RBN often creates incorrect spots for new DXCC/slots, callsigns that don’t real exist.
One indication if a call is real might be if any QRZ.COM entry exists.
BTW, I just did a QRZ database search for * and got
Hope you get a positive answer from QRZ.COM, but I’m afraid that the only method is what I mentioned, query database for call ‘*’.
Run through all result pages and parse the html text.
Perhaps not really practicable either.
Maybe some filters can also be set in the RBN clusters for greater reliability of the spots.
I have received a reply from QRZ.COM. Unfortunately a bulk download of all registered callsigns is not available. They told me that I could query the XML API, but given that HamAlert processes millions of spots per day with tens of thousands of unique callsigns (at least), and each XML API call is for a single callsign only, I’m pretty sure HamAlert would get banned from the API almost immediately, even when caching the results for a while.
It is possible to get all QRZ COM registered calls, all in one run, without API.
There is , at the top left, a search bar. Search for * and wait until result appears.
It needs an automated script to make this query and then load all result pages and
extract data.
Yes, that is to be assumed, the query is also only possible for registered users.
The background to the whole thing was the low reliability of the rbn spots. It may be possible to solve this differently by evaluating these spots for reliability. Perhaps something like a GROUP BY count, i.e. a spot is only reliable if a certain number of spotters have recognized it in exactly the same way.