"We have slightly modified the wireless sync behavior for Zune HD. Instead of remaining connected once you establish the wireless connection, you will now automatically exit the connection once the player determines there is no content to sync. In the auto sync wireless scenario, the player will continue to attempt to reconnect every 10 minutes if wireless sync has been set-up, the player has AC power, no media is playing, and there is no user activity on the player."
If you are trying to unlock every bit of potential that your new Zune HD has, then you might want to head over to AnythingButIpod and check out their forum post detailing every little thing that you may not have known how to do but want to. Or how to do things that you didn't even think about. ABI has TONS of tips up in its forum so if you're a proud new owner of a Zune HD you should definitely follow the link and see what cool things are hidden!