A month late, but I used to be forced to listen to country station KMPS at work, and they would play the anthem at noon every day.
When I was on vacation in San Diego, I woke up at midnight on Sunday night to hear boarder blaster (English language alternative rock) XETRA play the Mexican national anthem.
XETRA? Never heard of it.
XETRA, better known as "XTRA 690" was a Tijuana-based San Diego border-blaster that beamed its signal mostly toward LA. It was an easy listening station in the '60s and '70s, but became a sports station in the '80s, ending in 2005. It's now XEWW, and airs Chinese-language programming.
However, XERA (without the T) and XERF were the Mexican stations that inspired ZZ Top's "Heard It On The X."
XERA was based in Acuna, across the Rio Grande from Del Rio TX, in the 1930s. It was crooked from the word Go, and went off the air in 1939.
XERF started up in 1947, using XERA's old facilities. It eventually ran 250 kW (legal in Mexico), and was the home of Wolfman Jack in the early 1960s. After he left, the station ran all kinds of programming that can best be described as "one huckster after another," both religious and secular. It was audible in most of the country, and was an "interesting" station to say the least.
It's currently owned by the Mexican government, runs 100 kW, and simulcasts on XHRF-FM 103.9. Mexico is trying to turn off as many AM stations as possible, but border stations are exempt.
BTW, the call letter block XA-XI is assigned to Mexico. XE is assigned to AM stations, and XH is used for most FM stations. TV uses both. Five letter calls, such as XETRA, are allowed, unlike in the US.