Out of curiosity I decided to estimate the usefulness of the skywave signal of a 13.56 MHz transmit system radiating close to the FCC-legal 15,848 µV/m field at a distance of 30 meters from its antenna (see below).
The lack of any color-coded traces other than the MUF appearing on the calculation graphic shows that the maximum field at that receive site does not exceed the ambient noise level for that frequency and radiated power.
You could QSL them, if you were planning to send QSLs for reception.
I wonder if there are databases for station ops or beacon DXers, pages like QRZ that hams have? Beaconing seems like a real small slice of the DXing pie, but maybe there's some kind of organization around it.