I believe the proposed rule is 2 watts ERP. The typical 70 x 50 foot top band inverted-L can be base loaded on 500 kHz using a 500 kHz inductor. Given an inductor Q of 300 and ground loss of 20 ohms we have a radiation efficiency of 4%. Drive the antenna with 50 watts and you're on the air at the legal limit. Dave WX7G