Talk:Through-the-earth mine communications

First paragraph
In the first sentence it is being said that the waves are low-frequency, the second one speaks of high-frequency signals. Is that a mistake or intentional? --Misericordia (talk) 06:20, 22 July 2015 (UTC)

Radio waves arriving in less than a minute
arriving in less than a minute Electro-magnetic radiation speeds? Jidanni (talk) 14:29, 8 September 2023 (UTC)