FPV VTX Power and Frequency Bands: Legal Limits Every Pilot Should Know
Your video transmitter is the piece of equipment most likely to get you into legal trouble, and most pilots do not realize why. VTX power and frequency affect everyone around you, from other pilots in the air to licensed services on nearby bands. Flying legally is mostly a matter of choosing the right power level and staying on the right channels. Here is what you need to know.
How VTX Power Affects Everyone
Video transmitters are rated in milliwatts. A 25 mW VTX is enough for close-range flying; 200 mW reaches further; 800 mW and above is meant for long range and penetration through trees and buildings. Higher power gives more range but also more interference. A single pilot blasting 1.2 watts can wash out the video of every other pilot on the field, which is why most clubs and events cap power at 25 mW for the majority of participants.
High power also generates heat. A VTX running at full output draws more current and can overheat if it lacks airflow, so it is common to keep a VTX at low power on the bench and only raise it once airborne. Always check that your antenna is attached before powering up, because running a transmitter without an antenna can permanently damage the output stage.
Frequency Bands and Channel Selection
FPV video runs in the 5.8 GHz band, divided into channels you may know as the “band and channel” grid used by receivers. Different regions allow different portions of the band, and some channels overlap with radar and other licensed services. Flying on the wrong channel at high power can interfere with systems that are legally protected, which is a serious problem even if no one notices.
Stick to the channels your receiver and your region actually allow. When flying with others, coordinate channels and keep power low so everyone gets clean video. A channel chart and a quick pre-flight check prevent most multi-pilot interference problems before they start.
Licensing and Local Rules
In many places, FPV flying falls under hobby or amateur rules that carry specific power limits and channel restrictions. A license may be required above a certain output power or on certain bands. Remote ID rules, where they apply, add another layer of compliance for the aircraft itself. The exact requirements vary by country and sometimes by region, so verify the rules that apply to where you fly before investing in high-power gear.
The safest default is to fly at the lowest power that gives reliable video, on channels you are certain are legal, with your antenna matched and attached. Legal flying is rarely about the hardware being illegal; it is usually about a pilot who never checked the limits. A few minutes of research keeps your flying both enjoyable and lawful.
Bench and Pre-Flight Habits
Most VTX damage happens on the bench. Always attach an antenna before powering up, set the transmitter to its lowest power level, and use a fan if you will be powered on for more than a minute or two. A VTX without an antenna turns its own energy back into heat and can burn out the output stage in seconds.
Before every flight, confirm your power level and channel against the plan you agreed on with the other pilots on site. Logging which channel and band you use makes troubleshooting interference far easier, and it keeps you honest about staying inside the legal limits for your region.
Finally, remember that output power is a tool, not a status symbol. More milliwatts rarely fix a bad antenna or poor placement, and the cleanest video usually comes from a well-matched antenna at moderate power, not maximum output.