RE: ASSAN 2.4 GHz Transmitter module/receivers
The range of 2.4GHz gear increases *significantly* once you get even a few feet above the ground.
I've not heard of anyone having range-issues with Assan gear and the V2 systems are (reportedly) dual frequency systems.
Still, it's not the kind of system I'd use on anything larger than a .40-sized sport model.