Don't konow a lot, but have had nothing but trouble with the radalts fitted to the 206L and 407 (KRA10A type)especially when the antenna is fitted in the passengers chin bubble.
Only time they gave any kind of accurate or believable information was with the antenna fitted under the belly of the helicopter. The engineers at Westpac in Newcastle made up a mounting box for the antenna and the other bits that placed them on the belly between the cross tubes. Did a good job too.
Have been trying for a number of months now to get the problem resolved, but it is slow going. Nobody can, or wants to have a shot at fixing it............