No official radio stations broadcast on AM frequency 261 kHz:List of L.W. transmitters List of L.W. transmitters on mediumwaveradio.com
Inactive Germany: Formerly Radio Wolga and Radioropa Info from Burg Bulgaria: Formerly Radio Horizont Russia: Formerly Radio Rossii
Former France: NRJ on Longwave (Switched off in Late 2010s)
Proposed The Burg AM transmitter in Germany to be used by Europe 1 to transmit traffic information.
Unofficial A station called Radio Luxemburg was heard on 261 kHz in December 2016.Radio Luxemburg 261 kHz - Achims Free Radio Desaster
References
fi:261 kHz