SELECT AVG("Frequency MHz") FROM table_67920 WHERE "Program" = 'radio rezonans'
What is the average MHz Frequency of radio rezonans?
CREATE TABLE table_67920 (
    "Program" text,
    "Frequency MHz" real,
    "ERP kW" real,
    "Polarisation" text,
    "Antenna Diagram around (ND) / directional (D)" text
)