A/V sender

Would wiring inside my walls interfere with a 2.4 av sender.
I get a mean signal, and then about 30 seconds later, it starts breaking up. Ive tried turning off my wireless router - no luck. Would a wireless phone cause any probs? I purchased a specific one to not interfere with my interwebs.
Could it be interference from another electrical device, it worked perfectly in my old house, and I have not bought anything new since moving.

Help?

Try turning off everything else (including the hotwater) at the switch board. then try sending for a really short distance - eg 1m (but even that might be too close).