I lost one mavic and I want to buy a GPS locator or anything that can help me find it if it gets lost. Any recommendation?

Many of us use Trackimo

I am really sorry for your loss, had you contact our support for this case? If you haven't, I suggest contacting our support and see if there is anything we can help you. Here’s the link to contact us: http://www.dji.com/support
But for the GPS tracker, since we don't recommend to assembly the unauthorized accessories on the drone, so I am sorry to say we have no recommendation.

I have tried a sim based gps watch strapped to the mavic but it seems that it screws up the compass. the mavic has a compass at the front top cover and one at the rear so very hard to find a place to put a tracker. blue tooth ones are useless has they only work within a few feet but the sim based gps trackers scrambles the compass readings. I have mine on the front arm strapped with Velcro and tested it for a few flights seems to work with no issues.

Suren Posted at 2018-1-13 22:36
I have tried a sim based gps watch strapped to the mavic but it seems that it screws up the compass. the mavic has a compass at the front top cover and one at the rear so very hard to find a place to put a tracker. blue tooth ones are useless has they only work within a few feet but the sim based gps trackers scrambles the compass readings. I have mine on the front arm strapped with Velcro and tested it for a few flights seems to work with no issues.

Thank you!