CREATE TABLE table_77227 ("Call sign" TEXT, "Frequency MHz" FLOAT, "City of license" TEXT, "ERP W" FLOAT, "Class" TEXT, "FCC info" TEXT)

What is Call Sign, when City of License is Brownfield, Texas?
SELECT "Call sign" FROM table_77227 WHERE "City of license" = 'brownfield, texas'
SELECT "Call sign" FROM "table_77227" WHERE "City of license" = 'brownfield, texas'