Sometimes stations make mistakes in the QSLs they send, especially when you report something unusual which not everybody at the station understands or knows about. My reception was before I got my frequency meter and as a consequence my dial readouts were poor in accuracy then. So I cannot say more than "20 MHz". But as you can see, during my visit they confirmed that my observation was correct and that their previous mention of their BC QRG was not. You can see from the letter they had this circuit with Berna on the occasion of the 1966 World Soccer Championship in London.(MvD)