CREATE TABLE table_name_50 (purpose VARCHAR2, freq_currently VARCHAR2, area_served VARCHAR2)

What is the purpose for the katherine freq of 8rn?
SELECT purpose FROM table_name_50 WHERE freq_currently = "8rn" AND area_served = "katherine"
SELECT "purpose" FROM "table_name_50" WHERE "8rn" = "freq_currently" AND "area_served" = "katherine"