Hello, I think that all the EFB Admins dealing with iPad devices are struggling with the same issue. Apple will never tell you this information. I've tried to request it several times since 2015. Some years ago, Jeppesen said that as far as you have an accurate gps signal, you will have the location on FDProX. If the signal strength is not enough, then it will dissappear and will not be displayed. At the end, we have the AMM and we cannot use it because we cannot prove that the iPad's built-in GPS receiver has 12 channels. Apple should provide this information. They are fully aware that airlines are big users of this product. C'mon guys, the only thing you have to do is to write a statement in the specifications saying that! We don't want to know the manufacturer name of that antenna! Only how many channels there are!