I have a 3-day old SIM-free iPhone 6s that I bought from Apple online. It's set up to display actual signal strength instead of dots (used field test mode to set it). In the span of a few minutes, the signal strength will be -75 dBm (5 dots) and then suddenly drop to -110 to -112 dBM (2 dots). My wife's iPhone 5 will show a constant -74 dBm that whole time. It will stay at -110 dBm until I toggle airplane mode on and off. I see lots of entries on a thread at apple discussions about this, but no resolution. 1) Do any of you have the same problem? 2) Is there a real fix? 3) Do I have the same 14-day return window with Apple directly that others have buying through a carrier? The nearest Apple Store is 175 miles away, and our whole area is in the midst of an ice storm.