This is almost as bad as the Phantom 3. I changed my service provider for my RF-V16 tracker from AT&T to T-Mobile due to a much better price. They both work OK in my area. I ported my number from AT&T. Did all the "work" online. After 5 days and no change, I called. OOOOPs! Gave T-Mobile wrong account number. The person from "T" stated there may be some odd connections if using the phone for about 24 hours. OK, so I waited almost that long. Unlocked GoPhone worked so I put sim in tracker. Got GPS and asked it where my Phantom was. Two minutes later map shows up and what??? Zoomed out from map and it showed I was on the other side of Lake Michigan. About 63 miles away! If I was searching for a lost quad, that sure would have been a LARGE area to search! About three hours later another check and it was 30 feet away. Still working good.