"Longwave" has no universally agreed defintion, but good news, amateur radio already has usage of 135.7 kHz to 137.8 kHz.
Building equipment that works on frequencies this low, and avoiding natural interference, can be extremely difficult.
"Longwave" has no universally agreed defintion, but good news, amateur radio already has usage of 135.7 kHz to 137.8 kHz.
Building equipment that works on frequencies this low, and avoiding natural interference, can be extremely difficult.
Building aerials that work efficiently at 136kHz is difficult (although I have a croft that's approximately long enough for a half-wave dipole in NW Scotland, close to the sea for a good groundplane).
Actually generating the signal you could do with a moderately expensive USB soundcard, directly synthesizing it with simple VST-like plugin. Mad to think about, really.