6900 kHz or 6.900 MHz is the "home channel" for Spanish speaking operators on 43 meters. Usually its 6900 LSB. See also: 6666.6 kHz USB and a seemingly endless number of others. 6900 LSB is the most often logged though. They are land based stations having an informal ham radio ragchew-like (or CB 11 meter like) QSO, often in "roundtable" format with a loose net control operating style.
At 2203 UTC I am hearing Spanish speakers chatting away on 6900 LSB and 6900 USB. Hearing "over" (in Spanish) and other indicators that the guys talking at least know the basics of radio procedure.