CREATE TABLE table_26387 ("Branding" TEXT, "Callsign" TEXT, "Frequency" TEXT, "Power kW" TEXT, "Coverage" TEXT)

What is the callsign when power kw is 25kw?
SELECT "Callsign" FROM table_26387 WHERE "Power kW" = '25kW'
SELECT "Callsign" FROM "table_26387" WHERE "Power kW" = '25kW'