CREATE TABLE table_35480 ("Call sign" TEXT, "Frequency MHz" TEXT, "City of license" TEXT, "ERP W" FLOAT, "FCC info" TEXT)

Which Frequency MHz has an ERP W larger than 4, and a Call sign of w218ap?
SELECT "Frequency MHz" FROM table_35480 WHERE "ERP W" > '4' AND "Call sign" = 'w218ap'
SELECT "Frequency MHz" FROM "table_35480" WHERE "Call sign" = 'w218ap' AND "ERP W" > '4'