Help with 75 MHz Transmitter & Receiver

Hi all! I am currently designing a robot for my Engineering class and the controller is giving me some problems.

The robot has to be controlled through a Steel Sheet Metal tunnel. My robot loses signal about a quarter of the way through the tunnel without fail. It regains signal when I point the transmitter inside the tunnel when I am standing next to it. However, I can not do this during the actual project. Do you guys have any ideas? I tried adding an antenna and soldering the Receiver to it, yet that was no better. My professor said the antenna should’ve helped slightly and she would talk with the electronics department about it. Do you guys have any tips or advice? I’m stumped.

Sorry about the delayed answer.

I discussed this with our programming team and this is a limit of the radio transmitter as your teacher suspected. The steel sheet metal tunnel is blocking / funneling the radio signal out both ends. If you cannot maintain a connection with the robot through the tunnel the next best option would be to program to robot to autonomously drive through the tunnel. This could be enabled via normal driving up to the tunnel mouth, then a button to engage a drive forwards program, with a secondary button to disengage the program. Not a pretty solution, however, there is no way to manually operate the robot if it is not able to send / receive a signal from the joystick.

Hope your project is a success, please let us know if you have any further question.