Although some top-40 stations such as CKLW in Windsor, Ontario, made their mark by integrating a large amount of R&B and soul product into their predominantly pop playlists as early as 1967, such stations were still considered mainstream top 40 (a cycle that continues to dominate the current Top 40/CHR chart).
This development was largely spurred by the highly successful "worst-to-first" debut of the disco-based format on WKTU on 92.3 FM in New York City (now WINS-FM) in 1978.
For example, Detroit's successful WDRQ included artists such as Cyndi Lauper, Culture Club and The Romantics in its urban format circa 1984.
But it wasn't until January 11, 1986, that KPWR in Los Angeles, a former struggling adult contemporary outlet, began to make its mark with this genre by adopting this approach.
The new breed of crossover stations broke a number of popular artists, including Expose and The Cover Girls, but such artists couldn't reach the top of either the Billboard Hot 100 or Hot Black Singles charts because their airplay was split between a handful of mainstream top-40 and black reporting stations.
Billboard magazine thus debuted its first rhythmic top-40 airplay chart, the "Hot Crossover 30," in its February 28, 1987, issue.
The Crossover panel's initial lineup of 18 stations included five exclusive Crossover reporters (KPWR, WQHT, WHQT Miami, WMYK Norfolk, and WOCQ Ocean City, MD) as well as 13 stations which also retained their prior CHR or black reporter status (among them WPOW Miami, WHRK Memphis, KMEL San Francisco, WHYT Detroit, WQUE New Orleans, WLUM Milwaukee.