Try hundreds of meters deep in seawater, all around the earth:
https://en.wikipedia.org/wiki/Communication_with_submarines#...
Bandwidth is even worse though (<<1 baud), and don't start on antenna length.
https://en.wikipedia.org/wiki/Communication_with_submarines#...
Bandwidth is even worse though (<<1 baud), and don't start on antenna length.
Mud modulation.
Basically, while drilling, mud is pumped down the drill string and back out for cooling and cleaning purposes.
Some genius at one of the major oil drilling companies (maybe Schlumberger?) came up with the crazy idea of modulating the mud pressure to transmit information into the depths of the earth. You can control the drill bit speed, angle of drilling, and monitor all sorts of diagnostics over a mud-based communication channel. The bandwidth is decent (think: dial-up), especially when the drilling tools use an efficient modulation scheme.
It's amazing stuff to see first-hand.
wait until you see the NSA mud-pipe-tap.
Very clever...
>Instead, one has to find an area with very low ground conductivity (a requirement opposite to usual radio transmitter sites), bury two huge electrodes in the ground at different sites, and then feed lines to them from a station in the middle, in the form of wires on poles. Although other separations are possible, the distance used by the ZEVS transmitter located near Murmansk is 60 kilometers. As the ground conductivity is poor, the current between the electrodes will penetrate deep into the Earth, essentially using a large part of the globe as an antenna. The antenna length in Republic, Michigan, was approximately 52 kilometers (32 mi).
> "This article needs additional citations for verification."