While I was active duty Navy, I was involved in a lot of strategic communication studies that involved researching and computer modeling to find ways to guarantee reliable communications under all circumstances – including things like the worst possible weather, earthquakes, terrorists and nuclear attack. We called it Communications Continuity. The objective is to have assured communications in the trans and post attack phase of a nuclear war or other crisis. That means that you cannot rely on any fixed installation since it will be bombed in the opening salvo. Likewise all of the satellites and fixed communications centers, including phone and computer lines and all of the major nodes on the internet will be destroyed.Despite all this, there are entire networks that are designed to survive and work even after a major attack. The one that is most reliable is to use is low frequency radio waves in the ELF range. Extremely Low Frequency. Way below the AM broadcast band. These frequencies have two very good characteristics: They will punch thru the static and noise created by atom bomb blasts and they will penetrate into the water to reach submerged submarines. Unfortunately, they also have two bad characteristics. To make use of ELF effectively, you need a BIG antenna to receive and transmit and you need a whole bunch of power like in the multiple megawatt range.To receive ELF, subs use a trailing wire antenna that can drag behind the submerged sub by more than a mile, if needed. Aircraft (like SAC bombers) have drop-down wires that can reach out 18,000 feet to snag an ELF signal. Since these guys mostly receive only, they do not need the power of a megawatt transmitter to respond to these signals. But someone has to have that power and a really big antenna. Its there, right under your nose and you have probably seen it and did not know it.One of the backups to the backups that the military uses to send ELF messages is the power lines that normally deliver power to your homes and businesses. By cutting these wires at two ends and making some other minor changes, they can turn a stretch of highway telephone pole power wires into a very long ELF antenna. This allows them to not have to use tuning systems to try to pump out all that power into a ¼ wavelength antenna or shorter, less efficient antenna.The power comes from two 18 wheeler trucks. One has fuel and a small command post and the other is one huge generator capable of creating about 20 megawatts of electrical power. A third vehicle is usually an RV with the crew quarters and other support. These three vehicles travel in teams around the US constantly in motion driving along routes that have been surveyed to make ideal ELF antennas. They are all disguised as normal 18 wheelers and have all the fake papers to let them move among all the other truckers on the road.At last count, there are 24 of these teams covering an area of 350, 000 square miles from Alaska to Florida and all of Canada. They never stop. There are dozens of crews that are rotated out every 45 days at special bases where they can get equipment spares and run testsNext time you have a totally unexplained power outage, look for two 18 wheelers and an RV traveling together or near each other. You might have just witnessed a test of the emergency communications network.Think this is far fetched. Consider this. Each military and intelligence service has an office dedicated to this subject as well as several entire organizations (DIA, DISA, DSS, NRO, NSA, CSC, etc.)but the overall office with DoD is the Assistant Secretary of Defense for Communications, Command, Control and Intelligence (ASD-C3I). There is also a new office called the Assistant Secretary of Defense for Networks and Information Integration (ASD-NII).