Below is the list of tables from the database along with their columns and datatype. Need to generate an accurate SQL query for the question.
Only use the columns present in the respective table. Only use the columns which are required to generate the SQL query. Only use table joins if required and not otherwise.

### Tables ###
TABLE: CREATE TABLE table_78179 ( "Call sign" text, "Frequency MHz" real, "City of license" text, "ERP W" real, "Class" text, "FCC info" text )

### Question ###
What is the Frequency MHz for the station with a call sign of w224bn?

### Accurate SQL ###

SELECT AVG("Frequency MHz") FROM table_78179 WHERE "Call sign" = 'w224bn'