Effective range of Bullseye Camera system

[300 whby]

Hi gents, after a bit of advice re how far I can expect the Bullseye camera system to work.. At the moment it's fine out to 1200 mts, but go out to 1400 & it loses contact with the camera, Is there a system that will reliable get to a mile (1600 mts)
Any advice would be greatly appreciated..

Bill Mac...