Transatlantic 500kHz reception - VX9MRC

This evening at around 2200z I heard my first ever North American ham station on 500kHz. VX9MRC, the beacon operated by VO1NA was coming through on CW (about 10wpm) on 507.77kHz in and out of the noise at about RST339 at best. On WSPR he would have been solid copy.