Whistler (Radio)

dvh6y ago· 3 in thread

So this is 1kHz radio wave (300km wave length), I didn't know they can get that low, what is theoretical limit? One of my favorite explanation of how the now-debunked em-drive supposed to work was that it produces radio waves with such a long wavelengths that it doesn't fit observable universe and that makes it push in one direction.

65816y ago

> So this is 1kHz radio wave (300km wave length), I didn't know they can get that low, what is theoretical limit?

The theoretical limit is the size of the universe. For practical purposes, this is about the lowest: https://en.m.wikipedia.org/wiki/Extremely_low_frequency

hn33336y ago

Interesting, clicked a bit further and found out that submarines use VLF communication, however it's one way only:

"Submarines carry only a VLF reception aerial and do not respond on such low frequencies, so a ground-to-submarine VLF broadcast is always a one-way broadcast, originating on the ground and received aboard the boat."

https://en.m.wikipedia.org/wiki/Communication_with_submarine...

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oh_sigh6y ago

How would the wave know how big the observable universe is?

bondarchuk6y ago

Just found this yt channel which has audio of whistlers from various space missions:

https://www.youtube.com/user/VoyagerPWS/

timthorn6y ago

The British Antarctic Survey has collaborated with a musician to create a work incorporating these and other Sounds of Space:

https://www.bas.ac.uk/project/sounds-of-space/

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