sentences:  This is seen the calls of CBS's KCBS (AM) being based in their original city of San Francisco instead of Los Angeles (the use of KCBS-TV in Los Angeles only dates back to 1984), while KNBR (which was subsequently sold to another party by NBC in 1987) was formerly known as KNBC before the network moved those calls to KRCA-TV in Los Angeles in 1962.ABC, CBS and NBC are headquartered in New York City, which is the largest television market in the U.S., so their respective radio and television stations in that market are considered the overall network flagship stations.As programming schedules increased and modern technology improved transmission to affiliates, the networks set up operations centers in New York City (for the East Coast feed) and Los Angeles (for the West Coast feed).