Fangy and I did a bit of testing today. First off stated with me at the end of Olive Road Falcon, and Fangy at the eastern end of Nairns foreshore. A distance of about 9km, no signal was received, so I moved closer to Mandurah keys Marina a distance of 4.7km, still no signal. Then drove to the end of Beecham St, just over a Km away from Fangy, this time he had a signal from me. So then I drove west to the Creery Island carpark, at 2km away we had no signal, so I started walking towards Ross and he had a signal at 1.8km apart.
I have a feeling my receiver has a problem, as couldn't pick up his signal.

These tests were done with the units at waist high on the waters edge, trying to simulate a unit help up at arms length while sitting on a board.

I think we need to see just how much height above the water affects the signal range, and if orientation of the unit is a factor.
If the antenna has any directional bias. Aiming it at where your mates are and keeping your hand out of the way, would help

Does anybody have a signal strength meter???

One thing we noticed, the identification sent isn't the "nickname" that's set in the config file, it's the identity number that's seems to be part of the unit, I'll ask Julien about this.