I just bought one of these 800mw systems too. Total was $32.99 with shipping - it was another Hong Kong eBay seller. I was amazed the thing even worked for that price
I got rid of the Y connector and the RCA cable mess too. Unfortunately, I must have missed the voltage regulator in the cable "Y" when I ohm'd it out. I've got to double check that. I did power up the camera with a 9 volt battery and it seemed to work fine. The the missing regulator may not smoke the camera immediately.
I plan to mount the camera and xmitter on my Sky Scooter Pro II sometime soon. My thought is to just tap into the 8.4v NiCd pack that powers everything on the plane.
-Greg