the simplest antenna can be made with nothing more than a piece of twin-lead, available from your local hardware store.
Cut a piece 10 meters long and solder the conductors together at the ends. Then cut only only one conductor in the middle, then solder more twin-lead to those exposed wires. The free end of that connects to your radio antenna inputs.
Arrange the antenna in a right angle, corner in the center. This will make it omnidirectional. Place it as close to your ceiling as possible.
I've done this same thing for years in my home and other places.