I would be interested in hearing your final solution.
I have 2 color cams and a B/W each located about 30-40 feet from my receiver.
They are all located outside of a brick home at about a 7' height.
I also have a 2.4ghz portable phone but it does not seem to interfer with my cams...
Maybe I have to be using it at the same time..not sure.
Reception from the cams with a VR31A appears ok with the va11a and much better going straight into the PC via a video card input.
I am interested if you have been able to solve your range problem ?
regards,
SteveRF