Ipad losing connection with lasers

I keep having problems losing connection between my ipad and lasers during sprint timing events. For example, I was running flying starts with two lasers for about 10 athletes. I was doing 20 yard flys. I was standing half way between the two lasers. Lasers would work fine for a few runners and then lose connection. I would have to reconnect lasers on ipad and walk closer to the lasers to do so. My ipad didn't have a cell connection. Just used bluetooth with the ipad connecting to the lasers. Very frustrating as this happens consistently with the dashr timing. I am not sure if a better device such as android would work better or if this happens with weak batteries but it is very frustrating. Any advice would be appreciated.