Well I'm on the other side of the beach ball (Australia) and I get the same regularly in more urban areas, a couple of times only 300 feet before the video signal warning, as does another guy I know on the other side of my country. Yet out in the sugar cane fields I got 3100 meters (10170 feet) before even a hint of video signal loss, at which time I turned around.
Oddly I seem to get more bad signal messages when on the way back. For instance, on that 3100 meter flight, I had the bad video signal at that distance, then turned around and then inbound at 900 meters (2952 feet), I got a bad RC signal (which lasted about 4 seconds)
I'm a noob but although worrying about all this at first, Iv come to the conclusion this must be normal and as someone else said, you can probably most of the time, keep flying on, or gain some altitude, and get through the problem area although I admit at this stage, I'm still mostly finding myself turning around when it happens....