Next Friday, the Swedish VLF transmitter SAQ at Grimeton [17,2 kHz] will send a Christmas message. You will be able to hear the mechanical 200 kW transmitter starting up at 07:30 UTC, and sending a CW message at 19:00 UTC on Christmas Eve. Also on air will be SK6SAQ on 3535kHz, 7035kHz and 14035 kHz CW, and on 3755 kHz and 7140 kHz SSB. Reception of the VLF signal requires either an up-converter for an HF receiver, or a simple longwire into the microphone socket of a pc, laptop or phone. The signal can then be heard and seen with the help of the very simple to use software made available by the Grimeton Crew.
Mike Terry to Longwaveradiolistening iog (2021-12-20)