Originally Posted by Simi 60
Really, how accurate do you need them to be.
They are meant as an "aid" to navigation, not a black out the windows and blindly go in with instruments only.
I agree, however there are places around here when having an accurate GPS can be very helpful when going to through narrow channels with nasty rocks. These rocks are very accurately charted and an accurate GPS can do a much better job than I can at knowing where I am.
My older RM GPS antenna is accurate within 5m. The BadElf dongle claims accuracy “up to” 2.5m. There is a big difference between “up to 2.5” and “better than 5m accuracy”.
While I am not sure, I think that both of those are more accurate than an iPhone not connected to a cell network.