Does a digital signal travel farther than an analog signal?

You need to make a distinction between analog and digital signals, and analog and digital data. Digital data can be sent on an analog signal by using a modem. Digital data sent on a digital signal is done over a wire using voltage pulses at two or more levels. Digital signals can't travel very far without amplifiers, but analog signals can cover huge distances, such as with satellite communications and even communications with deep space probes.