Bill WAØTFT and I were listening to a NDB on 253 KHz the other night, and for the life of me, I could not find any data about it. After searching a bunch of personal websites maintained by LW enthusiasts, I found a great site. The site is called RNA and it's author is Martin Francis. Just click here to find the page.
By the way, the signal we were hearing 253 KHz was from the Chisholm/Hibbing airport, and it's ID in CW is JA. Thanks Bill for initiating the search, which nearly drove me silly, until I found it.