3 ms·
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-de
by dvh 6y ago
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.
- 6581 6y 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 https://en.m.wikipedia.org/wiki/Extremely_low_frequency
- hn3333 6y agoInteresting, 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_submarines https://en.m.wikipedia.org/wiki/Communication_with_submarine...
- PoachedSausage 6y agoHave a look at the photos of the Rugby VLF Transmitter to see why it is not practical to put one on a sub: https://www.subbrit.org.uk/sites/rugby-radio/ https://www.subbrit.org.uk/sites/rugby-radio/
- oh_sigh 6y agoHow would the wave know how big the observable universe is?