Are you connecting all coax shields to ground? You shouldn't have noise.
You don't really need Rt if the coax is that short. In fact, you shouldn't really even need coax. Three inches is too short to cause reflections at video frequencies. You do need all grounds connected together (source, amplifier and destination). It is not clear in the schematic from Analog Devices that the coax shields must all be grounded.
Keep in mind that there may already be a 75 ohm termination somewhere.

 

Look unless you haven't noticed car are made of mostly of steel. and the rubber tire insulates the earth return. what it means is that you need a better signal inside the car as opposed to in a home.

 

Look unless you haven't noticed car are made of mostly of steel. and the rubber tire insulates the earth return. what it means is that you need a better signal inside the car as opposed to in a home.

I think you need to go back and read our OP's first post in this thread.

 

what it means is that you need a better signal inside the car as opposed to in a home.

Yes, and that is exactly the object of this project. Thank you for clarifying for everyone

 

Yes, and that is exactly the object of this project. Thank you for clarifying for everyone

There is no doubt that a car generates a lot of EMI (mostly ignition noise when the engine is running), but a connection to earth would not reduce this phenomenon.
I thought Italo was thinking about receiving a modulated RF source (TV signal) that was generated outside the vehicle.