I have been chasing navigation beacons on frequencies 190 khz to 535 khz in North America .. to 1750 khz with some overseas beacons. I started doing this to check propagation for 160 and it turned into a habit. There is some great software to waterfall the beacons, and software with an NDB database and logging program.
ARGO is the weak signal waterfall software and is located at : www.weaksignals.com
The database and logging software WWSU can be found at www.ve3gop.com
The database program WWSU is not freeware is you like it, it costs $20.00 US, please support Alex if you use the software.
There is also a Facebook presence for this pursuit, search “NDB Chat”