CREATE TABLE table_39696 ("Call sign" TEXT, "Launched" TEXT, "Transmitting from" TEXT, "Coverage" TEXT, "Languages" TEXT, "Frequency" TEXT)

What is the frequency of the station that was launched on 21 August 1994?
SELECT "Frequency" FROM table_39696 WHERE "Launched" = '21 august 1994'
SELECT "Frequency" FROM "table_39696" WHERE "Launched" = '21 august 1994'