I’ve been warning people on the Drone Forums that they modify their video transmitters with a risk of violating various FCC rules. Hobby King has been served with a Notice of Apparent Violation by the FCC for selling video transmitters in the U.S. A $2.8 Million fine would hurt just about any business, even Hobby King.
Basically the FCC rules require all unlicensed (I.E. Part 15) emitters to be certified as compliant to the current FCC rules. (“Emitters” includes transmitters, of course, and any device that can radiate RF energy. This includes your microwave oven, your phone, your TV receiver, countless “therapy” devices, and anything with a microprocessor inside). It can cost up to $20,000 to do the engineering studies on the candidate device. The testing is performed by third-party labs, not the FCC.
What trips users up is the FCC rules prohibiting modifications by the end-user. 47 CFR 15.203 Antenna Requirements requires that a Part 15 device antenna be permanently attached or integral to the device to obtain certification. CFR 15.204 External Amplifiers And Antenna Modifications does allow for the manufacture and marketing of after-market antennas, but the modified device must undergo expensive certification testing with the new antenna.
There’s also a plum in CFR 15.204 for the end-user that permits changing the antenna connector, but the device is no longer marketable because it is out of Part 15 compliance.
So, how does the drone pilot get into trouble? If you bought a 2- or 3-Watt video transmitter, can you expect a visit from the FCC? Legally, yes, but in reality, unless there’s a complaint of interference from your device, the FCC has no reason to bother with you. They are more likely to go after the distributor or manufacturer of the device (like Hobby King), and part of the settlement will likely include a requirement that the distributor buy back all of the illegal devices they sold.