I just thought of something else, I saw that someone had put a ferrite ring around the wire from the UBEC to the Rx. The ferrite ring helps surpress any noise that the UBEC might generate.
Something liek this might help.
http://cgi.ebay.com/ws/eBayISAPI.dll...m=290210641745
Not really sure if that particular one is the right size, but just to give you an idea of what I am talking about.