How make a passive antenna?

To make a passive antenna, you need a conductive material, such as copper wire, to form the antenna's elements. Cut the wire to the desired length, typically around half the wavelength of the frequency you want to receive. Shape the wire into a simple design, like a dipole or loop, and connect it to a coaxial cable or directly to your radio receiver. Finally, ensure the antenna is properly positioned and grounded for optimal reception.