backup camera on trailer

I recently bought a WiFi Hitch Camera from Rear View Safety. It uses a dedicated WiFi signal from an Ipad via a free app. It not only works while on my tailgate (magnetic mount) when viewing my hitch ball and trailer tongue, but when mounted on the wheel of my spare tire, allows me a good view of what's behind my trailer when backing up. The camera runs on a rechargeable battery and the charge will last for a few hours. This works for me since I only use it to hitch up the trailer or back up the trailer at a campsite or my storage space. It wouldn't be suitable for constant use while travelling down the highway. I should add that my trailer is only 16' long and, while the signal from the back of the trailer to the cab is very good, I don't know if it would work well on a trailer that was much longer.