Think about how these thingies are supposed to work. The reflectors are purported to be parabolic shapes, which in theory will alter the beam width of the stock antenna to focus the radiated energy forward. If (BIG IF!!) the reflectors were perfect parabolas, and IF the spacing between the reflector and the radiating element is exactly right, the antenna pattern will be as described, and a minute increase in range/reliability would be realized. The problems, however, are my imperfect measurements on the devices I have show them to be far from the accurate shape needed. Next, the distance from the radiator varies with the manner in which the R/C is held (due to slop in the attachment methods. Finally, you don't get sumthin' for nuttin' Increased radiation in one direction means a reduction in energy elsewhere, and if the devices work to perfection you'll have to be spot on in aiming the beam (which you can't see). Really tough to do when wearing goggles or using a sun shade hood on the R/C.
IMNSHO, the hassles are not worth it. Just Sayin'
