To get Signal finder you have to do the steps below.
1. Head to the planet Naboo the
city of Lake Retreat.
It Location is -5433, 111.
2. Outside of the Hotel you will find a NPC named Rovim Minnoni take his mission and he will give you the signal finder, cancel the mission to receive another one.
3. Here is the Signal Finder you are given. the is an actual pieces of Star Wars equipment seen in the movies.