Phantom 1 loses connection and can't see more than 6 satellites

[sundancepen]

I bought a used Phantom 1 and was testing it. After I started the RC and then the quad, I let the quad warmup. In GPS mode I got a continuous sequence of green and two reds. Sometimes I would get a green and 1 red. I would never get a continuous sequence a green blinking. If I moved more than about 8 to 10 feet away, I would get continuous yellow blinking. So it seems that I am losing transmission beyond 8 to 10 feet. On my phone and tablet I can see 12 satellites. I'm trying to determine what is wrong. Could both these problems have a common cause? All batteries are fully charged.