How to Find Downed and Lost FPV Drone

by Oscar
Published: Last Updated on

How often do you lose your mini quad after a crash, and no matter what, you just can’t find it! In this article I will show you how you can find your downed drone and precautions you can take.

Click on the links below will take you directly to the sections in this article.

The methods depend on whether your quad is still being powered. If the battery is still connected:

If the LiPo battery gets disconnected in the crash (How to tell? You probably lost both radio/video signals at this point):

Must Have – Activate Beeper

Hopefully you already know this one. If not, here is how to Install a buzzer in your quad, and enable beeper mode in Betaflight’s modes tab. Also it’s really useful to enable DShot ESC beacon as backup.

The only downside with buzzer, is that you have to be very close to the quad to hear the beeping,

if you still have radio signal (e.g. telemetry), but can’t hear the buzzer, it probably means you are too far away. Try the next method in this case.

Check DVR (Video Recording)

I cannot stress enough, ALWAYS record your flight with a DVR. When you crash, you can look back and find out where about you crashed. From my last crash in the sea, I was able to get my quad back only because I had DVR!

In Fatshark Goggles, you can enable “Auto-Record” in the DVR menu.

Using Goggles To Find Your Lost Drone

Not many people know this trick, but it can be extremely handy and helpful!

You can use the video receiver in your FPV goggles to find your downed drone! This trick is based on the RSSI value (signal strength).

Remove the onmi-directional antenna, use only one directional antenna, such as a helical or patch antenna (the higher gain the better).

With only a directional antenna pointing at your drone, RSSI will be at its highest. When you point it away from the drone, RSSI will go down. So you can track down which direction your drone is.

I made this Info-graphics to help you visualize how it works :)

using fpv goggles diversity module to find lost fpv drone with RSSI

This trick would only work if your quad is still powered on. As you get closer to the quad, it will become harder to tell which direction, in this case try to lower the VTX power in Betaflight OSD menu (if you have VTX control setup). And use beeper to help.

Some VRX modules have built in “finder mode” which has nicer interface, but the principle is the same.

Using Radio Transmitter To Find Your Lost Drone

Based on a similar concept, you can also use your radio transmitter to find your downed quadcopter.

It’s best if your TX gives you numerical RSSI readout, if not just look at the signal bar on top of the screen.

The signal is the weakest when the antenna is pointing directly at the quad. So move your transmitter antenna around and when you find the lowest RSSI, walk where the antenna is pointing.

using radio to find lost fpv drone with RSSI

As you get closer to the quad, the signal will get stronger, and it will be harder to identify the direction. Just put the transmitter into range test mode (In Taranis model setup page, right next to “Bind” option, you should see “Range” option).

Again, this will only work if your quad is still powered on. If your battery came disconnected, you will have to rely on some of the following methods.

Buzzer with Its Own Battery

These self powered buzzers will continue to work even when your main LiPo battery gets ejected. And they can replace your ordinary buzzer in the quad, so the added weight and space is minimal.

I have a post comparing a few popular options.

Although some of these options are louder than ordinary beepers, you do still have to be close enough to the quad in order to hear it.

Last GPS Coordinates

If you have GPS module installed, you can either display the GPS coordinates in the OSD, or record it in your Taranis as part of the telemetry data.

Here I have a tutorial explaining how to log GPS coordinates in the Taranis.

Once you get the coordinates, simply copy and paste them in Google map and it should show you the location.

Drone Finding Systems

There are some other more specialized systems for tracking down downed drones.

Loc8tor Lite

Locates your drone up to 120 meters, based on radio waves I believe? Correct me if I am wrong. Product Page: https://amzn.to/2DkCObL

tBeacon GPS Tracker

Some pretty expensive GPS trackers you can install in your quadcopters. Product Page: https://tbeacon.org/?page=10&language=en

I am sure there are other similar products out there, I will keep the list updated. Let me know if I am missing any.

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7 comments

Ben 4th September 2020 - 8:40 pm

Here’s a trick from amateur radio that we can use to locate the direction of a radio source:

Your battery needs to still be attached.
Pull the radio transmitter close to your body, like against your stomach, and look at the RSSI value.
Now, slowly spin in place 360 degrees making note of where the RSSI value is maximized. Basically, you’re using your body as a shield to block the signal.
Wherever RSSI is maximized is the direction of your quad. I was able to use this to find a downed quad on my second day of flying after I crashed in tall grass.

Reply
Maxwell 4th July 2019 - 9:09 am

I wonder if it’d would be worth trying to deliberately block/shroud your FPV goggle antenna somehow to “focus” where it’s receiving signal from to a smaller and more directional area? Maybe placing a metallic tube over it with a pin hole or slot in one side?
Or would that not work with the radio signal bouncing off a lot of things anyway? I’m new to this stuff and don’t know much about RF stuff.

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Oscar 15th July 2019 - 4:39 pm

Not really necessary…
Bouncing shouldn’t affect it.

Reply
Emmanuel 12th November 2018 - 11:09 pm

I would add:

Stick a label with a phone number or an email under your quadcopter. It cost nothing and it may give you a good surprise when somebody finds it before you.

Reply
Oscar 23rd November 2018 - 4:21 am

Yes, we actually make a battery strap with that feature in mind :)

Reply
Chris C 5th November 2018 - 6:57 pm

“Just put the transmitter into range test mode”.
How do you enable this mode on a Taranis?

Reply
Oscar 5th November 2018 - 8:20 pm

In Model Setup page, Next to the Bind Option, you should see “Range” option.

Reply