Question David... why is Chicago such a strong market for Latin formats targeted directly at Mexicans? Why is there almost no Hispanic FM radio in Detroit or Minneapolis or Milwaukee? Or even Memphis or Nashville? But Chicago now has three big FM signals broadcasting Regional Mexican music.
Chicago is over 21% Hispanic, or 1.9 million persons. That is a top-20 market hiding inside the 3rd market.
Detroit is 4% Hispanic, or about 175,000 Hispanics.
Minneapolis is 5% Hispanic, or about 155,000 persons. Yet there are 4 bad-signal AMs in Spanish.
Milwuakee is 10% Hispanic, or 170,000 persons. There is a Spanish language regional Mexican FM and two Spanish language AMs.
Apparently Chicago's Latin population is mostly Mexicans. Otherwise WNUA's original format may have worked, a Latin Hits format that could be enjoyed by Hispanics from other regions. Obviously in markets where there are both Mexican immigrants as well as Latin listeners from the Carribean and South America, you'd go for a general Latin Hits format, not just Regional Mexican with singers wearing sombreros and cowboy hats that have nothing to do with other parts of the Latin world.
Markets that have experienced enormous Hispanic immigrant growth since the mid-50s like Chicago, Dallas, and Phoenix have increased almost entirely with Mexican immigrants from rural areas. So the overwhelming format choice is regional.
A market that grew enormously from semi-urban and urban Mexican immigrants is Houston, where the contemporary format does almost as well as regional.
In Mexico City, regional (called "grupera" in Mexico) only accounts for about 22% of listening... the rest is pop, AC, rock (all three either in English or Spanish), talk, oldies, etc.
Even in the San Diego market, right on the Mexican border, there are two full power FM stations broadcasting in Spanish. One is Regional Mexican, one is a Spanish Hits format.
The US licensed Spanish language stations are KLNV, which is regional, and KLQV, which is oldies / adult hits. Neither is a contemporary music format, although some of the KLQV music is pop songs from the 70's and 80's.
But, there are 5 AC/Pop/CHR stations in Tijuana, easily listenable in all or part of the San Diego market... XHLTN, Galaxia, Pulsar, 107.7 and XHMOR. Together, they have about a 5 share in San Diego.
Chicago is now more a Regional Mexican market than San Diego is (aside from the cross-border Mexican stations, not all of which broadcast Regional Mexican, either).
The San Diego population has not grown as fast as others, and it has very different composition.
Tijuana only has two regional FM stations of significance in SD, since Caliente has a very marginal signal. That's because Tijuana is an established urban market where pop and AC rule.