Rather than a technological approach, I think that the first line of attack is to complain at radio stations that deliberately flout the RDS spec. It explicitly states that the 8-character station name field should not be used for non-constant text (this is considered a safety issue in e.g. cars), and that this is what the 64-character long text field is for. (Sorry I've forgotten their official names)

Your BBS bio doesn't say what country you're in, but most places have a national radio regulator; you might want to mention that you will be complaining to them if the transmissions are not fixed to conform to the standard.

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Toby Speight - 040103385