I live in Minnesota. I have an Adafruit RFM69 433MHz transmitter and receiver.

I'm building a quadcopter drone and wondering if I'm allowed as a hobbyist to send continuous data to my drone (such as joystick axis information) over 433.0 MHz legally. Who could I email/call contact directly for a straight answer?

  • \$\begingroup\$ How continuous you mean by continuous? A packet of few bytes every second, or really continuous stream of data? Don't the ISM band have certain power and duty limits? \$\endgroup\$
    – Justme
    Commented Feb 25, 2022 at 22:23
  • \$\begingroup\$ I'd say maybe a few bytes every 100ms. \$\endgroup\$
    – Alex Fish
    Commented Feb 25, 2022 at 22:30
  • \$\begingroup\$ no, you have a 5-second limit. I doubt you'll get busted though... edn.com/… you might want to look into ESP-NOW on the ESP line of cheap MCUs, which uses wifi hardware but isn't wifi but is legal. \$\endgroup\$
    – dandavis
    Commented Feb 25, 2022 at 22:41
  • \$\begingroup\$ Thanks! I'll check it out. \$\endgroup\$
    – Alex Fish
    Commented Feb 25, 2022 at 22:48
  • \$\begingroup\$ @AlexFish I have planned to do the same thing, I have developped a motherboard with an ATMEGA328PB and a RFM69HCW. I don't know what are your objectives but maybe we could help each other. github.com/ARMaudV86/RFMdLib Sources are here if you want to check. It's still work in progress tho.. \$\endgroup\$ Commented Mar 3, 2022 at 9:06

1 Answer 1


433MHz isn't a license-free band in USA - devices using that band for continuous transmission need to reduce output power to some <1mW which probably won't work in your case. You should be using the part "RFM69 @ 900 MHz" designed for the 915MHz band, read the link you posted yourself.

Also no matter band, you need a FCC approved radio. If this board has FCC Part 15 approval then you are ready to go. If not, you can't use it.


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