Not many know that Marconi had many rivals who wanted to prove him wrong.
Marconi claimed that his Wireless transmission was unhackable and could not be interrupted or encroached on.
A rival inventor named Nevil Maskelyne went on to prove him wrong.
Maskelyne was the one who intruded in the signal with morse code.
He sent one message for Marconi: rats, rats.
source: www.techworm.net