It is normal for the antenna icon or out-of-range symbol to come up for 10-15 minutes at a time while in range. The receiver and transmitter can miss a couple of readings resulting in 10-15 minutes of the antenna icon. Keep the receiver and transmitter near each other and wait for the signal to pick back up. If you are getting the antenna icon regularly for more than 20 minutes at a time or permanently, please call the Dexcom Product Support team at 877-339-2664.