This is a very basic question but one to which I could not find a definitive answer. I am about to solder a wire onto an FS-1000A 433 MHz transmitter. Does it matter whether the wire is bare or insulated? I'm going to make it 1/4 wavelength size, is that the best choice, generally speaking? Thank you, please pardon my ignorance to what is probably a very simple answer.
It doesn't matter. It is usually more convenient to use insulated wire in an application like this, just in case the antenna might come in contact with a nearby metallic object or an electronic component.
Use 1/4 wavelength (about 17 cm) of stiff wire, preferably straight up and down, on both transmitter and receiver.