The first step to becoming a cable installer is to gain experience in the field. With a high school diploma, you can meet most educational requirements, but without training in the field, you'll probably be denied. The best way to learn is to find an internship program through a major cable provider in your area. Most companies have established programs, but if not, you can certainly call the company and arrange a time to meet with a technician to get some hands-on experience.
While a high school diploma is all that is usually required, it doesn't hurt to fortify your knowledge on the subject matter. By enrolling in intermediate adult-education physics and mathematics courses, you'll be putting yourself ahead of the curve in the pool of future applicants. These courses will review the fundamentals of electricity (positivity, negativity, flow of electrons), and basic mathematical principles such as fractions, algebra and equations that will help when dealing with electric currents.
Enroll in more advanced mathematical courses to get a thorough understanding of electromagnetism. Learning about DC electricity is an important component to the cable installer's job.
After spending at least three to four months under the supervision of an installer or a technician and refreshing your knowledge on rudimentary mathematics, begin to apply for positions. You may consider graduating with an associates degree to show your commitment to the field. Make sure to get references from academic advisoes and professors as well as your mentor and/or apprentice leader. Continue to learn more about the field (e.g., fiber optics) as an advanced understanding will help you get a job and advance in a company.