You know to watch out for obvious stuff when flying your fishing drone – your rod, other people, birds, and so on. But there's an invisible danger lurking out there: Electromagnetic interference (EMI).

EMI can really mess with your drone's navigation, especially the "return to home" feature.  Anything with power or a signal can cause it – power lines, phones, even other drones.


What is Electromagnetic Interference?

Basically, it's invisible energy that messes with electronics. Think of it like this: every electrical device gives off an invisible field.  The bigger the current, the stronger the field.  Your phone is pretty weak, but power lines? Those are strong and can affect your drone from a distance.



How to Spot EMI Trouble Zones

This is tricky because you can't see EMI. But here are some clues:

  • Use an EMF app on your phone.  There are apps like "Ultimate EMF Detector" for Android and "EMF Radiation Detector Reader" for Apple. If the reading is over 60 microTesla, be careful.
  • Look for obvious EMI sources:
    • Caravans: They're big hunks of metal with a bunch of electronics inside. Steer clear, especially around freedom camping spots.
    • Power lines and cell towers:  These are big EMI sources. Check out gis.geek.nz to see where cell towers are in your area.
    • Other drones and phones:  While your phone alone shouldn't cause major issues, it's best to put it away when calibrating your drone.


Heads up! Some spots in New Zealand are known for bad signal interference, like Papamoa and Orewa. Orewa has a submarine cable running nearby, and Papamoa is often packed with people and motorhomes.



Tips for Flying in EMI Zones

  • Calibrate your drone away from potential problems. Do this before every trip. Drones keep flight logs, and if you skip calibration and have an issue, your warranty might be void.
  • Wait for a good GPS signal. Aim for a signal strength of at least 8, but 10 is ideal. This gives your drone a solid lock for "return to home."
  • Don't rely on "Return to Home." It's a last resort, not an everyday feature. Fly in GPS or ATTI mode for more control.
  • Learn to fly in ATTI mode.  This is the mode your drone switches to if it loses GPS. It basically means you're flying manually. Practice this before you need it!
  • Replace or recharge your batteries often. Don't wait until the last minute.  Many drones automatically return home when the battery gets low, and if your GPS signal is weak, you could be in trouble.
  • Get drone insurance. Things can go wrong, even if you're careful. Check your house and contents insurance or get specific drone coverage.


Flying a drone safely takes practice and preparation. Always assume you might lose signal and plan. If your drone starts acting up, don't use "Return to Home." Switch to ATTI or Manual mode and fly it back yourself.  Practice flying in ATTI mode – it's different from GPS mode, and your drone might drift with the wind.