC
Smart audio from TBS.
Though their inner workings differ, they both serve the same purpose under two different names. VTX’s support either of the two protocols, depending on the protocol your VTX supports and select accordingly in Betaflight.

Pit Mode

Pitmode allowing you to boot up your VTX in an extremely low power mode, which lets you change your band and channel without disturbing anyone currently in the air. Transmission range in this mode is limited to just a few feet.

Or when it’s crashed, as the quad is stationary on the ground and with no air flow across the VTX, it tends to become very hot, hence to minimize the risk of burning the VTX.

Input Voltage

Some VTX’s support a wide range of voltage inputs ranging from 2-6s.

It is strictly not advised to power your VTX directly through the battery. Our LiPo batteries cannot handle the high current draws of most modern motors and cause voltage spikes. These voltage spike causes momentary voltage drops across the VTX.
You can combat this problem by using LC power filters or through dedicated ports on FC’s and PDB’s , that filter out these voltage spikes.

on the FC rather than powering the VTX directly from the battery which is of course more convenient.

Antenna Connectors

There are 3 major connectors, UFL, SMA and MMCX.
SMA connectors come in 4 configurations- SMA male, SMA female, RP-SMA male and RP-SMA female.

If you use adapter connectors, there is a performance penalty for every adapter you use (3db of signal loss for each adapter).

Never Power VTX without an AntennaIf you power up your VTX without an antenna, energy has no where to escape and heat will build up in the transmitter. It will get so hot and burned!

Microphone

Microphones record audio which get transmitted through the VTX. But microphones are totally a personal preference thing. Some people do not like the buzzing sound of the air flowing over the quad.