Could be. We've had ours out 11 miles with no problems. We did have trouble in 2 fields closer than that but they are directly on the other side of town from us and the tractor on the grain cart never lost signal but the combine did. I think it was a combination of the reciever being below the level of the hopper extensions and often times a pile of grain in the hopper as well as trying to bounce signal over town. We have a big omni-directional antenna mounted 65' in the air on our base.

I'll know more about the situation next spring. Often times we are working in the same relative area with another machine so we could just use the other local machine doubled as a rover & repeater.