Most of the Spanish speaking fellows I hear on and near 6900 are from Texas, Mexico or in the Gulf. Occasionally I hear reports of Portuguese speakers from the NE coast area, but I rarely hear 'em unless I use a web tuner. When I do hear Portuguese speaking folks between 6900-7000 they turn out to be from Brazil - very active especially on 7000 LSB.
A North American shortwave pirate op used one of those CB transverters two or three years ago - I heard him pretty well here. I think he said he borrowed it for awhile and had to return it. Seems like an interesting offshoot from Brazil's flourishing tech savyy pirate communications industry. They're also known for pirating satellites for two-way comms. Clever fellows.