One can send data over longer wavelengths but the tradeoff is the longer the wavelength (hence lower the frequency) the lower the data rate (look up Nyquist and Shannon if you want to start learning about that). The US military sends data globally over extremely low frequencies (look up ELF and HARP for starters) to reach submarines around the world but they transmit with a lot of power (more than you can get out of an AC outlet) and the data rate is in a few bits per MINUTE, not megabits per SECOND. Useful if you can fit your say in a word but not much good for even a tweet which could easily take an hour or two to send. Of course, the other issue is manmade. Regulations (some by country, many by international treaty) prohibit people from emitting electromagnetic waves except with certain wavelengths and power without getting a license or permission. In the US it is the FCC that regulates that.