Original sentence: SECAM was a popular choice in countries with much hilly terrain, and countries with a very large installed base of older monochrome equipment, which could cope much better with the greater ruggedness of the SECAM signal
Edited sentence: SECAM was a popular choice in countries with much hilly terrain, and technologically backward countries with a very large installed base of monochrome equipment, since the greater ruggedness of the SECAM signal could cope much better with poorly maintained equipment