OurAirports has records for 6 different navaids with the identifier "OS". Please select the one you'd like to view.
China
241 KHz (OS --- ...)
--- ...
Russia
650 KHz (OS --- ...)
600 KHz (OS --- ...)
United States
515 KHz (OS --- ...)
395 KHz (OS --- ...)
278 KHz (OS --- ...)