OurAirports has records for 4 different navaids with the identifier "MRN". Please select the one you'd like to view.
Brazil
320 KHz (MRN -- .-. -.)
-- .-. -.
Colombia
113.00 MHz (MRN -- .-. -.)
Spain
115.30 MHz (MRN -- .-. -.)
115.50 MHz (MRN -- .-. -.)