A new US Navy radio system is having an unexpected jamming effect on an unusual target, garage doors. The Newport Daily News reported yesterday that the new radio system at Newport’s naval base operates on the same frequencies as some remote garage door openers. The interference leaves the openers ineffective. Naval officials said the base started using the system May 5. One manufacturer said 30 customers in the area have reported malfunctioning garage door openers. Wall-mounted openers, which do not rely on radio waves, are unaffected. Naval officials said they did not know that the system would cause interference.